CVS-cardiac cycle and BP

Question 1

what is the definition of blood pressure?

Answer 1

the measurement of the force against the walls of the arteries

Question 2

what is blood pressure measured in?

Answer 2

mmHg

Question 3

what is the definition of systolic pressure?

Answer 3

maximum arterial (aortic) pressure during left ventricular contraction

Question 4

what is the definition of diastolic pressure?

Answer 4

Minimal arterial (aortic) pressure during left ventricular relaxation

Question 5

what is pulse pressure?

Answer 5

strength of contraction

Question 6

how would you work out pulse pressure?

Answer 6

systolic- diastolic= PP

Question 7

how would you work out mean arterial pressure?

Answer 7

diastolic pressure -1/3 pulse pressure

or

CO x systematic vascular pressure

Question 8

why is mean arterial pressure important?

Answer 8

the heart does not spend an equal amount of time in systole and diastole

Question 9

what proportion of time does the heart spend in diastole?

Answer 9

2/3

Question 10

what proportion of time does the heart spend in diastole?

Answer 10

1/3

Question 11

how would you measure blood pressure?

Answer 11

cardiac output x peripheral resistance

Question 12

how would you measure cardiac output?

Answer 12

stroke volume x heart rate

Question 13

what is the normal value for cardiac output?

Answer 13

~5L/min

Question 14

how would you work out stroke volume?

Answer 14

end diastolic volume (EDV) - end systolic volume (ESV)

Question 15

what is the equation for working out ejection fraction?

Answer 15

stroke volume/ EDV

Question 16

what is the normal range for ejection fraction in a healthy person?

Answer 16

55-75%

Question 17

what is stroke volume?

Answer 17

Amount of blood transferred from left ventricle to the aorta in systole.

Question 18

which 3 factors is stroke volume dependent on?

Answer 18

• preload
• contractility
• afterload

Question 19

what is preload?

Answer 19

volume of blood that the ventricle has available to pump

Question 20

what is contractility?

Answer 20

force that the muscle can contract with

Question 21

what is afterload?

Answer 21

the arterial pressure (aorta) against which the (left) ventricle will contract against

Question 22

what is the end diastolic volume (EDV)?

Answer 22

Total volume of blood left in the ventricle at the end of diastole

Question 23

what is EDV dependent on?

Answer 23

preload

Question 24

what is end systolic volume (ESV)?

Answer 24

Total volume of blood left in the ventricle at the end of systole

Question 25

what is ESV dependent on?

Answer 25

contractility + afterload

Question 26

does the LV ever empty at the ends of systole?

Answer 26

no

Question 27

what should the SV be in a healthy person?

Answer 27

>60ml

Question 28

outline the 7 phases of the cardiac cycle.

Answer 28

1-Atrial systole / Ventricular Diastole 2-Isovolumetric contraction (pressure increases without a change in volume) 3-Rapid ejection of blood out of the ventricles 4-Reduced ejection of blood out of the ventricles 5-Isovolumetric relaxation (pressure decreases without a change in volume) 6-Rapid filling 7-Reduced filling (diastasis)

Question 29

With regards to afterload: A-It refers to the mean arterial pressure in the systemic vasculature B-It refers to the left ventricular end-diastolic pressure C-It refers to the jugular venous pressure D-It refers to the pressure the heart must work against to eject blood during systole E-It refers to myocardial contractility

Answer 29

D

Question 30

With regards to ejection fraction: A-In a normal healthy heart, ejection fraction is ~33% B-In a normal healthy heart, ejection fraction is 100% C-It describes the remaining volume of blood in the ventricle at the end of systole D-It describes the remaining volume of blood in the ventricle at the end of diastole E-It can be calculated by dividing Stroke Volume by End Diastolic Volume

Answer 30

E

Question 31

which 2 mechanisms control blood pressure?

Answer 31

- endocrine (RAAS) | - neuronal

Question 32

which mechanism of BP control is longterm?

Answer 32

endocrine-RAAS

Question 33

which mechanism of BP control is short term?

Answer 33

neuronal

Question 34

which cells sense a decreased flow/ NaCl (indicative of low BP) concentration?

Answer 34

Macula Densa cells of the ascending Loop of Henle in the kidneys

Question 35

which cells secrete renin in response to detected low BP (by macula densa cells)?

Answer 35

juxtaglomerular granular cells

Question 36

what is the role of renin in the RAAS system of BP control?

Answer 36

The enzyme renin converts angiotensinogen (released by the liver) to angiotensin I.

Question 37

which enzyme converts angiotensin I to angiotensin II?

Answer 37

ACE-released by lungs

Question 38

which hormone of the RAAS system has widespread, systemic effects which increase BP?

Answer 38

Angiotensin II

Question 39

outline the effects of angiotensin 2

Answer 39

- Cardiac and vascular hypertrophy - **Systemic vasoconstriction** - Acts on Adrenal Cortex (Zona Glomerulosa) to release Aldosterone->increases kidney NaCl + H2O retention (increase BP) - Acts on the posterior pituitary gland to release ADH-> increases kidney NaCl + H2O retention

Question 40

where is the cardiovascular centre located?

Answer 40

medulla oblongata

Question 41

what does the cardiovascular centre regulate?

Answer 41

- heart rate | - stroke volume

Question 42

what are the 3 types of input sensory receptors?

Answer 42

- proprioceptors - baroreceptors - chemoreceptors

Question 43

what is the role of proprioceptors?

Answer 43

increase heart rate if there is an anticipation for increase in heart rate, e.g. before exercise

Question 44

what do baroreceptors detect?

Answer 44

changes in blood pressure

Question 45

what do chemoreceptors detect?

Answer 45

chemoreceptors

Question 46

does the sympathetic nervous system increase or decrease BP?

Answer 46

increase BP

Question 47

does the parasympathetic nervous system increase or decrease BP?

Answer 47

decrease

Question 48

what do cardiac accelerator nerves of SNS control?

Answer 48

SAN AVN chambers

Question 49

how do cardiac accelerator nerves of SNS control the heart?

Answer 49

releasing noradrenaline that acts on β1 adrenoreceptors.

Question 50

what are the SNS effects on the heart?

Answer 50

-Increase heart rate (positive chronotropic) -Increase contractility (positive inotropic) - Increase CO - Cause peripheral vasoconstriction

Question 51

how does the SNS increase HR?

Answer 51

speeds up the rate of spontaneous depolarisation of pacemaker cells

Question 52

how does the SNS increase contractility?

Answer 52

-increasing CO->increases Ca2+ influx when the L-Type Ca2+ channels are open in contractile cells, thereby increasing contractility

Question 53

does the SNS cause peripheral vasoconstriction or vasodilation?

Answer 53

peripheral vasoconstriction

Question 54

how does the SNS cause peripheral vasoconstriction?

Answer 54

via α1 adrenoreceptors

Question 55

what is a positive chronotropic effect?

Answer 55

increase heart rate

Question 56

what is a positive inotropic effect?

Answer 56

increase contractility

Question 57

what is the effect of the parasympathetic NS on BP?

Answer 57

act to decrease BP

Question 58

through which nerve does the parasympathetic NS control the heart?

Answer 58

The Vagus Nerve (CN X)

Question 59

which heart structures does the parasympathetic NS control?

Answer 59

SAN | AVN

Question 60

which hormone is associated with the PSNS?

Answer 60

acetylcholine

Question 61

which receptor does ACh bind to in the PSNS?

Answer 61

M3 muscarinic receptors

Question 62

what is the effect of the PSNS on heart rate?

Answer 62

Decrease heart rate (negative chronotropic effect) (slows the rate of spontaneous depolarisation of pacemaker cells)

Question 63

what is the effect of the PSNS on contractility?

Answer 63

Little effect on contractility (As most CN X fibres terminate in the nodes and atria – no effect on the ventricles)

Question 64

What does renin produce angiotensin 1 from? ``` A-Angiotensin 2 B-Angiotensinogen C-ACE D-Aldosterone E-ADH ```

Answer 64

B

Question 65

What gland releases ADH? ``` A-Adrenal Gland B-Posterior Pituitary Gland C-Hypothalamus D-Anterior Pituitary Gland E-Salivary Gland ```

Answer 65

B

Question 66

Which receptors do noradrenaline and acetylcholine act on in relation to BP control? ``` A-B1 adrenoreceptor B-B2 adrenoreceptor C-M1 muscarinic receptor D-M2 muscarinic receptor E-M3 muscarinic receptor ```

Answer 66

E