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Physiology Fall 21' > CH. 13 Cardiovascular System: Cardiac Function > Flashcards

CH. 13 Cardiovascular System: Cardiac Function Flashcards

1
Q

What path is taken throughout the blood vessels?

A

heart - arteries - arterioles - capillaries - venules - veins

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2
Q

Function of erythrocytes?

A

transport oxygen and carbon dioxide

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3
Q

Function of leukocytes?

A

white blood cells that defend the body against pathogens

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4
Q

What is the path of the pulmonary circuit?

A
  • supplied by right heart

- blood vessels from heart to lungs, and from lungs to heart

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5
Q

What is the path of the systemic circuit?

A
  • supplied by left heart

- blood vessels from heart to systemic tissues, and from tissues to heart

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6
Q

Where does oxygenation of blood occur?

A

capillaries

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7
Q

What can occur from parallel blood flow within the systemic or pulmonary circuit?

A

independent regulation of blood flow to organs

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8
Q

What supplies the heart capillaries?

A

coronary arteries that arise from the aorta

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9
Q

What is the pericardium?

A

membranous sac surrounding the heart that lubricates the heart and decreases friction

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10
Q

What are the three layers of the heart wall?

A
  1. epicardium (outer)
  2. myocardium (middle)
  3. endothelium (inner)
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11
Q

What is the difference in muscle thickness of the left and right ventricle?

A

left ventricle is much thicker than the right

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12
Q

What do the heart valves allow for and how do they function?

A

they prevent the back flow of blood and open passively based on pressure gradient

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13
Q

What is meant by autorhythmicity?

A

the ability to generate its own rhythm

-

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14
Q

How do autorhythmic cells function in the heart?

A

they provide a pathway for spreading excitation through the heart

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15
Q

How is the conduction system of the heart broken down?

A

pacemaker cells and conduction fibers

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16
Q

How do pacemaker cells and conduction fibers work together to coordinate and provide rhythm to the heartbeat?

A

pacemaker cells produce spontaneously depolarizing membrane potentials that generate action potentials that are then rapidly conducted to the myocardium by conduction fibers

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17
Q

Where are pacemaker cells of the myocardium found?

A
  • sinoatrial node (pacemaker of the heart)

- atrioventricular node

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18
Q

Where are conduction fibers of the myocardium found?

A
  • internodal pathways
  • bundle of his
  • purkinje fibers
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19
Q

What is the firing rate of the SA node at rest?

A

70-80 AP/min

20
Q

What allows for the coordination of the conduction system of the heart?

A

presence of gap junctions and conduction pathways

21
Q

What are intercalated disks?

A

junctions between adjacent myocardial cells

22
Q

What causes spontaneous depolarizations of the heart autorhythmic cells?

A

closing of potassium channels

23
Q

What occurs in the electrical activity in a pacemaker cell?

A
  1. pacemaker potential goes to threshold
  2. rapid depolarization
  3. repolarization brings down to -70mV
  4. process repeats
24
Q

What are the 5 phases of electrical activity in cardiac contractile cells?

A

Phase 0: increased permeability to sodium
Phase 1: decreased permeability to sodium
Phase 2: increased permeability to calcium, decreased permeability to potassium
Phase 3: increased permeability to potassium, decreased permeability to calcium
Phase 4: resting membrane potential

25
Q

How is calcium removed from the cytosol of cardiac muscle?

A
  1. Calcium/ATPase in sarcoplasmic reticulum
  2. Calcium/ATPase in plasma membrane
  3. Sodium/Calcium exchange in plasma membrane
26
Q

What is an electrocardiogram?

A

external measure of electrical activity of the heart

27
Q

What are the factors that distance and amplitude of spread of an electrocardiogram dependent on?

A
  1. size of potentials

2. synchronicity of potentials from other cells

28
Q

What is ECG arrhythmias?

A

abnormal heart rates

29
Q

What is a sinus rhythm?

  • Tachycardia
  • Bradycardia
A
  • pace generated by SA node

- tachycardia is fast rhythm and bradycardia is slow rhythm

30
Q

What comes as a result of an extra contraction on an electrocardiogram?

A
  • results in an extra systole

- premature atrial contraction followed by an extra ventricular contraction

31
Q

What comes as a result of a ventricular fibrillation on an electrocardiogram?

A
  • loss of coordination of electrical activity of heart

- death can ensue within minutes unless corrected

32
Q

What are the two main periods of the cardiac cycle?

A
  1. systole: ventricle contraction

2. diastole: ventricle relaxation

33
Q

When do AV valves open and when do semilunar valves open?

A
  • AV valves: when atrial pressure is greater than ventricular pressure
  • Semilunar valves open when ventricular pressure is greater than arterial pressure
34
Q

What are the 4 phases of the cardiac cycle?

A
  1. ventricular filling (diastole)
  2. isovolumetric ventricular contraction (systole)
  3. ventricular ejection (systole)
  4. isovolumetric ventricular relaxation (diastole)
35
Q

How does the elasticity of the aorta and large arteries aid in maintaining blood flow through the entire cardiac cycle?

A
  1. acts as a pressure reservoir
  2. stores energy during systole as walls expand
  3. releases energy during diastole as walls recoil inward
36
Q

What is the equation for stroke volume?

A

SV = end-diastolic volume - end-systolic volume

37
Q

What causes the sound of a heart beat?

A

1st sound: AV valves close simultaneously

2nd sound: semilunar valves close simultaneously

38
Q

What is cardiac output and what is the equation used to find this?

A

volume of blood pumped by each ventricle per minute

  • cardiac output = SV x HR
39
Q

What are the extrinsic and intrinsic regulation of cardiac output?

A
  • extrinsic: neural and hormonal (autonomic)

- intrinsic: autoregulation

40
Q

What occurs when the SA node is under control of the ANS and hormones and is at rest?

A

parasympathetic system dominates

41
Q

What occurs when the SA node is under control of ANS and hormones and is excited?

A

sympathetic system takes over and heart rate increases

42
Q

What two hormones help to control heart rate?

A
  1. epinephrine: interacts with beta one receptors
    - increases AP frequency at SA node
    - increases velocity of AP conduction in muscle fibers
  2. glucagon: increases heart rate
43
Q

What are the primary factors affecting stroke volume?

A
  1. ventricular contractility: how well ventricles contract
  2. end-diastolic volume
  3. afterload: how much blood is in arteries all together
44
Q

What hormones can increase force of contraction?

A

thyroid hormones, insulin, and glucagon

45
Q

What two factors affect end-diastolic volume?

A
  1. end-diastolic pressure: preload
    - filling time
    - atrial pressure
    - central venous pressure
  2. afterload: pressure in aorta during ejection
46
Q

Describe what occurs at the different stages (A-H) of the left ventricular pressure-volume curve.

A 
A: Phase 1 - ventricular volume increase
B: Atrial contraction
C: Phase 2 - Volume remains constant; pressure increases dramatically
D: Semilunar valves blow open
E: Phase 3 - volume decreases to 60 mL, pressure rises, then falls precipitously
F: Semilunar valves shut 
G: Phase 4 - pressure continues to fall 
H: AV valves blow open

Physiology Fall 21' (15 decks)

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