cvs 4

Question 1

BF to an organ is proportional to its metabolic activity. IE more blood flow to exercising muscles is an example of

Answer 1

active hyperemia

Question 2

is an increase in blood flow to an organ to occurs after a period of occlusion of flow

Answer 2

reactive hyperemia

Question 3

what three organs exhibit auto-regulation

Answer 3

heart, brain, kidneys

Question 4

blood flow to an organ remains constant over a wide range of perfusion pressures- this is called

Answer 4

auto regulation

Question 5

what is used to explain autoregulation

Answer 5

myogenic hypothesis

Question 6

vascular smooth muscle contracts when it is stretched

Answer 6

myogenic hypothesis

Question 7

example of myogenic hypothesis

Answer 7

increase perfusion pressure to an organ increases stretch of vascular smooth muscle leads to contraction. the resulting vasoconstriction will maintain a constant flow.

Question 8

tissue supply of 02 is matched to tissue demand for 02

Answer 8

metabolic hypothesis

Question 9

in metabolic hypothesis vascular metabolites are produced as a result of metabolic activity in tissue. what are the vasodilators

Answer 9

c02
H+
K+
adenosine

Question 10

during exercise the increase metabolism leads to what

Answer 10

increase production of vasodilators, increase blood flow, increase 02 delivery to the tissue

Question 11

increase sympathetic tone causes

Answer 11

vasoconstriction

Question 12

decrease sympathetic tone causes

Answer 12

vasodilation

Question 13

what is bradykinin similar to

Answer 13

histamine

Question 14

what causes arteriolar constriction helps to prevent blood loss

Answer 14

serotonin 5-ht

Question 15

what is implicated in the vascular spasm of migraine headache

Answer 15

serotonin 5ht

Question 16

what are the effects of histamine

Answer 16

arteriolar dilation and venous constriction leads to increased capillary hydrostatic pressure and increased filtration out of the capillaries resulting in local edema

Question 17

how does histamine create local edema

Answer 17

artery dilation venous constriction
increase cap hydrostatic pressure
increased filtration out of the capillaries

Question 18

prostacyclin is a

Answer 18

vasodilator

Question 19

thromboxane A2 is a

Answer 19

vasoconstrictor

Question 20

what do baroreceptors do

Answer 20

alerts brain in case of low blood pressure

Question 21

what are baroreceptors

Answer 21

stretch receptor

Question 22

where are baroreceptor located

Answer 22

carotid sinus near the bifurcation of common carotid arteries

Question 23

what is responsible for the minute to minute regulation of arterial BP

Answer 23

baroreceptor

Question 24

what accounts for vasomotor tone and produces vasoconstrictor activity tonically

Answer 24

baroreceptor

Question 25

what controls circulation

Answer 25

sympathetic nervous system

Question 26

what controls the heart function via vagus nerve

Answer 26

parasympathetic nervous system

Question 27

where does the vasomotor center transmit its impulses

Answer 27

down the cord to almost all blood vessels

Question 28

where is the VMC located?

Answer 28

bilaterally in the reticular substance of the medulla and the lower third of the pons

Question 29

what is the vmc composed of

Answer 29

a vasoconstrictor area, vasodilator area, and sensory area.

Question 30

decrease stretch on the baroreceptors - what happens

Answer 30

the firing rate of the carotid sinus nerve hering nerve, CN IX, which stimulates the VMC in the brain

Question 31

The responses of VMC to a decrease MAP are:

Answer 31

Decrease parasympathetic (vagal) outflow to the heart Increase sympathetic outflow to the heart and blood vessels

Question 32

The following four effects attempts to increase the arterial pressure to normal

Answer 32

increase Heart rate ,resulting from decrease parasympathetic tone and increase sympathetic tone to the SA node increase Contractility and SV which produces increase in cardiac output increase vasoconstriction of arterioles; as a result TPR will increase , increasing arterial pressure increase vasoconstriction of veins resulting increase venous return

Question 33

A decrease in renal perfusion pressure causes the juxtaglomerular cells to secrete

Answer 33

renin

Question 34

ACE catalyzes the conversion of angiotensin I to angiotensin II in the

Answer 34

lungs

Question 35

ace inhibitors

Answer 35

e.g. captopril) blocks the conversion of angiotensin I to angiotensin II and therefore, BP

Question 36

arb action

Answer 36

Angiotensin receptor (AT1) antagonist (e.g. Losartan) block the action of angiotensin II at its receptor and decrease blood pressure.

Question 37

what does angiotensin 2 have for effect on aldosterone

Answer 37

synthesis and secretion of aldosterone by the adrenal cortex

Question 38

aldosterone increases what to be reabsorbed

Answer 38

Na+ reabsorption by the renal distal tubular, thereby increasing extracellular fluid volume

Question 39

increase HR= means? treatment?

Answer 39

increase 02 consumption decrease coronary blood flow give beta blockers

Question 40

increase BP | increase Wedge

Answer 40

increase afterload increase work of heart increase 02 consumption increase depth of anesthesia nitroglycerin

Question 41

decrease blood pressure | decrease or normal wedge

Answer 41

decrease TPR decrease BP and coronary blood flow decrease anesthesia fluids phenylephrine to improve BP and coronary circulation

Question 42

decrease BP | increase wedge

Answer 42

heart is failing intros phenylephrine nitroglycerine

Question 43

normal hemodynamics

Answer 43

ng and CA channel blockers

Question 44

Loss of circulating volume % | < 20 %

Answer 44

Skin changes BP normal Thirsty , cold , wake and alert

Question 45

20-40%

Answer 45

Oliguria (20 ml/hr) Restlessness decrease BP, weak pulse >120 Confusion

Question 46

> 40 %

Answer 46

Very low BP, no pulse >140 EKG changes Lethargic, coma No urine output

Question 47

Coronary Circulation %

Answer 47

5% of cardiac output (250 ml/min)

Question 48

Coronary Circulation | vasodilation

Answer 48

hypoxia and adenosine

Question 49

Bainbridge Reflex

Answer 49

Increase in atrial pressure increases heart rate Stretch of atria sends signals to VMC via vagal afferents to increase heart rate and contractility. Prevents damming of blood in veins atria and pulmonary circulation.

Question 50

Cushing reaction:

Answer 50

increased ICP causes compression of cerebral blood vessels leading to cerebral ischemia and increase cerebral PCO2 .The VMC directs an increase in sympathetic outflow to the heart and blood vessels, which cause a profound hypertension, bradycardia and irregular respiration (Cushing triade; opposite to shock !)

Question 51

Cerebral ischemia

Answer 51

Cerebral ischemia When the brain is ischemic the conc. of CO2 and H+ in brain tissue increases Chemoreceptor in the VMC respond by increasing sympathetic flow to heart and blood vessel Constriction of arterioles causes intense peripheral vasoconstriction and increase TPR Blood flow to other organs (e.g. kidneys) is significantly reduce in an effort to keep blood flow to brain MAP can increase to life-threatening levels

Question 52

Angiotensin II has four effects

Answer 52

It stimulates the synthesis and secretion of aldosterone by the adrenal cortex Aldosterone increases Na+ reabsorption by the renal distal tubule, thereby increasing extracellular fluid volume, blood volume and arterial pressure This action of aldosterone is slow because it requires new protein synthesis It increases Na+-H+ exchange  contraction alkalosis It increases thirst It causes vasoconstriction of the arterioles, thereby increasing the TPR and MAP

Question 53

Steps in the renin-angiotensin-aldosterone system

Answer 53

A decrease in renal perfusion pressure causes the juxtaglomerular cells to secrete renin Renin catalyzes the conversion of angiotensinogen to angiotensin I in plasma ACE catalyzes the conversion of angiotensin I to angiotensin II in the lungs ACE inhibitors (e.g. captopril) blocks the conversion of angiotensin I to angiotensin II and therefore, BP Angiotensin receptor (AT1) antagonist (e.g. Losartan) block the action of angiotensin II at its receptor and decrease blood pressure.

Question 54

Renin-angiotensin-aldosterone system

Answer 54

Is a slow, hormonal mechanism Is used in long-term blood pressure regulation by adjustment of blood volume Renin is an enzyme that catalyzes the conversion of angiotensinogen to angiotensin I in plasma Angiotensin I is inactive Angiotensin I is converted into Angiotensin II by ACE in lung Angiotensin II is physiologically active

Question 55

Valsalva maneuver

Answer 55

expiring against a closed glottis) Tests the integrity of baroreceptor mechanism Causes  intrathoracic pressure which  venous return The  venous return causes  in cardiac output and arterial pressure (Pa) If the baroreceptor reflex is intact, the decrease in Pa is sensed by the baroreceptor, leading to  in sympathetic flow to the heart and blood vessels. In the test,  in heart rate would be noted. When the person stops the maneuver, there is a rebound increase in venous return, cardiac output and Pa. The  in Pa is sensed by the baroreceptor, which direct a  in heart rate.