Cardiovascular And Respiratory Medicine Flashcards

1
Q

which arteries supply blood the the cardiac muscle

A

Aorta spilts into right and left coronary arteries

Left coronary artery branches into (left) circumflex artery first and left anterior descending further down

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2
Q

What the 2 semi lunar valves called

A

Pulmonary valve - on right side, pulmonary artery comes out of it
Aortic valve - on left side, aorta comes out of it

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3
Q

How much is stroke volume

A

Around 70 ml

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4
Q

What is ejection fraction

A

(100 x stroke volume) / end-diastolic volume

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5
Q

Normal range of ejection fraction

A

52-72 percent

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6
Q

What are pennate muscles

A

Fibres spread out from tendon at angles
Unipennate - all muscle fibres go in same direction from tendon
Bipennate - muscles fibres spread out from tendon in 2 directions along its length
Multipennate - multiple tendons

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7
Q

What factors affect resistance - also give the equation

A
Vessel length (L)
Vessel radius (r)
Blood viscosity (n)

R = 8 x L x n / pie x r^4

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8
Q

What is vascular tone

A

Partial contraction of arterioles

This allows them to contract further or dilate further - room for accomodation

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9
Q

What is MAP

A

Mean arterial pressure

93 mmHg

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10
Q

What is the usual/average pressure in the venules/capillaries

A

37 mmHg

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11
Q

What 2 fucntions of radii are arterioles adjusted independently to accomplish and what regulates each function

A

1) adjusting blood flow to meet the metabolic demands of specific tissues. Is regulated by intrinsic controls, independent of nervous and endocrine system
-chemically driven
or
-physically driven
(Vasodilation = active hyperaemia, vasoconstriction = myogenic autoregulation/vasoconstriction)

2) regulating systemic arterial blood pressure. Is regulated by extrinsic controls
-neural control
or
-hormonal control

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12
Q

What is total peripheral resistance

A

Sum of resistance of all the arterioles in the systemic circulation

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13
Q

How to calculate cardiac output

A

Use Q = delta P / R
Q = cardiac output
delta P = MAP (as venule pressure is negligible so total pressure difffernce across whole system is basically mean arterial pressure)
R = total peripheral resistance

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14
Q

Explain how the brain is involved in helping regulate arterial blood pressure

A

Cardiovascular control centre in the medulla oblongata

Causes vasocontrcition which decreases blood flow and increases blood pressure

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15
Q

Which 3 hormones can lead to vasoconstriction of arterioles in order to help regulate arterial blood pressure

A

ADH/vasopressin
Angiotensin II
adrenaline/noradrenaline

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16
Q

What is ficks law

A

The rate of diffusion across a surface is proportional to the concentration gradient

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17
Q

3 types of capillary structure

A

1) continuous - small h2o filled water channels that only electrlytes can pass through
2) fenestrated - fenestrae, slightly larger gaps that some larger molecules can pass through eg glucose
3) discontinuous - larger gaps in capillary wall. Found where WBCs need to get into blood eg in liver/spleen/bone marrow

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18
Q

Where does the thoracic duct of the lymphatic system drain into

A

Junction of the left subclavian and internal jugular veins

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19
Q

What causes elephantiasis

A

Rate of release of fluid into interstitial space exceeds rate of drainage
Caused by blocking of lymph nodes by parasites
Leading to oedema

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20
Q

What does a ventricular require for contraction

A

Excitation of the cell

Ca2+

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21
Q

Outline the basic process leading up to a contraction of a ventricular cell

A
Electrical event (AP)
Calcium transient - calcium in sarcoplasm increases for a short period of time 
Contractile event
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22
Q

Does skeletal muscle need external calcium for contraction

A

No

Only myocardial muscle

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23
Q

Outline the dimensions of a ventricular cell and T tubules

A

Ventricular cell: 100 um length, 15 um diameter
T tubule: 200 nm length, finger linke invaginations of the cell surface membrane which are 2 um apart, lie alongside each Z line of every myofibril

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24
Q

What is the relationship between force production (y) and intracellular signalling (x)

A

Sigmoidal

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25
Q

What are active and passive forces

A

Active: due to shortening of sarcomere - forces act in direction of point of muscular attachment towards centre
Passive: ressitance to stretch of a muscle

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26
Q

What is preload dependent on and measured by

A

Dependent on venous return

Measured by end diastolic volume, end diastolic pressure, and right atrial pressure

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27
Q

What measures does afterload involve

A

Diastolic blood pressure - pressure exerted by heart on arterial walls between contractions

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28
Q

Which 3 primary factors affect stroke work

A

Pre load
Contractility
Afterload

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29
Q

Stroke work

A

Stroke work = stroke volume x pressure at which blood is ejected

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30
Q

Law of la place

A
Tension = pressure x radius 
Or = pressure x radius / wall thickness
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31
Q

What happens to the structure of a failing heart

A

(Law of la place)
Becomes dilated
Increased radius
So tension/wall stress increases

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32
Q

What is the difference between type 1 amd 2 cells that civer the alveoli

A

Type 1: very thin - short diffusion distance for gas exchange, cover 95% of the alveolar surface
Type 2: chunkier than type 1, secrete surfactant to reduce surface tension, secrete proteases, carry out xenobiotic metabolism (metabolise harmful/noxious chemicals that might harm body), there are more type 2 cells than type 1 but type 2 cells only cover 5% of the alveolar surface

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33
Q

Whihc bronchioles are non cartilaginous

A

Terminal bronchioles

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34
Q

Describe airway branching in one word

A

Dichotomous

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35
Q

What is the purpose of nasal conchae

A

Highly vascular
Contribute to warming and humidifacation of inhlaed air
Nasal hairs filter out large particles

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36
Q

What do the conchae, meatuses and paranasal glands do

A

Secrete mucus to trap debris

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37
Q

What does cintraction of the smooth muscle in the trachea lead to and why

A

The inferior portion of the submucosal glands in embedded in the smooth muscle
So contraction of the smooth muscle leads to secretion of mucus into the lumen

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38
Q

What are the categories of airway cell types

A
Immune cells 
Neuroendocrine cells 
Lining cells 
Contractile cells
Vascular cells
Secretory cells
Connective tissue cells

IN LC V SC

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39
Q

What are the two types of airway submucosal glands

A

Mucous acini: secrete mucous
Serous acini: secrete antibacterial enzymes (more watery secretion so it can wash out the viscous secretion of mucous acini into the collecting ducts)

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40
Q

Describe the arrangemnt of serous and mucous acini

A

Serous acini are more distal to mucous acini

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41
Q

What are the main functions of the airway epithelium

A

1) Production of mucins, water and electrolytes
2) movement of mucous
3) physical barrier
4) production of inflammatory mediators
- chmeikines
- cytokines
- proteases
- arachidonic acid metabolites
- carbon monoxide
- nitric oxide

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42
Q

How do the cilia beat

A

In a metachronal rhythm

Backwards cilia sequnetially move through alternating forward and backwards movements

43
Q

What is the arrangement of ciliary structures

A

9 + 2 microtubule arrangement

44
Q

Describe teh structure of a single cilia

A

Apical hooks on top
Main body containing microtubles is called the axoneme
Anchoring hooks below the cell membrane surface

45
Q

What does brown staining on a histological section of a human airway indicate

A

Nitric oxide synthase

46
Q

3 functions of airway epithelium

A

1) tone - contraction/relaxation
2) structure - hypertrophy/proliferation
3) secretion - chemokines, cytokines, mediators

47
Q

What is the name of airway vasculature

A

Tracheo-bronchial airway vasculature

48
Q

How does blood return from tracheal or bronchial circulation

A

Blood returns from tracheal circulation via sympathetic veins
Blood returns from bronchial circulation via bronchial and pulmonary veins, to both sides of the heart

49
Q

What are the main functions of the tracheo bronhcial system

A

Humidifies air
Cleans air from inflammatory mediators
Cleans air from inhaled drugs
Warms up air
Goood gas exchange
Supplies tissues and lumen with inflammatory mediators
Supplies tissue and lumen with proteinaceous plasma

50
Q

Describe the sympathetic and parasympathetic control of the airway smooth muscle

A

Constriction: parasympathetic - sensory nerve via nodose ganglion to brainstem. Vagus nerve returns (is parasympathetic amd releases Ach) and causes smooth muscle to contract and therefore airway constricts

Dilation: sympathetic- sensory nerve via dorsal root ganglion to spinal cord. Sympathetic motor nerve then releases Nitric oxide whihc causes smooth muscle to relax and vessel to dilate
Adrenal galnd also releases adrenaline which causes the airway to dilate

51
Q

Describe the effects of inflammation on airway smooth muscle

A

Inflammation (cytokines/bacteria) cause airway smooth muscle to produce Nitric oxide synthase NOS which causes production of NO
and causes smooth muscle to produce Cylco oxygenase COX which causes prodcution of prostaglandins

In response to inflammation, Airway smooth muscle also stimulates production of cytokines, chemokines and adhension molecules - all of which cause immune cell recruitmemt

52
Q

What is the average minute ventilation of a 70kg healthy male

A

0.5 L x 120 breaths per minute = 6 L/min

53
Q

How can body size affect lung capacity

A

greater height = greater lung capacity

Weight does not affect it

54
Q

How does gender affect lung capacity

A

Males generally have greater lung capacity than females

55
Q

Define hypoventilation and hyperventilation

A
Hypoventilation = deficient ventilation of the lungs, unable to meet metabolic demand (increased PCO2 - acidosis)
Hyperventilation = excessive ventilation of the lungs, atop of metabolic demand (decreased PCO2 - alkalosis)
56
Q

What are the two main types of dead space found in the lungs

A
Conducting zone (anatomical dead space)
Non perfused parynchema (alveolar dead space)
57
Q

What zones are the brinchioles split into

A

Conducting zone: 16 generations, no gas exchange, equivalent to anatomical dead space
Respiratory zone: 7 generations, gas exchange, equivalent to alveolar ventilation

58
Q

Tyoical volume of conducting zone

A

150 ml

59
Q

How do you increase or decrease the amount of dead space

A

Increase: intubation
Decrease: tracheostomy

60
Q

Which way do the chest and lung naturally recoil

A

Lung naturally recoils inwards

Chest naturally recoils outwards

61
Q

What happens to the hcest and lung forces at functional residual capacity

A

Lung recoil = chest recoil

62
Q

What happens when chest recoil exceeds lung recoil

A

Inspiration

63
Q

Describe the membranes surrounding the lungs

A

Visceral pleura lines the lungs
Intrapleural space
Parietal pleura lines the inner chest wall

64
Q

What is a heamothorax

A

Bleeding into the intrapleural space

65
Q

What is a pneumothorax and why can it happen

A

Fluid building up in the intrapleural space - due to perforated chest wall or a punctured lung

66
Q

What is the difference between positive and negative pressure breathing

A

Negative pressure breathing: alveolar pressure is below atmospheric pressure so air is drawn into lungs (normal breathing)
Positive pressure breathing: atmospheric pressure is increased above alveolar pressure so air is pushed into the lungs (eg CPR, mechnaical ventilation etc)

67
Q

How do you calculate transrespiratory system pressure

A

P (alveolar) - P (atmospheric)

68
Q

What is Daltons law

A

The pressure of a gas mixture is the sum of the partial pressures of all the gases in the mixture

69
Q

What is Ficks law

A

The rate of diffusion of a gas down its concentration gradient is proportional to the steepness of the conc gradient, the exchange SA and the diffusion capacity of the gas
And is inversly proportional to the thickness of the exchange surface

70
Q

What is henrys law

A

At a constant temp, the amount of gas that dissolves in a liquid of given volume and type is directly proportional to the partial pressure of that gas in equilibrium with that liquid

71
Q

What is Boyles law

A

At a constant temp, the volume of a gas is inversely proportional to the pressure of the gas

72
Q

What is charles law

A

At a constant pressure, the volume of a gas is proportional to the temp of the gas

73
Q

How does the compostion of air breathed in chnage a)in a fire b) at high altitudes

A

a) O2 decreases
CO2 and CO increase

b) composition doesnt change the volume decreases so you breathe in less of all gases

74
Q

What 4 things happen to air as it passes down into respiratory tract

A

Warmed
Slowed
Humidified
Mixed

75
Q

What makes up HbA, HbA2 and HbF

A
HbA = 2 alpha, 2 beta
HbA2 = 2 alpha, 2 delta
HbF = 2 alpha, 2 gamma
76
Q

What does 2,3 DPG do to Hb

A

Binds to it allosterically and facilitates the unloading of O2 from the Hb

77
Q

Can you calculate O2 levels in the blood from just bpm (beats per minute) and SPO2% (%saturation of Hb)

A

No, you also need the amount of Hb
Because spo2 could be v high if you have a v low Hb - all Hbs will be fully saturated - so its not an accurate representation of the actual oxygen levels

78
Q

What causes right shift on o2 diss. Curve

A

Increased temp
Acidosis
Hypercapnia
Increased 2,3 DPG

BOHR EFFECT

79
Q

what causes left shift on o2 diss curve

A

Decreased temp
Alkalosis
Hypocapnia
Decreased 2,3 DPG

80
Q

What causes upward and downward shifts on O2 diss curve

A
Upward = polycythaemia (more RBCs)
Downward = anaemia
81
Q

How does CO affect o2 diss curve

A
Down and to the left 
When it binds to Hb, it increases the affinity of Hb for o2 
But it also takes up binding sites
- decrased capacity
-inceased affinity
82
Q

Which has higher o2 affinity, foetal Hb or myoglobin

A

Myoglobin, it extracts o2 from circulating blood and stores it

83
Q

How would uncontrolled type 1 diabetes affect the o2 disscociation curve

A

Would lead to ketones being used for fuel —> get diabetic ketoacidosis whihc reduces pH
Get acidosis so have a right shift (bohr effect)

84
Q

3 ways Co2 is tranported in blood

A

Dissolved as a gas
Transported as HCO3-
Transported as carboaminohaemoglobin

85
Q

When is the ventral group inactive

A

During quiet breathing

86
Q

Where is the dorsal respiratory group located

A

In the dorsomedial medulla, in the ventrolateral nucleus of the solitary tract

87
Q

Where is the ventral respiratory group relative to the dorsal resp group

A

Dorsal to it

88
Q

Where are the apneustic and pneumotaxic centres located

A

Apneustic centre = lower part of the pons

Pneumotaxic centre = upper part of the pons

89
Q

Do action potentials at a low frequency stimulate the apneustic centre or the pneumotaxic centre

A

Apneustic centre

90
Q

What effect does PC (pneumotaxic centre) have on action potentials and what is this effect followed by

A

PC causes cessation of action potentials

Followed by a period of latency before the AC then stimulates the DRG again to increase Action potential frequency

91
Q

Describe the motor and sensory innervations of the phrenic nerve

A

Motor innervation: diaphragm

Sesnory innervation: provodes sensation to central tendon aspect of diaphragm

92
Q

What happens when you reach the CO2 threshold for breathing

A

Accumulation of H+ beyond the blood brain barrier activates the DRG - “the struggke phase”

93
Q

What is the role of irritant receptors

A

Afferent fibres which detect foreign matter causing irritation and lead to cough reflex: forceful expiration/ high velocity expulsion of air against a closed glottis, leading to sudden opening of the glottis

94
Q

Where are pulmonary stretch receptors found

A

Past the second bronchi

95
Q

How are strectch receptors activated and what do they do once theyre activated

A

Excessive inflation of lungs activates the stretch receptors
Stretch receptors send afferent signals to turn off dorsal respiratory group and apneustic centre and switch on pneumotaxic ventral resp group
Leads to expiration

96
Q

Where are J receptors found

A

Alveolar walls in close proximity to capillaries

97
Q

Role of J receptors

A

Respond to oedema or pulmonary capillary engorgement

Leads to increase in breathing rate

98
Q

Formula for pH

A

-log 10 [H+]

99
Q

What is alkalaemia and how is it different to alkalosis

A
Alkalaemia = higher than normal pH of blood
Alkalosis = describes the circumstances that cause a decrease in [H+] and increase in blood pH
100
Q

What is the difference between acidaemia and acidosis

A
Acidaemia = lower than normal blood pH
Acidosis = describes the circumstances that cause an increase in [H+] and a decrease in pH of blood
101
Q

Where are peripheral chemoreceptors found

A

Near carotid baroreceptors
Carotid bodies in aortic arch
Aortic bodies in aortic arch

102
Q

What is the role of peripheral chemoreceptors

A

Stimulate breathing in response to hypoxia

103
Q

How is breathing affected by exercise

A

Nerve fibres between primary motor cortex and skeletal muscle innervate medulla, stimulatimg the respiratory groups

104
Q

Why does cardiac tissue produce a greater passive force

A

Because it’s less compliant and more resistant to stretch due to properties of the extra cellular matrix and cytoskeleton