Physiology

Question 1

How is the heart muscle supplied with blood?

Answer 1

Coronary arteries

Question 2

What is stroke volume?

Answer 2

The volume of blood ejected by each ventricle per heartbeat

Question 3

What does cardiac muscle need to contract?

Answer 3

Extracellular calcium ions

Question 4

What does the plateau phase in ventricular muscle action potential?

Answer 4

Calcium ion influx through voltage-gated calcium channels

Question 5

What does a long refractory period in cardiac muscle prevent?

Answer 5

Generation of tetanic contraction (continuous contraction) - protects heart

Question 6

What happens to the sodium channels in the plateau phase?

Answer 6

They are in the depolarised closed state

Question 7

SV = ?

Answer 7

End Diastolic Vol (EDV) - End Systolic Vol (ESV)

Question 8

How is stroke volume regulated?

Answer 8

Intrinsic (within the heart itself) and extrinsic (nervous and hormonal control)

Question 9

What is cardiac preload?

Answer 9

Initial stretching of the cardiac myocytes prior to contraction - indicated by EDV

Question 10

What is the EDV determined by?

Answer 10

Venous return to the heart

Question 11

What is Starling’s law of the heart?

Answer 11

The greater the EDV, the greater the SV

Question 12

How does stretch affect troponin?

Answer 12

Increases it’s affinity for calcium ions

Question 13

If venous return increases, what happens to EDV and SV?

Answer 13

They also increase

Question 14

What is afterload?

Answer 14

Resistance into which the heart is pumping

Question 15

If there is continuously increased afterload (e.g. untreated hypertension), what happens?

Answer 15

Ventricular muscle mass increases (ventricular hypertrophy) to overcome the resistance

Question 16

Ventricular muscle is supplied by which type of nerve fibres?

Answer 16

Sympathetic

Question 17

What is the neurotransmitter for the sympathetic nerve fibres supplying the ventricle?

Answer 17

Noradrenaline

Question 18

What effect does sympathetic stimulation have on the force of contraction?

Answer 18

Increases it

Question 19

What effect does sympathetic stimulation have on the heart rate?

Answer 19

It increase it

Question 20

What does Inotropic refer to?

Answer 20

Force of contraction

Question 21

What does chronotropic refer to?

Answer 21

Heart rate

Question 22

What does vagal stimulation have a major influence on?

Answer 22

Heart rate

Question 23

Why does vagal stimulation have so little effect on force of contraction?

Answer 23

There is very little parasympathetic innervation (if any) of the ventricles

Question 24

Where are adrenaline and noradrenaline released from?

Answer 24

Adrenal medulla

Question 25

What chronotropic and inotropic effects do noradrenaline and adrenaline have?

Answer 25

Minor effects compared with effects of noradrenaline from sympathetic nerves

Question 26

What is cardiac output?

Answer 26

The volume of blood pumped by each ventricle per minute

Question 27

CO = ?

Answer 27

SV x HR

Question 28

Describe blood flow across the heart, starting with the right atrium

Answer 28

Right atrium -\> right ventricle -\> pulmonary artery -\> lungs -\> pulmonary veins -\> left atrium -\> left ventricle -\> aorta -\> body tissues -\> SVC -\> right atrium

Question 29

What is the structure of a lipoprotein?

Answer 29

Question 30

What are the five classifications of lipoproteins?

Answer 30

Chylomicrons, Very low-density lipoproteins (VLDL), Intermediate-density lipoproteins (IDL), Low-density lipoproteins (LDL) and High density lipoproteins (HDL)

Question 31

What effect does HDL have on CHD and atherosclerosis?

Answer 31

Has a protective effect - the lower the amount of HDL, the higher the risk of CHD

Question 32

What are the normal triglyceride levels?

Answer 32

2.3mmol/L

Question 33

What do statins do and how?

Answer 33

Statins reduce amount of cholesterol in body. Act as HMG CoA reductase inhibitors and block the cholesterol synthesis pathway -\> acetyl CoA isn't then made into cholesterol

Question 34

What actions do statins have that aren't on lipids?

Answer 34

Improvement of endothelial dysfunction, increased nitric oxide bioavailability, antioxidant properties, inhibition of inflamm responses, stabilisation of atherosclerotic plaques

Question 35

What are some of the clinical markers of dyslipidaemia?

Answer 35

xanthelasms (xanthomas of the eyelids), tendon xanthomas, tuberous xanthomas, eruptive xanthomas, striate palmar xanthomas

Question 36

What effects does hypertension have on the arteries?

Answer 36

Can cause widening of the arteries - puts strain on the lining, can cause the artery muscle to thicken - restricts blood flow

Question 37

What are the two types of hypertension?

Answer 37

Essential hypertension (no underlying cause) and secondary hypertension (underlying cause)

Question 38

What are the lifestyle modifications to reduce hypertension?

Answer 38

Lose weight, limit alcohol intake, increase physical activity, reduce salt intake, stop smoking, limit intake of foods rich in fat and cholesterol

Question 39

What is the system of treatment for a recently diagnosed hypertensive treatment who is 55 years or older or black?

Answer 39

STEP 1: calcium-channel blocker or thiazide-type diuretic STEP 2: Add an ACE inhibitor to initial treatment STEP 3: All three drugs from above STEP 4: Add further diuretic therapy or and alpha/beta blocker, consider referral

Question 40

What is the sytem of treatment for a newly diagnosed hypertensive patient who is younger than 55 years old?

Answer 40

STEP 1: ACE inhibitor STEP 2: Add either a calcium-channel blocker or a thiazide-type diuretic STEP 3: All of the above STEP 4: Add further diuretic therapy or an alpha/beta blocker

Question 41

What effects does smoking have in relation to cardiovascular disease?

Answer 41

Increase blood pressure, decreases HDL, damages arteris and blood cells, increases risk of MI

Question 42

What is the metabolic syndrome?

Answer 42

Constellation of major risk factors, life-habit risk factors and emerging risk factors CLUE: distinctive body type with increased abdominal circumference

Question 43

What risk scoring do we use?

Answer 43

The Assign score (assign-score.com)

Question 44

Main therapeutics for tackling ischaemia?

Answer 44

Antianginal medications (calcium blockers, nitrates, beta blockers), revascularisation (angioplasty, CABG) and risk factor modification

Question 45

Main therapeutics for tackling atherothrombosis?

Answer 45

Aspirin, Statins, beta blocker, ACE inhibitor, exercise, smoking cessation, symptom control (antianginal medications and possibly revascularisation)