REGULATION OF BLOOD FLOW

Question 1

the heart pumps the of blood that the body needs is defined as?

Answer 1

cardiac output

Question 2

cardiac output control by the?

Answer 2

autonomics

Question 3

tissue control by?

Answer 3

local regulation

Question 4

which of the tissues require the most blood?

Answer 4

brain and heart because of work load

Question 5

what is the main cause for increase flow in local regulation?

Answer 5

increase metabolism or increase altitude in response to decrease local O2

Question 6

what is the vasodilator theory?

Answer 6

increase metabolism in which the cells release chemicals to increase:

hydrogen ion concentration
histamine
adenosine
CO2
potassium 
this leads to:

relax smooth muscle to decrease resistance to increase flow

Question 7

what is the most potent vasodilator?

Answer 7

adenosine

Question 8

what is the intrinsic property of smooth muscle? what type of regulatory mechanism is this?

what is the effect of increase pressure?

Answer 8

when stretched it contracts

non metabolic local regulatory mechanism

increases flow and increase resistance to flow is constant

Question 9

so if we have multiple neighboring capillary beds vasodilating, how do upstream vessels get the message?

Answer 9

EDRF

endothelial derived releasing factor aka nitric oxide which is a 6 second life span

Question 10

what does the heart undergo due to increased metabolic demand? population this usually occurs in?

Answer 10

increased vascularity due to angiogenesis which can take days to weeks

children, damaged tissue and cancers

Question 11

what are the signals that stimulate angiogenesis? and this is because of ____?

Answer 11

vascular endothelial growth factor (VEGF)
fibroblast growth factor (FGF)
angiogenin

increased metabolic demand

Question 12

what is angiogenesis?

Answer 12

promotes new vessels to sprout off of the existing vessels

Question 13

what are the important systemic vasoconstrictor humoral agents?

Answer 13

NE/EPI
Angiotensin II (constricts the arterioles and increases TPR to maintain BP)
Vasopressin
endothelin (produced by damaged vessels, limits blood loss at the wound site)

Question 14

what are the systemic vasodilators? how do these work?

Answer 14

bradykinin
histamine

increase flow and increase capillary porosity, so area becomes flushed and edematous

Question 15

what are the ions below affect on vascular function?

increase ECF calcium 
increase ECF magnesium
increase ECF potassium
increase ECF hydrogen ion
increase ECF PCO2

Answer 15

increase ECF calcium - vasoconstriction

rest, vasodilation and also in the brain when there is an increase in ECF PCO2

Question 16

T/F, cardiac output is affected by autonomic regulation? if so, which ones and how

Answer 16

T

both sympathetic (positive ionotropism and chronotropism) and parasympathetic (negative chronotropism)

Question 17

what do the sympathetics not innervate in terms of the arteries? where for the ones that do?

Answer 17

capillaries, precap sphincters, metarterioles

kidney
intestine
spleen
skin

not so effective in muscle and brain

Question 18

what is the effect of arterial vasoconstriction?

Answer 18

increase resistance
increase blood pressure
decrease BF to constricted area

Question 19

in terms of venous constriction, what happens when these larger veins are affected by the sympathetics?`

Answer 19

increase venous return
increase EDV
increase cardiac output
increase arterial pressure

Question 20

what causes the sympathetics to start firing? parasympathetics?

Answer 20

vasoconstrictor area of vasomotor center in the medullary reticular formation controls the vasoconstrictor outflow

vasodilator center also in vasomotor center and controls parasympathetic outflow

Question 21

since vessels are tonically partially contracted what is this called and mediated by?

Answer 21

sympathetic vasoconstrictor tone mediated by alpha one adrenergic receptors

Question 22

what inputs affect the vasomotor center?

Answer 22

1)pons and midbrain
2)hypothalamic neurons
limbic cortex
3)baroreceptors in the carotid sinus and aortic arch

Question 23

describe vasovagal syncope?

Answer 23

increase parasympathetic outflow leads to vasodilation and decrease venous return to decrease arterial pressure and then fainting

Question 24

so when the baroreceptors in the carotid sinus work what is the effect when there is a decrease in arterial P after 10 seconds?

Answer 24

increase SV, HR, TPR so overall increase in blood pressure

Question 25

where are key baroreceptors located? what do these sense? what is the result?

Answer 25

carotid sinus and aortic arch and also located in thoracic systemic arteries and these are called pressoreceptors

increase pressure causes stretch on vessel

increase vasodilator center, decrease vasoconstrictor center, increase vagal parasympathetic center

Question 26

what is the sensitivity range for the baroreceptors? effect outside this range

Answer 26

30-180 mm Hg

less than 30, no firing
more than 30, max discharge rate

Question 27

T/F, long term BP regulation is the job of baroreceptors? if not, Than what is?

Answer 27

nope, false but they can increase sodium and water loss (decrease plasma volume)

kidneys do long term

Question 28

what is the pressure a function of?

Answer 28

blood volume via kidneys (long term) and vascular volume (baroreceptors regulate in the short term)

Question 29

T/F, there are stretch receptors in the atria and pulmonary arteries? high or low pressure receptors? the affect on cardiac output

the atrial receptors also trigger what reflex?

Answer 29

T

low pressure receptors

decrease cardiac output

volume reflex

Question 30

what is the volume reflex?

Answer 30

increase blood volume sensed, increase VR, increase atrial P leading to receptors firing which inhibit ADH released vasodilator afferent arterioles in the kidney that overall leads to urine formation decrease blood volume and the atrial reflex

Question 31

the atrial reflex triggers this reflex?

Answer 31

bainbridge reflex which decreases the atrial P