Ch16 Pt1

Question 1

SA node:

Answer 1

Sinoatrial node -stimulus for heart action, “pacemaker”
-sets pace of heart, superior to right atrium
-sends signal to both atria and to atrioventricular node (AV node)
Healthy around 60-80 BPM

Question 2

What node gives rise to the AV bundle (bundle of His)

Answer 2

The AV Node
-transmits signals via Purkinje fibers to ventricles for contraction

Question 3

What are Purkinje Fibers

Answer 3

Very fast impulses sent to Bundle of His from AV Node
-0.06 seconds

Question 4

Cardiovascular control centre

Answer 4

Generates pulse
-located in the medulla in the brain stem
-regulates hearts output (SA and AV node input), distribution of blood in body, vasomotor tone in active muscle

Question 5

2 Parts of Autonomic Nervous System

Answer 5

Sympathetic and Parasympathetic

Question 6

Sympathetic Division

Answer 6

“Fight or Flight”
-catecholamine release (epinephrine and norepinephrine)
Leads to tachycardia (hr >100BPM)

Question 7

Parasympathetic Division

Answer 7

“Rest and Digest”
-acetylcholine release
-leads to brachycardia (HR<60BPM)
-can be positive in healthy individual as it means a more efficient heart, more blood pumped with each contraction

Question 8

Sympathetic Nervous System:

Answer 8

Increase Heart rate= chronotropic effect
Increase Contrasctility= isotopic effects
Increase vasodilation of arterioles of skeletal muscle
Increase vasoconstriction of visceral arterioles

Question 9

Parasympathetic Nervous System:

Answer 9

Decrease heart rate
Decrease contracility
Decrease vasodilation of arterioles of skeletal muscle
Decrease of visceral arterioles

Question 10

What nervous system is stimulated/ inhibited when we exercise?

Answer 10

Sympathetic is stimulated, parasympathetic is inhibited

Question 11

RMP of skeletal muscle:

Answer 11

More negative on inside, more positive on outside\
-polarized

Question 12

Depolarization

Answer 12

Membrane potential becoming more positive (influx of sodium)
=contraction -ventricles are depolarizing
SYSTOLE

Question 13

Repolarization

Answer 13

Membrane potential becoming more negative, back toward resting (efflux of potassium)
=relazation, ventricles are repolarizing
DIASTOLE

Question 14

ECG Stats: P wave

Answer 14

Atrial Depolarization
-P-R interval: time for conductions from SA node to ventricle

Question 15

QRS Complex

Answer 15

Ventricle depolarization (systyole), not atrial
(Often masks atrial repolarization)

Question 16

S-T segment

Answer 16

Time duration where entire myocardium is depolarized

Question 17

T-Wave

Answer 17

Ventricular repolarization (diastole)

Question 18

Which electrical activity represents a persons pulse?

Answer 18

QRS complex