Module 4: Cardiovascular System Flashcards Preview

BM1011 Physiological Systems > Module 4: Cardiovascular System > Flashcards

Flashcards in Module 4: Cardiovascular System Deck (74):
1

What are the layers of the heart

pericardian (outer), myocardian (middle), endocardial (inner most)

2

what are the 4 chambers of the heart

atriums(top), ventricles(bottom)

3

Distinguish between the right and left side of heart

right- receives blood from body and pumps to lungs. left- receives blood from lungs and pumps to body

4

Describe the flow of blood to the heart

Enters through vena cava, goes to right atrium then through the tricuspid valve. then to right ventricle then pumps to pulmonary arteries- goes to lungs. Returns from lungs oxygenated through pulmonary veins enters left ventricle goes through bicuspid valve, then to left ventricle then pumps to aorta then to the rest of the body

5

describe arteries

elastic, large, low resistance, more elastin, evens out pulses from heart. muscular and more controlled flow to organ

6

what are the main arteries

Subclavian artery - arms. carotid artery - head, iliac artery - arms

7

what do blood vessels do

transport blood from heart to body

8

what do arteries do

transport blood away from the heart

9

what do veins do

transport blood towards the heart

10

whats the stimulus for a heart beat

the conductile network. automatic, always active and created by specialised cells which make an action potential

11

what are the key parts of the conductile system of the heart

sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, endocardial conducting network,

12

what happens in the sinoatrial node(SA)

master controller, depolarises faster than others, depolarises atria

13

what happens in the atrioventricular node (AV)

slower than SA node, controlled by SA, controls ventricular rhythm, sends signals to AV bundle

14

what are the main veins in the body

external jugular vein, internal jugular vein, superior and inferior vena cava, common iliac vein, subclavian vein

15

what do arterioles regulate and what allows them to

muscle, regulates flow to tissues

16

describe the arteries walls and what it regulates

has muscle and elastic connective tissue that regulate blood flow to organs (via diameter)

17

describe capillary walls

epithelia (thin - diffusion surface)

18

describe vein walls and what it allows them to do

elastic connective tissue so the can expand

19

what happens in the atrioventricular bundle

only electrical connection between atria and ventricles. auto rhythm slower than AV node

20

describe how to conductile network works

action potentials in pacemaker continuously generate (unstable resting membrane potential, causing continuous AP generation). conductile network controlled through SA node, SA node stimulates atria (contract) and AV node (signal) makes atria contract. AV node then stimulates bundle branches (signal), bundle branches then stimulate the endocardial network. Endocardial network then stimulates ventricular muslce (contract)

21

why do pacemakers have unstable membrane potential

because sodium leakage channels allow sodium to leak into cell

22

what happens when cell is at threshold

voltage gated calcium channels open, calcium enters cell and depolarisation occurs.

23

define pressure

total force acting over an area.

24

formula for pressure

pressure=force/area

25

how does a sphygmomanometer work

used to constrict blood flow in a vessel. when the flow returns the brachial artery is very contracted resulting in turbulent and noisy flow. this is the systolic pressure. when the flow returns to continuous, laminar and quiet it is the diastolic pressure

26

what is diffusion

the spontaneous movement of particles in a fluid from a high concentration to low concentration

27

what happens as pressure and densities increase in diffusion

diffusion rates decrease because the material is more closely packed

28

what does the amount of diffusion depend on

surface area and thickness of the membrane

29

what is osmosis

the diffusion of water through a semi-permeable membrane

30

what does the semi-permeable membrane allow

diffusion of water but no other substance or particles

31

what are the effects of osmosis

as diffusion continues, the region into which the water diffuses increases in volume creating excess pressure

32

what is an isotonic solution

cells retain their normal size and shape, water moves in and out

33

what is hypertonic solution

cells lose water by osmosis and shrink, more solute (e.g salt)

34

what is hypotonic solution

cells take in too much water and become bloated and burst. lower concentration of solute

35

what ion causes the muscle cells to start contracting

calcium

36

what components of the muscle cell store calcium

endoplasmic reticulum and sacroplasmic reticulum

37

what two protein bundles are in myofibrils

actin (and troponin) and myosin, contractile units.

38

how does an action potential stimulate muscle contraction

action potential travels along membrane to sarcoplasmic reticulum (SP), and releases calcium. calcium binds to troponin on actin and allows actin and myosin to interact

39

what is the contraction-sliding filament theory

actin can now interact with myosin, myosin pulls past actin, using ATP and the muscle shortens

40

what happens when the muscle shortens in the heart

this makes the muscle smaller, which makes the chamber smaller. pressure increase, blood moves out of chamber into area of lower pressure

41

is the pressure high or low when the atrioventricular valves open

low pressure

42

is the pressure high or low when the atrioventricular valves closes

high pressure

43

is the pressure high or low when the arterial valves open

high pressure

44

is the pressure high or low when the arterial valves close

low pressure

45

name the phases in which the atria and ventricles are filling

passive ventricular filling

46

what happens in atrial contraction

the atria are topping up the ventricles

47

what happens in isovolumetric contraction

the ventricles are in systole but not ejecting blood

48

what happens in ventricular ejection

the ventricles are in systole ejecting blood

49

what happens when the AV valves close

isovol contraction, vent ejection

50

what happens when the AV valves open

passive filling, atrial contraction

51

what happens when the Semilunar valves close

all but ventricular ejection

52

what happens when the semilunar valves open

ventricular ejection

53

summarise the contraction sequence to end of atrial contraction

the passive ventricular filling, heart muscle is relaxed. the contraction starts conductile cells in the SA node generate AP, AP travels to atrial node and AV node. Atrial pressure rises above ventricular pressure, blood passes from atria to ventricles. end of atrial contraction. AV valves close, signal goes from AV node to AV bundle. Start of ventricular contraction.

54

summarise the contraction sequence to end of ventricular contraction

Start of ventricular contraction. Signal goes from AV bundle to bundle branches then to endocardial network. Ventricles start to contract= isovolumetic contraction. pressure in ventricles rises above pressure in arteries to force SL valves open - causing ventricular ejection= blood goes into arteries. pressure in ventricles drops below pressure in arteries so Sl valves shut. ventricular muscle relaxes (repolarising). blood stops moving into arteries. this is isovolumetric relaxation. Finally AV valves open and passive ventricular filling begins again.

55

what is cardiac output

total volume pumped out of the heart in 1 minute= stroke volume * heart rate

56

what is the stroke volume

blood pumped out per beat

57

blood pumped out of heart per beat is the sum of...

end diastolic volume - end systolic volume

58

the amount of blood which flows through a blood vessel depends on what

blood pressure and vessel's diameter

59

what to do to increase flow`

either pressure has to increase or resistance has to decrease (blood vessels dilate)

60

what is the pulse pressure

difference between systolic and diastolic pressures

61

where is pulse pressure greatest and least and why

greatest in arteries and zero in veins because pressure drops through the cycle

62

what tissue does all blood vessels have in their walls

epithelial tissue

63

what do arteries have in their walls

muscle, elasticity =regulate pressure

64

what do arterioles have in their walls

mostly muscle = regulate pressure

65

what do capillaries have in their walls

only epithelium

66

what do veins have in their walls

elastic tissue

67

which node is the heart regulated by

sino-atrial (SA) node

68

what happens n sympathetic stimulation

increases cardiac contraction, increases heart rate, increases cardiac output

69

what happens in parasympathetic stimulation

doesn't affect cardiac contraction, decreases heart rate, decreases cardiac output

70

how is blood pressure regulated

blood flow to organs depends on the body's requirements, there is a homeostatic set point for rest but gets altered depending on activity.

71

what receptors sense the arterial blood pressure

baroreceptors

72

where are the baroreceptors located

aorta and carotid arteries

73

if baroreceptors sense a fall in BP what will happen

the vasomotor centre will stimulate contraction of arteries (vasoconstriction)

74

if baroreceptors detect rise in BP what will happen

the cardio inhibitory centre will cause the heart rate to decrease