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BHSC 2203 - Patho > Unit 3 - Cardiovascular System > Flashcards

Unit 3 - Cardiovascular System Flashcards

1
Q

What are the 4 components of the circulatory system?

A
  1. Propulsive organ
  2. Arterial system
  3. Capillary beds
  4. Venous system
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2
Q

What is the function and property of the propulsive organ?

A
  • Forces blood around the body

- rhythmic contractions

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3
Q

What is the function and property of the arterial system?

A
  • Distributes blood and pressure reservoir

- Elastic vessels

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4
Q

What is the function and property of the capillary beds?

A
  • Transfer of materials btw circulation and tissues

- Thin walls

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5
Q

What is the funciton and property of the venous system?

A
  • Returns blood back to heart and volume reservoir

- compliant vessels

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6
Q

What happens to circulation if the venous system becomes MORE compliant?

A

Increase compliance of the veins = blood is going to pool in the veins and risk of blood clotting increases

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7
Q

Why does the heart have rhythmicity?

A

Result of electrical events in the heart (SA node)

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8
Q

Describe the steps of depolarization of the heart

A
  1. Slow Na+ inflow into the SA node (pacemaker potential)
  2. Fast Ca+2 inflow into the SA node (action potential)
  3. Fast K+ outflow (efflux and repolarization)
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9
Q

If there is 1 action potential (depolarization), how many heart contractions will there be?

A

1

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10
Q

Why is the duration of the action potential so long in the heart

A

The calcium channels remain open for a long period of time

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11
Q

Name the order of the conduction through the heart

A
  1. SA node
  2. AV node
  3. Right and left bundle branches
  4. Purkinje fibers
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12
Q

What does the P wave indicate?

A
  • SA node fires
  • Atrial depolarization
  • Atrial Systole
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13
Q

What does the QRS complex indicate?

A
  • AV node fires
  • Ventricular depolarization and systole
  • (Atrial re-polarization and diastole)
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14
Q

What does the T wave indicate?

A

Ventricular re-polarization

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15
Q

What are the 4 valves in the heart?

A
  1. Tricuspid valve
  2. Bicuspid valve
  3. Pulmonary valve
  4. Aortic valve
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16
Q

Which sides of the heart are the bi-cuspid and tri-cuspid valves located?

A 
Tri = right side
Bi = left side
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17
Q

Why do valves open and shut in the heart?

A

Because of pressure gradients between the chambers

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18
Q

If the ventricles are relaxed (during diastole), are the AV valves open or closed?

A

AV = open!

So that the ventricles can fill with blood

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19
Q

What do the S1 and S2 represent?

A 
S1 = closure of AV values
S2 = closure of semilunar valves (pulmonary and aortic valves)
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20
Q

Where do you hear the AORTIC SEMILUNAR VALVE SOUND?

A

RIGHT side of the chest (between ribs 2-3)

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21
Q

Where do you hear the PULMONARY SEMILUNAR VALVE SOUND?

A

LEFT side of the chest (between ribs 2-3)

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22
Q

What is the formula for cardiac output (CO)?

A

CO = Stroke volume (SV) x Heart Rate (HR)

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23
Q

What is the difference in the resting vs. exercise levels of cardiac output?

A 
Resting = 4-6 L/min
Exercising = 21-35 L/min
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24
Q

How is stroke volume calculated?

A

SV = EDV - ESV

difference between end diastolic volume and end systolic volume

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25
Q

What are the 3 factors that govern stroke volume?

A
  1. Preload
  2. Afterload
  3. Contractility
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26
Q

What is preload?

A

Amount of tension (stretch) in the ventricles before they contract

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27
Q

What happens to stroke volume as you increase pre-load?

A

Pre-load increases = Stroke volume increases

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28
Q

What does the Frank-Starling Law state?

A

The more you fill the heart, the more the heart will contract (otherwise you will have blood pooling in the heart)

29
Q

What is the contractility of the heart?

A

Contraction force for a given pre-load

30
Q

What happens to stroke volume as you increase contractility?

A

Contractility increases = Stroke volume increases

31
Q

What are factors that increase contractility?

A
  1. Hypercalcemia
  2. Catecholamines ( E and NE)
  3. Glucagon
32
Q

What are factors that decrease contractility?

A
  1. Hyperkalemia (K+)
  2. Hypocalcemia
  3. Hypoxia
  4. Hypercapnia
33
Q

Why is hyperkalemia so dangerous?

A

Excessive amounts of K+ makes it harder for the heart to depolarize = can stop the heart

34
Q

What is afterload?

A

Pressure in the arteries above the semilunar valves

- pressure OPPOSES the OPENING OF THE VALVES

35
Q

What happens to stroke volume if you increase afterload?

A

Increased afterload = DECREASED stroke volume

36
Q

What happens to afterload if the semilunar valves are stiff?

A

Stiff valves will contribute to afterload

37
Q

Why do the elderly have higher heart rates than young adults?

A
  • increased afterload
  • arteries become more stiff
  • when afterload is higher, SV is lower, only was to MAINTAIN CARDIAC OUTPUT is to INCREASE HR
38
Q

Why do athletes have very low heart rates?

A

Because their SV is SO HIGH

- their HR can be lower and still achieve adequate CO

39
Q

What is the formula for mean arterial pressures (MAP)?

A

MAP = CO x TPR

cardiac output x total peripheral resistance

40
Q

If we have a high blood pressure, what can we do about it?

A
  • decrease CO
  • decrease TPR
  • decrease both
41
Q

How can we decrease EDV?

A

Using a diuretic

42
Q

What is peripheral resistance influenced by?

A
  1. Blood viscosity (decreases with anemia and hypoproteinemia)
  2. Vessel radius
43
Q

What will Sickle Cell Anemia do to blood viscosity? (Increase or decrease)

A

Sickle cell anemia forms small clots in the blood which actually INCREASES the viscosity of the blood

44
Q

What is the most power influence over total peripheral resistance?

A

Vessel radius

- most adjustable

45
Q

What happens to total peripheral resistance when blood wall tension increases?

A

Vessel radius decreases, and TPR increases

46
Q

What happens to total peripheral resistance when the sympathetic stimulation decreases?

A

Wall tension decreases and vessel radius increases

47
Q

What are the 3 determinants of blood flow?

A
  1. Viscosity and velocity (of blood)
  2. Vessel radius
  3. Vessel elasticity
48
Q

What is the difference between velocity and flow?

A

Velocity = cm/sec
Flow = mL/sec
(a mL is a cubic cm)

49
Q

What is the formula for flow?

A

FLOW = VELOCITY x cross-sectional area (of the vessel)

50
Q

What is the relationship between flow and blood pressure?

A

When you decrease peripheral resistance, the cross-sectional area of the vessel increases –> increases flow.
When the cross-sectional area increases, peripheral resistance is decreased.
THEREFORE, WHEN FLOW INCREASES, BLOOD PRESSURE DECREASES

51
Q

Describe the metabolic theory of autoregulation.

A

When a tissue is inadequately perfused, wastes accumulate. These wastes stimulate vasodilation locally.

52
Q

What do baroreceptors detect?

A

Stretch in the arteries

resulting from BP

53
Q

What happens if the vasomotor center is inhibited?

A
  • Less contraction of blood vessel walls
  • Reduced sympathetic tone = less NE released
  • Reduced vasomotor tone = results in vasodilation
54
Q

What happens if the caridoinhibitory center is stimulated?

A

Slows down the heart when it is stimulated

  • decrease HR = decreased CO
  • decreased CO = decreased BP
55
Q

What are the two pathways that neural control of BP occurs?

A
  1. Vasomotor center
  2. Cardioinhibitory center
    - both result from baroreceptors increasing their firing
56
Q

Does neural control of BP happen slowly or quickly?

A

QUICKLY!

57
Q

Describe the system that is triggered when the kidneys sense a low BP.

A
  1. Kidneys release renin
  2. Renin activates angiotensinogen I
  3. ACE (converting enzyme in lungs) converts angiotensinogen I to II.
  4. Angiotensinogen II is a VERY POTENT vasocontrictor.
  5. Increases BP
58
Q

What happens when aldosterone is released into the system?

A

Promotes Na+ re-absorption (water follows Na+)

- increases blood volume and therefore, BP

59
Q

What happens to BP when E and NE are released into the body?

A

Constrict blood vessels (most)

- DILATE blood vessels in skeletal and cardiac muscle

60
Q

Where is the blood flowing when the body is at rest?

A
  • Digestion (27%)
  • Renal system (22%)
  • Muscular (20%)
61
Q

Where is the blood flowing during exercise?

A
  • Muscular (71%)

- Cutaneous (11%)

62
Q

What is the capacity of total blood volume of the capillaries?

A

14%

63
Q

What is the actual blood volume of the capillaries?

A

5-7%

64
Q

What accounts for the difference between the actual and total capacity of total blood volume in the capillaries?

A

Capillaries are NOT always open

- if capillaries don’t need blood, they close

65
Q

What forces materials into the cells and out of the blood vessels?

A

Higher pressure on arterial side as opposed to venous side

66
Q

What are the mechanisms that help with venous return?

A
  1. Venous pressure
  2. Gravity (from head and neck)
  3. Skeletal muscle pump
  4. Thoracic pump (diaphragm)
67
Q

Explain the effect of the thoracic pump on venous return.

A

When the diaphragm contracts, it move downward - decreased pressure in the area of the heart = draws blood into the heart
When the diaphragm relaxes, it moves upward - increased pressure = pushes blood out of the heart area

68
Q

How does exercise increase venous return?

A
  • heart beats faster, increase CO and BP
  • vessels of skeletal muscles, lungs and heart dilate = increase flow
  • increase RR, increase action of thoracic pump
  • increase skeletal muscle pump

BHSC 2203 - Patho (13 decks)

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