Circulatory system Flashcards Preview

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Flashcards in Circulatory system Deck (85):
1

What are the 5 types of vessels (in order from heart)

1. Arteries
2. Arterioles
3. Capillaries
4. Venules
5. Veins

2

what is an artery

a vessel that takes blood from the heart

3

what is a vein

a vessel that takes blood to the heart

4

what is the function of arteries

they are designed for rapid transport, they are large in diameter with low resistance. They are elastic and designed to withstand pressure

5

What is the function of arterioles

They are the primary control of resistance in the circulatory system. They are muscley and able to dialate and constrict

6

What is the function of capillaries

location of nutrient exchange

7

What is the function of venules

they collect blood from capillaries

8

what is the function of veins

serve as a blood resevoir because they can dialate and constrict

9

how do arteries act as pressure resevoirs

they are elastic and can expand when pressure is high, then an inflow decreases they shrink back down to size and push the blood to the rest of the body

10

how does pressure and resistance affect blood flow through a vessel

Flow = pressure gradient/ resistance

11

what is the pressure gradient

the difference in pressure between the aorta and the vena cava (85mmhg)

12

pressure in aorta

85 mmhg

13

pressure in vena cava

0 mmhg

14

pressure gradient in systemic circut

85 mmhg

15

pressure in respiratory circut

15 mmhg

16

is flow equal in systemic circut and respiratory circut

yes

17

is resistance in pulmonary circut high or low

low

18

what are the factors that affect resistance to flow

1. viscosity of fluid
2. length of vessel
3. radius of vessel

19

which factor affecting resistance is most important

radius of vessel

20

why does radius of vessel matter so much

the smaller the vessel the more surface area contact that occurs with the blood and the more resistance that occurs

21

how much does vessel diameter affect resistance

R = 1/r^4

doubling the vessel size gives 1/16 the resistance cutting in in half gives 16 times the resistance

22

What is normal systolic BP

120 mmhg

23

what is normal diastolic BP

80 mmhg

24

how do you find pulse pressure

systolic - diastolic

25

how do you find MAP with systolic and diastolic BP

systolic + 2 diastolic / 3

26

why does diastolic get twice the credit in MAP equation

it lasts about twice the time as systolic

27

What is TPR

total peripheral resistance (combined resistance of all the vessels in the circuit)

28

How can you measure BP

1. inserting a cannula directly and measuring it
2. auscultatory method

29

how do you do the auscultatory method

1. you put a cuff on their arm and pump it up
2. you listen to the vessel
3. when you first hear some noise you check your pressure gage and that is systolic
4. when the noise goes away you check your pressure gage and that is the diastolic BP

30

what is pulse pressure

is the pressure that is caused by the contraction of the heart

31

what is mean arterial pressure

it's the average pressure in the artery

32

What two factors affect MAP

1. Cardiac output
2. Total peripheral resistance

MAP = CO x TPR

33

what are the factors that affect CO

1. heart rate
2. stroke volume

34

how do we change TPR

Arteriole diameter

35

what part of the brain controls sympathetic controle of vasoconstrictor muscles

vasomoter center in medulla of brain

36

what are baroreceptors

pressure receptors

37

how often are baroreceptors firing

always

38

when high pressure, baroreceptors ...

fire more

39

when low pressure, baroreceptors ...

fire less

40

practice drawing what happens when BP is high and low

ok i will

41

how does general vasoconstriction protect the brain?

if blood volume is low, most vessels constrict, but not the brain, this ensures that the brain gets what it needs.

42

how does general vasoconstriction help muscles during exercise

1. vessels to intestines constrict
2. arterioles in muscle dialate,
3. precapilary sphincters relax

43

what are the factors that affect venous return

1. Low pressure gradient (pushes blood to heart)
2. Low resistance in veins (doesn't slow it down)
3. one way valves in veins (prevent backflow)
4. Muscle pump (squeezes blood only up because of valves)
5. Respiratory movements (Pressure in thorax decreases with respiration and pulls blood into thorax)
6. sympathetic constriction of veins (squeezes vessels and pushed blood to the heart

44

What are the major components of blood

1. erythrocytes
2. leukocytes
3. platelets
4. plasma

45

What are erythrocytes and what do they do

biconcave cells (surface area), have lots of hemoglobin and no organelles. they transport O and Co2.

46

What are leukocytes and what do they do

fight off infection

47

what are platelets and what do they do

(thrombocytes) they are fragments of megakaryocytes that are important in hemostasis. they plug up holes in vessels

48

what is plasma and what does it do

water portion of blood (91-92% water), it carries proteins, hormones, urea, and dissolved gasses

49

what are the important plasma proteins

albumin (most abundant)
Globulins
fibrinogen

50

what is the function of albumin

1. helps maintain oncotic pressure (prevent adema)
2. serves as a carrier for fatty acids and hydrophobic substances (hormones)

51

What is the function of globulin

1. helps in blood clotting
2. helps in immunodefense

52

what is the function of fibrinogen

helps in blood clotting

53

what is oncotic pressure

its the osmotic pressure developed across the capillary membranes due to the proteins in plasma

54

how do the proteins in plasma affect oncotic pressure

they can't diffuse so they are stuck inside and water wants to come in to balance out osmoles

55

what is the direction of osmotic movement

from low concentration of solutes to high

56

how does albumin prevent adema

it's the most abundant plasma protein so it's presence keeps osmotic pressure pushing water into the capillaries

57

How does oncotic pressure work

25 mmhg of oncotic pressure tries to push water into veins, when blood first enters capillaries the pressure is greater than that so water flow out, but as is leaves capillaries it is less than 25 mmhg so the oncotic pressure pushes water into the capillaries

58

How and where are RBC (erythrocytes) produced

1. Kidneys detect low O2 levels (due to lower capacity of RBC's to carry O2)
2. Kidneys release erythoropoetin (EPO)
3. EPO stimulates erythropoesis in bone marrow
4. these new RBC's are detected by kidneys and EPO secretion is lessened.

59

What is a hematocrit

its a measurement of what percent of blood is made up by RBC's

60

is hematocrit usually higher in men or in women

men (42- 54) .....45......
women (38 - 46)

61

how is a hematocrit measured

they centrifuge the blood and see what percent of blood (by volume) is made up of RBC's

62

how does blood doping affect hematocrit

blood doping is when you put more RBC's in your blood, or EPO

63

how does dehydration affect hematocrit

it raises the hematocrit, but not because it increases RBC's but because it decreases plasma

64

what is anemia

a deficiency of RBC's, which leads to a decrease of oxygen transportation

65

what are the symptoms of anemia

dyspnea
tachicardia
fatigue

66

at what point do we diagnose anemia

<37 hematocrit in women

67

what are the types of anemia

1. hemorrhagic (loss of blood)
2. Pernicious (nutritional deficiency (B12))
3. Sickle-cell (abnormal hemoglobin)
4. Renal (kidney disease = decrease erythropoesis)
5. aplastic (bone marrow cells destroyed) (radiation and drugs)

68

What is polycythemia

too many RBC's

69

what are the types of polycythemia

1. Primary (bone marrow tumor)
2. secondary (chronic hypoxia - high altitude)
3. Blood doping (inject RBC's or EPO)

70

what is hemostasis

cessation of bleeding

71

what are the three major steps of hemostasis

1. vasoconstriction
2. formation of platelet plug
3. formation of fibrin mesh

72

What is fibrinogen

a plasma protein

73

how is fibrogen different than fibrin

fibrinogen is kind of the inactive version, when fibrinogen comes in contact with collagen it turns into fibrin and forms the fibrin mesh (clot)

74

what activates platelets

the Von willebrand factor (vwf)

75

what do platelets do

aggregate in the hole
they secrete hormones to cause vasoconstriction
they also secrete ADP which encourages platelet aggregation

76

what role does collagen play in hemostatis

1. it binds to vwf, which causes platelets to aggregate
2. they also cause fibrinogen to turn to fibrin and create the fibrin mesh or fibrin clot

77

what does thrombin do

it stimulates the creation of fibrin and does positive feedback to create more of itself

78

what is the difference between intrinsic and extrinsic pathway to formation of fibrin cloth

the intrinsic pathway has 7 steps and all of it's chemicals are found in the blood
the extrinsic pathway only has 4 steps and it's chemicals are released by the damaged tissue

79

do both intrinsic and extrinsic work together, how

yes, intrinsic works inside the vessel and extrinsic works in the surrounding tissues

80

what does it mean to have A blood

your red blood cells have A antigens

81

What are AB bloodies called

universal acceptor

82

What are O bloodies called

universal donor

83

O has no antigens

yep

84

What is the Rh-factor

rh + has antigen d
rh- doesn't have antigen d

85

what about rh is bad

if mother is rh negative and baby is rh positive it's bad