Cardiac Physiology

Question 1

Basic Anatomy

Answer 1

made up of four chambers: two upper chambers known as the left atrium and right atrium and two lower chambers called the left and right ventricles.

Question 2

Electrical Activity in the Heart

Answer 2

Pacemakers...
– Sinoatrial (SA) node
– Atrioventricular (AV) node
– Bundle of His
– Bundle branches
– Purkinje Fibers

Question 3

CO = HR X SV

Answer 3

CO = Cardiac Output
HR = Heart Rate
SV = Stroke Volume

Question 4

How to Change Heart Rate

Answer 4

Autonomic Innervation, Both work through the cAMP second

messenger system.

Question 5

Parasympathetic change in heart rate

Answer 5

muscarinic associated with

inhibitory G protein.

Question 6

Sympathetic change in heart rate

Answer 6

β1 adrenergic receptor and

stimulatory G protein

Question 7

Parasympathetic Innervation

At SA and AV nodes

Answer 7

By way of the vagus nerve

Question 8

Parasympathetic Innervation

Increases K+ permeability

Answer 8

Hyperpolarizes membrane. Reduces rate of depolarization during
pacemaker potential

Question 9

Sympathetic Innervation

Decreases K+ permeability

Answer 9

Depolarizes membrane and Increases depolarization during pacemaker
potential

Question 10

How to Change Stroke Volume

Answer 10

SV = EDV – ESV

Question 11

SV = EDV – ESV

Answer 11

SV = Stroke Volume
EDV = End-Diastolic Volume
ESV = End-Systolic Volume