CV System: The Heart

Question 1

Similarities of cardiac and skeletal mechanism of contraction

Answer 1

Striated- myosin/actin mechanism

T-tubule mechanism-acting on sarcomas mic reticulum

Question 2

T tubules store more/less Ca++ in the heart than skeletal

Answer 2

More

Question 3

What does the cardiac muscle plateau result in

Answer 3

Longer time of contraction

Question 4

What is the strength of cardiac muscle dependent on

Answer 4

Extracellular Ca++

Question 5

Order of conduction system

Answer 5

SA node, AV node, bundle of His, bundle branches, purkinje fibers

Question 6

An increase in Ca++ permeability facilitates

Answer 6

Action potential

Question 7

Increase in K+ permeability

Answer 7

Hypopolarizaiton

Question 8

P wave

Answer 8

Atrial depolarization

Question 9

QRS complex

Answer 9

Ventricular depolarization

Question 10

T wave

Answer 10

Ventricular repolarization

Question 11

Diastole

Answer 11

Relaxation, fills with blood

Question 12

Systole

Answer 12

Contraction, ejects blood

Question 13

Ejection fraction

Answer 13

Fraction of EDV ejected

Question 14

P wave detail

Answer 14

Spread of depolarization through atrial tissue followed by contraction - increase in atrial pressure

Question 15

QRS complex detail

Answer 15

Spread of depolarization through ventricular tissue followed by contraction - increase in ventricular pressure

Question 16

T wave detail

Answer 16

Repolarization of ventricles which represents ventricular relaxation

Question 17

Atrial pressure changes. (A,C,V waves)

Answer 17

A- during atrial contraction
C- onset of ventricular contraction
V- end of ventricular contraction

Question 18

Preload

Answer 18

End-diastolic pressure when the ventricle is filled; amount of tension on the muscle when it begins to contract

Question 19

After load

Answer 19

Pressure in the artery leading from the ventricle; load against which the muscle exerts its contractile force

Question 20

10-30 % of energy derived from oxidative metabolism of ______, and majority 70-90% of ______

Answer 20

Lactose or glucose
Fatty acids
*can also use lactic acid generated by skeletal muscle activity

Question 21

Amount of blood pumped determined primarily by rate of blood flow into heart

Answer 21

Frank-Starling Mechanism

Question 22

Intrinsic regulation of heart pumping

Answer 22

Frank-starling mechanism

Question 23

Extrinsic regulation of the cardiac pump

Answer 23

Norepinephrine released by the sympathetic nervous system in response to stressors such as fright, anxiety, or exercise; threshold reached more quickly

Question 24

Parasympathetic extrinsic regulation of cardiac pump

Answer 24

Reduces HR when stressors removed by opening K+ channels and acetyloholine hyperpolarizes membranes of cells
*note this primarily affects HR rather than contractility

Question 25

Vagal tone is exhibited in the heart when

Answer 25

It is at rest. And the dominant influence is inhibitory

Question 26

Percutaneous transluminal coronary angioplasty (PTCA)

Answer 26

The use of a balloon tipped catheter to enlarge a narrowed coronary artery