Body Systems Assessment Qs

Question 1

[Select the one INCORRECT option] Simple columnar epithelium

1.
is found in areas where diffusion of gases take place

2.
is one cell layer thick

3.
may have microvilli on the luminal surface

4.
consists of tall cells with basally located nuclei
muscle

4.
connective tissue

Answer 1

4. is found in areas where diffusion of gases take place

Gas exchange occurs across flat squamous epithelium.
Columnar epithelial cells often have microvilli to increase the surface area available for absorption.

Question 2

[Select the one INCORRECT option] The four basic tissue types include

1.
bone

2.
epithelium

3.
muscle

4.
connective tissue

Answer 2

1. bone

Bone is a specialised connective tissue.

Question 3

[Select the one INCORRECT option] Negative feedback control systems are involved in the control of

1.
body temperature

2.
blood coagulation (formation of blood clots) 

3.
the concentration of calcium ions in the plasma

4.
systemic arterial blood pressure

Answer 3

2. blood coagulation (formation of blood clots)

Blood clot formation mechanism uses positive feedback.

Question 4

[Select the one INCORRECT option] Homeostasis

1.
usually involves continuous activity of sensory receptors

2.
refers to the maintenance of a relatively constant internal environment

3.
protects cells against fluctuations in the external environment

4.
usually involves positive feedback control mechanisms

Answer 4

4. usually involves positive feedback control mechanisms

Homeostasis usually involves NEGATIVE feedback.

Question 5

[Select the one INCORRECT option] The sodium/potassium ATPase pump

1.
pumps 3 potassium ions in for every 2 sodium ions pumped out of the cell

2.
helps maintain the cell’s resting membrane potential

3.
pumps sodium ions out of the cell and potassium ions in

4.
consumes a large proportion of cellular energy

Answer 5

pumps 3 potassium ions in for every 2 sodium ions pumped out of the cell

The NA/K ATPase protein pumps 2 potassium ions in for every 3 sodium ions pumped out.

Question 6

[Select the one CORRECT option] Two solutions are separated by a semipermeable membrane with the same properties as a cell membrane. Solution A is 5% glucose and solution B is 10% glucose. Under these circumstances, which of the following would most likely occur?

1.
glucose will move from solution B to solution A

2.
glucose will move from solution A to solution B

3.
water will move from solution A to solution B

4.
water will move from solution B to solution A

Answer 6

3. water will move from solution A to solution B

Question 7

[Select the one CORRECT option] In the sympathetic nervous system

1.
the preganglionic nerve fibres are long

2.
the preganglionic nerve fibres leave the central nervous system at the thoraco-lumbar levels of the spinal cord

3.
the postanglionic nerve fibres are short

4.
the chemical transmitter substance released at the majority of neuroeffector junctions (i.e. the junction between the postganglionic neurone and the target organ) is acetylcholine

Answer 7

1. the preganglionic nerve fibres leave the central nervous system at the thoraco-lumbar levels of the spinal cord

Most of these synapses use the neurotransmitter noradrenaline.

Question 8

[Select the one CORRECT option] The plasma membrane is composed of a

1.
bilayer of lipids

2.
bilayer of proteins

3.
bilayer of carbohydrate molecules

4.
complex combination of carbohydrates and proteins

Answer 8

1. bilayer of lipids

The plasma membrane comprises a bilayer of phospholipid molecules with outward facing hydrophilic heads and inward facing hydrophobic tails.

Question 9

[Select the one CORRECT option] A process that requires cellular energy to move a substance against its concentration gradient is called

1.
active transport

2.
facilitated transport

3.
diffusion

4.
passive transport

Answer 9

1. active transport

Question 10

[Select the one CORRECT option] The three basic fibre types in connective tissue are

1.
collagen, reticular and elastic

2.
loose, dense and irregular

3.
hyaluronic acid, chondroitin sulphate and dermatan sulphate

4.
macrophages, adipocytes and fibroblasts

Answer 10

1. collagen, reticular and elastic

These fibres are embedded in the extracellular matrix between the cells.

Question 11

[Select the one INCORRECT option] The following are at high concentration in the cytoplasm of most cells

1.
free calcium

2.
organic anions

3.
potassium

4.
proteins

Answer 11

1.
free calcium

Free calcium is kept at VERY low concentrations in the cytoplasm.
Many organic anions are involved in metabolic processes.
potassium -> This ion is actively pumped into cells.

Question 12

[Select the one INCORRECT option] The endocrine system

1.
releases chemical messengers called hormones

2.
can produce effects that last for days or longer

3.
produces a more rapid response to body changes than the nervous system

4.
can produce an effect that involves several organs or tissues at the same time

Answer 12

3. produces a more rapid response to body changes than the nervous system

Responses to nervous stimulation occur within seconds whereas responses to hormones take minutes to days.

Question 13

[Select the one CORRECT option] The reference plane that divides the body into right and left regions is the

1.
transverse plane

2.
coronal plane

3.
sagittal plane

4.
frontal plane

Answer 13

3. sagittal plane

Question 14

[Select the one CORRECT option] The division of the autonomic nervous system that maintains homeostasis during resting conditions is the

1.
somatomotor division

2.
parasympathetic division

3.
sympathetic division

4.
visceral motor system

Answer 14

3. parasympathetic division

The parasympathetic division mediates relaxation, food processing and energy absorption.
Sympathetic stimulation increases heart rate and contracts arterioles, raising systemic blood pressure as part of the ‘fight or flight’ response.

Question 15

[Select the one CORRECT option] Connective tissues

1.
are capable of contraction and therefore produce movement

2.
line body cavities, cover body surfaces and form glands

3.
contain an abundance of cells with little extracellular matrix

4.
include blood and bone

Answer 15

2. include blood and bone

connective tissues support and protect other body tissues and can be of varying consistency.
Connective tissue has few cells but an abundance of extracellular matrix.
Epithelium line body cavities, cover body surfaces and form glands

Question 16

[Select the one CORRECT option] Cardiac muscle cells

1.
have multiple, peripherally located nuclei

2.
are non-striated

3.
are innervated by the somatic nervous system

4.
are connected to adjacent cells by gap junctions

Answer 16

3. are connected to adjacent cells by gap junctions

Intercalated discs contain gap junctions.
The somatic nervous system innervates skeletal muscle; the heart is innervated by the autonomic nervous system.

Cardiac muscle is striated; smooth muscle is non-striated.

Question 17

[Select the one INCORRECT option] Activation of postganglionic sympathetic fibres results in

1.
reduced circulation to the skin

2.
decreased heart rate

3.
increased sweat secretion

4.
increased blood flow to skeletal muscle

Answer 17

4.decreased heart rate

Sympathetic stimulation of the heart INCREASES heart rate. Sympathetic stimulation redirects blood towards the working skeletal muscles.
Sympathetic stimulation increases sweat production.
Sympathetic stimulation redirects blood flow away from the skin.

Question 18

[Select the one INCORRECT option] Intracellular fluid

1.
normally has a lower K+ concentration than interstitial fluid

2.
normally has a higher protein concentration than interstitial fluid

3.
is separated from the interstitial fluid by the plasma membrane

4.
accounts for about two-thirds of total body water

Answer 18

4. normally has a lower K + concentration than interstitial fluid

Intracellular K + concentration is normally HIGHER than the interstitial fluid K + concentration.
Approximately two-thirds of two body water is held within the cells.

Question 19

[Select the one CORRECT option] Select a type of unicellular exocrine gland

1.
thyroid gland

2.
simple tubular gland

3.
salivary gland

4.
goblet cells

Answer 19

4. goblet cells

These are the ONLY type of unicellular exocrine gland.

Question 20

[Select the one INCORRECT option] The body’s extracellular fluid

1.
is regulated in the main by homeostatic negative feedback systems

2.
has a higher potassium concentration than intracellular fluid

3.
has a smaller volume than intracellular volume

4.
is divided into plasma and interstitial fluid

Answer 20

2.has a higher potassium concentration than intracellular fluid

The intracellular fluid has a larger volume than the extracellular fluid.
Homeostasis of the extracellular fluid is important for body function.
The plasma and interstitial fluid are both components of the extracellular fluid.

Question 21

[Select the one INCORRECT option] The left ventricle of the heart

Answer 21

3. possesses papillary muscles whose role is to open the bicuspid valve

Contraction of the papillary muscles prevents eversion of the bicspid valve (prevents it from swinging into the left atrium). It does not open the valve.

Question 22

[Select the one INCORRECT option] Elastic arteries

Answer 22

3. distribute blood to arterioles

Elastic arteries conduct blood to muscular arteries. Muscular arteries are known as distributing arteries as they distribute blood to arterioles.

Question 23

[Select the one INCORRECT option] The microcirculation is comprised of

Answer 23

1. the aorta

Question 24

[Select the one INCORRECT option] The following structures are all found within the right atrium of an adult heart

Answer 24

3. bicuspid valve

This is located between the left atrium and ventricle.

Question 25

[Select the one INCORRECT option] The ductus arteriosus

Answer 25

1. connects the right and left atria

The fossa ovalis connects the right and left atria together, not the ductus arteriosus.

Question 26

[Select the one CORRECT option] The innermost layer of the heart wall is called the

Answer 26

4. endocardium

This is the inner layer of simple squamous epithelium.

Question 27

[Select the one CORRECT option] Elastic arteries

Answer 27

receive the output of the left ventricle.

Question 28

[Select the one CORRECT option] The tunica intima

Answer 28

1. contains highly specialized endothelial cells

Question 29

[Select the one CORRECT option] Blood returning to the heart from the pulmonary circulation first enters the

Answer 29

4. left atrium

The left atrium receives oxygenated blood from the lungs.

Question 30

[Select the one CORRECT option] The heart

Answer 30

2. chambers are lined by endothelium

Question 31

[Select the one INCORRECT option] The right ventricle

Answer 31

is continuous with the aorta

The right ventricle is continuous with the pulmonary trunk.

Question 32

[Select the one INCORRECT option] The right femoral artery

Answer 32

is a continuation of the

The femoral artery is a continuation of the external iliac artery. The internal iliac artery supplies the pelvis.

Question 33

[Select the one CORRECT option] The pulmonary system

Answer 33

It empties blood into the left atrium.

Question 34

[Select the one CORRECT option] Elastic arteries

Answer 34

1. usually contain vasa vasorum

Question 35

[Select the one CORRECT option] In the foetal circulation the ductus arteriosus

Answer 35

4. is a vessel that connects the pulmonary trunk with the aorta

Question 36

[Select the one CORRECT option] Blood pressure is lowest in

Answer 36

3. veins

Pressure in the venous system is only about 10% of that in the arterial system.

Question 37

1. Select the CORRECT option: The three basic fibre types in connective tissue are

Answer 37

There are three types of connective tissue, which are classified as loose, dense or irregular; however the three basic fibre types are collagen, reticular and elastic. The key word here is fibre.

Question 38

Select the CORRECT option: Two solutions are separated by a semipermeable membrane with the same properties as a cell membrane. Solution A is 5% glucose and solution B is 10% glucose. Under these circumstances, which of the following would most likely occur?

Answer 38

34 people picked the wrong answer ‘glucose will move from solution B to solution A’.
We are told that the membrane separating the glucose solutions is semipermeable and that it has the same properties as a cell membrane. So first we need to remember the properties of a cell membrane: unless there is a specific transporter present, ions and other solutes cannot cross the membrane. Knowing that, we have to reason that glucose could not cross the membrane. Water, however, can cross the cell membrane so if the concentration of glucose is different on one side of the membrane compared with the other, then water will diffuse from the side with the lower glucose concentration (solution A) to the side with the higher glucose concentration (solution B).

Question 39

Select the CORRECT option: Connective tissues…

Answer 39

28 people picked the wrong answer ‘contain an abundance of cells with little extracellular matrix’.
Connective tissue does indeed contain both cells and extracellular matrix. However if you remember that the role of connective tissue is to protect and support other body tissues, then it should be apparent that extracellular matrix - which comprises fibrous proteins and glycosaminoglycans - is the most abundant part of connective tissue. The cells that are present are there primarily to secrete the components of the matrix. Therefore connective tissue consists of few cells but an abundance of extracellular matrix.The correct statement is ‘include blood and bone’ as both of these tissues are classified as connective tissue.

Question 40

Select the INCORRECT option: The body’s extracellular fluid….

Answer 40

28 people picked the wrong answer ‘is divided into plasma and interstitial fluid’.
Extracellular fluid does indeed include plasma and interstitial fluid, as well as transcellular fluid. The answer does not say that extracellular fluid is only made up from plasma and interstitial fluid, nor does it say that transcellular fluid is not part of the extracellular fluid: it simply states that extracellular fluid is divided into plasma and interstitial fluid. The more obvious incorrect statement is ‘has a higher potassium concentration than intracellular fluid’. This statement is clearly incorrect, as the potassium concentration inside cells is much higher than that outside cells. There are no deliberate trick questions; however there are some like this one that are designed to make you think. So when you are faced with a question where one statement could be incorrect and one is very obviously incorrect, then you should select the one that is ‘most wrong’.

Question 41

[Select the one INCORRECT option] Increased erythropoietin production is seen in

1.
HIV

2.
hypoxia

3.
anaemia

4.
altitude training

Answer 41

4. HIV

HIV will not have any effect on erythropoietin production.

Question 42

[Select the one INCORRECT option] Anaemia

Answer 42

3. affects 2/3rd of the world’s population

Anaemia affects 1/3rd of the world’s population.

Question 43

[Select the one INCORRECT option] A mature red blood cell

Answer 43

1. contains a highly condensed nucleus

Mature red blood cells do not contain a nucleus. It is expelled at the reticulocyte stage of erythropoiesis before entering circulation.

Question 44

[Select the one INCORRECT option] Lymphocytes

Answer 44

4. are granulocytes

Lymphocyes are agranular.

Question 45

[Select the one INCORRECT option] Haemostasis involves

Answer 45

3. increased blood flow

In haemostasis blood flow is reduced initially due to vascular spasm.

Question 46

[Select the one CORRECT option] During the platelet phase of haemostasis

Answer 46

The blood vessel undergoes vasoconstriction.

Question 47

[Select the one CORRECT option] Platelet adhesion is mediated by specific platelet membrane receptors and

Answer 47

Thrombopoietin regulates the production of platelets.

Question 48

[Select the one CORRECT option] In blood grouping

Answer 48

2. 85% of the general population are Rh(D) positive

85% of the population are RhD+ and 15% RhD-ve.

Question 49

[Select the one CORRECT option] Where is the majority of erythropoietin normally produced?

1.
bone marrow

2.
red blood cells

3.
kidney

4.
liver

Answer 49

3. Kidney

Question 50

[Select the one CORRECT option] Haemoglobin

1.
transports CO2 from lungs to tissues

2.
consists of 4 α (alpha) subunits

3.
transports O2 from tissues to lungs

4.
is normally found in the blood at a concentration of approx. 15g/dL of blood

Answer 50

4. is normally found in the blood at a concentration of approx. 15g/dL of blood

. This is the approx. value for both adult males and females. Range for males: 13.5-17.5g/dL and for females 12-16g/dL.

Question 51

[Select the one INCORRECT option] An increase in mean arterial blood pressure may result from

1.
an increase in discharge of the sympathetic vasoconstrictor nerves

2.
an increase in cardiac output

3.
a decrease in total peripheral resistance

4.
narrowing of arterioles

Answer 51

1. a decrease in total peripheral resistance

Since BP = CO x TPR, (Total peripheral resistance) increased cardiac output will increase arterial pressure.
Since BP CO x TPR, a decrease in peripheral resistance will decrease arterial pressure.

Question 52

[Select the one INCORRECT option] Starling’s law of the heart

1.
relates stroke volume to ventricular end-systolic volume

2.
states that the heart ejects whatever it receives

3.
is important for balancing the outputs of the two sides of the heart

4.
states that the energy of contraction of cardiac muscle fibres is proportional to their initial length

Answer 52

Starling’s law states ‘more in = more out’. Under normal conditions, stretching the ventricle leads to greater contractile force to eject the blood.
The law states that the stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles, before contraction.

4?

Question 53

[Select the one INCORRECT option] Regarding cardiac output

1.
cardiac output = stroke volume x heart rate

2.
stroke volume is determined by the differences in the end diastolic volume and the end systolic volume (i.e. EDV-ESV)

3.
stroke volume is unrelated to venous return

4.
stroke volume is defined as the volume of blood per heart beat

Answer 53

3. stroke volume is unrelated to venous return

Venous return has a significant role in determining both the EDV and the ESV

Question 54

[Select the one INCORRECT option] Arterial baroreceptors

1.
decrease their discharge rate when there is an increase in arterial blood pressure

2.
are present in the carotid sinuses

3.
are tonically active at normal blood pressures

4.
are stretch receptors

Answer 54

Tonic activity allows the receptors to respond to decreases and increases in blood pressure.

1?

Question 55

[Select the one INCORRECT option] Cardiac output

1.
is the volume of blood ejected by each ventricle per minute

2.
is determined by heart rate and stroke volume

3.
increases during vigorous exercise

4.
is normally about 1 litre per minute in human adults at rest

Answer 55

4. is normally about 1 litre per minute in human adults at rest

The stroke volume is around 80 mL. At a heart rate of 70 bpm this equates to a cardiac output of about 5.5 litres per minute.

Question 56

[Select the one CORRECT option] During increased tissue metabolism which of the following will lead to arteriole dilation?

1.
decreased K+ concentrations

2.
increased O2 levels

3.
increased adenosine concentrations

4.
decreased CO2 levels

Answer 56

3. increased adenosine concentrations

Increased adenosine levels are a key vasodilator metabolite. In the heart they have a major influence on the intrinsic regulation of coronary circulation.
The levels of O 2 will decrease during tissue metabolism.

Question 57

[Select the one CORRECT option] Vasoconstriction is mediated by

1.
cardiac muscle

2.
striated muscle

3.
the internal elastic layer of the blood vessel

4.
vascular smooth muscle

Answer 57

4. vascular smooth muscle

Contraction of this muscle results in vasoconstriction.

Question 58

[Select the one CORRECT option] Regarding mean arterial pressure

1.
chemoreceptors (located in the carotid body and the aortic body) detect changes in CO2 or pH and inhibit the cardioacceleratory and vasomotor centres

2.
in response to a rise in blood pressure, activated baroreceptors stimulate the vasomotor centres and cause a change in the total peripheral resistance (TPR)

3.
baroreceptors are chemoreceptors located in the carotid sinus, aortic arch and wall of the right atrium

4.
the mean arterial pressure is calculated as the diastolic pressure + 1/3 pulse pressure

Answer 58

4. the mean arterial pressure is calculated as the diastolic pressure + 1/3 pulse pressure

Remember that the pulse pressure is determined as the difference between the systolic and the diastolic pressures.

Question 59

[Select the one CORRECT option] Contraction of the heart

1.
is normally initiated at the atrioventricular node

2.
occurs during the ventricular diastole period of the cardiac cycle

3.
decreases the pressure in the left ventricle to about 120 mmHg

4.
occurs at a higher frequency if the sympathetic nerves supplying the heart are more active

Answer 59

4. occurs at a higher frequency if the sympathetic nerves supplying the heart are more active

SNS agonists have a positive chronotropic influence, increasing the heart rate. In addition they will increase the force of contraction, the velocity of conduction of cardiac impulses and the speed of cardiac muscle contraction and relaxation.

Question 60

[Select the one CORRECT option] Regarding arrhythmias

1.
tachycardia is the term used to describe an reduced rhythm of <60 bpm

2.
bradycardia is the term used to describe an accelerated rhythm >60 bpm

3.
long-QT syndrome is a potentially lethal disease associated with arrhythmias

4.
arrhythmias are defined as changes in cardiac output without a deviation of the heart’s normal sinus rhythm

Answer 60

3. long-QT syndrome is a potentially lethal disease associated with arrhythmias

LQTS leads to an abnormally long delay between electrical excitation and relaxation of the ventricles.

Question 61

[Select the one INCORRECT option] Heart rate in adult humans

1.
falls if the parasympathetic (vagal) nerves supplying the heart are stimulated

2.
is normally about 70 beats per minute at rest

3.
rises if the arterial baroreceptors detect a fall in arterial blood pressure

4.
is normally determined by pacemaker cells found in the left ventricle

Answer 61

4. is normally determined by pacemaker cells found in the left ventricle

The primary pacemaker of the heart is found in the sinoatrial (SA) node.

Question 62

[Select the one INCORRECT option] Regarding capillary exchange

1.
capillary blood pressure declines from the arterial end to the venous end

2.
the net colloid osmotic pressure is the difference blood colloid osmotic pressure and the interstitial fluid colloid osmotic pressure

3.
the net hydrostatic pressure is the difference between the capillary hydrostatic pressure and the hydrostatic pressure of the interstitial fluid

4.
the net filtration pressure is the product of the net hydrostatic pressure and the net colloid osmotic pressure

Answer 62

4. the net filtration pressure is the product of the net hydrostatic pressure and the net colloid osmotic pressure

The net filtration pressure is the difference between the net hydrostatic pressure and the net colloid osmotic pressure.

Question 63

[Select the one INCORRECT option] During the cardiac cycle

1.
phase 2 is associated with isovolumetric contraction

2.
phase 3 is associated with the highest ventricular pressure

3.
phase 4 is associated with a maintained ventricular pressure

4.
phase 1 is associated with ventricular filling

Answer 63

Answer 4 is incorrect.

during atrial systole the mitral valve is open (the atrial valve is closed) and the ventricles fill.

Question 64

[Select the one CORRECT option] Blood pressure is lowest in

1.
capillaries

2.
veins

3.
large arteries

4.
arterioles

Answer 64

2. veins

Pressure in the venous system is only about 10% of that in the arterial system.

Question 65

[Select the one CORRECT option] Which of the following drugs are used in the treatment of hypertension?

1.
ACE stimulators

2.
thiazide diuretics

3.
β-adrenoceptor agonists

4.
calcium channel agonists

Answer 65

2. thiazide diuretics

Thiazides will increase Na + and water loss by the kidneys which decreases fluid volume, venous return and cardiac output.

Question 66

Question 1
[Select the one INCORRECT option] The lower respiratory tract is composed of the

1.
alveoli

2.
bronchi

3.
pharynx

4.
trachea

Answer 66

3. pharynx

Upper -> Nose, pharynx, larynx
Lower -> Trachea, bronchi, bronchioles, alveolar ducts, alveolar sacs, alveoli

Question 67

Question 2
[Select the one INCORRECT option] Bones which contribute to the bony thorax include the

1.
thoracic vertebrae

2.
sternum

3.
ribs

4.
clavicle

Answer 67

4. clavicle

The clavicle contributes to the pectoral girdle not the thorax.

-	Bony Thorax:
	Forms skeleton of chest wall
	Components:
 12 pairs ribs
    -> 7 true pairs
    -> 3 false pairs
    -> 2 floating
 12 thoracic vertebrae
 Sternum
-	Sternum:
	Breast bone
	Components:
 Manubrium 
 Body 
 Xipisternum

Question 68

Question 3
[Select the one INCORRECT option] The diaphragm is attached to the

1.
costal margin

2.
xiphisternum

3.
upper lumbar vertebrae

4.
ribs 1-5

Answer 68

4. ribs 1-5

The diaphragm is attached to the lower 6 ribs and their costal cartilages.

-	Diaphragm:
	Dome shaped-skeletal muscle with central tendon
	Attached: 
 Xiphisternum
 Costal Margin
 11th & 12th ribs
 Left & Right Crus 
      -> Arise -> Lumbar vertebrae
	Innervated -> phrenic nerve
	Most important muscle -> ventilation. 
	Structures / components:
 Skeletal muscle -> outside 
 Centrally-placed tendon 
    -> No body attachments
	Openings:
 Inferior vena cava (T8)
 Oesophagus (T10)
 Abdominal aorta (T12)
	Fibrous pericardium fused -> central tendon.

Question 69

Question 4
[Select the one INCORRECT option] The diaphragm is

1.
innervated by the autonomic nervous system

2.
pierced by the oesophagus

3.
composed, in part, of striated (skeletal) muscle fibres arranged radially

4.
composed, in part, of a sheet-like tendon

Answer 69

Skeletal muscle fibres radiate outwards from the central portion of the diaphragm.
The central portion of the diaphragm is formed of a tendon named the central tendon.

-	Diaphragm:
	Dome shaped-skeletal muscle with central tendon
	Attached: 
 Xiphisternum
 Costal Margin
 11th & 12th ribs
 Left & Right Crus 
      -> Arise -> Lumbar vertebrae
	Innervated -> phrenic nerve
	Most important muscle -> ventilation. 
	Structures / components:
 Skeletal muscle -> outside 
 Centrally-placed tendon 
    -> No body attachments
	Openings:
 Inferior vena cava (T8)
 Oesophagus (T10)
 Abdominal aorta (T12)
	Fibrous pericardium fused -> central tendon.

Question 70

Question 5
[Select the one INCORRECT option] Pseudostratified columnar epithelium is found within the

1.
trachea

2.
primary bronchi

3.
secondary bronchi

4.
alveoli

Answer 70

4. alveoli

The alveoli contain squamous epithelium.

Nose -> (mucosa) -> Ps. col 
Trachea -> Ps. sol 
Bronchi -> Ps col
Bronchioles -> Simple col. w/goblet cells
-->Terminal -> Simple col. w/cilia
-->Respiratory -> Simple cuboidal
Alveoli -> Simple squamous

Question 71

Question 6
[Select the one CORRECT option] In the lungs, gas exchange occurs in the

1.
terminal bronchioles

2.
secondary bronchi

3.
alveoli

4.
bronchopulmonary segment

Answer 71

3. alveoli

The alveoli are the primary gas exchange surfaces of the lung.

-> Also occurs in respiratory bronchioles

Question 72

Question 7
[Select the one CORRECT option] The left lung has

1.
4 bronchopulmonary segments

2.
1 fissure

3.
3 lobes

4.
3 secondary bronchi

Answer 72

1 fissure

It is the oblique fissure.
The left lung contains 2 lobes.

•	Left Lung:
-	Narrower
-	Longer
-	2 lobes
	Superior        (upper lobe)
	Inferior           (lower lobe)
-	1 fissure
	Oblique

Question 73

Question 8
[Select the one CORRECT option] Bronchioles differ from bronchi in that they lack

1.
cartilage

2.
goblet cells

3.
striated muscle

4.
epithelium

Answer 73

1. cartilage

Bronchi posses either cartilage rings of plates; bronchioles do not.

	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 & 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 & 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

Question 74

Question 9
[Select the one CORRECT option] When taking a deep breath in, the following diameter of the thoracic cage is increased

1.
coronal

2.
antero-posterior

3.
mid-sagittal

4.
sagittal

Answer 74

2. antero-posterior

• 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)

Question 75

Question 10
[Select the one CORRECT option] The hilum of the lung is

1.
where the bronchial veins exit the lung

2.
where the pulmonary veins enter the lung

3.
where the bronchial arteries exit the lung

4.
located on the sternocostal surface

Answer 75

1.
where the bronchial veins exit the lung ??

The pulmonary veins LEAVE the lung at the hilum, not enter it.
The bronchial arteries ENTER the lung at the hilum, not exit it.

-> Bronchial veins -
lungs -> bronchi
Therefore leave lungs to go to bronchi

-> Pulmonary veins
- Lungs -> heart
Therefore leave lungs to go to heart

-> Bronchial arteries
- Heart -> Bronchi
Therefore leave heart to suppl yoxygenated blood to lungs

Question 76

Question 1
[Select the one INCORRECT option] The larynx

1. Can be palpated in the neck

2.
possesses a wall composed of cartilage, membrane and muscle

3.
is involved in speech production

4.
maintains a patent (open) airway at all times

Answer 76

1. Can be palpated in the neck

Nine cartilages form the framework of the larynx; these are the single thyroid, cricoid and epiglottis, and the paired arytenoids, corniculate and cuneiforms.

-> Adams apple (cartilage comprising the larynx) can be palpated.  Structure:
Cartilaginous skeleton
&raquo_space; Epiglottis
&raquo_space; Thyroid cartilage (Adam’s Apple)
&raquo_space; Cricoid cartilage
&raquo_space;Arytenoid cartilage

Question 77

Question 2
[Select the one INCORRECT option] Pseudostratified columnar epithelium is found within the

1.
secondary bronchi

2.
alveoli

3.
trachea

4.
primary bronchi

Answer 77

2. alveoli

The alveoli contain squamous epithelium.

Nose -> (mucosa) -> Ps. col 
Trachea -> Ps. sol 
Bronchi -> Ps col
Bronchioles -> Simple col. w/goblet cells
-->Terminal -> Simple col. w/cilia
-->Respiratory -> Simple cuboidal
Alveoli -> Simple squamous

Question 78

Question 3
[Select the one INCORRECT option] The apex of the lung

1.
can be palpated above the clavicle

2.
is the region where the bronchi, blood vessels, lymphatics and nerves enter and exit the lung

3.
is enclosed and protected by the pleural membrane

4.
is part of the superior lobe of the lung

Answer 78

2. is the region where the bronchi, blood vessels, lymphatics and nerves enter and exit the lung

The bronchi, blood vessels, lymphatics and nerves enter and exit the lung at the hilum.

Question 79

Question 6
[Select the one CORRECT option] The external intercostal muscles

1.
relax to bring about exhalation

2.
contract to increase intrathoracic pressure

3.
are involved in internal respiration

4.
contract to increase the vertical diameter of the thorax

Answer 79

3.
are involved in internal respiration

Contraction of the external intercostals increases the AP and horizontal diameters.

•	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 & Transverse 
     diameters. 
-	Forced:
	Pectoralis major 
	Pectoralis minor
	Scalenes
	Serratus anterior
	Sternocleidomastoid
 Assist -> rib elevation 
    -> Incr. speed & amount of movement

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

Question 80

Question 7
[Select the one CORRECT option] The Hering-Breuer (inflation) reflex

1.
involves afferent impulses being transmitted by the vagus nerve

2.
involves stretch receptors located in the parietal pleura

3.
lengthens the period of inspiration

4.
is triggered by a fall in pH

Answer 80

1. involves afferent impulses being transmitted by the vagus nerve

The impulses are transmitted by the vagus nerve to the pneumotaxic centre.

•	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 81

[Select the one INCORRECT option] Regarding the respiratory system

1.
at rest a normal human breathes 12-15 times/minute

2.
about 500 mL air per breath is inspired and expired

3.
humans have approximately 300 alveoli

4.
O2 enters blood in pulmonary capillaries by simple diffusion

Answer 81

3. humans have approximately 300 alveoli

This is the main region of gas exchange. Humans have approximately 300 MILLION alveoli.

Question 82

[Select the one INCORRECT option] Intrapulmonary pressure

1.
is the pressure inside the respiratory tract

2.
does not change on exhalation

3.
will decrease on inhalation

4.
along with atmospheric pressure determines the direction of airflow

Answer 82

2. does not change on exhalation

Intrapulmonary pressure increases on exhalation.

 Boyle’s Law:
 The pressure of a given quantity of gas is inversely proportional to it’s volume.
 Decr. thoracic Vol -> Incr. pressure
 Incr. thoracic Vol -> Decr. pressure
 Air flows from area -> high pressure to low pressure.
 Incr. thoracic volume -> decr. pressure
&raquo_space; Air moves in
 Decr. volume -> incr. pressure
&raquo_space; Air expelled

• 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

Question 83

Question 3
[Select the one INCORRECT option] In asthma the following are present

1.
loss of lung elasticity

2.
airway obstruction

3.
episodic or chronic wheezing

4.
airway inflammation

Answer 83

1. loss of lung elasticity

Asthma does not affect the elasticity of the lungs.

-	Obstruction:
	Conditions -> Impede rate of flow into & out of lungs. 
	Incr. airway resistance
>> Narrowed airways
	Decr. outflow pressure
>> Loss of elastic recoil -> Lung tissue

	Athsma:
-	Symptoms:
>> Incr. airway resistance
	Bronchoconstriction 
	Oedema -> Airway mucosa
	Mucus – secretion 
-	Causes:
	Hypersensitivity -> allergens
	Air pollution 
	Exercise -> Cold air
	Emotional stress
	Possibly genetics
-	Mechanics:
	Mast cell activation 
>> Release Histamine & cytokine 
	Odeoma & mucus
	Contraction -> smooth muscles. 
-	Treatment:
	Bronchodilators 
Eg. salbutamol (beta-2-adrenoceptor agonist)
	Anti-inflammatories
 Approx. 5.4 mill -> UK receiving treatment. 
                      >> Incl. 1.1 mill children
                         ->> 1 in 11 children
                    --> Many receiving treatment do not actually have disease

Question 84

Question 4
[Select the one INCORRECT option] Pulmonary ventilation is

1.
measured by respiratory minute volume

2.
the amount of air moving in and out of the respiratory tract

3.
can be calculated by multiplying respiratory rate x tidal volume

4.
the amount of air reaching the alveoli each minute

Answer 84

4. the amount of air reaching the alveoli each minute

This is alveolar ventilation not pulmonary ventilation.

• Pulmonary Ventilation Rate: (Minute Ventilation)
- Respiratory Minute Volume
» Volume of air inhaled / exhaled per minute
- Respiratory Rate x Tidal Volume
» 0.5 L x 12 /min = 6 L/min

-	Respiratory Rate 
>> No. of breaths per minute
-	Tidal Volume 
>> Volume of air inhaled / exhaled per breath
-	Normal Values
>> Males -> 0.5L
>> Females -> 0.5L

• Alveolar Ventilation:
- Volume of air reaching alveoli per minute
- [Respiratory Rate] x [(Tidal Volume) - (Anatomical dead space)]
» 12 x (0.5 – 0.15) = 4.2 L/min

Question 85

Question 5
[Select the one INCORRECT option] Formation of HCO3- in systemic blood

1.
accounts for approximately 10% of transported carbon dioxide

2.
occurs almost exclusively in red blood cells

3.
results in the formation of H+

4.
is assisted by deoxygenation of haemoglobin

Answer 85

1. accounts for approximately 10% of transported carbon dioxide

Around 70% of the carbon dioxide is transported in this form.

• CO2:
- Generated -> Aerobic metabolism -> Peripheral tissues
- Enters blood & transported by 1 of 3 methods:
1. 70% converted -> carbonic acid formation -> H2CO3-
&raquo_space; Carbonic anhydrase enzyme
-> Transported in plasma -> Bicarbonate ion HCO3-
&raquo_space; CO2 + H2O -> H2CO3
H2CO3 -> H+ & HCO3-
-> Chloride shift
&raquo_space; HCO3- moves out RBCs & replaced by Cl -
2. 23% Bound -> Haemoglobin
-» Carbahameoglobin
&raquo_space; Hb-(NH2) + CO2  Hb-(NHCOOH)
-> Carbamino group
3. 7% dissolved -> Plasma

Question 86

[Select the one CORRECT option] In the lungs, gas exchange occurs primarily at

1.
terminal bronchioles

2.
secondary bronchi

3.
alveoli

4.
bronchopulmonary segment

Answer 86

3. alveoli

The alveoli are the primary gas exchange surfaces of the lung.

-> Also occurs in respiratory bronchioles

Question 87

Question 7
[Select the one CORRECT option] The shift in the haemoglobin saturation curve with pH is known as

1.
Dalton’s effect

2.
the chloride shift

3.
the Bohr effect

4.
Boyle’s Law

Answer 87

3. the Bohr effect

Oxygen affinity decreases with pH.

 O2 Dissociation (Saturation) Curve
 Saturation of Hb in relation to P(O2) in blood
&raquo_space; % saturation of Hb incr. with incr. P(O2)
&raquo_space; % saturation with incr. P(O2) slows
–» P(O2) ~ 40mmHg
-> Enters systemic tissues -> 75% sat.
-> 15 ml O2 / dL Blood
&raquo_space; 100% sat. of Hb at P(O2) = 100
-> Alveoli
-> 20ml O2 / dL Blood
–» Occurs due to unloading of O2 to systemic tissues
-> Between 15-20 ml O2 /dL Blood
 The higher the P(O2)
-> The more O2 binds -> Hb

 Unloading of O2 -> Tissues
   >> Decr. pH & Incr. CO2
o	Curve shifts   -->
>> Bohr Shift 
>> Incr. efficiency of unloading
>> Higher % saturation at lower P(O2) 
                                 >>  Incr. temperature
                                    -  Higher -> Active tissues
                                    -  Incr. 2,3 diphosphoglycerate (2,3-DPG) -> Anaerobic conditions
o	Curve shifts   -->
>> Bohr Shift 
>> Incr. efficiency of unloading
>> Higher % saturation at lower P(O2) 

• Dalton’s Law of Partial Pressure:
 Total pressure exerted by mixture of gases = Sum of pressures exerted independently by each gas in mixture.
 Partial pressure
 Pressure exerted by each gas
 Directly proportional to % in total gas mixture

• Henry’s Law:
- The amount of gas that dissolves in water determined by
 Solubility in water
 Partial pressure in air
- At equilibrium:
 Vol. -> Dissolved gas in solution proportional to partial pressure of gas.
Eg. Incr. P(Gas) -> Incr. # gas molecules in solution
Incr. P(O2) -> Incr. amount of O2 in solution.

• CO2:
- Generated -> Aerobic metabolism -> Peripheral tissues
- Enters blood & transported by 1 of 3 methods:
1. 70% converted -> carbonic acid formation -> H2CO3-
&raquo_space; Carbonic anhydrase enzyme
-> Transported in plasma -> Bicarbonate ion HCO3-
&raquo_space; CO2 + H2O -> H2CO3
H2CO3 -> H+ & HCO3-
-> Chloride shift
&raquo_space; HCO3- moves out RBCs & replaced by Cl -

 Boyle’s Law:
 The pressure of a given quantity of gas is inversely proportional to it’s volume.
 Decr. Vol -> Incr. pressure
 Incr. Vol -> Decr. pressure
 Air flows from area -> high pressure to low pressure.
 Incr. thoracic volume -> decr. pressure
&raquo_space; Air moves in
 Decr. thoracic volume -> incr. pressure
&raquo_space; Air expelled

Question 88

Question 8
[Select the one CORRECT option] Which of the following statements is correct when considering factors that affect the affinity of haemoglobin for oxygen?

1.
carbon monoxide will not affect the binding of oxygen to haemoglobin

2.
an increase in body temperature will result in increased affinity for oxygen

3.
an increase in pH will result in increased affinity for oxygen

4.
pCO2 will not affect the affinity of haemoglobin for oxygen

Answer 88

• Transportation of O2:
- Approx. 97% O2 transported in Blood -> Using Hb
- Remaining 3% O2 transported in Blood -> Plasma
- Each haem portion -> Hb
 Carries 4 mol O2
 Hb changes shape upon binding with O2
&raquo_space; Enables further uptake of O2 -> Positive Feedback
&raquo_space; Binding of O2 mol. to Hb cause change in shape of Hb
> Enables easier successive binding of O2 to Hb.
&raquo_space; As max. limit of O2 binding approaches, affinity decreases.
 Hb Saturation:
 % of haem units per Hb mol containing bound O2
&raquo_space; 4 mol O2 bound -> 100% Saturation
 Affected by:
» Partial pressure O2 - > P(O2) -> Blood
» Blood pH
» Temperature
» No. of O2 mol. already bound -> haem
—> O2 dissociation Curve
 O2 Dissociation (Saturation) Curve
 Saturation of Hb in relation to P(O2) in blood
 Factors influencing affinity for O2:
% saturation & affinity of Hb for O2:
&raquo_space; Increases with each successive binding of O2 to Hb
&raquo_space; Increases with incr. P(O2)
&raquo_space; Decr. with incr. pH
> Incr. pH (incr. H+ conc.) alters ionic bonds -> protein structure of Hb
> Changes shape of Hb
-> Less able to bind -> O2
&raquo_space; Decr. with incr. p(CO2)
> Incr. CO2 causes incr. acidity of blood
-> Incr. pH -> change in shape -> proteins of Hb
-> Less able to bind -> O2
&raquo_space; Decr. affinity with incr. temperature
> Incr. temperature denatures bonds within Hb
> Changes shape of Hb
-> Less able to bind -> O2

   Steep portion of curve
    >> Range ->  % saturation within systemic capillaries. 
       > 75 – 100% saturation
         -->> P(O2) ~ 40mmHg 
    >> 100% sat. of Hb within alveoli

 Unloading of O2 -> Tissues
   >> Incr. pH & Incr. CO2
o	Curve shifts   -->
>> Bohr Shift 
>> Incr. efficiency of unloading
>> Higher % saturation at lower P(O2) 
                                 >>  Incr. temperature
                                    -  Higher -> Active tissues
                                    -  Incr. 2,3 diphosphoglycerate (2,3-DPG) -> Anaerobic conditions
o	Curve shifts   -->
>> Bohr Shift 
>> Incr. efficiency of unloading
>> Higher % saturation at lower P(O2) 

•	Types of Haemoglobin:
-	Carboxyhaemoglobin:
	Stronger binding -> CO 
>> (200x greater)
	Greatly reduces ability of O2 binding to Hb
-	Methaemoglobin:
	Fe2+ oxidised -> Fe3+
>> Drugs
	Unable to carry O2
>> Slow reconversion
-	Foetal haemoglobin:
	2 alpha & 2 ץ
	Higher affinity -> O2
	Important -> O2 transfer across placenta
	Higher % saturation at lower P(O2)

• CO2:
- Generated -> Aerobic metabolism -> Peripheral tissues
- Enters blood & transported by 1 of 3 methods:
1. 70% converted -> carbonic acid formation -> H2CO3-
&raquo_space; Carbonic anhydrase enzyme
-> Transported in plasma -> Bicarbonate ion HCO3-
&raquo_space; CO2 + H2O -> H2CO3
H2CO3 -> H+ & HCO3-
-> Chloride shift
&raquo_space; HCO3- moves out RBCs & replaced by Cl -
2. 23% Bound -> Haemoglobin
-» Carbahameoglobin
&raquo_space; Hb-(NH2) + CO2  Hb-(NHCOOH)
-> Carbamino group
3. 7% dissolved -> Plasma

• Buffering in RBCs:
- Every CO2 -> HCO3- reaction yields H+
» Leads to acidic pH
- Consumption / release of H+ minimises incr. pH
» Imidazole groups of histidine residues in haemoglobin
-> Act as buffers.
&raquo_space; Hb-(N)-(NH) + H+  Hb-(N)-(NH2+)
- Deoxygenated Hb -> Strongest affinity for H+

•	Haldane Effect:
-	Lungs:
	Oxygenation of Hb
>> Conformational change -> Hb
	Lower affinity -> H+
>> Decr. buffering ability 
	H+ released
>> Aids in unloading of O2 -> lungs
-	Tissues:
	Deoxygenation of Hb
>> Conformational change -> Hb
	Higher affinity -> H+
>> Incr. buffering ability
	Uptake of H+
	Transportation of CO2 from tissues

Question 89

Question 9
[Select the one CORRECT option] During hyperventilation which of the following would be expected to happen?

1.
an increase in the acidity of arterial blood

2.
an increase in the pO2 of arterial blood

3.
an increase in the pCO2 of arterial blood

4.
a decrease in pH of arterial blood

Answer 89

• CO2 & H+ -> Most important factors influencing Gas Exchange & Breathing

-	Incr. P(CO2)
 Eg. Limited gas exchange -> Emphysema 
        -> Incr. P(CO2) -> ( > 43mmHg )
	CO2 + H2O   H2CO3   H+ + HCO3- 
	 Eqn pushed   -->
  Incr. H+ -> Decr. pH 
                             >> (Incr. Acidity)                         Respiratory Acidosis -> (pH < 7.35) 

• Decr. P(CO2)
  Eg. Hyperventilation
  [ Excessive ventilation of the lungs, beyond what is required. Rate or tidal volume of breathing eliminates more carbon dioxide than the body can produce.
  Little effect on arterial pO2 and almost no effect on oxygen saturation which is nearly 100%
  under normal circumstances. Its main effect is to lower pCO2 and produce a respiratory
  alkalosis. ]
  -> Decr. P(CO2) -> ( <37mmHg )
   CO2 + H2O  H2CO3  H+ + HCO3-
   Eqn pushed Incr. pH
  &raquo_space; (Incr. Alkalinity) Respiratory Alkalosis (pH > 7.45)

-	Changes -> P(O2)
	Incr. P(O2) 
Eg. Breathing -> O2 rich gas mixtures
>>  Generates free radicals 
    > Coma & Death 
	Decr. P(O2) 
>> Arterial P(O2) must drop below 60mmHg before ventilation incr. 
>> Central chemoreceptors switch off 
>> Peripheral chemoreceptors incr. breathing rate

Question 90

Question 10
[Select the one CORRECT option] Vital capacity is the sum of

1.
expiratory volume, the tidal volume and the inspiratory reserve volume

2.
residual volume and the tidal volume

3.
tidal volume and the minimal volume

4.
functional residual capacity and the tidal volume

Answer 90

1. expiratory volume, the tidal volume and the inspiratory reserve volume

Vital capacity is the maximum volume of air that can be exhaled after a maximum inhalation.

•	Vital Capacity: (VC)
-	Maximum volume of air expired after max. inspiratory effort
-	VC = TV + IRV + ERV
-	Normal Values:
>> Men -> 4.8 L
>> Women -> 4.2 L

•	Residual Volume: (RV)
-	Volume of air remaining in lungs following max expiration
-	Normal Values:
>> Men -> 1.2 L
>> Women -> 1.1 L

•	Tidal Volume: (TV)
-	Volume of air inhaled / exhaled per breath
-	Normal Values
>> Males -> 0.5L
>> Females -> 0.5L

•	Expiratory Reserve Volume: (ERV)
-	Volume of air forcibly exhaled following normal tidal volume exhalation
-	Normal Values:
>> Men -> 1.0 L
>> Women -> 0.7 L

•	Inspiratory Reserve Volume: (IRV) 
-	Volume of air forcibly exhaled following normal tidal volume inhalation 
-	Normal Values:
>> Men -> 3.3 L
>> Women -> 1.9 L

• Pulmonary Ventilation Rate:
- Respiratory Minute Volume (Minute Ventilation)
» Volume of air inhaled / exhaled per minute
- Respiratory Rate x Tidal Volume
» 0.5 L x 12 /min = 6 L/min

Question 91

[Select the one INCORRECT option] The partial pressure of oxygen required to produce 50% saturation of haemoglobin

1.
is half that required to produce 100% saturation

2.
is lower when the temperature of blood is low

3.
is lower when the partial pressure of carbon dioxide is low

4.
is lower in foetal blood than in adult blood.

Answer 91

1. is half that required to produce 100% saturation

The saturation curve is sigmoid in shape.
->

• Transportation of O2:
- Approx. 97% O2 transported in Blood -> Using Hb
- Remaining 3% O2 transported in Blood -> Plasma
- Each haem portion -> Hb
 Carries 4 mol O2
 Hb changes shape upon binding with O2
&raquo_space; Enables further uptake of O2 -> Positive Feedback
&raquo_space; Binding of O2 mol. to Hb cause change in shape of Hb
> Enables easier successive binding of O2 to Hb.
&raquo_space; As max. limit of O2 binding approaches, affinity decreases.
 Hb Saturation:
 % of haem units per Hb mol containing bound O2
&raquo_space; 4 mol O2 bound -> 100% Saturation
 Affected by:
» Partial pressure O2 - > P(O2) -> Blood
» Blood pH
» Temperature
» No. of O2 mol. already bound -> haem
—> O2 dissociation Curve
 O2 Dissociation (Saturation) Curve
 Saturation of Hb in relation to P(O2) in blood
 Factors influencing affinity for O2:
% saturation & affinity of Hb for O2:
&raquo_space; Increases with each successive binding of O2 to Hb
&raquo_space; Increases with incr. P(O2)
&raquo_space; Decr. with incr. pH
> Incr. pH (incr. H+ conc.) alters ionic bonds -> protein structure of Hb
> Changes shape of Hb
-> Less able to bind -> O2
&raquo_space; Decr. with incr. p(CO2)
> Incr. CO2 causes incr. acidity of blood
-> Incr. pH -> change in shape -> proteins of Hb
-> Less able to bind -> O2
&raquo_space; Decr. affinity with incr. temperature
> Incr. temperature denatures bonds within Hb
> Changes shape of Hb
-> Less able to bind -> O2

   Steep portion of curve
    >> Range ->  % saturation within systemic capillaries. 
       > 75 – 100% saturation
         -->> P(O2) ~ 40mmHg 
    >> 100% sat. of Hb within alveoli

 Unloading of O2 -> Tissues
   >> Incr. pH & Incr. CO2
o	Curve shifts   -->
>> Bohr Shift 
>> Incr. efficiency of unloading
>> Higher % saturation at lower P(O2) 
                                 >>  Incr. temperature
                                    -  Higher -> Active tissues
                                    -  Incr. 2,3 diphosphoglycerate (2,3-DPG) -> Anaerobic conditions
o	Curve shifts   -->
>> Bohr Shift 
>> Incr. efficiency of unloading
>> Higher % saturation at lower P(O2) 

•	Types of Haemoglobin:
-	Carboxyhaemoglobin:
	Stronger binding -> CO 
>> (200x greater)
	Greatly reduces ability of O2 binding to Hb
-	Methaemoglobin:
	Fe2+ oxidised -> Fe3+
>> Drugs
	Unable to carry O2
>> Slow reconversion
-	Foetal haemoglobin:
	2 alpha & 2 ץ
	Higher affinity -> O2
	Important -> O2 transfer across placenta
	Higher % saturation at lower P(O2)

• CO2:
- Generated -> Aerobic metabolism -> Peripheral tissues
- Enters blood & transported by 1 of 3 methods:
1. 70% converted -> carbonic acid formation -> H2CO3-
&raquo_space; Carbonic anhydrase enzyme
-> Transported in plasma -> Bicarbonate ion HCO3-
&raquo_space; CO2 + H2O -> H2CO3
H2CO3 -> H+ & HCO3-
-> Chloride shift
&raquo_space; HCO3- moves out RBCs & replaced by Cl -
2. 23% Bound -> Haemoglobin
-» Carbahameoglobin
&raquo_space; Hb-(NH2) + CO2  Hb-(NHCOOH)
-> Carbamino group
3. 7% dissolved -> Plasma

• Buffering in RBCs:
- Every CO2 -> HCO3- reaction yields H+
» Leads to acidic pH
- Consumption / release of H+ minimises incr. pH
» Imidazole groups of histidine residues in haemoglobin
-> Act as buffers.
&raquo_space; Hb-(N)-(NH) + H+  Hb-(N)-(NH2+)
- Deoxygenated Hb -> Strongest affinity for H+

•	Haldane Effect:
-	Lungs:
	Oxygenation of Hb
>> Conformational change -> Hb
	Lower affinity -> H+
>> Decr. buffering ability 
	H+ released
>> Aids in unloading of O2 -> lungs
-	Tissues:
	Deoxygenation of Hb
>> Conformational change -> Hb
	Higher affinity -> H+
>> Incr. buffering ability
	Uptake of H+
	Transportation of CO2 from tissues

Question 92

[Select the one INCORRECT option] Tidal volume

1.
is 500 mL for males

2.
is the amount of air that normally moves into (or out of) the lungs with each breath

3.
cannot be measured on a spirometer

4.
is 500 mL for females

Answer 92

3. cannot be measured on a spirometer

Tidal volume CAN be measured using a spirometer.

•	Tidal Volume: (TV)
-	Volume of air inhaled / exhaled per breath
-	Normal Values
>> Males -> 0.5L
>> Females -> 0.5L

•	Assessment -> Lung Function:
	Breath Sound
	Presence -> mucous / fluid
	Absence -> Breathing sounds -> Possible collapsed lung
	Pulmonary Function Tests
	Peak Flow meter
>> Measures speed of air exhalation
>> Regularly used -> Chronic asthmatics
	Spirometer
	Measures lung volumes & capacities
	Findings: (Litres)
>> Inspiratory Reserve Volume (IRV)
      > Men -> 3.3 
      > Women -> 1.9
   >> Tidal Volume (TV)
      > Men -> 0.5 – 4.8 
      > Women -> 0.5 – 3.1 
   >> Expiratory Reserve Volume (ERV)
      > Men -> 1.0
      > Women -> 0.7
   >> Residual Volume (RV)
      > Men -> 1.2 
      > Women -> 1.1
   >> Total Lung Capacity
      > Men -> 6.0
      > Women -> 4.2

Question 93

[Select the one INCORRECT option] Lung volumes are usually

1.
smaller in shorter people then in taller people

2.
affected by smoking

3.
smaller in females than males

4.
smaller in people living at high altitude compared with those living at low altitude

Answer 93

4. smaller in people living at high altitude compared with those living at low altitude

Lung volumes tend to be larger in people living at high altitude then those living at low altitude.

Question 94

[Select the one CORRECT option] The product of tidal volume and breathing frequency is

1.
total lung capacity

2.
respiration rate

3.
minute ventilation

4.
alveolar ventilation

Answer 94

3. minute ventilation

•	Tidal Volume: (TV)
-	Volume of air inhaled / exhaled per breath
-	Normal Values
>> Males -> 0.5L
>> Females -> 0.5L

• Respiratory system adapts -> Varying oxygen demands by altering:
- Respiratory Rate
» No. of breaths per minute
- Tidal Volume
» Volume of air inhaled / exhaled per breath

•	Total Lung Capacity: (TLC)
-	Maximum volume of air contained in lungs following maximum inspiratory effort
-	TLC = TV + IRV + ERV + RV
-	Normal Values:
>> Men -> 6.0 L
>> Women -> 4.2 L

• Pulmonary Ventilation Rate:
- Respiratory Minute Volume (Minute Ventilation)
» Volume of air inhaled / exhaled per minute
- Respiratory Rate x Tidal Volume
» 0.5 L x 12 /min = 6 L/min

• Alveolar Ventilation:
- Volume of air reaching alveoli per minute
- [Respiratory Rate] x [(Tidal Volume) - (Anatomical dead space)]
» 12 x (0.5 – 0.15) = 4.2 L/min

Question 95

[Select the one CORRECT option] Regarding oxygen transport

1.
approximately 97% of O2 transported in the blood is combined with haemoglobin

2.
none can be transported in plasma

3.
each haemoglobin molecule can can carry 2 molecules of O2

4.
after binding with O2 haemoglobin changes shape to inhibit further uptake

Answer 95

1. approximately 97% of O 2 transported in the blood is combined with haemoglobin

Aprroximately 97% (or can be more) of O 2 is transported bound to haemoglobin.

• Transportation of O2:
- Approx. 97% O2 transported in Blood -> Using Hb
- Remaining 3% O2 transported in Blood -> Plasma
- Each haem portion -> Hb
 Carries 4 mol O2
 Hb changes shape upon binding with O2
&raquo_space; Enables further uptake of O2 -> Positive Feedback
&raquo_space; Binding of O2 mol. to Hb cause change in shape of Hb
> Enables easier successive binding of O2 to Hb.
&raquo_space; As max. limit of O2 binding approaches, affinity decreases.
 Hb Saturation:
 % of haem units per Hb mol containing bound O2
&raquo_space; 4 mol O2 bound -> 100% Saturation
 Affected by:
» Partial pressure O2 - > P(O2) -> Blood
» Blood pH
» Temperature
» No. of O2 mol. already bound -> haem
—> O2 dissociation Curve
 O2 Dissociation (Saturation) Curve
 Saturation of Hb in relation to P(O2) in blood
 Factors influencing affinity for O2:
% saturation & affinity of Hb for O2:
&raquo_space; Increases with each successive binding of O2 to Hb
&raquo_space; Increases with incr. P(O2)
&raquo_space; Decr. with incr. pH
> Incr. pH (incr. H+ conc.) alters ionic bonds -> protein structure of Hb
> Changes shape of Hb
-> Less able to bind -> O2
&raquo_space; Decr. with incr. p(CO2)
> Incr. CO2 causes incr. acidity of blood
-> Incr. pH -> change in shape -> proteins of Hb
-> Less able to bind -> O2
&raquo_space; Decr. affinity with incr. temperature
> Incr. temperature denatures bonds within Hb
> Changes shape of Hb
-> Less able to bind -> O2

   Steep portion of curve
    >> Range ->  % saturation within systemic capillaries. 
       > 75 – 100% saturation
         -->> P(O2) ~ 40mmHg 
    >> 100% sat. of Hb within alveoli

 Unloading of O2 -> Tissues
   >> Incr. pH & Incr. CO2
o	Curve shifts   -->
>> Bohr Shift 
>> Incr. efficiency of unloading
>> Higher % saturation at lower P(O2) 
                                 >>  Incr. temperature
                                    -  Higher -> Active tissues
                                    -  Incr. 2,3 diphosphoglycerate (2,3-DPG) -> Anaerobic conditions
o	Curve shifts   -->
>> Bohr Shift 
>> Incr. efficiency of unloading
>> Higher % saturation at lower P(O2) 

•	Haldane Effect:
-	Lungs:
	Oxygenation of Hb
>> Conformational change -> Hb
	Lower affinity -> H+
>> Decr. buffering ability 
	H+ released
>> Aids in unloading of O2 -> lungs
-	Tissues:
	Deoxygenation of Hb
>> Conformational change -> Hb
	Higher affinity -> H+
>> Incr. buffering ability
	Uptake of H+
	Transportation of CO2 from tissues