Cardiovascular Physiology and Hemodynamics Flashcards Preview

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Flashcards in Cardiovascular Physiology and Hemodynamics Deck (70)
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1

what does the heart do in systole
what does it do in diastole

systole: contracts
diastole: relaxes

2

where does the right heart pump blood into
where does the left pump blood into

right: lungs and then blood returns to the left heart
left: systemic arteries, body

3

how large are arterioles

10-100 micrometers in diamter

4

what are capillaries the site of

transport of water, gases, electrolytes, substrates, and waste products

5

what do post capillary venules drain

drain the capillaries

6

blood flow to one organ is not dependent on flow to another, what is the exception

GI portal system
hypophyseal portal systemin the pituitary
portal system

7

how does the GI portal system work

-liver obtains blood from portal vein and can be considered in series w/ much of splanchnic circulation
-blood to liver is venous blood, 1/3 is oxygenated from the heart

8

how does the portal system work

2 capillary beds linked by portal vein
venules feed another capillary bed instead of going through the normal series of vessels

9

what is hemodynamics

what is it generated by

in order for blood to flow, there must be a pressure difference at the 2 ends of the vessel (by gravity)
-generated by contraction of ventricles

10

what is peak/systolic pressure
what is relaxation/diastolic pressure

120 mmHg
80mmHg

11

how does gravity affect hemodynamics

gravity subtracts 40 mmHg of pressure from the arteries and veins in the head and then adds about 90 mmHg of pressure to the legs and feet
-veins=flexible so blood pools in legs when standing

12

what is the equation for blood flow

Flow (vol/min) = (change in pressure) / resistance

Flow=velocity x area

13

what is resistance determined by

vessel's diameter and tone as well as blood's viscosity
resistance = 1/ (radius of vessel)
-small radius vessel will have a huge resistance, therefore a tiny amount of flow

14

veins are high _______ vessels
esp those in...

compliance -they can better accommodate increased volume/pressure

legs

15

when is flow rate slower

when vessel diameter is lower

16

if the collective surface area is very large, velocity will be....

slow

17

where is the largest cross-sectional area in the circulatory system

capillary beds
-so velocity is reduced in capillaries

18

***in which region of the vasculature is there the largest drop in blood pressure?

across the arterioles bc its the site of greatest resistance in the cardiovascular system

19

what does slower velocity allow for

more time for gas and metabolite exchange

20

what is transmural pressure (P)

the pressure diff across the wall of a vessel
'across the wall'

21

what is transmural pressure countered by

opposing tension (T) supplied by muscle and connective tissue in the vessel wall

22

what is vascular compliance

change in volume in a vessel for a given chnage in transmural pressure: C= change V / change P

23

what is arteriosclerosis

hardening and thickening of the vessel walls and loss of elasticity

24

what is atherosclerosis

characterized by atheromatous (fatty deposit) and fibrosis of the inner layer of the arteries

25

what do arteriosclerosis and atherosclerosis do to compliance

decrease compliance

26

what is bernoulli's principle

for an inviscid (no viscocity) flow, an increase in the speed of the fluid applies less pressure to the walls

27

what is rheology

the study of fluid dynamic properties of blood

28

what cna happen if velocity is too fast in a vessel

-breakup of the streamlining flow
-streamlining flow involves an optimal alginment of RBScs traveling through vessels at fairly high speeds
-velocity of cells at the center is higher than at the edge
-pressure on the walls will then increase

29

what is streamline flow
what is turbulent flow

velocity center > velocity edge (optimal)
chaotic velocities

30

what do arterioles control
what do they + pre capillary sphincters control

blood flow into a region of tissue
the distribution of flow w/in a capillary network

31

what does ANS control regulate bloodflow through

pre capillary spincters

32

what is the preferential route through the capillary bed

metarteriole

33

what do all endothelial cells have tiny pores (clefts) for?

allow small water soluble molec to pass

34

what are larger pores referred to as? where are they found

fenestra -allow for larger water sol substances, proteins to pass, but most moved by pinocytosis
capillary beds

35

in sinusoidal capillary bed, _____ occur btwn cells
how do lipids cross the membrane

gaps
simple diffusion

36

what is the starling-landis equation

what pressures can it define

determines how much fluid is left back after blood goes through a capillary bed

-roles of hydrostatic and colloid osmotic pressures

37

what is the mean capillary pressure of the arterial end of a capillary?
what is the neg interstitial fluid pressure?
what is the interstitial fluid colloid osmotic pressure? (oncotic pressure)

17 mmHg
7mmHg
4.5mmHg

total=28.5mmHg

38

what is oncotic pressure aka insterstitial fluid colloid osmotic pressure (pulling water in)

created by differences in protein concentration across membrane

39

what would an IOP greater than what block capillary pressure

17

40

in the venous end of a capillary, only a small amount of oncotic pressure remains, how and why

wants to pull fluid into tissues to dilute proteins

28.5mmHg + (-28) = 0.5 mmHg left, results in some fluid being left behind
-lymph vessels return fluid to the venous system

41

what are the functions of lymphatic vessels

1. return of fluids from the extravascular space to the blood
2. provides conduit for return of lymphocytes from tissues to the blood
3. transports fats from GI tract to the blood

42

where are central lacteals located
what do they do

inside villi of the small intestine
absorb fat

43

how do lacteals absorb fat

fats are hydrophobic so they don't mix well into the blood
-create cyle: a fluid formed by chylomicron lipoproteins and triglycerides
-apolipoproteins coat the fat to make it more hydrophili/easier to absorb

44

where does the thoracic duct receive chyle from

the intestine and lymph from the ab
lower limbs
entire left side of the body

45

what is cysterna chyli

a coalescing lymphatic vessel from leg and ab regions

46

what is the thoracic duct responsible for the return of

lymphatic fluid, lymphocytes, chylomicrons

47

what does the right lymphatic duct drain

right arm, right uppper torso and right side of the head

48

what is elephantiasis

obstruction of lymphatics by parasitic filarial worms
-fluid gets left behind, leading to massive swelling of limbs/scrotum

49

waht do lymphatics play an important role in

ensuring there's no net fluid accumulation in the interstitial spaces

50

where is most blood flow in the coronary
waht is it linked to
what is the vasodilator
what kind of innervation is to the coronary vessels

diastole
oxygen demand
adenosine
adrenergic innervation => results in dilation

51

what do vessels in the CNS dilate in response to

does adrinergic (sympathetic) stimulation lead to CNS constriction?

dilate locally as a result of buildup of substances (response to H and CO2) indicating the tissue is in need

NO

52

in skeletal muscle, what molec are involved, waht is blood flow related to

blood flow coupled to activity
H and NO involved

53

in the skin, what are arteriovenous anastomoses?

how do sympathetics converse heat in these?

involved in temp regulation, want blood close to the surface at warmer times and further in the cold

-constricts to conserve heat

54

how does skin circulation dissipate heat? conserve body temp?

blood flow to extremities promoted
sealed off

55

what is raynaud's phenomenon

reversible ischemia of peripheral arterioles
-body part experience vasospasm (sudden constriction of blood vessel) w/ assoicated pallor (pale) and cyanosis
-followed by a hyperemic (excess of blood)

56

what nerve brings back info for the aortic arch, carotid body and carotid sinus

vagus-aortic arch
hypoglossal- carotid body and sinus

57

waht is sensed by the baroreceptors
what is sensed by chemoreceptors

blood pressure changes
changes in oxygen, co2 and pH (primarily ventilation but also blood flow)

58

what is important regarding which nerve brings back information

LOCATION, NOT TYPE OF INFO

59

what does the barorecptor reflex activate

hormonal system that changes blood prssure

60

what is the renin-angiotensin aldosterone system (RAAS) system critical in?

regulation of blood pressure

61

what does angiotension 2 act as

most potent vasocontrictor

62

what is renin secreted by

cells lining the afferent arteriole in the kidney

63

what do cells in the glomerulus sense?

reduced Na in filtered fluid, indicating not enough fluid filtered aka bp too low

64

what converts angiotensinogen to angiotensinogen 1
what converts it to angiotension 2

renin
ACE

65

what do ace inhibitors do

reduce high blood pressure

66

when do muscle cells (atrial cardiocytes) in the RA produce atrial natriuretic factor (ANF)

what do they increase in urine

when they sense higher blood volume (hihg bp) in the RA
-ANF=increase in Na excretion in the urine

67

what does the atrial natriuretic factor counteract

volume overload

68

what is erythropoietin (EPO)

hormone released by peritubular cells in the kidneys in response to hypoxia or reduced hematocrit

69

what does EPO act on? where is it expressed? what does it lead to an increase in?

bone marrow cells w/ EPO receptor s
brain and retina
RBC production

70

what may EPO be useful for

treatment of diabetic retinopathy and ME
-expressed in retina
-protects against VEGF-induced permeatbility of the bbb