Chapter 17: Cardiac function

Question 1

describe the circulatory system

Answer 1

left side heart chambers: produce the force to propel blood through the vessels of the systemic (body) circulation
left atrium: receives oxygenated blood from the lungs by way of the pulmonary veins and delivers it to the left ventricle
oxygenated blood is pumped by the left ventricle into the aorta which supplies the arteries of the systemic circulation
venous blood is collected from the capillary networks of the body and is returned to the right atrium by way of the vena cava
blood from the head returns via the inferior vena cava

Question 2

the blood supplied to the heart muscle is provided by?

Answer 2

coronary arteries

Question 3

describe the cardiac cycle

Answer 3

each heartbeat is composed of a period of ventricular contraction (systole) followed by a period of relaxation (diastole)

Question 4

what does blood flow equal to ?

Answer 4

blood flow= pressure/ resistance

Question 5

what are the two determinants of coronary vascular resistance?

Answer 5

artery diameter

varying degrees of external compression by myocardial contraction and relaxation

Question 6

what are the two general cardiac myocytes?

Answer 6

working cells (mechanical pumping function) 
electrical cells ( transmit electrical impulses )

Question 7

how do the heart cells store excess ATP?

Answer 7

as creatine phosphate by the enzyme creatine kinase

Question 8

true or false: both cardiac contraction and relaxation require energy

Answer 8

true

Question 9

describe the determinants of stroke volume

Answer 9

preload: volume of blood in the heart
afterload: resistance to ejection from the ventricle