17-5: Factors affecting heart rate and heart diseases Flashcards Preview

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Flashcards in 17-5: Factors affecting heart rate and heart diseases Deck (35)
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1
Q

The basic heart rate is set by ___, but can be altered by: ___.

A

the conduction system (SA node); autonomic nervous system, chemicals, emotions, temperature, and gender and age

2
Q

What has the most important influence on heart rate?

A

cardiovascular center of the autonomic nervous system

3
Q

cardioacceleratory center

A

sends impulses over cardiac nerves to the heart when under stress

4
Q

What kind of nerves are cardiac nerves?

A

sympathetic motor neurons

5
Q

What do cardiac nerves release?

A

norepinephrine, which binds to adrenergic receptors at the SA node, causing it to fire more rapidly and the heart rate to increase

6
Q

cardioinhibitory center

A

sends impulses over the Vagus nerve (cranial nerve X) to the heart

7
Q

What does the vagus nerve release?

A

ACh, binding to colinergic receptors at the SA and AV node, causing it to fire more slowly and heart rate decreases

8
Q

The cardioacceleratory center is controlled by the __ nervous system and the cardioinhibitory center is controlled by the __.

A

sympathetic; parasympathetic

9
Q

vagal tone

A

when resting, the heart is in vagal tone - vagus nerve (PANS) in control

10
Q

baroreceptors

A

special neurons in the carotid artery, aortic arch, and atria, that detect changes in blood pressure and send signals to the CAC and CIC to correct the problem

11
Q

epinephrine

A

hormone produced by the adrenal gland when under stress

12
Q

Epinephrine causes heart rate to ___ by ___.

A

increase by increasing the excitability of the SA node

13
Q

hyperkalemia can lead to __.

A

heart block and cardiac arrest

14
Q

hypokalemia can lead to __.

A

arrhythmias and a weak heart beat

15
Q

hypercalcemia can lead to ___.

A

increased heart rate

16
Q

hypocalcemia can lead to __.

A

slowed heart rate

17
Q

How does emotion affect heart rate?

A

strong emotions like fear, anger and anxiety tend to increase heart rate; depression and grief cause heart rate to go down

18
Q

How does temperature affect heart rate?

A

increased body temp (eg. fever, exercise) causes heart rate to go up

19
Q

Women have ___ heart rate than men

A

faster

20
Q

Heart rate ___ with age

A

decreases

21
Q

myocardial infarction

A

the result of interrupted blood supply to an area of the myocardium; without O2, the area of heart tissue infarcts (dies) and the heart weakens

May be caused by thrombus, embolus, or atherosclerosis

22
Q

thrombus

A

blood clot formed in coronary vessel

23
Q

embolus

A

blood clot formed elsewhere, but travels to heart and lodges there

24
Q

atherosclerosis

A

vessel blocked due to accumulated fatty deposits

25
Q

How is a myocardial infarction diagnosed?

A

enlarged Q wave on EKG and serum enzyme studies

26
Q

angina pectoris

A

temporary ischemia (reduced blood flow/O2 supply) to the myocardium causes myocardial cells to weaken but not die

may experience chest pain and tightness, difficulty breathing

27
Q

What are some causes of angina pectoris?

A

coronary vessels constrict due to stress, atherosclerosis, strenuous exercise after a meal, or high blood pressure

28
Q

heart murmur

A

abnormal heart sound; usually asymptomatic, but may lead to congestive heart failure and need to be repaired or replaced

29
Q

What are the causes of a heart murmur?

A

faulty heart valve that allows regurgitation (some flow of blood backwards) or stenosis (a narrow, incompletely open valve); most common type is mitral valve prolapse

30
Q

congestive heart valure

A

venous return > cardiac output (blood is returning faster than it is pumped out)

31
Q

When does congestive heart failure occur?

A

when either ventricle fails to pump blood out as fast as it entered; blood backs up in the heart ,and it fails to meet the O2 demand of the body’s tissues

32
Q

What can cause congestive heart failure?

A

long term hypertension, multiple heart attacks, coronary atherosclerosis

33
Q

CHF can result in a pulmonary edema if __ ventricle fails, and/or a peripheral edema if __ ventricle fails

A

left (blood backs up into lungs); right (blood backs up in systematic loop)

34
Q

Tachycardia

A

rapid heartbeat

35
Q

Bradycardia

A

slow heartbeat