Blood Vessels Flashcards Preview

Human Anatomy & Physiology 2 > Blood Vessels > Flashcards

Flashcards in Blood Vessels Deck (83):
1

arteries

away from the heart

2

veins

toward the heart

3

capillaries

site of exchange between arteries and veins

4

3 Layers of the blood vessel wall

tunica intima
tunica media
tunica externa/adventitia

5

tunica intima (3)

inner layer
keeps clotting from occurring
simple squamous endothelium that is continuous with endocardium of the heart

6

tunica media (2)

middle layer
usually thickest with smooth muscle for vasomotion

7

tunica externa (2)

outermost layer
loose connective tissue

8

Which lumen is largest, vein or artery? Why?

Vein because they are low resistance pathway

9

What are the 4 types of arteries?

conduction or elastic
distributing or muscular
resistance or arterioles
metarterioles

10

resistance//arterioles

control the amount of blood to various organs (vasocontrict or vasodilate)

11

metarterioles

short vessels that connect arteries to capillaries

12

conducting//elastic (2)

pulmonary, aorta, and common carotid
expand and recoil to lessen fluctuation in blood pressure

13

distributing//muscular

distributes blood to specific organs

14

3 types of capillaries?

continuous
fenestrated
sinusoid

15

continuous capillaries (2)

occur in most tissues
endothelial cells have tight junctions with intercellular clefts

16

fenestrated capillaries (3)

kidneys and small intestines
organs that require rapid absorption or filtration
has filtration pores

17

sinusoid capillaries (2)

liver, bone marrow, spleen
irregular blood filled spaces (allow proteins and blood cells to enter)

18

What do capillary beds consist of? (3)

metaterioles
thoroughfare channel
true capillaries w/ precapillary sphincter

19

precapillary sphincters (2)

regulates the blood flow into the true capillaries
3/4 of them are closed at anytime

20

what regulates the precapillary sphincters? (3)

autonomic nervous system
heat
local chemicals

21

venous sinuses

a type of vein with thin walls and no smooth muscles

22

veins (4)

lower blood pressure
thinner walls
expand easily
valves aid skeletal muscles in upward blood flow

23

What is the capacitance of veins?

contain 75% of the total blood due to large lumen

24

What causes blood to be moved over to the arterial side from the venous side?

massive sympathetic stimulation

25

What is the classic route of the circulatory system?

heart->artery->arterioles->capillaries->venules-> veins

26

portal system

blood flow that goes through 2 consecutive capillary networks before entering the heart

27

What are the 3 portal systems in the body?

hypothalamus-anterior pituitary
found in kidneys
between intestines-liver

28

anastomoses

point where 2 blood vessels merge

29

arteriovenous anastomosis

artery flows directly into vein

30

venous anastomosis (2)

vein to vein
alternate drainage of organs

31

arterial anastomosis (2)

artery to artery
collateral circulation

32

hemodynamics (2)

distribution of blood within the cardiovascular system
distribution of the cardiac output within the different tissues

33

Distribution of blood is determined by (3)

blood flow
blood pressure
resistance

34

tissue blood flow? the total amount equals what?

amount of blood flowing per min
cardiac output

35

perfusion

rate of blood flow through a vessel per gram of tissue

36

What does flow determine?

the speed of nutrient delivery and waste removal

37

True or False, does each organ have its own value for flow? What is it defined as?

TRUE; percentage of the total flow or cardiac output

38

What are the 2 factors that determine blood flow?

blood pressure differences
resistance

39

blood pressure? what causes this?

the force exerted by blood against the blood vessel wall; the contraction of the heart generating a hydrostatic pressure that is conducted in all directions

40

in the systemic loop, the delta P is the pressure differnce between....

the start of the aorta and the right atrium (95mmHg to 5mmHg)

41

What are the 3 types of blood pressure?

arterial
venous
capillary

42

arterial blood flow

measured at brachial artery of the arm
is pulsatile

43

systolic pressure

BP during ventricular systole (contraction)

44

diastolic pressure

BP during ventricular diastole (relax)

45

normal blood pressure

120/75 mmHg in young adult

46

pulse pressure (3)

can be felt with finger
systolic-diastolic
important measure of stress exerted on arteries

47

MAP? what is the best estimate?

mean arterial pressure
measurement taken at intervals of cardiac cycle
(diastolic pressure + (1/3 of pulse pressure))

48

Where is the largest pressure drop?

in the arterioles

49

what is the importance of arterial elasticity? (3)

expansion and recoil maintains steady flow of blood throughout cardiac cycle
smooths out pressure fluctuations
decrease stress on small arteries

50

As BP rises with age; arteries become?

less distensible (recoil and elastic capability)

51

Why must capillary blood pressure be low? (3)

capillaries are fragile
capillaries are permeable
capillary flow rate is very low for nutrient exchange

52

What are the 2 mechanisms of venous return?

skeletal muscle pump in the limbs
thoracic pump

53

thoracic pump: during inhalation the thoracic cavity ______ which causes the BP to _____. The abdominal pressure _______ forcing blood ____

expands; decrease; increase; upward

54

resistance

any force that opposes movement

55

total peripheral resistance? where is most of the resistance?

the resistance that blood encounters as it travels through the circulatory system; on the arterial side

56

What are the resistance sources of blood flow? (3)

viscosity
length
radius

57

blood viscosity

thickness or stickness of blood
greater the thickness the greater the resistance

58

blood viscosity is due mainly to? (2)

erythrocytes
albumin

59

vessel length (2)

not used to regulate flow
the longer the vessel the greater the cumulative friction

60

blood vessel radius (2)

smaller the radius the greater the friction
is changed moment to moment

61

turbulence (2)

more of a pathological issue
normally blood flow is laminar (in layers)

62

bruit? murmur?

turbulence in a vessel; turbulence in the heart

63

what is the main purpose of the cardiovascular system?

to provide the tissues with the appropriate amount of nutrients & remove toxic waste

64

blood flow is regulated by (3)

changing the cardiac output
modifying peripheral resistance
modifying blood pressure

65

the goal of cardiovascular regulation is to alter (3)

flow at the appropriate time
flow to the appropriate areas
flow without drastically changing flow to vital organs (heart and brain)

66

What are the mechanisms used to regulate blood flow?

-local control or autoregulation
-neural mechanism
-endocrine mechanism

67

auto-regulation occurs within a ______ while __ ___ and ___ ___ remain ____.How does it work?

tissue; cardiac output; blood pressure;stable
-works by adjusting peripheral resistance (blood vessel radius) within a tissue

68

what are some local acting vasodilators (5)

-dropping O2 levels
-rising CO2 levels
-rising K levels
-acid
-heat

69

what are some local acting vasocontrictors (2)

-prostaglandin
-endothelin

70

how does heat increase flow for vasodilation?

relaxing the smooth muscle of the arterial walls and precapillary sphincters

71

During neural mechanism, the ___ has control of the CO and peripheral resistance. Where does this mechanism originate?

ANS
-medulla oblongata

72

What is the cardiovascular center contain? (2)

cardiac center
vasomotor center

73

the cardiac center regulates ____; while the vasomotor center regulates ___ ___ to control flow

cardiac output; peripheral resistance

74

vasocontriction neurons

sympathetic fibers that constrict smooth muscle of vessels; "close" them

75

vasorelaxation neurons

sympathetic fibers that relax vessels of the skeletal muscle; "open" them

76

baroreceptors; where are they found?

pressure receptors
aortic and carotid

77

when there is a drop in pressure what does this cause the baroceptors to do? (2) Overall?

-stimulate cardioaccelatory center->increase CO
-stimulate vasocontriction center-> increase peripheral resistance
overall it increases flow to vital tissues

78

when there is an increase in the pressure what does this cause the baroceptors to do? (2)

-inhibit cardioacceleratory center->decrease CO
-inhibit vasocontriction center-> decrease peripheral resistance

79

the chemoreceptors in the vasomotor center stimulate what when there is a drop in O2 and increase in CO2 and acid?

-stimulate cardioacceleratory & vasocontriction

80

consequences of edema? (4)

-tissue necrosis
-pulmonary edema
-cerebral edema
-circulatory shock

81

hypoproteinemia

low protein in liver

82

which mechanism that regulates blood flow has both long and short term regulation?

endocrine

83

long term endocrine mechanism results from regulating?short term?

blood volume; peripheral resistance and CO