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Anatomy & Physiology 210 > The Heart Ch 19 > Flashcards

The Heart Ch 19 Flashcards

1
Q

What and where are the three layers of the heart wall?

A

Epicardium – visceral layer

Myocardium – cardiac muscle

Endocardium – inner myocardial surface (touches heart chamber)

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2
Q

What is coronary circulation and collateral routes?

A

Functional blood supply to the heart muscle

Alternate route of blood delivery to heart muscle.
Anastomoses-arteries grown together

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3
Q

What is thoracic pain caused by deficient blood delivery to myocardium?

A

Angina pectoris

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4
Q

What is myocardial infarction?

A

Heart attack. Lack of oxygen due to blockage of coronary system.

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5
Q

What anchors cardiac cells together and allow free passage of ions? What two things are they made of?

A

Intercalated discs

Desmosomes and gap junctions

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6
Q

What is functional syncytium?

A

cardiac muscle functions as one group. Single coordinated unit.

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7
Q

What are autorhythmic cells?

A

The cell that creates the action potential that travels through gap junctions to depolarize the contractile cells

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8
Q

Explain the action potential steps of the “pacemaker potential” autorhythmic cells.

A

(pacemaker potential): Slow Na+ channels open-Na+ enters cell

(depolarization): fast Ca+ channels open-Ca+ enters cell

(Repolarization): k+ channels open, k+ exits the cell

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9
Q

Explain step two of cardiac muscle contraction with the contractile cell.

A

Calcium from adjacent cells initiates:

(Depol)Fast Na+ channels open, Na+ enter cell.

(Plateau): Slow Ca+ channels open, Ca+ enters cell. (long period)

Ca+ also exits from sarcoplasmic reticulum to start muscle contraction.

(Repolarization ): k+ channels open, k+ exits the cell.

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10
Q

List the five steps of the conduction pathway of heart cells

A

1-SA node (spreads through atria)
2-AV node (sends to ventricles)
3-AV bundle of His (splits into two)
4-2 bundle branches (inside the interventricular septum)
5-Purkinje fibers (carries to heart apex and ventricular walls)

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11
Q

What is pericarditis?

A

Inflammation of pericardium

Visceral and parietal periCardia stick together.

Inflammatory fluid compresses heart limiting pumping action: cardiac tamponade.

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12
Q

What is an arrhythmia?

A

Irregular heart rhythm

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13
Q

What is fibrillation?

A

Rapid random contractions, SA node not in control. Defibrillation needed to shock heart to reestablish rhythm through SA node.

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14
Q

A defective SA node can lead to what three issues?

A

1-ectopic focus: SA node is replaced by another pacemaker, like AV node.

2-junctional rhythm: pace set by AV node l(esser than SA node, Bpm 50)

3-extrasystole: (arrhythmia) Hyperexcitable region of heart causes premature contractions before SA initiates regular contraction. PVCs most problematic. No blood to ventricle from pumping too soon.

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15
Q

What is a heart block? And the two types?

A

Inability of ventricles to receive impulse from AV node

Total heart block: ventricles forced to beat at own slow autorhythmic rate. Too slow for adequate circulation.

Partial heart block: some signals from SA node transmitted to AV node, but not all. Extra P waves without QRS or T wave afterward.

Pacemakers needed for both.

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16
Q

The heart is stimulated and inhibited by what centers? What result, what nerve, and what Chemical?

A

Stimulated by sympathetic cardioacceleratory center. Sympathetic cardiac nerve. Increases HR. Norepinephrine.

Inhibited by parasympathetic cardioinhibitory center. Vegas nerve. Decrease HR. Acetylcholine.

17
Q

According to the electrical activity shown on an ECG, what represents each piece of a cardiac rhythm?

A

P wave: depolarization of SA node

QRS complex: ventricular depolarization (atrial masked here)

T-wave: ventricular Repolarization

18
Q

The first sound of heart beat occurs as _____ valves close and signifies the beginning of ________.

Second sound occurs when ______ valves close at the beginning of ________ ________.

A

AV, systole

SL, ventricular diastole

19
Q

What is a heart murmur? And two possible reasons?

A

Abnormal heart sounds.

1-incompetent valve: incomplete close valve/s

2-stenotic valve: incomplete opening of valve/s

20
Q

What is a cardiac cycle and how long does each part take?

A

All events associated with blood flow through the heart.
Average heartbeat 75/min
Cardiac cycle takes .8 seconds

.1 for atrial systole
.3 for ventricle systole
.4 quiescent period

21
Q

When is ventricular filling taking place? What are the valves and atrium doing? And what is EDV?

A

Mid to late diastole. AV valve open. 80% of blood flow to ventricle. Atrial systole occurs delivering remaining 20%.

EDV: volume of blood in each ventricle at the end of ventricle diastole.

22
Q

What is happening in the ventricular systolic phase (2)?

And what is ESV?

A

1-Atria relax and ventricles contract.
2-Rising ventricular pressure results in closing of AV valves.

3-Isovolumetric contraction in phase: all valves closed.
4-ejection phase, ventricular pressure exceeds pressure in artery, SL valves forced open.

ESV: volume of blood remaining in each ventricle

23
Q

Phase 3 of the cardiac cycle.

When is isovolumetric relaxation and what is occurring?

A

Early diastole.

1-Ventricles relax.
2-Backflow of blood in aorta and pulmonary trunk closes SL valves:
Dicrotic notch caused by backflow of blood rebounding off closed SL valve.

24
Q

What is cardiac output? And the formula to define it?

A

Amount of blood pumped by each ventricle in one minute.

CO = HR • SV

25
Q

What is HR, SV, and cardiac reserve?

A

HR – number of heartbeats per minute

SV – amount of blood pumped out by ventricle beat. EDV-ESV=SV

CR – difference between resting and maximal CO (co-blood pumped in 1min).

26
Q

What are the three factors that affect stroke volume?

A

Preload contractility and afterload

27
Q

What is Frank starling law of the heart.?

A

Preload is the critical factor in controlling SV.

  • give more blood, pumps more blood.
28
Q

What are the five factors of preload?

A

1-cardiac muscle exhibits a length tension relationship.
2-at rest, cardiac muscle cells are shorter than optimal length.
3-slow heartbeat and exercise increased venous return and SV.
4-increased venous return stretches ventricles and increases contraction force.
5-blood loss and extremely rapid heartbeat decrease SV.

29
Q

The factor affecting SV: contractility, does what?

A

(measurement of how strong the heart is )
Increase in contractile strength (independent of stretch and EDV)
Because:

Increased sympathetic stimuli
Certain hormones
Calcium and drugs similar to epi-and and digitalis
Called: positive inotropic agents

30
Q

What factors decrease contractility, making the heart weaker? And what are those called?

A

Acidosis.
Increased extracellular potassium. Calcium channel blocker’s.

Negative inotropic agents.(lowers SV and CO)

31
Q

Positive and negative chronotropic factors to do what?

What do you call clinically abnormally high or low heart rate?

A

Positive – increased heart rate
Negative – decrease heart rate

Tachycardia – abnormally high heart rate
Bradycardia – abnormally low HR

32
Q

Sympathetic nervous system stimulation is activated by _____, and releases ______.

A

Stress, anxiety, excitement or exercise

Epinephrine and norepinephrine

33
Q

Parasympathetic nervous system stimulation is mediated by ________, and opposes _________.

A

ACH

SNS

34
Q

What is the atrial reflex?

A

Sympathetic reflex initiated by increased blood in the atria

  • causes stimulation of SA node triggering atrial contraction and faster HR
  • simulate baroreceptors in atria causing increased SNS stimulation
  • give heart more blood, beats faster
35
Q

What is hypocalcemia?

What is hypercalcemia?

A

Hypo: depresses heart rate

hyper: prolongs plateau phase in leads to spasms that do not allow hard to rest

36
Q

What is hypo kalemia?

What is hyperkalemia?

A

Hypo: makes heartbeat feebly and arrhythmically

Hyper: interferes with depolarization by lowering action potential. May lead to heart block and cardiac arrest.

37
Q

What is congestive heart failure caused by?

A
  • blood flow problem

Coronary atherosclerosis
Persistent hi blood pressure
Multiple myocardial infarction
Dilated cardiomyopathy(ventricle walls stretched becoming flabby)

38
Q

What do the left and right heart failure’s congest?

A

Left heart failure: pulmonary congestion

Right heart failure: Peripheral congestion

39
Q

What are the fetal heart structures and their function?

A

Foramen ovale: connects two atria

Ductus arteriosus: connect pulmonary trunk in aorta

Anatomy & Physiology 210 (21 decks)

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