Blood flow (exam 3)

Question 1

BP should linearly inc. with inc. work loads, but if it’s not behaving correctly, when do u stop exercise?

Answer 1

if systolic decreases by 20 mmHG

or if diastolic inc. by 10 mmHG

Question 2

formula for BP/ MAP

Answer 2

BP= Q (SVxHR) x TPR

Question 3

does Max BP change with training?

Answer 3

no, ur max is ur max

Question 4

Nervous control of BP: long term solution

Answer 4

kidneys and fluid balance (through blood volume)

Question 5

Nervous control of BP: short term

Answer 5

CV system (HR slows or speeds up to control BP)

Question 6

what role do the atria play in controling BP?

Answer 6

stretch receptors in the atria (barroreceptors-mechanical stretch), detect stretch in atria walls due to inc. blood volume and they signal the brain, whoa hello too much volume/pressure here, so the brain triggers vasodilation in the vv of the legs to decrease the amount coming back to the heart to fast while simultaneously inc. ADH release to make sure it doesn’t decrease too much all at once.

Question 7

what does the vasomotor center of the medulla do?

Answer 7

uses a pressor and depressor to regulate BP

Question 8

where does the vasomotor sensor receive stim. from?

Answer 8

input from sensors all over the body (chemoreceptors, baroreceptors, mm afferent receptors) and from cortex and hypothalamus

Question 9

what does stim of the pressors/ depressors do?

Answer 9

pressor- inc. HR and force of contraction, constricts vascular smooth mm in arterioles and what little their is in vv
depressor= exact opp. of all that- dec. HR, dec. force of contraction, vasodilates, etc.

Question 10

what happens to end diastolic filling with age?

Answer 10

it decreases

Question 11

define velocity

Answer 11

rate, speed at which blood is traveling

Question 12

define flow

Answer 12

volume, amount of blood/time

Question 13

types of flow

Answer 13

laminar- linear, smooth

turbulent- bubbly, going all diff. directions (happens at divergences,tears/flaps in vessel walls, plaques)

Question 14

Darcy’s law

Answer 14

Q (flow this time)= [(P1-P2)/R]

Question 15

what vessels have the lowest velocity of flow in order to allow for blood product exchange between them and their target tissues?

Answer 15

capillaries

Question 16

in what vessels is vascular resistance highest?

Answer 16

arterioles (tiny holes, makes cells get down to one lane, and they have mm walls- think traffic going from three lane highway to one lane walled off bc of construction)

Question 17

what is defined as the total vascular resistance from the aorta to the R atrium

Answer 17

TPR

Question 18

what vessels have lowest vascular resistance to flow?

Answer 18

veins

Question 19

velocity of flow is _______ proportional to the cross sectional area of the vessel

Answer 19

inversely (think, big pipe= flows slower, tiny pipe= must flow faster)

Question 20

if length of tube doubles, what happens to flow?

Answer 20

decreases by 50% (duh, can now only move halfway thru in the same amount of time)

Question 21

if tube radius doubles, what happens to flow?

Answer 21

increases 16 fold! (pouring a gallon of milk through a PVC pipe or through a drinking straw)

Question 22

if viscosity of the liquid doubles, what happens to flow?

Answer 22

it decreases by half (think pouring water through a funnel or pouring honey through the same funnel)

Question 23

where is blood flow the fastest? when does this principal become a problem?

Answer 23

fastest in center of vessel bc encounters no resistance there, around the sides of the vessel it has friction from the vessel walls. this becomes problematic if vessels aren’t elastic enough (due to connective tissue disorders like marfan’s syndrome, or due to plaque buildup) to vasodilate when pressure is too great and they tear or break

Question 24

what does the shearing forces of the blood friction on the vessel walls trigger to be releases?

Answer 24

nitric oxide–>tells brain to vasodilate

Question 25

these types of vessels have inc. motor tone compared to these vessels which always need to stay open?

Answer 25

heart, mm, skin= inc. tone

cerebral and renal= dec. tone bc they always need to be open!

Question 26

what does bradykinin do

Answer 26

vasodilates

Question 27

what does norepinephrine do?

Answer 27

vasoconstriction

Question 28

what does angiotensin II do?

Answer 28

vasoconstriction

Question 29

what does vasopressin (ADH) do?

Answer 29

vasoconstriction

Question 30

what does the symp. NS do?

Answer 30

inc. vasomotor tone

Question 31

what does the parasymp. NS do?

Answer 31

dec. vasomotor tone

Question 32

what is a potent vasodilator and is released with inc. metabolic activity or when ATP levels are low… ?

Answer 32

adenosine!

Question 33

what does K+ do and how does it do it?

Answer 33

vasodilation of blood vessels, hyperkalemia= decreases Ca which is what goes to the vascular smooth mm cells to make them contract, less Ca= less contracting=relaxation and dilation ;)

Question 34

what do arachidonic acid and histamine do to tone?

Answer 34

can inc. or dec. tone

Question 35

what does myogenic mechanisms in vasc. smooth mm cells do?

Answer 35

inc. tone

Question 36

what do endothelial factors such as nitric oxide and endothelin do?

Answer 36

inc. or dec. tone

Question 37

what is reactive hyperemia?

Answer 37

momentary inc. of blood flow after brief period of total ischemia, like after getting ur BP taken, or having a turnicate on. RELEASE the flood gates!

Question 38

active hyperemia

Answer 38

actively increasing blood flow, like by running

Question 39

loss of what cells will keep vessels from being able to dilate or constrict?

Answer 39

endothelial cells

Question 40

what happens to vessels that aren’t used as much, say from injury or say in a SCI when a person doesn’t use their leg mm so their vessels don’t pump to the mm near as much anymore?

Answer 40

the vessels constrict, but blood flow and diameter will increase with training or e-stim, etc. things that get those mm working again.

Question 41

will the affected limb ever match the nonaffected limb again?

Answer 41

no, it will improve, but not match it, as far as blood flow goes.