Cardiophysiology

Question 1

Epicardium

Answer 1

(upon the heart) visceral layer of the serous pericardium. Right on top of muscle layer.

Question 2

Myocardium

Answer 2

spiral bundles of cardiac muscle cells. fibrous skeleton of the heart.

Question 3

Endocardium

Answer 3

continuous of endothelial lining of blood vessels. The inner layer of the heart. under muscle layer

Question 4

Atria

Answer 4

Means entry way. Small, thin-walled walls ridges by pectinate muscles. S, I Vena cava and coronary sinus enter into R atrium.

Question 5

Ventricles

Answer 5

Discharging chambers. walls are ridges by trabeculae carnae. Papillary muscles project into ventricular cavities. Left is thicker than right

Question 6

Papillary muscles

Answer 6

They brace the ventricle for contraction.

Question 7

Coronary Circulation

Answer 7

Shortest circulation in the body. Right and left coronary

Question 8

Coronary arteries

Answer 8

Right coronary –> R. Marginal Artery, Post. intraventricular artery (PDA).
Left Coronary –> LAD, circumflex

Question 9

Coronary Veins

Answer 9

small cardiac, anterior cardiac, great cardiac. drain into coronary sinus and into R atrium

Question 10

Angina Pectoris

Answer 10

Thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium

Question 11

Myocardial Infarction

Answer 11

Prolonged coronary blockage. Areas of cell death are replaced with noncontractile scar tissue.

Question 12

Chordae Tendinae

Answer 12

“Heart strings” go from valves to the papillary muscles

Question 13

3 types of heart muscle

Answer 13

Atrial, ventricular, autoregulatory.

Question 14

The heart has a long…

Answer 14

absolute refractory period. Increases cardiac output, allows time for filling.

Question 15

Things that make cardiac muscle unique

Answer 15

Branching, 1 or 2 nucleii generally in the middle. Intercalated discs (gap junctions, desmosomes). Lots of mitochondria

Question 16

T-tubule

Answer 16

Increases surface area of the cell. allows calcium to dive into the cell for absorption.

Question 17

Intrinsic cardiac conduction

Answer 17

A network of noncontractile (autothythmic) cells that initiate and distribute impulses to coordinate the depolarization of the heart.

Question 18

Pathway of the electrical heartbeat

Answer 18

Begins in SA node
Internodal pathway to AV node
Impulse delayed in AV node and bundle
AV bundle takes impulse to ventricles
L and R bundles of purkinjie fibers take impulses to Ventricles

Question 19

Autorhythmic cells

Answer 19

Have unstable resting potentials due to open slow Na channels.
At threshold, Ca channels open
Repolarization results from inactivation of Ca channels and opening of voltage gated K channels

Question 20

Sinoatrial (SA) node

Answer 20

Acts as pacemaker. Generates impulses at about 75 times/minute.
Depolarizes faster than any other part of the myocardium.
“normal sinus rhythm”

Question 21

Atrioventricular (AV) Node

Answer 21

Smaller fibers, fewer gap junctions.
Depolarizes about 50 times/minute.
“Junctional rhythm”

Question 22

Atrioventricular Bundle

Answer 22

Bundle of His

Only electrical connection between atria and ventricles.

Question 23

R and L bundle branches

Answer 23

2 pathways in interventricular septum that carries impulses toward the apex of the heart.

Question 24

Purkinje Fibers

Answer 24

Complete the pathway to apex and ventricular walls. Only depolarize 30 times/minute in absence of AV node input.

Question 25

Cardiac centers are located in...

Answer 25

Medulla Oblengota

Question 26

S1

Answer 26

AV valves close (mitral and tricuspid). Lub

Question 27

S2

Answer 27

Semilunar valves close (atrial and pulmonic). Dub

Question 28

Isovolumetric contraction and relaxation

Answer 28

Period where all 4 valves are closed.

Question 29

3 factors that affect Stroke volume

Answer 29

preload --> EDV afterload -->ESV contractility --> ESV

Question 30

Preload

Answer 30

The degree of cardiac muscle stretch before they contract. Stretching of cardiac cells results in an increase of contractile force. Increased venous return increases contraction force.

Question 31

Inotropic agents

Answer 31

``` Positive increase contractility: - increased Ca - Hormones (epi, glucagon, thyroxine) Negative decrease contractility - Acidosis - Increased extracellular K - Ca channel blockers ```

Question 32

Afterload

Answer 32

Pressure that must be overcome for ventricles to eject blood. Hypertension increases afterload, which results in increased ESV and reduced SV Results in hypertrophe

Question 33

Chronotropic Factors

Answer 33

Positive increase HR Negative decrease HR HR and contractility must go up together for adequate perfusion.

Question 34

Parasympathetic response

Answer 34

Ach hyperpolarizes pacemaker cells by opening K channels | The heart exhibits a vagal tone

Question 35

Atrial (Bainbridge) reflex

Answer 35

A sympathetic reflex initiated by increased venous return. Stretch of atrial walls stimulates the SA node Also stimulates atrial stretch reflexes activating sympathetic reflexes.

Question 36

Beta Blockers

Answer 36

Decrease HR and contractility. End in lol

Question 37

Calcium channel blockers

Answer 37

Decrease contractility

Question 38

L sided heart failure leads to...

Answer 38

RIght sided heart failure