Lecture 20

Question 1

describe flow of blood through the heart

Answer 1

vena cava to right atrium through tricuspid valve to right ventricle to semilunar valve to pulmonary arteries to pulmonary veins to left atrium to mitral (bicuspid) valve to left ventricle to semilunar valve to aorta.

Question 2

How do the two types of valves prevent backflow?

Answer 2

AV valves have chordae tendinae attached to papillary muscles
cup shaped semilunar valves fill with blood to prevent backflow

Question 3

Describe the structure of cardiac myocytes

Answer 3

cardiac myocytes = muscle contractile cells of the ehart
irregularly shaped, striated
1-2 nuclei
cells connected by intercalated disks (synapses composed of gap junctions and desmosomes to transmit physical force)

Question 4

Describe electrical conduction through the heart

Answer 4

autorhythmic cells in SA node (pacemaker) then down to AV node (delays transmission to allow for atrial contraction) then flows down AV bundle (Bundle of His) then up Purkinje fibers