circulation pt2

Question 1

what is the Frank-Starling effect?

Answer 1

an increase in end-diastolic volume (blood in ventricle during diastole, before contraction) results in a more forceful contraction and increased SV (stroke volume)

length-tension relationship for muscle

heart automatically compensates for increases in volume of blood returning to the heart (AUTOREGULATION)

more blood enter ventricle, more forceful contraction (increase SV, more blood leave ventricle)

Question 2

what would happen if the Frank-Starling effect did not occur?

Answer 2

blood would pool, large amounts of venous blood will be stuck in ventricle bc increased venous blood are entering the ventricle but blood leaving the ventricle remains the same
(more blood enter than leave ventricle)

Question 3

level of sympathetic activity shifts the position of…

Answer 3

the cardiac muscle length-tension relationship

(stroke volume will be higher during increased sympathetic activity compared to basal level, even when end-diastolic volume are the same)

Question 4

how do arterioles control blood distribution

Answer 4

arranged in parallel so can alter blood flow to various organs

by vasoconstriction of vasodilation (change resistance)

Question 5

factors that control vasoconstriction and vasodilation

Answer 5

autoregulation (direct response of arteriole smooth muscle to blood pressure)

intrinsic factor (metabolic rate of tissue)

extrinsic factor (nervous and endocrine systems)

Question 6

what are the 2 organs that receive the highest percentage of blood in humans?
why?

Answer 6

liver + digestive tract

kidneys

bc they detoxify blood

Question 7

contraction of what reduces blood flow to capillary bed?

why do they want to reduce blood flow to certain areas?

Answer 7

contraction of pre-capillary sphincters

reduce tissues that are not being used and bring blood to tissues that need them more

Question 8

what are some myogenic autoregulation of flow

Answer 8

smooth muscle cells in arterioles are sensitive to stretch and contract when blood pressure increases-> to keep things constant

(negative feedback loop, prevents excessive flow of blood into tissue) may have pooling in tissues without this response

Question 9

what is the process for blood flow to match to metabolic requirements?

Answer 9

tissue metabolic rate up
O2 down, CO2 up, waste up
arteriolar smooth muscles sense this
vasodilation
resistance down
blood flow up
O2 delivery up, CO2 removal up, waste removal up
tissue O2 up, tissue CO2 down, waste down

(negative feedback loop)

Question 10

hormones that cause vasoconstriction

Answer 10

Vasopressin (ADH) from posterior pituitary
Angiotensin II in response to decreased blood pressure
norepinephrine from sympathetic neurons

Question 11

hormones that cause vasodilation

Answer 11

decreased sympathetic tone (norepinephrine)
atrial natriuretic peptide (ANP) in response to increased blood pressure

Question 12

why does pressure and pulse decrease in arterioles

Answer 12

due to high resistance

Question 13

how does the aorta act as a pressure reservoir

Answer 13

with elastic vessel wall, expands during systole and recoil during diastole

dampens pressure fluctuations

Question 14

what is vein volume controlled by

Answer 14

sympathetic nerves-> venomotor tone

Question 15

which contains more volume of blood vein or arteries

Answer 15

veins

Question 16

what are the 2 pumps that assist in moving blood back to heart?

why do they need the pumps?

Answer 16

skeletal muscle (contraction of muscle squeezes vein) and respiratory pumps (pressure changes in thoracic cavity during ventilation)

because blood in veins is under low pressure

Question 17

equation for mean arterial pressure

Answer 17

MAP = CO * TPR

CO= cardiac output
TPR= total peripheral resistance

Question 18

what are baroreceptors?
where are they found?
what do they do?

Answer 18

stretch-sensitive mechano receptors in walls of many major blood vessels

in carotid arteries and aorta

send nerve signals to cardiovascular control center-> regulates MAP

Question 19

how do kidneys help maintain blood volume?

Answer 19

excrete or retain water to adjust blood volume and pressure

Question 20

what is the starling principle?

Answer 20

net filtration pressure = (Pcap - Pif) - (picap - piif)

Pcap= hydrostatic pressure of blood in the capillary
Pif= hydrostatic pressure of interstitial fluid
picap= osmotic pressure in the capillary
piif= osmotic pressure interstitial fluid

Question 21

what is osmotic pressure caused by?
what does it do?

Answer 21

salts and proteins in solution
if osmotic pressure is higher in interstitial fluid than capillary, fluid will enter the capillary

Question 22

what does capillary hydrostatic pressure do?
why does capillary hydrostatic pressure decrease over time?

Answer 22

forces fluid out of capillaries
bc of resistance

Question 23

describe the osmotic pressure in capillary over time

Answer 23

stays the same

Question 24

describe filtration and reabsorption as blood travels from aortic end to venous end

Answer 24

aortic end: pressure in capillary higher than osmotic pressure, fluid moves out of capillary-> net filtration

venous end: pressure in capillary lower than osmotic pressure, fluid enters capillary-> net reabsorption

Question 25

what does the lymphatic system do?

Answer 25

collects excess filtered fluid and returns it to circulatory system

Question 26

what do lymph nodes do?

Answer 26

filter lymph to remove pathogens

Question 27

what is edema?

Answer 27

accumulation of interstitial fluid

Question 28

equation for hydrostatic pressure

Answer 28

delta P = rho * g * delta h

Question 29

how do body positions alter blood pressure and flow?

Answer 29

changes relative to gravity standing up causes pooling of blood in lower body (venous return down, SV down, MAP down)

Question 30

what can bring the MAP back to normal when standing?

Answer 30

baroreceptor reflex HR up, SV up, MAP up

Question 31

what is orthostatic hypotension

Answer 31

low blood pressure upon standing when reflex is too slow can result in fainting

Question 32

what are some adaptations the giraffe has to overcome hydrostatic pressure?

Answer 32

very strong heart w/ low stroke volume and fast heart beat that generates super high MAP muscular arteries skin on legs very tight tight endothelium venous valves

Question 33

how does hydrostatic pressure impact animals in water

Answer 33

blood and water have a similar density and hydrostatic effects outside the animal cancel out the gravitational effects

Question 34

steps of tissue regeneration

Answer 34

wound healing blastema formation cells differentiate and tissue regeneration

Question 35

what are the steps to wound healing

Answer 35

hemostasis inflammation and proliferation remodeling/ maturation

Question 36

in humans, which organs can regenrate?

Answer 36

liver organs such as thyroid gland, kidney, lungs have facultative regeneration (depend on type of damage and severity)

Question 37

in the study, gill regeneration was higher in which treatment for the gills?

Answer 37

50% resection gills had higher levels of regeneration (compared to 30% resection)