heart pt.5

Question 1

Cardiac muscle twitch lasts longer because _____ ___ continue to enter for extended period.

Answer 1

calcium ions

Question 2

Calcium channels will begin ______, slow potassium channels ____ to bring muscle back to resting potential

Answer 2

closing, open

Question 3

Composite of all action potentials of nodal and myocardial cells detected, amplified and recorded by electrodes on arms, legs, and chest

Answer 3

electrocardiogram (ECG)

Question 4

wave in ECG signaling atrial depolarization. atria begin contraction 25msec after this wave starts

Answer 4

P wave

Question 5

signals ventricular depolarization. larger wave due to larger ventricle muscle mass. ventricular systole

Answer 5

QRS complex

Question 6

signals ventricular repolarization. diastole of ventricles

Answer 6

T wave

Question 7

ECGs valuable for detecting/and diagnosing

Answer 7

arrythmias

Question 8

abnormal patterns of cardiac electrical activity

Answer 8

cardiac arrhythmias

Question 9

Premature atrial contraction triggers flurry of atrial activity. Ventricles keep pace. Heart rate jumps to about 180 beats per minute

Answer 9

paroxysmal atrial tachycardia (PAT)

Question 10

Impulses move over atrial surface at up to 500 beats per minute. Atria quiver—not organized contraction. Ventricular rate cannot follow, may remain fairly normal. Atria nonfunctional, but ventricles still fill passively. Person may not realize there is an arrhythmia

Answer 10

Atrial fibrillation

Question 11

Also known as V F or V-fib
Responsible for condition known as cardiac arrest
Rapidly fatal because ventricles quiver, but cannot pump any blood

Answer 11

ventricular fibrillation

Question 12

neurotransmitter for parasympathetic neurons. decreases HR. hyperpolarizes

Answer 12

acetylcholine (ACh)

Question 13

sympathetic stimulation increases ___ ___. decreases repolarization.

Answer 13

heart rate.

Question 14

resting HR slower than 60

Answer 14

bradycardia

Question 15

resting HR faster than 100 bpm

Answer 15

tachycardia

Question 16

location of cardia centers in CNS

Answer 16

medulla oblongata

Question 17

Controls parasympathetic neurons; slows heart rate. Parasympathetic supply to heart via vagus nerve

Answer 17

cardio inhibitory center

Question 18

Controls sympathetic neurons; increases heart rate. Sympathetic innervation to heart via postganglionic fibers in cardiac nerves

Answer 18

cardio acceleratory center

Question 19

Sympathetic and parasympathetic stimulation. Rising body temperature will increase heart rate. Lowering body temperature will decrease heart rate.
Many hormones increase heart rate (epinephrine and thyroxine)

Answer 19

factors affecting HR

Question 20

amount of blood pumped by the left ventricle in one minute.

Answer 20

cardiac output

Question 21

two contributors to cardiac output

Answer 21

HR and Stroke volume