Physiology

Question 1

How is called absolute volume of blood ejected from LV with each contraction?

Answer 1

stroke volume

Question 2

How to calculate SV? (since it’s volume - take in equation volume!)

Answer 2

LVEDV - end systolic volume

Question 3

What is normal stroke volume? in ml

Answer 3

70ml

Question 4

What is ejection fraction?

Answer 4

Relative volume of blood ejected from the LV with each contraction

Question 5

How to calculate EF?

Answer 5

SV/LVEDV

Question 6

Normal value of EF?

Answer 6

50 or more proc

Question 7

what if difference between SV and CO?

Answer 7

SV - volume of each contraction

CO - volume per minute

Question 8

How to count CO?

Answer 8

SV x HR

Question 9

Why equation CO = SVxHR overestimates CO in mitral regurgitation?

Answer 9

because a portion of stroke volume flows backward into the left atrium with each contraction

Question 10

How is compensated decreased CO in HF?

Answer 10

increased HR
CO=SVxHR.
eg if the heart cannot properly pump blood –> lower volume ejected; therefore need to increase HR

Question 11

How can calculate CO in two ways?

Answer 11

CO=SVxHR

CO= rate of O2 consumption/arteriovenours O2 content difference

Question 12

Arterial oxygen content is measured directly from ………..

Answer 12

arterial blood

Question 13

Mixed venous oxygen content is measured from ………………….

Answer 13

pulmonary arterial blood

Question 14

What catheter and principle can be used in CO determination?

Answer 14

Pulmonary artery catheter (Swan-Ganz)

Applying the Fick principle

Question 15

The rate of oxygen consumption can be determined with an oxygen meter by measuring ………..

Answer 15

The rate of disappearance of oxygen in exhaled air.

Question 16

arteriovenous difference in oxygen content can be calculated by ……….

Answer 16

arterial blood O2 content - venous blood O2 content

Question 17

Decrease in CO and BP –> reduced stretch of the arterial wall –> reduced baroreceptor firing and ……………….. activation of ……….. nucleus

Answer 17

decreased activation of the solitary nucleus

Question 18

Decreased activation of the solitary nucleus: sympathetic and parasympathetic outflow?

Answer 18

Increase in sympathetic outflow; decrease in parasympathetic

Result: vasoconstriction and incr. HR and contractility

Question 19

ANP in decreased baroreceptors firing?

Answer 19

Reduced atrial stretch –> decreased ANP secretion

Question 20

In hypervolemic states, blood pressure is increased, leading to …….. baroreceptor firing.

Answer 20

increased

Question 21

In hypervolemia: sympathetic and parasympathetic flow?

Answer 21

Increased baroreceptor firing –> incr. solitary nucleus? –> dec. sympathetic and incr. parasympathetic
Result: decr. vascular tone, HR and contractility

Question 22

ANP in hypervolemia?

Answer 22

Incr atrial wall stretching –> incr. ANP release –> vasodilation and diuresis

Question 23

In which artery is carotid sinus?

Answer 23

internal carotic artery just above bifurcation

Question 24

The carotid sinus reflex has an ………… limb that arises from the baroreceptors in the carotid sinus and travels to the …………. centers via the ……………. a branch of the …………….. nerve (CN IX).

Answer 24

Afferent limb;

medullary centers via the Hering nerve, a branch of the glossopharyngeal nerve (CN IX).

Question 25

The .............. limb of the carotid sinus carries parasympathetic impulses via the ............ (CN X)

Answer 25

``` Efferent limb; vagus nerve (CN X) ```

Question 26

Carotid massage: sympathetic and parasympathetic?

Answer 26

Massage --> increased firing --> inhibition of sympathetic and activation of parasympathetic output

Question 27

Nervus vagus is afferent in ...........

Answer 27

aortic arch

Question 28

nervus vagus is efferent in ........

Answer 28

carotid sinus

Question 29

In carotid sinus hypersensitivity presyncope etc results from overly sensitive receptors that stimulate ............. response to tactile stimulation

Answer 29

stimulate vasovagal response

Question 30

CSH is most commonly in ................. (what population). What underlying conditions (2) are risk factors for CSH?

Answer 30

elderly men; | Underlying atherosclerotic disease and prior neck surgery

Question 31

increased parasympathetic output leads to prolonged .................... (eg. ....-.... seconds)

Answer 31

prolonged sinus pause; | 3-5 seconds

Question 32

Decreased sympathetic outflow in CSH causes marked .......................

Answer 32

Peripheral vasodilation

Question 33

What 2 components in CSH leads to profound reduction in blood pressure?

Answer 33

Delay in ventricular contraction + decreased systemic vascular resistance