Body Systems Past Papers Flashcards

Question 1

Q

In a homeostatic regulatory system, a change in the external environment is detected by a(n)

a. effector
b. sensor
c. integrating centre
d. stimulus

Answer

A

b. sensor

Change in variable -> detected by sensory receptor cells (sensor).
Receptor cells send signals to CNS & endocrine glands -> Integrating centre -> Afferent pathway
CNS & endocrine cells send impulses to muscle & secretory cells (effector).
Effectors correct change in variable -> stimulates sensory receptor cells.
Receptor cells send signals to CNS & endocrine glands -> stop sending electrical impulses to effector cells. -> Stops further fluctuation of controlled variable.

Question 2

Q

Transport of ions by the Na+:K+ATPase pump

a. involves the exchange of intracellular K+ for extracellular Na+
b. is only dependent on the concentration of K+ ions
c. results in the exchange of 3 Na+ ions for every 2 K+ ions
d. is a passive process

Answer

A

c. results in the exchange of 3 Na+ ions for every 2 K+ ions

The Na+/K+-ATPase enzyme is active (i.e. it uses energy from ATP). For every ATP molecule that the pump uses, three sodium ions are exported and two potassium ions are imported.
Na+/K+ pump -> gradient maintenance -> actively transports ions so everything else can diffuse passively (down conc. gradient)

Question 3

Q

Sympathetic ganglia differ from parasympathetic ganglia in

a. the type of cholinesterase present at neuronal synapses
b. their anatomical location c. the neurotransmitter released by the pre-ganglionic neuron
d. the types of acetylcholine receptors present on post-ganglionic neuron cell bodies

Answer

A

d. the types of acetylcholine receptors present on post-ganglionic neuron cell bodies ??

1.Parasympathetic:
Preganglionic fibre -> ganglion 
-> releases acetylcholine (ACh) 
-> activates nicotinic (N2) receptor 
-> action potential moves along postganglionic fibre 
-> releases acetylcholine (ACh) 
-> activates muscarinic (M) receptor.

2.Sympathetic:
i) Symapthetic:
Preganglionic fibre -> ganglion
-> releases acetylcholine (ACh)
-> activates nicotinic (N2) receptor
-> action potential moves along postganglionic fibre
-> releases norepinephrine (NA)
-> activates (alpha/beta) adrenergic receptor

Question 4

Q

The extracellular matrix found in connective tissue is synthesized by

a. adipocytes
b. fibroblasts
c. macrophages
d. mast cells

Answer

A

b. fibroblasts

Cells within Extracellular matrix
i) Cell types:
> Fibroblasts -> Main cell type -> Synthesises extracellular matrix
>Apipocytes
>Macrophage cells
>Mast cells
ii) Exctracellular matrix:
 Ground substance
 Tissue (extracellular fluid)
 Fibres:
->Collagen
->Reticular
->Elastic

Question 5

Q

The vessels that are most distensible and therefore hold the major proportion of the intravascular blood are the

a. arterioles
b. elastic arteries
c. muscular arteries
d. veins

Answer

A

• Veins -> capacitance vessels
 Classified according to size (diameter)
Small: <2mm
Medium: 2-9mm
Large: >9mm -> Eg. superior & inferior vena cavae
 Low pressure
 Easily distensible (capacitance)
 Thin walls
 Predominant tunica externa
 Valves -> aid blood flow
• Systemic venous system -> 65-70% blood distribution.

•	Arteries:
	High pressure -> thick muscular walls
	Small lumen
	Maintains shape -> elastic 
	Resilient
	No valves

Question 6

Q

The popliteal pulse can be palpated

a. at the wrist
b. in the neck
c. on the dorsum of the foot d. posterior to the knee

Answer

A

d. posterior to the knee

Cephalic -> Head
Jugular -> Neck
Brachium -> Arm
Popliteal fossa -> Back of knee
Axillary fossa -> Arm pit

Question 7

Q

Veins contain valves which

a. are folds of the tunica intima
b. permit blood flow in both directions
c. enable blood to pool in the lower extremities
d. allow backflow of blood

Answer

A

a. are folds of the tunica intima

Tunica intima -> Innermost layer of blood vessels
•	Veins:
	Low pressure -> thin walls
	Wide lumen 
	Less elastic &amp; resilient
	Valves -> prevent backflow.

Question 8

Q

In an infant, erythropoiesis will occur in

a. all bone marrow
b. only red bone marrow
c. the spleen
d. the yolk sac and liver

Answer

A

d. the yolk sac and liver

•	Erythropoiesis:
	Production of erythrocyte (RBCs)
         Requires:
-	Enthyropoietin (EPO) -> hormone
->Initiates erythropoiesis 
-	Iron 
-	Vitamin B12 &amp; folic acid (B9)
-	Intrinsic factor
-	Amino acids
         Location:
-	Foetus ->Early in yolk sac, then liver &amp; spleen
            ->Later -> bone marrow
-	Infant -> All bone marrow
-	Adult -> Red bone marrow only
              -->Ribs, vertebrae, skull, upper ends -> long bones. 
              >Can digress &amp; erythropoiesis occur in all parts of adult body when necessary.

Question 9

Q

Monocytes are white blood cells that mainly

a. function outside the blood
b. defend against bacteria
c. activate immunological defence mechanisms
d. initiate the inflammatory response

Answer

A

a. function outside the blood

	Monocytes:
- Agranulocytes
-	2-10% WBCs
-	Structure:
Largest white cell 
Up to 20 micrometres diameter
Large kidney/Horse-shoe shaped nucleus
Extensive cytoplasm
-	Function:
Little function -> blood
Migrate out -> circulation after 3-4 days
Tissue macrophages 
    >>Several months-yrs
Phagocytic

Question 10

Q

In haemostasis, the first event that occurs after blood vessel damage is

a. clotting
b. platelet activation
c. platelet adhesion
d. vasoconstriction

Answer

A

d. vasoconstriction

• Haemostasis:

Vasoconstriction – blood vessels
Platelet adhesion & aggregation
Clotting -> coagulation

•	Platelets: 
-	Structure: 
Small
Oval 
No nucleus
2-3 micrometres diameter
Contain granules
-	Functions:
Megakaryocyte cytosplasm
Production controlled by 
    >>No. circulating platelets -> negative feedback
    >>Thrombopoietin (TPO) release -> incr. platelet no.s
Lifepsan 7-10 days
Variety functions -> essential -> haemostasis

Question 11

Q

Platelets

a. have a diameter of 20-30 µm
b. contain granules
c. remain in the circulation for 120 days
d. are formed in the liver

Answer

A

b. contain granules

•	Platelets: 
-	Structure: 
Small
Oval 
No nucleus
2-3 micrometres diameter
Contain granules
-	Functions:
Megakaryocyte cytosplasm
Production controlled by 
    >>No. circulating platelets -> negative feedback
    >>Thrombopoietin (TPO) release -> incr. platelet no.s
Lifepsan 7-10 days
Variety functions -> essential -> haemostasis

Question 12

Q

Systemic blood pressure is

a. the product of total peripheral resistance and heart rate
b. the product of total peripheral resistance and stroke volume
c. the product of total peripheral resistance and cardiac output
d. none of the above

Answer

A

c. the product of total peripheral resistance and cardiac output

Blood pressure (BP) is determined by cardiac output (CO) and total peripheral resistance (TPR)
BP = CO x TPR.

Cardiac output (CO) is affected by two factors, the heart rate (HR) and the stroke volume (SV)
CO = HR x SV,

Therefore BP = HR x SV x TPR

Question 13

Q

Baroreceptors are located

a. in both the carotid artery and aortic arch
b. only in the carotid artery c. only in the pulmonary artery
d. in both the carotid artery and the pulmonary artery

Answer

A

a. in both the carotid artery and aortic arch

Baroreceptors are pressure sensors located in the carotid sinus & and the aortic arch

Question 14

Q

The heart rate of trained individuals is generally

a. the same as untrained individuals
b. the same as untrained individuals, but their cardiac output is higher
c. lower than untrained individuals, but their cardiac output is higher
d. lower than untrained individuals, but their cardiac output is the same

Answer

A

c. lower than untrained individuals, but their cardiac output is higher

Non-Athlete Resting ; Excersised ;
Athlete Resting ;
Excersised

CO (L/min)
	~5	~20	~5.5	~30
HR (bpm)	
75	190	55	180
SV (ml)	
65	105	100	165

Question 15

Q

The ECG trace

a. is generally described in terms of the P, Q, R, S and T waves
b. can be used to measure blood pressure
c. detects only sinoartial node events
d. detects only muscle contraction

Answer

A

??

 ECG detects electrical responses -> heart
» Profile -> accumulative representation -> action potentials across heart.
» Reflects stages of cardiac cycle:

i. ) Atrial contraction / relaxation
ii. ) Ventricular contraction / relaxation
iii. ) Conduction velocities -> electrical signals

P-wave:
»Atrial depolarization & contraction
QRS Complex:
»Spread -> electrical signal
>Causes ventricular myocyte depolarisation
& contraction
-»Arterial relaxation event masked -> larger ventricular event.
T-wave:
»Ventricle repolarisation & relaxation
QT interval:
»Time from initiation -> ventricular contraction -> end -> ventricular relaxation.

Question 16

Q

The rate of blood flow through the cardiovascular system is

a. independent of gravity
b. independent of the viscosity of blood
c. highest during the diastolic phase of the cardiac cycle
d. regulated by blood vessel tone

Answer

A

d. regulated by blood vessel tone

Question 17

Q

Chronic heart failure

a. affects only the left side of the heart
b. arises when venous return is reduced, but cardiac output is normal
c. may lead to peripheral oedema
d. can be treated using β-adrenoceptor agonists

Answer

A

c. may lead to peripheral oedema

• Chronic Heart Failure:
 Inadequate cardiac output
-> Despite venous return
 Due to:
Decline in contractility
Inability to develop forceful contracture
 Insufficient blood causes overworking of heart -> leads to stretching of heart muscle over time so stretched thin chmabers insufficient generation of force on contraction.
 Diastole:
> Inability to fill
-> Stiff, thick chambers
 Insufficient blood causes overworking of heart
&raquo_space; Leads to stretching of heart muscle over time
Stretched thin chambers -> insufficient generation of force on contraction
 Systole:
> Inability to contract
-> Stretched, thin chambers
 Caused by:
> Muscle damage Eg. CAD
> Additional work of heart Eg. Hypertension
> Valve defects
 Causes:
> Breathlessness & fatigue
> Left Ventricular Failure:
-> Fluid accumulation -> lungs due to congestion of veins in lungs
> Right Ventricular Failure:
-> Fluid accumulation -> especially in tissues of legs & abdominal organs due
to incr. systemic capillary pressure.

Question 18

Q

The left lung has

a. one fissure
b. two bronchopulmonary segments
c. three lobes
d. four secondary bronchi

Answer

A

• Left Lung:

Narrower
a. one fissure
Longer
2 lobes
 Superior (upper lobe)
 Inferior (lower lobe)
1 fissure
 Oblique

Question 19

Q

Alveoli

a. number about 250 million in each lung
b. form part of the respiratory membrane
c. contain cuboidal epithelial cells called type I pneumocytes
d. consist mainly of type II pneumocytes

Answer

A

a. number about 250 million in each lung

Pneumocytes -> Cells in alveoli
 Alveoli
 Site -> gas exchange
 Surrounded by network of capillaries
 150-250 mill per lung
 Blood Supply
 Structure:
 Type I Alveolar Cell:
&raquo_space; Simple squamous epithelium
> Forms wall of alveolus
 Type II Alveolar Cell:
&raquo_space; Secretes Surfactant
 Macrophage:
&raquo_space; Phagocytozes small inhaled particles & bacteria
 Capillary
 Respiratory membrane
&raquo_space; Epithelium -> Type I alveolar cell
&raquo_space; Basement membrane -> Type I alveolar cell
&raquo_space; Basement membrane -> Capillary
&raquo_space; Endothilium -> Capillary
-» Basement membranes often fused together.

Question 20

Q

The Hering-Breuer reflex

a. is triggered by a decrease in plasma pH b. involves afferent impulses carried to the respiratory centres by the phrenic nerve c. reduces the duration of inspiration d. is triggered when the respiratory rate is elevated

Answer

A

•	Hering-Breuer Reflex:
-	Prevents over-inflation of lungs
-	Stretch receptors 
 Visceral pleura
 Bronchioles
 Alveoli 
-	Impulses sent via vagus nerve 
 Pneumotaxic centre
-	Duration of inspiration shortened.

Question 21

Q

In the rhythmicity centre of the brain, E neurons

a. are activated by I neurons b. are located in the dorsal respiratory group
c. regulate activity of the phrenic nerve
d. are only active during forced breathing

Answer

A

??

• Neural Control of Ventilation:
- Chemoreceptors detect changes in PO2, PCO2 & pH
-> Send impulses / signals
 Vagus (CN X) & Glossopharyngeal (CN IX) nerves
(Afferent pathway)
- Impulses transported -> Vagus (CN X) & Glossopharyngeal (CN IX) nerves
 Respiratory Centres of Brain Stem
- Respiratory Centres of Brain stem
-> Send impulses / signals
 Phrenic, intercostal & other nerves
(Efferent pathway)
- Impulses transported -> Phrenic, intercostal & other nerves
 Muscles in ventilation

• Respiratory Centres:
- Group of neurons -> Brain stem
- Send impulses to muscles of ventilation
- Medullary Rhythmicity Area
 Dorsal Respiratory Group (DRG)
 Sets rhythm, stimulates muscles of quiet inspiration
 Ventral Respiratory Group (VRG)
 Involved in forced inspiration & expiration
- Pneumotaxic area (Pons)
 Influences DRG by regulating duration of inspiration.

The respiratory centre is divided into three major groups, two in the medulla and one in the pons. The two groups in the medulla are the dorsal respiratory group and the ventral respiratory group.
The dorsal respiratory group (DRG) initiating inspiration (inhalation)
-> End-point for sensory information arriving from the pontine respiratory group, and from two cranial nerves – the vagus nerve, and the glossopharyngeal nerve.

Question 22

Q

The appearance of chest over-inflation in chronic obstructive pulmonary disease (COPD) is due to

a. decreased vital capacity b. increased residual volume
c. infection and inflammation d. reduced compliance

Question 23

Q

Carbon monoxide (CO) is poisonous because it

a. binds to haemoglobin and displaces oxygen
b. displaces oxygen in the lungs, preventing haemoglobin from taking up oxygen
c. binds to globin chains to prevent pH buffering
d. binds to globin chains to give toxic carbamino compounds

Question 24

Q

select the ONE INCORRECT option from those provided

Parasympathetic nerves

a. have short post-ganglionic fibres
b. release acetylcholine as a neuroeffector transmitter
c. have pre-ganglionic fibres that originate in the cranial and cervical regions of the spinal cord
d. have stimulatory effects on the gastrointestinal tract

Answer

A

c. have pre-ganglionic fibres that originate in the cranial and cervical regions of the spinal cord

-> Originates -> spinal chord & base of brain
> Not cranial region of spinal chord.

Parasympathetic Nervous system -> Spinal cord & base of brain.

Outflow from CNS: Parasympathetic -> Cranial & sacral
Preganglionic fibre:
-> Long
Ganglionic transmitter:
-> ACh (N2)
Postganglionic fibre:
-> Short
Neuroeffector transmitter:
 Parasympathetic -> ACh (M)

The parasympathetic nervous system (PNS) controls homeostasis and the body at rest and is responsible for the body’s “rest and digest” function.

Question 25

Q

select the ONE INCORRECT option from those provided

The adrenal medulla

a. contains chromaffin cells
b. possesses nicotinic receptors
c. secretes aldosterone into the circulation
d. is innervated by the sympathetic nervous system

Answer

A

?
c. secretes aldosterone into the circulation

ii) Adrenal medulla:
-> Sympathetic Nervous system
Preganglionic fibre -> adrenal medulla
-> releases acetylcholine (ACh)
-> stimulates chromaffin cell
-> makes epinephrine
-> moves along postganglionic fibre
-> releases epinephrine
->sent into circulatory system
-> stimulates adrenergic receptors of heart
-> incr. heart rate.

Question 26

Q

select the ONE INCORRECT option from those provided

Smooth muscle

a. forms sphincters in the urinary tract
b. is located in the airway walls
c. alters the diameter of blood vessels
d. is involved in gastrointestinal movement

Answer

A

a. forms sphincters in the urinary tract

Smooth
 Forms walls of organs, blood vessels & airways
 Gastrointestinal movement
 Alters diameters -> airways & blood vessels
- Short, fusiform (narrow at ends) cells
- Non striated (not striped)
- Single central nucleus
- Innervated -> autonomic nervous system

Skeletal muscle forms sphincters in urinary tract

Question 27

Q

select the ONE INCORRECT option from those provided

Connective tissue is comprised of

a. macrophages
b. adipocytes
c. mast cells
d. reticulocytes

Answer

A

d. reticulocytes

Connective tissue

Structural framework for body
Supports surrounds & interconnects tissues
Protects delicate organs
Transports fluids & dissolved materials
Stores energy reserves
Defence -> microorganisms
Classification of connective tissue:
1.Specialised connective tissue
2.Connective tissue proper
-> 1. Loose areolar/irregular
Variety of cells
- Fibroblasts, adiposcytes, macrophages (transient)
  ->2. Dense irregular connective tissue:
  ->Few cells
- Mainly fibroblasts
  ->3. Dense regular connective tissue
  -> Few cells
  - Mainly fibroblast

Question 28

Q

select the ONE INCORRECT option from those provided

In the coronary circulation, the coronary sinus receives blood from the

a. anterior cardiac vein
b. great cardiac vein
c. middle cardiac vein
d. small cardiac vein

Question 29

Q

select the ONE INCORRECT option from those provided

The lymphatic system

a. is involved in defence against infection
b. returns excess interstitial fluid to the vascular system
c. does not contain valves
d. includes blind-ended capillaries

Answer

A

c. does not contain valves
- >Process of elimination

	Lymphatic circulation:
-	Network lymphatic vessels 
-	Lymph 
-	Lymphatic tissues &amp; organs 
	Defence mechanisms
	Drains interstitial fluid

Removal of excess interstitial fluid:
1. Fluid -> out of capillary-> interstitial space -> arterial end of capillary
2. Fluid -> into capillary -> venous end of capillary
15% fluid remains -> interstitial space
->Enters lymphatic system -> lymphatic capillary -> becomes lymph
->Returned to blood
Lymph capillaries -> Blind-ended tubes
- > adjacent -> capillary beds

 Lymphatic drainage:
Lymph capillaries -> Lymph vessels -> Lymph nodes -> Lymph trunks
 i) Thoracic duct
ii) Right lymphatic duct

Lymphatic drainage:
-	RHS head, neck , thorax &amp; upper limb
Right lymphatic duct 
Right subclavian vein
-	Rest of body
Thoracic duct 
Left subclavian vein

Question 30

Q

select the ONE INCORRECT option from those provided

The pericardial cavity is

a. found between the visceral and parietal pericardia
b. deep to the parietal pericardium
c. found between the parietal and fibrous pericardia
d. superficial to the visceral pericardium

Answer

A

b. deep to the parietal pericardium

•	Fibrous Pericardium:
Characteristics:
-	Inelastic sac -> dense tissue
-	Inferior fusion -> diaphragm
-	Superior infusion -> large vessels
Function:
-	Prevents overfilling of heart 
-	Anchors position

•	Serous pericardium:
Characteristics:
-	Double-layered serous membrane
-	Lies -> deep within -> fibrous pericardium
-	Contains:
1.	Parietal pericardium:
	Lines inner surface -> fibrous pericardium
2.	Visceral pericardium: 
	Tightly adhered -> surface of heart
3.	Pericardial cavity:
	Space between parietal &amp; visceral layers
Contains tissue fluid. 
Function:
	Prevents friction.

•	Heart wall:
-	3 layers:
i)	Endocardium:
	Inner layer -> Endothelium
ii)	Myocardium:
	Middle layer -> Cardiac muscle
iii)	Epicardium:
	Outer layer -> Visceral pericardium

Question 31

Q

select the ONE INCORRECT option from those provided

Red blood cell production is stimulated by

a. bleeding
b. low altitude
c. low oxygen levels in the blood
d. erythropoietin released from the kidney

Answer

A

b. low altitude

• Erythrocyte Homeostasis:
 Low conc O2
 Detected by kidneys -> stimulates incr. production -> erythropoietin
 Detected -> stem cells -> incr. production of RBCs
 More RBCs -> higher O2 transportation capacity -> incr. O2 conc.
 Causes of hypoxia (low O2 conc)
- Incr. excersise
- High altitude
- Smoking
- Bleeding

    Production of erythrocyte: 	Production of RBCs required 	Triggers kidneys -> release erythropoietin hormone  	Erythropoietin -> acts on stem cells 	Instigates specialisation of stem cell -> production -> RBCs 	Proerythroblast -> immature cell -> bone marrow Matures -> Erythroblast  	Normoblast -> containing full haemoglobin conc.  -->Constant production of haemoglobin during these stages 	Normoblast ejects nucleus -> reticulocyte Reticulocyte still contains some ribosomal RNA    >If Reticulocyte released -> circulation prematurely -> still some ability to 
   produce haemoglobin.  Small number in circulation -> later mature -> RBCs Lots of reticulocytes 
 ->Anaemia  	Erythrocyte (RBC)

Question 32

Q

select the ONE INCORRECT option from those provided

Granulocytic white blood cells

a. are nucleated
b. contain granules
c. generally survive in the blood for a short time
d. include lymphocytes

Answer

A

d. include lymphocytes

i) Granulocytes
- Neutrophils
- Eosinophils
- Basophils
ii) Agranulocytes
- Lymphocytes
- Monocytes

	Neutrophils:
-	50-70% of WBCs -> most common 
-	Structure:
9-15 micrometres diameter
Distinctive nucleus
 >>2-5 lobes
 >>Granular cytoplasm
-	Function:
1st line defence -> bacterial infection
Phagocytic
Mobile
Circulate -> blood -> approx. 10hrs
Major component -> pus

	Eosinophils:
-	2-4% of WBCs
-	Structure:
10-12 micrometres diameter
Bilobular nucleus
-	Function:
Circulate -> blood -> approx. 8-12 hrs
    >>Migrate -> tissues
Lifespan approx. 1-3 days
Release toxic compounds
     Eg. NO &amp; cytotoxic enzymes
Allergies
    >>Athsma
Combat -> parasitic infections
Attack bacteria, protozoa, debris

	Basophils:
-	>1% WBCs -> least common
-	Structure:
8-10 micrometres diameter
Bilobed “S” shaped nucleus
   >>Large cytoplasmic granules
Granules 
    >>Histamine 
    >>Heparin
-	Function:
Inflammatory response
Unknown lifespan
Possible precursors -> mast cells 
    >>Share common bone marrow precursor

Question 33

Q

select the ONE INCORRECT option from those provided

The initiation phase of coagulation includes the following elements

a. activation of FX to FXa
b. Factor Va as a co-factor
c. Factor VII
d. tissue factor

Answer

A

d. tissue factor

•	Coagulation:
-	Conversion -> soluble plasma protein -> insoluble rigid polymer -> fibrin
Fibrinogen -> soluble 
Thrombin -> enzyme -> polymerisation
     >>Fibrinogen -> Fibrin.
Fibrin -> insoluble 
Factor XIII -> stabilises Fibrin

 Initaiation of coagulation:
- Extrinsic pathway
 Tissue factor
»Binds to Factor VII -> Tissue Factor-FVIIa complex
&raquo_space;Binds -> FX -> activates transformation -> FXa
- Intrinsic pathway
 Factor IX & co-factor VIII
&raquo_space;Binds -> FX -> activates transformation -> FXa
Slower -> extrinsic pathway
- Common pathway
 Prothrombinase
Comprised FXa & FVa as co-factor
&raquo_space;Binds -> Prothrombin -> produces -> thrombin
&raquo_space;Thrombin -> converts -> Fibrinogen -> Fibrin

Question 34

Q

select the ONE INCORRECT option from those provided

Neutrophils

a. are the least common type of white blood cell
b. have a lobular shaped nucleus
c. engulf and destroy bacteria
d. are approximately 12 µm in diameter

Answer

A

a. are the least common type

	Neutrophils:
-	50-70% of WBCs -> most common 
-	Structure:
9-15 micrometres diameter
Distinctive nucleus
 >>2-5 lobes
 >>Granular cytoplasm
-	Function:
1st line defence -> bacterial infection
Phagocytic
Mobile
Circulate -> blood -> approx. 10hrs
Major component -> pus

Question 35

Q

select the ONE INCORRECT option from those provided Capillary fluid exchange

a. has a null point which is towards the arterial end of a capillary network
b. is dependent upon a decline in blood pressure from the arterial end to the venous end of the capillary network
c. enables high rates of net reabsorption to be maximised at the venous end of the capillary network d. is determined by the balance of osmotic and hydrostatic fluids across a capillary network

Answer

A

a. has a null point which is towards the arterial end of a capillary network

• Dynamics of capillary exchange:
 Arterial end
 High hydrostatic pressure -> forces fluid out capillary network
&raquo_space; Opposed -> high osmotic potential gradient
 Capillary Hydrostatic Pressure (CHP) -> 35mmHg
 Blood Colloid Osmotic Pressure (BCOP) -> 25mmHg
-» CHP > BCOP
-» Net filtration pressure -> +10mmHg
&raquo_space; Forces fluid & dissolved substances out -> capillary network
 Significant rate of filtration -> 24 L/day

 Venous end
 Hydrostatic pressure decline -> incr. distance -> heart
 Same osmotic potential
 Capillary Hydrostatic Pressure (CHP) -> 18mmHg
 Blood Colloid Osmotic Pressure (BCOP) -> 25mmHg
-» CHP < BCOP
-» Net Filtration Pressure -> -7mmHg
&raquo_space;Movement of fluid -> into capillary network
 Significant Rate of reabsorption -> 20.4 L/Day

 Net difference in water -> Rate of filtration & absorption
Collected -> Lymphatic System

 Centre -> Capillary Network
Approx. centre -> capillary network
->Equal values -> CHP & BCOP -> Net filtration pressure = 0.
-> No net movement -> fluid.
 Max filtration pressure always greater -> max absorption pressure
&raquo_space; Point at which net filtration pressure = 0
-> further towards venous end -> capillary
-» More filtration than absorption along capillary.
¬-» Enables provision -> tissues with required molecules over greater
distance -> capillary network
> Rapid reabsorption -> molecules & waste products -> venous end.

Question 36

Q

select the ONE INCORRECT option from those provided

Physiological responses to hypotension include

a. increased sympathetic stimulation of the heart
b. an increase in the blood volume
c. inhibition of the cardiovascular centres in the brain
d. an elevation of blood pressure triggered by hormones

Answer

A

c. inhibition of the cardiovascular centres in the brain ?

Look at treatments & what they cause -> actual hypotension woukd be causing opposite effect of that as treatment inhibiting/counteracting it. Also look at risks associated and what causes those risks to occur.

• Hypertension:
 Affects nearly one billion
 One of the main causes -> premature death.
 Nearly 8 million fatalities per year
 Types:
- Primary Hypertension
(Essential / Idiopathic)
 Unknown medical cause
 Links:
 Genetic predisposition
 Alcohol consumption
 Obesity
 Lack of excersise
 Diabetes
 Intrauterine environment
- Secondary Hypertension
 Known medical cause
1) Kidney Disease:
 Incr. Angiotensin II
» Vasoconstriction & expansion -> cellular fluid
2) General endocrine disorders
Eg. Diabetes, Cushing’s
3) Adrenal medulla disease (Phaeochroocytoma)
 Excessive adrenaline secretion
 Treatment:
- Inhibit angiotensin II production -> Angiotensin-Converting-Enzyme (ACE)
» Prevents renal absorption -> Na+/H2O
> Prevents incr. blood volume
- Ibhibition -> Angiotensin II induced vasoconstriction -> Angiotensin II receptor
blocker.
&raquo_space; Inhibitd membrane cardiac / vascular depolarizoation
> Decr. CO -> vasodilation.
- Calcium-channel blocker / thiazide diuretic
&raquo_space; Incr. loss -> Na+ & H2O
> Decreases fluid volume, venous return & cardiac output.
- Reduce TBR -> inhibition -> noradrenaline action.
- Alpha-adrenoreceptor Antagonists (alpha-Blockers)
 Reduce TBR -> inhibition -> noradrenaline action.
- Beta-adrenoreceptor Antagonists (beta-Blockers)
 Decr. CO2,
 Decr. central activity -> Symapthetic nervous system
 Decr. release -> Renin
-» Favourable secondary actions
 Risks:
- Atherosclerosis
- Stroke / Cerebrovascular Accident
- Heart Failure
- Renal Failure
- Aneurysms

Question 37

Q

select the ONE INCORRECT option from those provided

Bradycardia

a. can be caused by elevated plasma potassium concentration
b. is defined as an increase in heart rate
c. occurs from ionic defects in control of the ventricular action potential
d. can result in ventricular arrhythmias

Answer

A

b. is defined as an increase in heart rate

• Arrhythmias:
 Deviation of heart’s normal sinus (SAN) rhythm.
 Relatively rare
-> 1 in 5000-10000
 Found -> young individuals ; <25yrs
 Many arise
-> Defects in ion channels regulating ventricular action potentials
 Cause spontaneous multiple depolarizations
&raquo_space; Ventricular arrythmias
 Produce sustained abnormal rhythm
 Asymptomatic
 Palpitations
 Dizziness
 Syncope
 Heart Failure
 Sudden Death

1.	Bradycarida:
	Slow Rhythm (<60bpm)
Causes:
 Slowed signal -> sinus bradycardia
 Pause / sinus arrest 
 Blockage 
      >> Due to SAN / conducting tissue damage
Treatment:
 Artificial pacemaker

Question 38

Q

select the ONE INCORRECT option from those provided

Heart rate is

a. described as a chronotropic variable
b. increased by acetylcholine
c. increased by glucagon
d. increased by noradrenaline

Answer

A

a. described as a chronotropic variable

The heart rate is influenced by chronotropic variables!

•	Chronotropic Effect:
-	Influence effecting heart rate. 
•	Innervation of Heart:
1.	Cardioregulatory centre &amp; chemoreceptors -> medulla oblongata
Via -> Sensory Nerve Fibres
->> Baroreceptors -> wall of internal carotid artery
->> Carotid body chemoreceptors
->> Baroreceptors -> Aorta
2.	Adrenal Medulla
i)  Via -> Parasympathetic nerve fibres
    ->> Sinoatrial (SA) Node
ii)  Via -> Sympathetic nerve fibres
    ->> Heart
3.	Adrenal Medulla
Via -> Sympathetic nerve fibres -> adrenal gland 
>Release adrenaline/noradrenaline -> circulation 
->>Heart

• Regulation of blood pressure:

Decreased blood pressure detected by baroreceptors.
Baroreceptors send signals along glosso-pharyngeal nerve to the Medulla oblongata -> brain.
Medulla oblongata sends incr. impulses along autonomic nerves to heart blood vessels.
Incr. no of impulses -> incr. cardiac output & vasoconstriction of heart blood vessels. -> Blood pressure increases to optimal level.
Increased blood pressure detected by baroreceptors.
Baroreceptors send signals along glosso-pharyngeal nerve to Medulla oblongata.
Medulla oblongata decr. impulses along autonomic nerves to blood vessels of heart.
Blood vessels decr. cardiac output & vasoconstriction -> preventing further fluctuation of pressure.

Question 39

Q

select the ONE INCORRECT option from those provided

Long-QT syndrome

a. leads to arrhythmias
b. is caused by ion channel gene defects
c. can be detected on an ECG recording
d. originates from defects in the sinoatrial node

Answer

A

d. originates from defects in the sinoatrial node

Long QT syndrome (LQTS) is a disorder of the heart’s electrical activity, usually caused by a faulty gene inherited from a parent.
It can cause sudden, uncontrollable, dangerous arrhythmias

Question 40

Q

select the ONE INCORRECT option from those provided

Essential (idiopathic) hypertension

a. is associated with obesity b. is linked to alcohol intake c. may be predetermined by the intrauterine environment d. is caused by elevated aldosterone levels

Answer

A

d. is caused by elevated aldosterone levels
- >Other anseers imply causes ; or associations however this states this is the cause ; despite cause is unknown.

Essential hypertension (also called primary hypertension or idiopathic hypertension) is the form of hypertension that by definition has no identifiable cause. It tends to be familial and is likely to be the consequence of an interaction between environmental and genetic factors.

Question 41

Q

select the ONE INCORRECT option from those provided

The conductive portion of the respiratory tract is concerned with

a. filtering the air
b. gas exchange
c. humidifying the air
d. warming the air

Answer

A

b. gas exchange

The conducting portion consists of the air-transmitting passages of the nose, nasopharynx, larynx, trachea, bronchi and bronchioles. This part of the respiratory system serves to filter, warm and humidify air on its way to the lungs.

Question 42

Q

select the ONE INCORRECT option from those provided

Structures that enter the lung at the hilum include

a. bronchial arteries
b. phrenic nerve
c. primary bronchus
d. pulmonary artery

Answer

A

Hilum of lung:
 Located -> mediastinal surface
Region of entry -> lungs for blood vessels, lymphatics, nerves & bronchi.

Question 43

Q

select the ONE INCORRECT option from those provided

During exercise the muscles of forced inspiration are recruited; these include the

a. pectoralis minor
b. rectus abdominus
c. serratus anterior
d. sternocleidomastoid

Answer

A

b. rectus abdominus

•	Inspiration:
-	Active process
-	At rest:
	Diaphragm (75%)
	External intercostal muscles (25%)
 Contracted diaphragm flattens
   -> Vertical diameter of thorax increased. 
 External intercostals elevate ribs -> incr. Anterior Posterior &amp; Transverse 
     diameters. 
-	Forced:
	Pectoralis major 
	Pectoralis minor
	Scalenes
	Serratus anterior
	Sternocleidomastoid
 Assist -> rib elevation 
    -> Incr. speed &amp; amount of movement

Question 44

Q

select the ONE INCORRECT option from those provided

Surfactant

a. helps to decrease surface tension in the lungs
b. is a mixture of phospholipids
c. is less concentrated in smaller alveoli
d. is secreted by type II alveolar cells

Answer

A

Type II Alveolar Cell:
&raquo_space; Secretes Surfactant
b. is a mixture of phospholipids

Pulmonary surfactant is a mixture of lipids and proteins which is secreted by the epithelial type II cells into the alveolar space.
The main function of pulmonary surfactants is to reduce the surface tension at the air/liquid interface in the lungs.
As the alveoli increase in size, the surfactant becomes more spread out over the surface of the liquid. This increases surface tension effectively slowing the rate of expansion of the alveoli. This also helps all alveoli in the lungs expand at the same rate, as one that expands more quickly will experience a large rise in surface tension slowing its rate of expansion. It also means the rate of shrinking is more regular, as if one reduces in size more quickly the surface tension will reduce more, so other alveoli can contract more easily than it can. Surfactant reduces surface tension more readily when the alveoli are smaller because the surfactant is more concentrated.

Question 45

Q

select the ONE INCORRECT option from those provided

Gas exchange occurs by diffusion and is dependent upon

a. co-ordinated blood and air flow
b. how insoluble gases (oxygen and carbon dioxide) are in blood
c. short diffusion distance
d. large moist surface area

Answer

A

b. how insoluble gases (oxygen and carbon dioxide) are in blood

Question 46

Q

select the ONE INCORRECT option from those provided

Peripheral chemoreceptors act in response to

a. a change in pH
b. hypercapnia
c. hypoxia
d. lung inflation (stretch)

Answer

A

Hypercapnia, also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood

Question 47

Q

select the ONE INCORRECT option from those provided

The main symptoms of asthma are

a. bronchoconstriction
b. chronic productive cough c. oedema of airway mucosa d. secretion of mucus

Question 48

Q

select the ONE INCORRECT option from those provided

Restrictive lung diseases such as fibrosis

a. exhibit increased lung compliance
b. are characterised by the development of excess connective tissue
c. are associated with decreased vital capacity
d. may be caused by inhaled environmental and occupational pollutants

Question 49

Q

A process that requires cellular energy to move a substance against its concentration gradient is called

a. active transport
b. diffusion
c. facilitated transport
d. passive transport

Answer

A

a. active transport

Question 50

Q

Compared with intracellular fluid, the extracellular interstitial fluid concentration of

a. chloride is low
b. potassium is high
c. protein is low
d. sodium is low

Answer

A

c. protein is low

Extrarcellular fluid has :

Lower K conc
Higher Na conc
Slightly higher (but sill low) conc of Ca
Higher conc. Cl
Lower Org conc
Lwer Protein conc

Question 51

Q

The reference plane that divides the body into superior and inferior regions is the

a. coronal plane
b. frontal plane
c. sagittal plane
d. transverse plane

Answer

A

d. transverse plane

•	Anatomical position:
	Position of the upright body -> arms at sides -> palms facing forwards.
-	Anterior (Ventral):
	Front / Underside 
-	Posterior (Dorsal)
	Behind/ Upperside/back
-	Superior
	Towards the head
-	Inferior
	Towards the feet
-	Medial 
	The core/centre
-	Lateral
	Towards the side/ away from core/centre 
-	Proximal 
	Closer towards the trunk
-	Distal 
	Further from the trunk
-	Coronal/frontal plane:
	Divides into front &amp; back planes -> Anterior/ventral &amp; posterior/dorsal
-	Horizontal/transverse plane 
	Divides into top &amp; bottom planes -> Above &amp; below waist -> Superior &amp; Inferior
-	Midsagittal plane 
	Divides into right &amp; left halves -> medial &amp; lateral

Question 52

Q

Epithelial cells are bound to the basement membrane by

a. desmosomes
b. gap junctions
c. hemidesmosomes
d. tight junctions

Answer

A

c. hemidesmosomes

• Intercellular junctions:
- Specialised areas of cell mem -> bind cells to one another.
- Types of intercellular junction:
 Desosomes:
Strong
Join adjacent cells
Resist stretching & twisting.
 Hemidesosomes:
Stabilising
 Attach cells to basement mem
Anchor to underlying tissue
 Tight junctions
Binds adjacent cells -> interlocking proteins
Prevents passage of water & solutes between cells
Found on Apical side of cells
Eg. Digestive tract -> Prevents digestive fluids passing between epithelial cells.
 Gap junctions:
Interlocking mem proteins (connexons) bind cells together
 Connexons – central pore enabling movement of small molecules & ions between cells
 Cardiac muscle

Question 53

Q

The blood vessel layer that consists of simple squamous epithelium and subendothelial connective tissue is the tunica

a. adventia
b. externa
c. intima
d. media

Answer

A

c. intima

 Endothelium -> simple squamous epithelium
 Basal lamina of epithelial cells
 Subendothelial connective tissue

Tunica media:
 Smooth muscle fibres -> loose connective tissue
 May contain elastic fibres
Tunica adventitia:
 Connective tissue
 Merges -> surrounding connective tissue
 May contain vaso vasroum

Question 54

Q

Blood that is low in oxygen moves from the right side of the heart to the lungs through the

a. foetal circulation
b. portal circulation
c. pulmonary circulation
d. systemic circulation

Answer

A

•	Foetal circulation:
-	Oxygen &amp; nutrients received from placenta 
Umbilical vein
-	Bypasses non-functional lungs
 3 shortcuts:
i)	Ductus venosus 
 >> Umbilical vein -> inferior vena cava
ii)	Foramen ovale 
 >> Right -> left atria
iii)	Ductus arteriosus
 >> Pulmonary trunk -> arch of aorta.

•	Portal circulations:
-	Blood drains -> one capillary bed 
->Vein -> 2nd capillary bed
->Heart. 
Eg. Hypophyseal portal system 
	Hypothalmus -> pituitary gland 
Eg. Hepatic portal system 
	Gastrointestinal tract -> liver. 
 The right-hand side of the heart collects deoxygenated blood from the body and pumps it to the lungs (to collect more oxygen). This is called pulmonary circulation.

 Systemic circulation:
 High pressure -> arterial
 Transports oxygenated blood -> LHS heart -> body tissues
 Returns deoxygenated blood – RHS heart

Question 55

Q

Blood is prevented from flowing back into the left atrium by the

a. aortic valve ‘
b. bicuspid valve
c. pulmonary valve
d. tricuspid valve

Answer

A

b. bicuspid valve

• Blood flow through heart:

Deoxygenated blood from body tissues
- > Superior & Inferior vena cava -> right atrium
2. Right atrium
- > Tricuspid (right atrioventricular) valve -> right ventricle.
3. Right ventricle
- > Pulmonary semilunar valve -> pulmonary trunk & arteries.
4. Pulmonary trunk & arteries
- > Lungs -> Oxygenated -> Pulmonary veins.
5. Pulmonary veins
- > Left atrium
6. Left atrium
- > Bicuspid (mitral/left atrioventricular valve) -> Left ventricle
7. Left ventricle
- > Aortic semilunar valve -> aorta.
8. Aorta
- > Body tissues.

Question 56

Q

Haematopoiesis is the term which describes the production of

a. all types of blood cell
b. haemoglobin
c. platelets
d. red blood cells

Answer

A

a. all types of blood cell

•Haematopoiesis/Haemopoiesis:
 Process -> formation -> blood cells
 All cells produced -> 1 haematopoietic stem cell
Self-renewing
Differentiates -> different cells -> depending on requirements of body
i) Common myeloid progenitor -> production -> all cells except lymphocytes
ii) Common lymphoid progenitor -> production -> lymphocytes

• Erythropoiesis:
 Production of erythrocyte (RBCs)

•	Haemoglobin:
	Transports O2  &amp; CO2
	Synthesis begins -> proerythroblast
65% -> erythroblast
35% -> reticulocyte
	280 million per RBC
	15g/dl 
	4 subunits:
2 alpha &amp; 2 beta
Each contains haem 
     >Bound -> globin -> long polypeptide chain
Ferrous iron atom Fe2+ at centre of each subunit
     >>Can reversibly bind -> O2

Question 57

Q

Eosinophils

a. are inactive during an allergic response
b. are the least common white blood cell
c. are the largest white blood cell
d. have a bilobed nucleus

Answer

A

 Eosinophils:
d. have a bilobed nucleus

Eosinophils:
-	2-4% of WBCs
-	Structure:
10-12 micrometres diameter
Bilobular nucleus
-	Function:
Circulate -> blood -> approx. 8-12 hrs
    >>Migrate -> tissues
Lifespan approx. 1-3 days
Release toxic compounds
     Eg. NO &amp; cytotoxic enzymes
Allergies
    >>Athsma
Combat -> parasitic infections
Attack bacteria, protozoa, debris

Question 58

Q

The coagulation phase of haemostasis is initiated by

a. factor X
b. prothrombin
c. thrombin
d. tissue factor

Answer

A

d. tissue factor

Coagulation:
-	Conversion -> soluble plasma protein -> insoluble rigid polymer -> fibrin
Fibrinogen -> soluble 
Thrombin -> enzyme -> polymerisation
     >>Fibrinogen -> Fibrin.
Fibrin -> insoluble 
Factor XIII -> stabilises Fibrin

 Initaiation of coagulation:
- Extrinsic pathway
 Tissue factor
»Binds to Factor VII -> Tissue Factor-FVIIa complex
&raquo_space;Binds -> FX -> activates transformation -> FXa
- Intrinsic pathway
 Factor IX & co-factor VIII
&raquo_space;Binds -> FX -> activates transformation -> FXa
Slower -> extrinsic pathway
- Common pathway
 Prothrombinase
Comprised FXa & FVa as co-factor
&raquo_space;Binds -> Prothrombin -> produces -> thrombin
&raquo_space;Thrombin -> converts -> Fibrinogen -> Fibrin

Question 59

Q

Haemolytic disease of the newborn can develop with an

a. Rh -ve foetus and Rh +ve mother
b. Rh -ve foetus and Rh -ve mother
c. Rh +ve foetus and Rh -ve mother
d. Rh +ve foetus and Rh +ve mother

Answer

A

• Rh [D] Blood group:
c. Rh +ve foetus and Rh -ve mother

Rh -ve -> Antigen present
Rh +ve -> Antigen absent
» Rh -ve -> does not usually contain anti-Rh [D] antibodies
>Requires sensitisation -> exposure -> Rh +ve RBCs
Transfusion
Pregnancy/ birth
->Rh -ve mother & Rh +ve baby
->Haemolytic disease -> newborn -> HDN

Question 60

Q

The short-term control of blood pressure mainly involves

a. aldosterone production
b. changes in the heart rate
c. fluid loss
d. Na+ loss from the kidney

Answer

A

b. changes in the heart rate

• Pulmonary Circulation:
- Decr. O2 & Incr. CO2 -> constriction -> arterioles. Response & Regulation of Blood Pressure:
Homeostasis:
- Altered Blood pressure / volume
Physical stress
Eg. Trauma, high temp, etc.
Chemical changes
Eg. Decr. O2 / decr. pH / Incr. CO2 / Incr. vasodilatory metabolites
Increases tissue activity / Intrinsic Control
- Inadequate blood pressure & flow
»Autoregulation:
 Decr. resistance & incr. blood flow
> Homeostasis returned.
- Insufficient Autoregulation:
Stimulates receptors -> sensitive to systemic changes -> blood pressure /
Chemistry.
Activates cardiovascular centres -> Central Nervous System
Elevates Blood pressure -> Short Term
&raquo_space;Stimulation -> heart rate & peripheral vasoconstriction
–» Sensory Nervous System.
Return -> Homeostasis.

Question 61

Q

Baroreceptors

a. are only located in the aortic arch
b. are only located in the carotid artery
c. detect changes in blood metabolites
d. detect changes in vascular pressure

Answer

A

d. detect changes in vascular pressure

•	Baroreceptors:
Wall -> internal carotid artery
Aorta
Baroreceptors &amp; Control -> Blood Flow:
•	Inadequate Blood supply / Decr. Blood Pressure:
-	Inhibition -> baroreceptors
	 Activation 
 Cardioacceloratory Centre
Vasomotor Centres
	Inhibition
 Cardioinhibitory Centre
       >> Incr. Cardiac Output &amp; Heart Rate
-	Vasoconsriction

•	Rise -> Blood Pressure:
-	Stimulation -> Baroreceptors
	Activation
Cardioinhibitory Centre
	Inhibition
Cardioacceloratory Centre
Vasomotor Centres
       >> Decr. Cardiac Output &amp; Heart Rate
-	Vasodilation.

Question 62

Q

The heart

a. beats about 1,000 times per day
b. is an endocrine gland
c. is innervated by sympathetic nerve fibres but not by parasympathetic nerve fibres
d. is not affected by drugs that are used to treat hypertension

Answer

A

b. is an endocrine gland

Avg. HR per min = 75
So (75 x 60 ) x 24 = 108,000•

Endocrine glands are ductless glands of the endocrine system that secrete their products, hormones, directly into the blood. The major glands of the endocrine system include the pineal gland, pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland, hypothalamus and adrenal glands.

Innervation of Heart: 1.	Cardioregulatory centre &amp; chemoreceptors -> medulla oblongata Via -> Sensory Nerve Fibres ->> Baroreceptors -> wall of internal carotid artery ->> Carotid body chemoreceptors ->> Baroreceptors -> Aorta 2.	Adrenal Medulla i)  Via -> Parasympathetic nerve fibres
->> Sinoatrial (SA) Node ii)  Via -> Sympathetic nerve fibres
->> Heart 3.	Adrenal Medulla Via -> Sympathetic nerve fibres -> adrenal gland  >Release adrenaline/noradrenaline -> circulation  ->>Heart

Question 63

Q

The cardiac cycle

a. describes the integration of electro-mechanical coupling of the heart
b. is generally described in terms of the P, Q, R, S and T periods
c. takes approximately 3 milliseconds to complete
d. takes place in the sinoartial node

Answer

A

??

Cardiac electro-mechanical coupling is known to contribute to sudden cardiac death, a significant public health issue, but its role in the intact human heart

Described in terms of P-wave, QRS complex, T-wave & QT interval

Cardiac cycle occurs throughout heart.

Question 64

Q

The cardiac output of a non-athletic individual is

a. generally higher than that of a trained individual during exercise
b. generally the same as that of a highly-trained individual at rest
c. increased by 10-fold during modest exercise
d. independent of their heart rate

Answer

A

b. generally the same as that of a highly-trained individual at rest

Untrained -> Rest ; Excersised
–> Trained -> Rest ; Excersised

CO (L/min) ~5 ~20 ~5.5 ~30
CO = HR x SV

Answer 60

A

• Ischaemic Heart
c. most commonly caused by atherosclerosis of a coronary artery

Disease (Coranary Heart Disease -> CAD)
 Leading cause of death -> Developed world
 30% Males
 23% Females
 Common cause:
 Atherosclerosis -> coronary artery
 Most frequent -> Left anterior interventricular artery
 Occurs in Left ventricle
 Insufficient Blood flow to myocardium
» Angina Pectoris (ischemia-induced pain)
-»Mediated by endogeneous vasodilators
» Results -> myocardial infarction
-» Death of heart muscle within 20 mins

Answer 61

A

d. type II alveolar cells

 Alveoli
 Site -> gas exchange
 Surrounded by network of capillaries
 150-250 mill per lung
 Blood Supply
 Structure:
 Type I Alveolar Cell:
&raquo_space; Simple squamous epithelium
> Forms wall of alveolus
 Type II Alveolar Cell:
&raquo_space; Secretes Surfactant
 Macrophage:
&raquo_space; Phagocytozes small inhaled particles & bacteria
 Capillary
 Respiratory membrane
&raquo_space; Epithelium -> Type I alveolar cell
&raquo_space; Basement membrane -> Type I alveolar cell
&raquo_space; Basement membrane -> Capillary
&raquo_space; Endothilium -> Capillary
-» Basement membranes often fused together.

In the nose; one of the functional adaptations, the mucosa; contain goblet cells which produce mucous to trap particles.

Answer 62

A

Bony Thorax:
 Forms skeleton of chest wall
 d. transverse process of the thoracic vertebra

->Says attached, specifically articulated to sternum & thoracic vertebra

	Components:
 12 pairs ribs
    -> 7 true pairs
    -> 3 false pairs
    -> 2 floating
 12 thoracic vertebrae
 Sternum
-	Sternum:
	Breast bone
	Components:
 Manubrium 
 Body 
 Xipisternum
-	Ribs:
	Differ -> shape &amp; size
	Slope downwards &amp; forwards
	Attached by head &amp; tubercle -> thoracic vertebrae
	Ribs 1-10 attached by costal cartilage -> sternum
-	Thoracic Vertebrae:
	Head of rib articulates with body of thoracic vertebra
	Tubercle of rib articulates with transverse process of thoracic vertebra
-	Intercostal muscles:
	Span intercostal spaces
	External intercostals        
 Superficial layer
 Fibres run supero-lateral to infero-medial 
   -> Tubercles to costochondral junction        ->  (Downward-diagonally from  
                                                                              shoulder to core -   /  )
	Internal intercostals          
 Middle layer
 Fibres run infero-lateral to supero-medial 
   -> At angles to ends of intercostal spaces.   -> (Upward-diagonally from  
                                                                              hip to core -   \  )
	Innermost intercostals      
 Innermost layer
-	Intercostal Vessels &amp; Nerves:
	Intercostal spaces
	Supply muscles. Adjacent skin &amp; pleura. 
-	Diaphragm:
	Dome shaped-skeletal muscle with central tendon
	Attached: 
 Xiphisternum
 Costal Margin
 11th &amp; 12th ribs
 Left &amp; Right Crus 
      -> Arise -> Lumbar vertebrae
	Innervated -> phrenic nerve
	Most important muscle -> ventilation. 
	Structures / components:
 Skeletal muscle -> outside 
 Centrally-placed tendon 
    -> No body attachments

Answer 63

A

a. contraction of the diaphragm

• Incr. Thoracic Volume:
- Incr. Vertical diameter
 Contraction of diaphragm incr. vertical diameter
Responsible for 75% incr. thoracic capacity
- Incr. Anterior Posterior diameter
 Elevation of ribs incr. Anterior Posterior diameter
-> (Joint with Transverse Diameter)
Responsible for 25% thoracic capacity.
 Elevation of ribs -> external end -> makes them more horizontal & pushes sternum forward (pump handle movement)
Incr. AP diameter
- Incr. transverse diameter
 Elevation of ribs incr. transverse diameter
-> (Joint with Transverse Diameter)
Responsible for 25% thoracic capacity.
 Many of the ribs
 Lowest near their middle
 Rise at each end
Eg. Bucket handle
 Rise of middle of rib -> movement away from midline of body
Transversally widens chest (Left -> Right)

•	Inspiration:
-	Active process
-	At rest:
	Diaphragm (75%)
	External intercostal muscles (25%)
 Contracted diaphragm flattens
   -> Vertical diameter of thorax increased. 
 External intercostals elevate ribs -> incr. Anterior Posterior &amp; Transverse 
     diameters. 
-	Forced:
	Pectoralis major 
	Pectoralis minor
	Scalenes
	Serratus anterior
	Sternocleidomastoid
 Assist -> rib elevation 
    -> Incr. speed &amp; amount of movement

Answer 64

A

d. located just beneath the ventral surface of the medulla
??

•	Central Chemoreceptors:
-	Located -> Medulla oblongata of brainstem 
-	Respond to changes in PCO2 &amp; pH
•	Peripheral Chemoreceptors:
-	Detect changes -> PO2, PCO2 &amp; pH
-	Aortic Bodies
 Located -> Aortic Arch
 Innervated -> Vagus (CN X)
-	Carotid Body
 Located -> Common Carotid Artery
 Innervated -> Glossopharyngeal (CN IX)

• Respiratory Centres:
- Group of neurons -> Brain stem
- Send impulses to muscles of ventilation
- Medullary Rhythmicity Area
 Dorsal Respiratory Group (DRG)
 Sets rhythm, stimulates muscles of quiet inspiration
 Ventral Respiratory Group (VRG)
 Involved in forced inspiration & expiration
- Pneumotaxic area (Pons)
 Influences DRG by regulating duration of inspiration.

Answer 65

A

c. pneumotaxic centre

• Respiratory Centres:
- Group of neurons -> Brain stem
- Send impulses to muscles of ventilation
- Medullary Rhythmicity Area
 Dorsal Respiratory Group (DRG)
 Sets rhythm, stimulates muscles of quiet inspiration
 Ventral Respiratory Group (VRG)
 Involved in forced inspiration & expiration
- Pneumotaxic area (Pons)
 Influences DRG by regulating duration of inspiration

Answer 66

A

c. 152 mmHg

- > 20% of 760?

Answer 67

A

c. urine

The fluids that are not inside cells, but are separated from plasma and interstitial fluid by cellular barriers (e.g., cerebrospinal fluid, synovial fluid, pleural fluid).

Transcellular fluids are also a component of ECF and are found in the cerebrospinal column, pleural cavity, lymph system, joints, glandular secretions, and eyes

Synovial fluid is found in the cavities of synovial joints. It reduces friction between the articular cartilage of synovial joints during movement & is a small component of the transcellular fluid

The vitreous humor is a transparent, colorless, gelatinous mass that fills the space in the eye between the lens and the retina. It is surrounded by a layer of collagen called vitreous membrane separating it from the rest of the eye.

Blood plasma liquid component of blood that normally holds the blood cells in whole blood in suspension; this makes plasma the extracellular matrix of blood cells. It makes up about 55% of the body’s total blood volume. It is the intravascular fluid part of extracellular fluid (all body fluid outside cells).

Answer 68

A

c. urine

The fluids that are not inside cells, but are separated from plasma and interstitial fluid by cellular barriers (e.g., cerebrospinal fluid, synovial fluid, pleural fluid).

Transcellular fluids are also a component of ECF and are found in the cerebrospinal column, pleural cavity, lymph system, joints, glandular secretions, and eyes

Synovial fluid is found in the cavities of synovial joints. It reduces friction between the articular cartilage of synovial joints during movement & is a small component of the transcellular fluid

The vitreous humor is a transparent, colorless, gelatinous mass that fills the space in the eye between the lens and the retina. It is surrounded by a layer of collagen called vitreous membrane separating it from the rest of the eye.

Blood plasma liquid component of blood that normally holds the blood cells in whole blood in suspension; this makes plasma the extracellular matrix of blood cells. It makes up about 55% of the body’s total blood volume. It is the intravascular fluid part of extracellular fluid (all body fluid outside cells).

Answer 69

A

c. innervate skeletal muscle

Parasympathetic nerves comprise the autonomic nerves -> innervate smooth & cardiac mucle & involved
in subconscious activity

2.	Parasympathetic Nervous system -> Spinal cord &amp; base of brain.
Outflow from CNS:
	Parasympathetic -> Cranial &amp; sacral
	Parasympathetic -> Long
-	Ganglionic transmitter:
	Parasympathetic -> ACh (N2)
-	Postganglionic fibre: 
	Parasympathetic -> Short
-	Neuroeffector transmitter:
	Parasympathetic -> ACh (M)

Answer 70

A

c. are striated

Muscle:
c. are striated

Produces movement -> specialised for contraction
3 types – skeletal , smooth & cardiac.
 Similarirties
Elongated parallel to axis of contraction
Numerous mitochondria
-Contractile elements

1.	Skeletal
	Moves &amp; stabilises skeleton 
	Forms sphincters in digestive &amp; urinary tracts -> controls urges to pee etc. 
	 Involved in respiration
-	Long cylindrical cells 
-	Striated (striped)
-	Multinucleated (multiple per cell)  
-	Innervated -> somatic nervous system

Smooth
 Forms walls of organs, blood vessels & airways
 Gastrointestinal movement
 Alters diameters -> airways & blood vessels
- Short, fusiform (narrow at ends) cells
- Non striated (not striped)
- Single central nucleus
- Innervated -> autonomic nervous system

Answer 71

A

??

Simple squamous
 Exchange of nutrients & gases -> Blood vessels & alveoli
Non-keratinised stratified squamous
Protection -> Oral cavity & oesophagus
Keratinised stratified Squamous
 Waterproof protection/barrier -> Skin
Simple cuboidal epithelium
Secretion & absorption -> Glands & kidney tubules
Simple columnar epithelium
Absorption & secretion -> Gastrointestinal tract
–> also have microvilli -> Enabling absorption of nutrients.
Pseudostratified ciliated columnar epithelium with goblet cells
Mucociliary escalator -> produce mucous -> particles inhaled -> trapped in mucous.
-> Cilia moves mucous upwards to back of throat for swallowing.
-> Trachea & large respiratory airways.
-> Also has cilia & goblet cells.
Trachea appears stratified -> some cells don’t reach free surface -> All touch
basement mem.

Serous cavities are cavities lined by serous membrane serous cavity a coelomic cavity, like that enclosed by the pericardium, peritoneum, or pleura, not communicating with the outside of the body and lined with a serous membrane,(mesothelium)

Answer 72

A

a. appear to have a larger lumen

Answer 73

A

b. carotid artery
- > Carotid = neck

•	Major arteries:
-	Arm:
	Axillary -> Shoulder
	Brachial -> Upper arm 
	Radial -> Lateral
	Ulnar -> Medial
-	Leg:
	External iliac -> Hip area
	Femoral -> Upper leg
	Popliteal -> Back of knee
	Anterior tibial
-	Core:
	Right common carotid -> Right -> neck 
	Left common carotid -> Left -> neck 
	Brachiocephalic trunk -> Lungs 
	Right subclavian -> Right -> under collarbone
	Left subclavian -> Left -> under collarbone
	Aortic arch -> Main part of heart 
	Descending thoracic aorta -> Down inside lower end of rib cage -> spine
	Abdominal aorta -> Abdominal -> inside spine 
	Common iliac -> Top of hip
	External iliac -> Lower hip -> top of leg
	Internal iliac -> Backbone

Answer 74

A

c. pulmonary veins

The coronary sinus is a collection of smaller veins that merge together to form the sinus, located along the heart’s posterior surface between the left ventricle and left atrium
It drains deoxygenated blood into the right atrium of the heart. so it can be pumped to the lungs to
acquire oxygen.

Pulmonary veins are responsible for carrying oxygenated blood from the lungs back to the left atrium of the heart.

Answer 75

A

d. transports O2 from tissues to lungs

•	Haemoglobin:
	Transports O2  &amp; CO2
	Synthesis begins -> proerythroblast
65% -> erythroblast
35% -> reticulocyte
	280 million per RBC
	15g/dl 
	4 subunits:
2 alpha &amp; 2 beta
Each contains haem 
     >Bound -> globin -> long polypeptide chain
Ferrous iron atom Fe2+ at centre of each subunit
     >>Can reversibly bind -> O2

•	Structure of RBCs:
-	Biconcave disc 
Enables easy passage through vessels 
-	7-8 micrometeres -> diameter
-	Foldable &amp; flexible -> deforms easily 
-	Stable
-	No organelles 
more room for haemoglobin 
-	Function:
Transportation -> oxygen &amp; CO2
-	Life span 
 120 days 
    > Broken down &amp; recycled. 
-> So no ability to produce haemoglobin as no organelles/ nucleus

Production of erythrocyte:
 Production of RBCs required
 Triggers kidneys -> release erythropoietin hormone
 Erythropoietin -> acts on stem cells
 Instigates specialisation of stem cell -> production -> RBCs
 Proerythroblast -> immature cell -> bone marrow
Matures -> Erythroblast
 Normoblast -> containing full haemoglobin conc.
–>Constant production of haemoglobin during these stages
 Normoblast ejects nucleus -> reticulocyte
Reticulocyte still contains some ribosomal RNA
>If Reticulocyte released -> circulation prematurely -> still some ability to
produce haemoglobin.
Small number in circulation -> later mature -> RBCs
Lots of reticulocytes
->Anaemia
 Erythrocyte (RBC)

Answer 76

A

c. not able to migrate out of the bloodstream

•	White blood cells:
	Also known -> Leukocytes
	Nucleated
	Act mainly outside tissues 
In-transit -> sites of activity 
	Can migrate out of bloodstream -> extravastation (diapedesis)
	Capable -> amoebid movement
	Attracted -> specific chemical stimuli
	2 groups:
i)	Granulocytes
-	Neutrophils
-	Eosinophils 
-	Basophils 
ii)	Agranulocytes
-	Lymphocytes
-	Monocytes
	Neutrophils, eosinophils &amp; monocytes -> phagocytosis
	Functions:
-	Defence -> pathogens
-	Toxin &amp; waste removal 
-	Removal -> damaged cells

Answer 77

A

a. can accept blood from a person with A antigens on their red blood cells

A antigens on RBCs = A Blood Type -> A blood type cells produce anti-B antibodies which would then cause individual’s blood to clot by agglutination
In addition, their B Blood type cells will produce Anti-A antibodies to cause agglutination of type A cells for elimination.

Answer 78

A

b. when blood flow to the kidneys is increased ??

• Erythrocyte Homeostasis:
 Low conc O2
 Detected by kidneys -> stimulates incr. production -> erythropoietin
 Detected -> stem cells -> incr. production of RBCs
 More RBCs -> higher O2 transportation capacity -> incr. O2 conc.
 Causes of hypoxia (low O2 conc)
- Incr. excersise
- High altitude

Production of erythrocyte:
 Production of RBCs required
 Triggers kidneys -> release erythropoietin hormone
 Erythropoietin -> acts on stem cells
 Instigates specialisation of stem cell -> production -> RBCs
 Proerythroblast -> immature cell -> bone marrow
Matures -> Erythroblast
 Normoblast -> containing full haemoglobin conc.
–>Constant production of haemoglobin during these stages
 Normoblast ejects nucleus -> reticulocyte
Reticulocyte still contains some ribosomal RNA
>If Reticulocyte released -> circulation prematurely -> still some ability to
produce haemoglobin.
Small number in circulation -> later mature -> RBCs
Lots of reticulocytes
->Anaemia
 Erythrocyte (RBC)

Answer 79

A

a. always higher in arteries than veins 

Blood flow determined:

Resistance -> R
Pressure difference -> P

 F = ▲P / ▲R

             Determined by:
->> L = length of vessel 
->> r = radius of vessel
->> ꞃ = fluid viscosity 
       >>(protein conc.)

 R = (8Lꞃ) / (πr4)
 F = ▲P((πr4) / (8Lꞃ))

Answer 80

A

c. is dependent upon higher blood pressure at the venous end of the capillary compared with the arterial end ‘
- > This would mean more molecules still forced out of blood into extracellular fluid, further decr. vol. of fluid & dissolved subs. in capillaries & hence no time for reabsorption of waste products for removal.

• Dynamics of capillary exchange:
 Arterial end
 High hydrostatic pressure -> forces fluid out capillary network
&raquo_space; Opposed -> high osmotic potential gradient
 Capillary Hydrostatic Pressure (CHP) -> 35mmHg
 Blood Colloid Osmotic Pressure (BCOP) -> 25mmHg
-» CHP > BCOP
-» Net filtration pressure -> +10mmHg
&raquo_space; Forces fluid & dissolved substances out -> capillary network
 Significant rate of filtration -> 24 L/day

 Venous end
 Hydrostatic pressure decline -> incr. distance -> heart
 Same osmotic potential
 Capillary Hydrostatic Pressure (CHP) -> 18mmHg
 Blood Colloid Osmotic Pressure (BCOP) -> 25mmHg
-» CHP < BCOP
-» Net Filtration Pressure -> -7mmHg
&raquo_space;Movement of fluid -> into capillary network
 Significant Rate of reabsorption -> 20.4 L/Day

 Net difference in water -> Rate of filtration & absorption
Collected -> Lymphatic System

 Centre -> Capillary Network
Approx. centre -> capillary network
->Equal values -> CHP & BCOP -> Net filtration pressure = 0.
-> No net movement -> fluid.
 Max filtration pressure always greater -> max absorption pressure
&raquo_space; Point at which net filtration pressure = 0
-> further towards venous end -> capillary
-» More filtration than absorption along capillary.
¬-» Enables provision -> tissues with required molecules over greater
distance -> capillary network
> Rapid reabsorption -> molecules & waste products -> venous end.

Answer 81

A

b. described as an inotropic variable

• Chronotropic Effect:
- Influence effecting heart rate.
• Inotropic effects:
 Effects which alter the contractility of the heart

	Negative chronotropic effect:
       Slows Heart Rate
      Eg. Acetlycholine 
      ->> Via positive end -> muscarinic (ACh)-receptor gated K-channels
          Component of ‘vagal tone’
	Positive chronotropic effect:
 Increase Heart Rate
Eg. Noradrenaline &amp; adrenaline
->> Via stimulation -> hyperpolarisation-activated ion channels

In addition to its metabolic effects, glucagon is considered to increase heart rate and contractility, stimulation of glucagon receptors causes adenylyl cyclase activation and the consequent increase in 3′,5′-(cAMP) production.

Answer 82

A

c. involves slowing of the heart beat

• Arrhythmias:
 Deviation of heart’s normal sinus (SAN) rhythm.
 Relatively rare
-> 1 in 5000-10000
 Found -> young individuals ; <25yrs
 Many arise
-> Defects in ion channels regulating ventricular action potentials
 Cause spontaneous multiple depolarizations
&raquo_space; Ventricular arrythmias
 Produce sustained abnormal rhythm
 Asymptomatic
 Palpitations
 Dizziness
 Syncope
 Heart Failure
 Sudden Death

Tachycardia:
 Fast Rhythm (>100bpm)
 Sinus Tachycardia
 Innapropriate Sinus Tachycardia (IST)
Invlolves:
» Caffeine
» Amphetamines
» Overactive thyroid gland -> SNS
 Non-sinus Tachycardia
-> Addition of abnormal inpulses -> normal cycle
> Uncontrolled twitching / quivering -> muscle fibres (fibrils)
> Blood not removed from heart -> ventricular fibrillation
> Sudden cardiac death
Caused by:
» Automaticicity (enhanced pacemaker)
» Triggered Beats (Early / delayed depolarization)
» Re-entry Activity / Circus Activity (Conduction profile defects)
» Conduction Block
»Heart Damage

Answer 83

A

c. is unrelated to ion channel gene defects ??

Long QT syndrome (LQTS) is an inherited condition that can cause abnormal heart rhythms (arrhythmias) which affects repolarization of the heart.
Usually caused by a faulty gene inherited from a parent which affects the proteins that make up the ion channels regulating electricity in the heart. The ion channels may not work well, or there may not be enough of them, which disrupts the heart’s electrical activity.
It results in an increased risk of fainting (syncope) drowning, or sudden death

Answer 84

A

• Hypertension:
 Affects nearly one billion
 One of the main causes -> premature death.
 Nearly 8 million fatalities per year
 Types:
- Primary Hypertension
(Essential / Idiopathic)
 Unknown medical cause
 Links:
 Genetic predisposition
 Alcohol consumption
 Obesity
 Lack of excersise
 Diabetes
 Intrauterine environment
- Secondary Hypertension
 Known medical cause
1) Kidney Disease:
 Incr. Angiotensin II
» Vasoconstriction & expansion -> cellular fluid
2) General endocrine disorders
Eg. Diabetes, Cushing’s
3) Adrenal medulla disease (Phaeochroocytoma)
 Excessive adrenaline secretion
 Treatment:
- Inhibit angiotensin II production -> inhibition of Angiotensin-Converting-Enzyme (ACE)
» Prevents renal absorption -> Na+/H2O
> Prevents incr. blood volume
- Ibhibition -> Angiotensin II induced vasoconstriction -> Angiotensin II receptor
blocker.
&raquo_space; Inhibitd membrane cardiac / vascular depolarizoation
> Decr. CO -> vasodilation.
- Calcium-channel blocker / thiazide diuretic
&raquo_space; Incr. loss -> Na+ & H2O
> Decreases fluid volume, venous return & cardiac output.
- Reduce TBR -> inhibition -> noradrenaline action.
- Alpha-adrenoreceptor Antagonists (alpha-Blockers)
 Reduce TBR -> inhibition -> noradrenaline action.
- Beta-adrenoreceptor Antagonists (beta-Blockers)
 Decr. CO2,
 Decr. central activity -> Symapthetic nervous system
 Decr. release -> Renin
-» Favourable secondary actions
 Risks:
- Atherosclerosis
- Stroke / Cerebrovascular Accident
- Heart Failure
- Renal Failure
- Aneurysms

Answer 85

A

b. bronchioles

	Bronchi 
	Series of tubes 
    Smaller in diameter
    Display histological chabges
       >> Decr. quantity cartilage
       >> Incr. quantity smooth muscle
       >> Decr. height epithelial cells
	Pseudostratified ciliated columnar epithelium with goblet cells
	Cartilage plates
	Types:
 Primary bronchus
   >> Supply each lung
   >> 2-3cm long
   >> Right -> wider &amp; more vertical -> left
   >> C-shaped cartilages
 Secondary bronchus
   >> Lobar
   >> Supply lobes of lung 
        > 3 on right 
        > 2 on left
   >> Plates of cartilage
 Tertiary bronchus
   >> Segmental
   >> Supply lung segments 
        > 10 on right 
        > 8 on left
   >> Plates of cartilage

	Bronchioles
	No cartilage
	Smooth muscle
>> Can constrict &amp; dilate
	Simple columnar epithelium with some goblet cells
	Each has 50-80 terminal bronchioles
	Types:
     Terminal
                   >>Simple columnar epithelium with cilia
                   >> No goblet cells / mucous glands
                   >> Clara cells 
                       > Produce surfactant
                   >> Each gives 2 or more respiratory bronchioles
 Respiratory 
  >> Simple cuboidal epithelia 
      >Clara cells 
        ->> Produce surfactant
  >> No cilia
  >> Alveoli extend from lumen 
      > Site -> Gas exchange

	Larynx
	Functions:
 Maintenance -> open airway
 Prevents consumed substances entering lower respiratory system. 
 Sound production
	Involved:
 Coughing
         Defacecation
	Structure:
Cartilaginous skeleton
      >> Epiglottis 
      >> Thyroid cartilage (Adam’s Apple)
      >> Cricoid cartilage
                        >>Arytenoid cartilage
         Lined by memebranes
   Moved using muscles
	Paranasal tissues
	Functions:
	Warms &amp; moistens air
	Filters air 
	Involved -> Olfaction 
	Resonates sound

	Trachea
	Tough, flexible tube
	4.5cm length
	2.5cm diameter
	Extends -> larynx to carina 
	Anterior to oesophagus
	15-20 horseshoe-shaped cartilages
 Keep airway open
	Pseudostratified ciliated columnar epithelium with goblet cells
 Dust particles -> stuck in mucus layer
 Cilia move mucus layer towards mouth 
    >> Transports / removes dust particles

Answer 86

A

c. bronchioles ?
- > States bronchi only explicitly. Bronchioles may be too small / further down respiratory tract & wouldn’t need to enter lungs as attached to bronchi which already doing so.

Hilum of lung: 	Located -> mediastinal surface Region of entry -> lungs for blood vessels, lymphatics, nerves &amp; bronchi.

Bronchial arteries supply high-pressure oxygenated blood to the supporting structures of the lung, including the pulmonary arteries

Answer 87

A

a. internal intercostal

•	Inspiration:
-	Active process
-	At rest:
	Diaphragm (75%)
	External intercostal muscles (25%)
 Contracted diaphragm flattens
   -> Vertical diameter of thorax increased. 
 External intercostals elevate ribs -> incr. Anterior Posterior &amp; Transverse 
     diameters. 
-	Forced:
	Pectoralis major 
	Pectoralis minor
	Scalenes
	Serratus anterior
	Sternocleidomastoid
 Assist -> rib elevation 
    -> Incr. speed &amp; amount of movement

Answer 88

A

c. is less concentrated in smaller alveoli

Pulmonary surfactant are formed by type II alveolar cells
Greatly reduce surface tension, increasing compliance allowing the lung to inflate much more easily, reducing the work of breathing. It reduces the pressure difference needed to allow the lung to inflate.

As the alveoli increase in size, the surfactant becomes more spread out over the surface of the liquid. This increases surface tension effectively slowing the rate of expansion of the alveoli. Hence Surfactant reduces surface tension more readily when the alveoli are smaller because the surfactant is more concentrated.

Answer 89

A

c. protein is high

Compared to the extracellular fluid, the intracellular fluid has:

Higher K conc.
Lower Na conc
Lower Ca conc. (though extracellular is still low)
Lower Cl conc
Higher Org conc
Higher Protein conc.

Answer 90

A

b. are short

Sympathetic Nervous system -> Spinal cord
- Outflow from CNS:
 Sympathetic -> Thoracic & lumbar

-	Preganglionic fibre:
	Sympathetic -> Short 
-	Ganglionic transmitter:
	Sympathetic -> ACh (N2)
-	Postganglionic fibre: 
	Sympathetic -> Long
-	Neuroeffector transmitter:
	Sympathetic -> NA (alpha or beta)

Sympathetic:
i) Symapthetic:
Preganglionic fibre -> ganglion 
-> releases acetylcholine (ACh) 
-> activates nicotinic (N2) receptor 
-> action potential moves along postganglionic fibre 
-> releases norepinephrine (NA) 
-> activates (alpha/beta) adrenergic receptor.

Answer 91

A

Examples of epithelial tissue:
d. stratified squamous epithelium

Simple squamous
 Exchange of nutrients & gases -> Blood vessels & alveoli
Non-keratinised stratified squamous
Protection -> Oral cavity & oesophagus
Keratinised stratified Squamous
 Waterproof protection/barrier -> Skin
Simple cuboidal epithelium
Secretion & absorption -> Glands & kidney tubules
Simple columnar epithelium
Absorption & secretion -> Gastrointestinal tract
–> also have microvilli -> Enabling absorption of nutrients.
Pseudostratified ciliated columnar epithelium with goblet cells
Mucociliary escalator -> produce mucous -> particles inhaled -> trapped in mucous.
-> Cilia moves mucous upwards to back of throat for swallowing.
-> Trachea & large respiratory airways.
-> Also has cilia & goblet cells.
Trachea appears stratified -> some cells don’t reach free surface -> All touch
basement mem.

Answer 92

A

Connective tissue
- Structural framework for body
b. fibroblasts

Supports surrounds & interconnects tissues
Protects delicate organs
Transports fluids & dissolved materials
Stores energy reserves
Defence -> microorganisms
Cells within Extracellular matrix
i) Cell types:
> Fibroblasts -> Main cell type -> Synthesises extracellular matrix
>Apipocytes
>Macrophage cells
>Mast cells
ii) Exctracellular matrix:
 Ground substance
 Tissue (extracellular fluid)
 Fibres:
->Collagen
->Reticular
->Elastic

Answer 93

A

d. withstand the pressure changes in the cardiac cycle

> Muscles enable constriction
> Elastic fibres flexible therefore wouldn’t prevent distension / relaxation of walls
> From conducting arteries -> high pressure

• Characteristics of blood vessels:

Resilience
Flexibility
Constantly remain open
Tunica media:
 Smooth muscle fibres -> loose connective tissue
 May contain elastic fibres

Answer 94

A

b. portal circulation 

Pulmonary circulation: Low pressure 	Deoxygenated blood -> RHS heart -> lungs  	Oxygenated blood -> Lungs -> LHS heart  	Pulmonary arteries -> Low O2 	Pulmonary veins -> High O2

•	Portal circulations:
-	Blood drains -> one capillary bed 
->Vein -> 2nd capillary bed
->Heart. 
Eg. Hypophyseal portal system 
	Hypothalmus -> pituitary gland 
Eg. Hepatic portal system 
	Gastrointestinal tract -> liver.

Hepatic portal system:
Liver:
 Oxygenated blood -> LHS heart -> Abdominal aorta
-> Hepatic artery
 Liver -> respiring cells
 Deoxygenated blood -> RHS heart
-> Inferior vena cava (IVC)
1st Capillary beds:
 Oxygenated blood -> LHS heart ->1st capillary beds
i) Stomach, pancreas, spleen & large intestine
ii) Splenic vein -> Hepatic portal vein.
iii) Small & large intestines, stomach
iv) SMV-> hepatic portal vein -> liver
 Nutrients from 1st capillary beds deposited -> liver
 CO2 from liver collected -> blood from 1st capillary beds
 Deoxygenated blood -> RHS heart -> hepatic vein.

•	Systemic circulation:
	Artery -> capillary -> vein
•	Portal circulation:
	Artery -> capillary -> portal vessel 
-> capillary -> vein.

 Foetal circulation:

Specialised
Lungs, liver & GI tract -> not sufficiently developed -> foetus
> Bypassed.

Answer 95

A

d. tricuspid valve

• Heart Valves:
 Prevent backflow of blood
Atrioventricular:
- Tricuspid (Right AV) valve
- Bicuspid/mitral (Left AV) valve
 Between atria & ventricles
 Open -> blood flow -> atria to ventricles
 Anchored -> Chordae tendinae to papillary muscles.
 When ventricular pressure < atrial pressure
 Valve opens -> loose chordae tendinae
 When ventricular pressure > atrial pressure
Valve begins to close -> pulls chordae tendinae -> papillary muscle contracts -> prevents inversion of valve -> backflow of blood.

                     Semilunar: -	Pulmonary  -	Aortic 	Guard entrances -> aorta &amp; pulmonary trunk 	Open -> force of blood -> contraction of ventricles 	Bloodflow -> backwards -> aorta &amp; pulmonary trunk -> ventricular relaxation Accumulates in cusps -> shut.  	Prevent backflow of blood -> ventricles.

• Blood flow through heart:

Deoxygenated blood from body tissues
- > Superior & Inferior vena cava -> right atrium
2. Right atrium
- > Tricuspid (right atrioventricular) valve -> right ventricle.
3. Right ventricle
- > Pulmonary semilunar valve -> pulmonary trunk & arteries.
4. Pulmonary trunk & arteries
- > Lungs -> Oxygenated -> Pulmonary veins.
5. Pulmonary veins
- > Left atrium
6. Left atrium
- > Bicuspid (mitral/left atrioventricular valve) -> Left ventricle
7. Left ventricle
- > Aortic semilunar valve -> aorta.
8. Aorta
- > Body tissues.

Answer 96

A

b. normally consists of 2 alpha and 2 beta subunits
- > No nucleus / organelles in fully mature cell -> so cannot synthesise haemoglobin anymore.

•	Haemoglobin:
	Transports O2  &amp; CO2
	Synthesis begins -> proerythroblast
65% -> erythroblast
35% -> reticulocyte
	280 million per RBC
	15g/dl 
	4 subunits:
2 alpha &amp; 2 beta
Each contains haem 
     >Bound -> globin -> long polypeptide chain
Ferrous iron atom Fe2+ at centre of each subunit
     >>Can reversibly bind -> O2

•	Structure of RBCs:
-	Biconcave disc 
Enables easy passage through vessels 
-	7-8 micrometeres -> diameter
-	Foldable &amp; flexible -> deforms easily 
-	Stable
-	No organelles 
more room for haemoglobin 
-	Function:
Transportation -> oxygen &amp; CO2
-	Life span 
 120 days 
    > Broken down &amp; recycled.

    Production of erythrocyte: 	Production of RBCs required 	Triggers kidneys -> release erythropoietin hormone  	Erythropoietin -> acts on stem cells 	Instigates specialisation of stem cell -> production -> RBCs 	Proerythroblast -> immature cell -> bone marrow Matures -> Erythroblast  	Normoblast -> containing full haemoglobin conc.  -->Constant production of haemoglobin during these stages 	Normoblast ejects nucleus -> reticulocyte Reticulocyte still contains some ribosomal RNA    >If Reticulocyte released -> circulation prematurely -> still some ability to 
   produce haemoglobin.  Small number in circulation -> later mature -> RBCs Lots of reticulocytes 
 ->Anaemia  	Erythrocyte (RBC)

Answer 97

A

c. being the first line of defence

> Mobile
> Major cons. pus - >Leukocytes
> many first line defence
> Many diff shaped nuclei

•	White blood cells:
	Also known -> Leukocytes
	Nucleated
	Act mainly outside tissues 
In-transit -> sites of activity 
	Can migrate out of bloodstream -> extravastation (diapedesis)
	Capable -> amoebid movement
	Attracted -> specific chemical stimuli
	2 groups:
i)	Granulocytes
-	Neutrophils
-	Eosinophils 
-	Basophils 
ii)	Agranulocytes
-	Lymphocytes
-	Monocytes
	Neutrophils, eosinophils &amp; monocytes -> phagocytosis
	Functions:
-	Defence -> pathogens
-	Toxin &amp; waste removal 
-	Removal -> damaged cells

	Neutrophils:
-	Function:
1st line defence -> bacterial infection
Phagocytic
Mobile
Circulate -> blood -> approx. 10hrs
Major component -> pus
	Eosinophils
Bilobular nucleus
Circulate -> blood -> approx. 8-12 hrs
    >>Migrate -> tissues
Release toxic compounds
     Eg. NO &amp; cytotoxic enzymes
Allergies
    >>Athsma
Combat -> parasitic infections
Attack bacteria, protozoa, debris 
	Basophils:
Bilobed “S” shaped nucleus
Inflammatory response
	Monocytes:
Large kidney/Horse-shoe shaped nucleus
Migrate out -> circulation after 3-4 days
Phagocytic
	Lymphocytes:
Central role -> all immunological defence mechanisms
Circulate between -> various lymphoid tissues &amp; all other body tissues
    >>Via blood &amp; lymphatic vessels 
T-cells
   >>Mediate -> cell-mediated immunity
        Eg. Transplant rejection
B-cells 
    >>Differentiate -> plasma cells 
         >Secrete antibodies -> humoral immunity 
NK cells
>>Immune surveillance -> prevent cancer

Answer 98

A

-> Antigens A & B ,
No Anti-A or Anti-B antibodies

-> Produce Anti-A & Anti-B bodies to bind to foreign bodies & cause agglutination for elimination.

	Type A
Surface antigen A
Anti-B antibodies
	Type B
Surface antigen B
Anti-A antibodies
	Type AB 
Surface antigens A &amp; B
Neither anti-A nor anti-B antibodies
	Type O
Neither surface antigen A or B
Anti-A &amp; anti-B antibodies
	Rh [D] Blood Group: 
	Rh [D] +ve 
D antigen present
	Rh [D] -ve
D antigen absent

Answer 99

A

a. arteries
??
-> For pure reason of most contributing factors

• Arteries:
Elastic -> conducting
Continuous blood flow
Muscular -> distributing
 Distribute blood -> muscles & organs
 Vasodilation & vasoconstriction -> control rate of blood flow to organ
Arterioles -> resistance
 Vasoconstriction & vasodilation -> control blood flow to organs
 Involved -> control of blood pressure

• Veins:
 Valves -> prevent backflow.
• Valves -> prevent backflow of blood -> low pressure
• Musculovenous pump -> contracts to close valves & ensure constant bloodfow

• Capillaries:

Connect arterioles & venules -> microcirculation
Site of gaseous exchange
Thin walls -> lined with endothelial cells -> enable diffusion

Answer 100

A

b. plasma hydrostatic pressure

• Dynamics of capillary exchange:
 Arterial end
 High hydrostatic pressure -> forces fluid out capillary network
&raquo_space; Opposed -> high osmotic potential gradient
 Capillary Hydrostatic Pressure (CHP) -> 35mmHg
 Blood Colloid Osmotic Pressure (BCOP) -> 25mmHg
-» CHP > BCOP
-» Net filtration pressure -> +10mmHg
&raquo_space; Forces fluid & dissolved substances out -> capillary network
 Significant rate of filtration -> 24 L/day

 Venous end
 Hydrostatic pressure decline -> incr. distance -> heart
 Same osmotic potential
 Capillary Hydrostatic Pressure (CHP) -> 18mmHg
 Blood Colloid Osmotic Pressure (BCOP) -> 25mmHg
-» CHP < BCOP
-» Net Filtration Pressure -> -7mmHg
&raquo_space;Movement of fluid -> into capillary network
 Significant Rate of reabsorption -> 20.4 L/Day

 Net difference in water -> Rate of filtration & absorption
Collected -> Lymphatic System

 Centre -> Capillary Network
Approx. centre -> capillary network
->Equal values -> CHP & BCOP -> Net filtration pressure = 0.
-> No net movement -> fluid.
 Max filtration pressure always greater -> max absorption pressure
&raquo_space; Point at which net filtration pressure = 0
-> further towards venous end -> capillary
-» More filtration than absorption along capillary.
¬-» Enables provision -> tissues with required molecules over greater
distance -> capillary network
> Rapid reabsorption -> molecules & waste products -> venous end.

Answer 101

A

a. damage to the sinoatrial node ??

Normal heart rate approx. 60bpm

SAN gives regular electrical pulses. If it fails, the AV node should take over. But the spontaneous rate is lower than the SAN, Hence the heart rate will be lower. impulses are also transmitted simultaneously to atria and ventricles. Hence both atria and ventricles contract simultaneously. This prevents atrial contraction from helping the ventricular filling. This can lover the stroke volume, especially in those with stiff ventricles

Ventricular fibrillation is a heart rhythm problem that occurs when the heart beats with rapid, erratic electrical impulses.

Extrasystole: A premature contraction of the heart that is independent of the normal rhythm of the heart and that arises in response to an impulse in some part of the heart other than the normal impulse from the sinoatrial (SA) node.

 P-wave:
»Atrial depolarization & contraction
 QRS Complex:
»Spread -> electrical signal
>Causes ventricular myocyte depolarisation
& contraction
-»Arterial relaxation event masked -> larger ventricular event.
 T-wave:
»Ventricle repolarisation & relaxation
 QT interval:
»Time from initiation -> ventricular contraction -> end -> ventricular relaxation.

Answer 102

A

a. 4.9 L/min

CO = HR x SV
SV = 110-45= 65ml = 6.5 x 10^-2
HR = 800ms -> 1 contraction
800 x 10^3 = 0.8s 
60/0.8= 75bpm
HR = 75
CO = 75 x (6.5 x 10^-2) = 4.875L/min

Answer 103

A

d. pump blood with greater pressure

To distribute around body to tissues

Answer 104

A

b. calcium channel agonist

Risk factor associated with Hypertension & coronary heart disease, which are treated as follows:
-> “ possible treatments; where atherosclerosis risk of nayerism due to incr. blood volume enlargement etc therefore decr. blood vol more effective so CA agonist.

Inhibit angiotensin II production -> inhibit Angiotensin-Converting-Enzyme (ACE)
» Prevents renal absorption -> Na+/H2O
> Prevents incr. blood volume
- Ibhibition -> Angiotensin II induced vasoconstriction -> Angiotensin II receptor
  blocker.
  &raquo_space; Inhibitd membrane cardiac / vascular depolarizoation
  > Decr. CO -> vasodilation.
- Calcium-channel blocker / thiazide diuretic
  &raquo_space; Incr. loss -> Na+ & H2O
  > Decreases fluid volume, venous return & cardiac output.
- Reduce TBR -> inhibition -> noradrenaline action.
- Alpha-adrenoreceptor Antagonists (alpha-Blockers)
   Reduce TBR -> inhibition -> noradrenaline action.
  - Beta-adrenoreceptor Antagonists (beta-Blockers)
     Decr. CO2,
```
 Decr. central activity -> Symapthetic nervous system 
                    Decr. release -> Renin
                   ->> Favourable secondary actions
```

• Atherosclerosis:
 Narrowing of vessel lumen:
 Fibrous cap of dense extracellular matrix
Accumulation -> Plaque Formation:
 Lipids
 Macrophages
 Proinflammatory mediators
 White blood cells
 Endothelial cells
 Smooth muscle cells
&raquo_space; Arterial remodelling & neovessels occur -> compensatory enlargement
&raquo_space;Fragments of plaques can detach & lodge in small vessels
> Cause thrombosis
-» Restricts blood flow
> Lead to aneurysm formation & rupture

• Ischaemic Heart Disease (Coranary Heart Disease -> CAD)
 Leading cause of death -> Developed world
 30% Males
 23% Females
 Common cause:
 Atherosclerosis -> coronary artery
 Most frequent -> Left anterior interventricular artery
 Occurs in Left ventricle
 Insufficient Blood flow to myocardium
» Angina Pectoris (ischemia-induced pain)
-»Mediated by endogeneous vasodilators
» Results -> myocardial infarction
-» Death of heart muscle within 20 mins

Answer 105

A

b. primary bronchus

•	Lungs:
	Main features:
-	2 lungs 
-	Located -> Thoracic cavity
-	Separated by mediastinum
-	Extend from neck -> diaphragm
	Gross Anatomy:
-	Trachea
-	Primary Bronchi 
-	Right &amp; Left Lungs
	Structure:
-	Conical shaped structures
-	Soft, spongy texture
-	Each lung contains:
	Apex                       (top, tip of lung)
	3 surfaces
 Diaphragmatic    (basal surafce)
 Costal                 (outside-facing surface)
 Mediastinal         (inside surface -> facing other lung)

Answer 106

A

b. body of the third thoracic vertebra

> Articulates being key word
> Head of rib articulates -> therefore body of thoracic vertebra
Ribs:
 Differ -> shape & size
 Slope downwards & forwards
 Attached by head & tubercle -> thoracic vertebrae
 Ribs 1-10 attached by costal cartilage -> sternum
Thoracic Vertebrae:
 Head of rib articulates with body of thoracic vertebra
 Tubercle of rib articulates with transverse process of thoracic vertebra
Intercostal muscles:
 Span intercostal spaces
 External intercostals
 Superficial layer
 Fibres run supero-lateral to infero-medial
-> Tubercles to costochondral junction -> (Downward-diagonally from
shoulder to core - / )
 Internal intercostals
 Middle layer
 Fibres run infero-lateral to supero-medial
-> At angles to ends of intercostal spaces. -> (Upward-diagonally from
hip to core - \ )
 Innermost intercostals
 Innermost layer

Answer 107

A

a. includes the alveolar ducts

The terminal bronchiole is the most distal segment of the conducting zone. It branches off the lesser bronchioles. Each of the terminal bronchioles divides to form respiratory bronchioles which contain a small number of alveoli.

The respiratory tract is lined with respiratory mucosa or respiratory epithelium

•	Respiratory tract organised according to function:
-	Conductive:
	Filteration, warming &amp; moistening air
	Conducting air into lungs
Structures:
	Nasal cavity &amp; paranasal sinuses
	Pharynx
	Larynx
	Trachea
	Primary bronchi
	Secondary bronchi
	Tertiary Bronchi
	Bronchioles
	Terminal Bronchioles
-	Respiratory: 
	Sites of gas exchange
Structures:
	Respiratory Bronchioles
	Alveolar Ducts
	Alveolar Sacs
	Alveoli

Answer 108

A

a. abdominal muscles

•	Expiration:
-	At rest:
	Passive process
	Diaphragm 
	External intercostals
 Relaxation of diaphragm &amp; external intercostal muscles
-	Forced:
	Active process
	Internal intercostals
	Abdominal muscles
-> Rectus abdominis 
-> External oblique 
-> Internal oblique
-> Transversus abdominis
 Internal &amp; innermost intercostals depress ribs 
    -> Reduce size of thoracic cavity
 Abdominal muscles compress abdomen &amp; force diaphragm upwards

Answer 109

A

b. 148 mmHg

O2 = 20% of 740 = 148mmHg

Answer 110

A

a. decreased heart rate

2.Sympathetic:
i) Symapthetic:
Preganglionic fibre -> ganglion
-> releases acetylcholine (ACh)
-> activates nicotinic (N2) receptor
-> action potential moves along postganglionic fibre
-> releases norepinephrine (NA)
-> activates (alpha/beta) adrenergic receptor.
ii) Adrenal medulla:
Preganglionic fibre -> adrenal medulla
-> releases acetylcholine (ACh)
-> stimulates nicotinic receptor of chromaffin cell
-> makes epinephrine
-> moves along postganglionic fibre
-> releases epinephrine
->sent into circulatory system
-> stimulates adrenergic receptors of heart
-> incr. heart rate.

The sympathetic nervous system’s primary process is to stimulate the body’s fight-flight-or-freeze response. It is, however, constantly active at a basic level to maintain homeostasis homeodynamics.

Can accelerate heart rate; widen bronchial passages; decrease motility of the large intestine; constrict blood vessels; increase peristalsis in the oesophagus; cause pupillary dilation. perspiration and raise blood pressure.

Answer 111

A

d. secretes acetylcholine into the circulation

ii) Adrenal medulla:
Preganglionic fibre -> adrenal medulla 
-> releases acetylcholine (ACh) 
-> stimulates N2 (nicotinic) receptor of chromaffin cell 
-> makes epinephrine 
-> moves along postganglionic fibre 
-> releases epinephrine 
->sent into circulatory system 
-> stimulates adrenergic receptors of heart 
-> incr. heart rate.

It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine (adrenaline), norepinephrine (noradrenaline), and a small amount of dopamine in response to stimulation by sympathetic preganglionic neurons.

Answer 112

A

b. are vascular

Epithelia:
- Covers inner & outer surfaces
- Line cavities & tubes eg. Hollow organs, airways, blood vessels
- Glands
Characteristics:
 Attachment
 Avascularity -> no blood vessels run through it
 Regenerates
 Polarity (apical -> faces surface & basal -> bottom)
 Closely packed cells supported by basement mem
 Classification based on no of cells and shape in most superficial layer
No. of cell layers:
> Simple -> one layer
> Stratified -> more than one layer
Shape:
> Squamous (flat)
> Cuboidal (cube)
> Columnar (rectangle)

Examples of epithelial tissue:
- Simple squamous
 Exchange of nutrients & gases -> Blood vessels & alveoli
- Non-keratinised stratified squamous
Protection -> Oral cavity & oesophagus
- Keratinised stratified Squamous
 Waterproof protection/barrier -> Skin
- Simple cuboidal epithelium
Secretion & absorption -> Glands & kidney tubules
- Simple columnar epithelium
Absorption & secretion -> Gastrointestinal tract
–> also have microvilli -> Enabling absorption of nutrients.
- Pseudostratified ciliated columnar epithelium with goblet cells
Mucociliary escalator -> produce mucous -> particles inhaled -> trapped in mucous.
-> Cilia moves mucous upwards to back of throat for swallowing.
-> Trachea & large respiratory airways.
-> Also has cilia & goblet cells.
Trachea appears stratified -> some cells don’t reach free surface -> All touch
basement mem.

Answer 113

A

c. bronchioles

Examples of epithelial tissue:
- Simple squamous
 Exchange of nutrients & gases -> Blood vessels & alveoli
- Non-keratinised stratified squamous
Protection -> Oral cavity & oesophagus
- Keratinised stratified Squamous
 Waterproof protection/barrier -> Skin
- Simple cuboidal epithelium
Secretion & absorption -> Glands & kidney tubules
- Simple columnar epithelium
Absorption & secretion -> Gastrointestinal tract
–> also have microvilli -> Enabling absorption of nutrients.
- Pseudostratified ciliated columnar epithelium with goblet cells
Mucociliary escalator -> produce mucous -> particles inhaled -> trapped in mucous.
-> Cilia moves mucous upwards to back of throat for swallowing.
-> Trachea & large respiratory airways.
-> Also has cilia & goblet cells.
Trachea appears stratified -> some cells don’t reach free surface -> All touch
basement mem.

Both the endothelial lining of blood vessels and the mesothelial lining of the body cavities are simple squamous epithelium.

Bronchiole walls consist of ciliated cuboidal epithelium and a layer of smooth muscle.

Line several body cavities including the pleural cavity housing the lungs, peritoneum (abdominal cavity containing the stomach and intestines) and the mediastinum (part of the thoracic cavity that contains the heart, lungs, trachea and esophagus). These tissues are also called the endothelium when they form the inner lining of blood and lymph vessels

•	Fibrous Pericardium:
Characteristics:
-	Inelastic sac -> dense tissue
-	Inferior fusion -> diaphragm
-	Superior infusion -> large vessels
Function:
-	Prevents overfilling of heart 
-	Anchors position

•	Serous pericardium:
Characteristics:
-	Double-layered serous membrane
-	Lies -> deep within -> fibrous pericardium
-	Contains:
1.	Parietal pericardium:
	Lines inner surface -> fibrous pericardium
2.	Visceral pericardium: 
	Tightly adhered -> surface of heart
3.	Pericardial cavity:
	Space between parietal &amp; visceral layers
Contains tissue fluid. 
Function:
	Prevents friction.

•	Heart wall:
-	3 layers:
i)	Endocardium:
	Inner layer -> Endothelium
ii)	Myocardium:
	Middle layer -> Cardiac muscle
iii)	Epicardium:
	Outer layer -> Visceral pericardium

Answer 114

A

d. palms facing posteriorly

• Anatomical position:
 Position of the upright body -> arms at sides -> palms facing forwards.

Anterior (Ventral):
 Front / Underside
Posterior (Dorsal)
 Behind/ Upperside/back
Superior
 Towards the head
Inferior
 Towards the feet
Medial
 The core/centre
Lateral
 Towards the side/ away from core/centre
Proximal
 Closer towards the trunk
Distal
 Further from the trunk
Coronal/frontal plane:
 Divides into front & back planes -> Anterior/ventral & posterior/dorsal
Horizontal/transverse plane
 Divides into top & bottom planes -> Above & below waist -> Superior & Inferior
Midsagittal plane
 Divides into right & left halves -> medial & lateral

Answer 115

A

• Major arteries:
d. ulnar

-	Arm:
	Axillary -> Shoulder
	Brachial -> Upper arm 
	Radial -> Lateral
	Ulnar -> Medial
-	Leg:
	External iliac -> Hip area
	Femoral -> Upper leg
	Popliteal -> Back of knee
	Anterior tibial
-	Core:
	Right common carotid -> Right -> neck 
	Left common carotid -> Left -> neck 
	Brachiocephalic trunk -> Lungs 
	Right subclavian -> Right -> under collarbone
	Left subclavian -> Left -> under collarbone
	Aortic arch -> Main part of heart 
	Descending thoracic aorta -> Down inside lower end of rib cage -> spine
	Abdominal aorta -> Abdominal -> inside spine 
	Common iliac -> Top of hip
	External iliac -> Lower hip -> top of leg
	Internal iliac -> Backbone

Answer 116

A

c. pulmonary arteries

• Major arteries:
Pulmonary artery: carrying blood from the right ventricle of the heart to the lungs for oxygenation.

the subclavian arteries are paired major arteries of the upper thorax, below the clavicle. They receive blood from the aortic arch.

-	Arm:
	Axillary -> Shoulder
	Brachial -> Upper arm 
	Radial -> Lateral
	Ulnar -> Medial
-	Leg:
	External iliac -> Hip area
	Femoral -> Upper leg
	Popliteal -> Back of knee
	Anterior tibial
-	Core:
	Right common carotid -> Right -> neck 
	Left common carotid -> Left -> neck 
	Brachiocephalic trunk -> Lungs 
	Right subclavian -> Right -> under collarbone
	Left subclavian -> Left -> under collarbone
	Aortic arch -> Main part of heart 
	Descending thoracic aorta -> Down inside lower end of rib cage -> spine
	Abdominal aorta -> Abdominal -> inside spine 
	Common iliac -> Top of hip
	External iliac -> Lower hip -> top of leg
	Internal iliac -> Backbone

Answer 117

A

d. haemoglobin

haemoglobin found in RBCs, not plasma

•	Composition of blood:
-	Plasma: 55%
Water -> 92%
Plasma proteins -> 7%
    -->Albumin, Globulin, Fibrinogen, regulatory proteins
Other solutes -> 1%
    -->Electrolytes, organic nutrients, waste.
-	Red Blood Cells: 45%
-	White Blood cells: <1%
-	Platelets: <1%

Answer 118

A

c. Lymphocytes

•	White blood cells:
	Also known -> Leukocytes
	Nucleated
	Act mainly outside tissues 
In-transit -> sites of activity 
	Can migrate out of bloodstream -> extravastation (diapedesis)
	Capable -> amoebid movement
	Attracted -> specific chemical stimuli
	2 groups:
i)	Granulocytes
-	Neutrophils
-	Eosinophils 
-	Basophils 
ii)	Agranulocytes
-	Lymphocytes
-	Monocytes
	Neutrophils, eosinophils &amp; monocytes -> phagocytosis
	Functions:
-	Defence -> pathogens
-	Toxin &amp; waste removal 
-	Removal -> damaged cells

Answer 119

A

c. do not contain granules

•	Platelets: 
-	Structure: 
Small
Oval 
No nucleus
2-3 micrometres diameter
Contain granules
-	Functions:
Megakaryocyte cytosplasm
Production controlled by 
    >>No. circulating platelets -> negative feedback
    >>Thrombopoietin (TPO) release -> incr. platelet no.s
Lifepsan 7-10 days
Variety functions -> essential -> haemostasis

Answer 120

A

• Factors Influencing c. normally rises when a person suddenly stands up

Venous Return / Central Venous Pressure:
1. Posture:
- Blood volume influenced by gravity -> posture.
- Standing  venous pooling in legs
»Decr. venous return.
2. Muscle pump:
- Venomotor tone involving constriction -> veins -> skeletal muscles.
- Venous return facilitated -> valves
»Prevent backflow of blood
3. Respiratory Pump:
- Inspiration creates internal pressure difference by lowering intra-thoracic pressure & incr. intra-abdominal pressure.

Answer 121

A

c. physical stress/trauma ?

-> See below -> processes
-> Physical stress/ trauma & angiotensin not a process/ internal regulation it is likely a cause but not a mediator.
Physical stress/trauma cannot be regulated by body, angiotensin II can
-> Angiotensin -> Autoregulatory nervou system
-> Diurtetic hormones -> long term control
-> P
• Blood vessel tone controlled -> interrelated processes
 Automatic / intrinsic
 Short term
 Long term
Control measures.

• Response & Regulation of Blood Pressure:
Homeostasis:
- Altered Blood pressure / volume
Physical stress
Eg. Trauma, high temp, etc.
Chemical changes
Eg. Decr. O2 / decr. pH / Incr. CO2 / Incr. vasodilatory metabolites
Increases tissue activity / Intrinsic Control
- Inadequate blood pressure & flow
»Autoregulation:
 Decr. resistance & incr. blood flow
> Homeostasis returned.
- Insufficient Autoregulation:
Stimulates receptors -> sensitive to systemic changes -> blood pressure /
Chemistry.
Activates cardiovascular centres -> Central Nervous System
Elevates Blood pressure -> Short Term
&raquo_space;Stimulation -> heart rate & peripheral vasoconstriction
–» Sensory Nervous System.
Return -> Homeostasis.

Answer 122

A

c. extraction of oxygen at the capillaries is greater than in most other tissues ?
- > elimination?

• Haemodynamics:

Anything that makes the coronary supply routes restricted can build danger of angina

-> Pressure at ventricular systole highest as blood forced out of ventricles at high pressure.

 Blood flow determined:

Resistance -> R
Pressure difference -> P

 F = ▲P / ▲R

             Determined by:
->> L = length of vessel 
->> r = radius of vessel
->> ꞃ = fluid viscosity 
       >>(protein conc.)

• Afterload:
 Pressure opposing ejection of blood from heart
Influenced -> Blood vessel tone -> Vasoconstriction/dilation
Major effect -> cardiac output.

• Blood Pressure = Cardiac Output x Total Peripheral Resistance
 Cardiac Output -> ▲HR & SV

• Response & Regulation of Blood Pressure:
Homeostasis:
- Altered Blood pressure / volume
Physical stress
Eg. Trauma, high temp, etc.
Chemical changes
Eg. Decr. O2 / decr. pH / Incr. CO2 / Incr. vasodilatory metabolites
Increases tissue activity / Intrinsic Control
- Inadequate blood pressure & flow
»Autoregulation:
 Decr. resistance & incr. blood flow
> Homeostasis returned.
- Insufficient Autoregulation:
Stimulates receptors -> sensitive to systemic changes -> blood pressure /
Chemistry.
Activates cardiovascular centres -> Central Nervous System
Elevates Blood pressure -> Short Term
&raquo_space;Stimulation -> heart rate & peripheral vasoconstriction
–» Sensory Nervous System.
Return -> Homeostasis.

Answer 123

A

a. closes as a result of contraction of the papillary muscles

–> Remains closed from previous ventricular contraction & is only opened again by pressure changes during systole.

The sound of a heartbeat is caused by the heart valves opening and closing as they pump blood.

The papillary muscles attach to the cusps of the atrioventricular valves via the chordae tendineae and contract to prevent inversion or prolapse of these valves on systole

• Heart Valves:
 Prevent backflow of blood
Atrioventricular:
- Tricuspid (Right AV) valve
- Bicuspid/mitral (Left AV) valve
 Between atria & ventricles
 Open -> blood flow -> atria to ventricles
 Anchored -> Chordae tendinae to papillary muscles.
 When ventricular pressure < atrial pressure
 Valve opens -> loose chordae tendinae
 When ventricular pressure > atrial pressure
Valve begins to close -> pulls chordae tendinae -> papillary muscle contracts -> prevents inversion of valve -> backflow of blood.

                     Semilunar: -	Pulmonary  -	Aortic 	Guard entrances -> aorta &amp; pulmonary trunk 	Open -> force of blood -> contraction of ventricles 	Bloodflow -> backwards -> aorta &amp; pulmonary trunk -> ventricular relaxation Accumulates in cusps -> shut.  	Prevent backflow of blood -> ventricles.

Answer 124

A

Baroreceptors & Control -> Blood Flow:

c. parasympathetic nerve activity

•	Inadequate Blood supply / Decr. Blood Pressure:
-	Inhibition -> baroreceptors
	 Activation 
 Cardioacceloratory Centre
Vasomotor Centres
	Inhibition
 Cardioinhibitory Centre
       >> Incr. Cardiac Output &amp; Heart Rate
-	Vasoconsriction

•	Rise -> Blood Pressure:
-	Stimulation -> Baroreceptors
	Activation
Cardioinhibitory Centre
	Inhibition
Cardioacceloratory Centre
Vasomotor Centres
       >> Decr. Cardiac Output &amp; Heart Rate
-	Vasodilation.

-> Vasodilation -> Incr. diameter of vessels -> decr. resistance -> decr. pressure

• Blood Pressure = Cardiac Output x Total Peripheral Resistance
 Cardiac Output -> ▲HR & SV
 Total Peripheral Resistance -> ▲Arteriolar Radius

Parasympathetic more active -> vegetative (passive/calm) situations.
Parasympathetic controls when in relaxed state -> decr. activity of active mecahnisms controlled by sympathetic
Therefore would decr. increases in heart rate

Answer 125

A

•	Hypertension:
	Affects nearly one billion 
	One of the main causes -> premature death. 
	Nearly 8 million fatalities per year
a. ACE-activators

Types: -	Primary Hypertension (Essential / Idiopathic)   Unknown medical cause  Links: 	Genetic predisposition 	Alcohol consumption 	Obesity 	Lack of excersise 	Diabetes 	Intrauterine environment -	Secondary Hypertension  Known medical cause 1)	Kidney Disease:  Incr. Angiotensin II  >> Vasoconstriction &amp; expansion -> cellular fluid 2)	General endocrine disorders Eg. Diabetes, Cushing’s 3)	Adrenal medulla disease (Phaeochroocytoma)  Excessive adrenaline secretion 	Treatment: -	Inhibit angiotensin II production -> inhibit Angiotensin-Converting-Enzyme (ACE) >> Prevents renal absorption ->  Na+/H2O 
> Prevents incr. blood volume
  -     Ibhibition -> Angiotensin II induced vasoconstriction -> Angiotensin II receptor 
        blocker. 
         >> Inhibitd membrane cardiac / vascular depolarizoation
            > Decr. CO -> vasodilation. 
  -      Calcium-channel blocker / thiazide diuretic 
          >> Incr. loss ->  Na+ &amp; H2O
             > Decreases fluid volume, venous return &amp; cardiac output. 
  -         Reduce TBR -> inhibition -> noradrenaline action.
  -        Alpha-adrenoreceptor Antagonists (alpha-Blockers)
            Reduce TBR -> inhibition -> noradrenaline action.
              -        Beta-adrenoreceptor Antagonists (beta-Blockers)
                        Decr. CO2, 
                        Decr. central activity -> Symapthetic nervous system 
                        Decr. release -> Renin
                       ->> Favourable secondary actions 	Risks: -	Atherosclerosis -	Stroke / Cerebrovascular Accident -	Heart Failure  -	Renal Failure  -	Aneurysms

Answer 126

A

• Respiratory tract organised according to function:
b. respiratory bronchioles

-	Conductive:
	Filteration, warming &amp; moistening air
	Conducting air into lungs
Structures:
	Nasal cavity &amp; paranasal sinuses
	Pharynx
	Larynx
	Trachea
	Primary bronchi
	Secondary bronchi
	Tertiary Bronchi
	Bronchioles
	Terminal Bronchioles
-	Respiratory: 
	Sites of gas exchange
Structures:
	Respiratory Bronchioles
	Alveolar Ducts
	Alveolar Sacs
	Alveoli

Answer 127

A

d. relaxation of the diaphragm

•	Incr. Thoracic Volume:
•	Ventilation:
-	Atmospheric pressure > Intrapulmonary / Intraalveolar pressure
       Air enters lungs
-	Intrapulmonary / intraalveolar pressure > atmospheric pressure 
       Air expelled from lungs
-	Change -> volume = change -> pressure
-	Atmospheric pressure = 760mmHg

• Incr. Thoracic Volume:

Incr. Vertical diameter
-> Incr. thoracic volume incr. movement of air to lungs

 Contraction of diaphragm incr. vertical diameter
Responsible for 75% incr. thoracic capacity
- Incr. Anterior Posterior diameter
 Elevation of ribs incr. Anterior Posterior diameter
-> (Joint with Transverse Diameter)
Responsible for 25% thoracic capacity.
 Elevation of ribs -> external end -> makes them more horizontal & pushes sternum forward (pump handle movement)
Incr. AP diameter
- Incr. transverse diameter
 Elevation of ribs incr. transverse diameter
-> (Joint with Transverse Diameter)
Responsible for 25% thoracic capacity.
 Many of the ribs
 Lowest near their middle
 Rise at each end
Eg. Bucket handle
 Rise of middle of rib -> movement away from midline of body
Transversally widens chest (Left -> Right)

•	Inspiration:
-	Active process
-	At rest:
	Diaphragm (75%)
	External intercostal muscles (25%)
 Contracted diaphragm flattens
   -> Vertical diameter of thorax increased. 
 External intercostals elevate ribs -> incr. Anterior Posterior &amp; Transverse 
     diameters. 
-	Forced:
	Pectoralis major 
	Pectoralis minor
	Scalenes
	Serratus anterior
	Sternocleidomastoid
 Assist -> rib elevation 
    -> Incr. speed &amp; amount of movement

Answer 128

A

Pulmonary surfactant are formed by type II alveolar cells
Greatly reduce surface tension, increasing compliance allowing the lung to inflate much more easily, reducing the work of breathing. It reduces the pressure difference needed to allow the lung to inflate.

As the alveoli increase in size, the surfactant becomes more spread out over the surface of the liquid. This increases surface tension effectively slowing the rate of expansion of the alveoli. Hence Surfactant reduces surface tension more readily when the alveoli are smaller because the surfactant is more concentrated.

Answer 129

A

? -> small surface area decr. rate of diff but still has an effect on g.e. Q isn’t specific on whther dpendency is negative or positive so is this incorrect or not??

Henry’s law states that the concentration of gas in a liquid is directly proportional to the solubility and partial pressure of that gas. The greater the partial pressure of the gas, the greater the number of gas molecules that will dissolve in the liquid. The concentration of the gas in a liquid is also dependent on the solubility of the gas in the liquid.

Ventilation causes partial pressures of oxygen and carbon dioxide change, affecting the diffusion process that moves these materials across the membrane. This will cause oxygen to enter and carbon dioxide to leave the blood more quickly.

-> Short diffusion distance -> faster diffusion

Higher conc. gradient -> faster diffusion

-> small surface area -> decr. rate of diffusion

Answer 130

A

d. respond to hypoxia

• Neural Control of Ventilation:
- Chemoreceptors detect changes in PO2, PCO2 & pH
-> Send impulses / signals
 Vagus (CN X) & Glossopharyngeal (CN IX) nerves
(Afferent pathway)
- Impulses transported -> Vagus (CN X) & Glossopharyngeal (CN IX) nerves
 Respiratory Centres of Brain Stem
- Respiratory Centres of Brain stem
-> Send impulses / signals
 Phrenic, intercostal & other nerves
(Efferent pathway)
- Impulses transported -> Phrenic, intercostal & other nerves
 Muscles in ventilation

• Central Chemoreceptors:

Located -> Medulla oblongata of brainstem
Respond to changes in PCO2 & pH

Hypercapnia, also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood.

Hypoxia is a condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level

•	Peripheral Chemoreceptors:
-	Detect changes -> PO2, PCO2 &amp; pH
-	Aortic Bodies
 Located -> Aortic Arch
 Innervated -> Vagus (CN X)
-	Carotid Body
 Located -> Common Carotid Artery
 Innervated -> Glossopharyngeal (CN IX)

• Respiratory Centres:
- Group of neurons -> Brain stem
- Send impulses to muscles of ventilation
- Medullary Rhythmicity Area
 Dorsal Respiratory Group (DRG)
 Sets rhythm, stimulates muscles of quiet inspiration
 Ventral Respiratory Group (VRG)
 Involved in forced inspiration & expiration
- Pneumotaxic area (Pons)
 Influences DRG by regulating duration of inspiration.

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