lecture 25/26

Question 1

papillary muscles and chordae tendinae help control what?

Answer 1

are important structures as they help control the movement of AV valve flaps

papillary muscles contract to pull on the chrdae tendineae during ventricular systole. This helps to keep the valve flaps closed and not inverted

Question 2

ventricular contraction causes what?

Answer 2

systole

Question 3

What happens when the heart is in systole

Answer 3

AV valves are shut due to the high pressure in the ventricles relative to the lower pressure in the atria

semilunar valves are open as the ventricular pressure overcomes the pressure in the aorta and pulmonary trunk

Question 4

the chordae tendineae and papillary muscles are important in what?

Answer 4

preventing the atrioventriular valves from opening up into the atria (overclosing or inverting

Question 5

Heart sounds:

lub-dub occurs why?

Answer 5

due to valves closing

Question 6

in the cardiac cycle valves open and close as directed by pressure differences. when the ventricles contract which valves are forced close?

Answer 6

right and left atrioventricular valves

Question 7

cardiac electrical conducting system:

what are the pacemaker cells?

what is the primary and secondary?

Answer 7

sinoatrial node and atrioventricular node

SA = pacemaker

AV = secondary pacemaker

Question 8

Nodes and conducting fibers of the heart:

What are the AV and SA node composed of?

Answer 8

specialized cardiac muscle cells

Question 9

how do the purkinje fibers envelop the ventricles?

Answer 9

from the bottom up

Question 10

Conduction pathway of the heart:

5 places and their functions

Answer 10

SA node: right atrial wall, posterior primary pacemaker

AV node: right atrium, inferior medial wall secondary pacemaker

AV bundle: relay station

Bundle branch (right and left) down either side of interventricular septum

Purkinje fibers

Question 11

Autonomic control of heart:

which NT is used to keep the heart rate lower than inherent SA node rhythm?

Answer 11

ACH via vagus nerve

Question 12

What is the primary pacemaker of the heart?

Answer 12

Sinoatrial node (SA)

Question 13

Blood flow for the heart:
Coronary vessels:

what are the three?

Answer 13

right coronary artery:

• marginal (toward posterior/medial aspect)
• posterior interventricular artery

Left coronary artery:

• anterior interventricular artery
• cicumflex- to posterior aspect of ventricle

Cardiac vein
- feed into coronary sinus into right atrium

Question 14

blockage of a coranary artery does what?

Answer 14

deprives the heart muscle of blood and o2 causing injury to the myocardium

coranary athrosclerosis

blood clot

Question 15

what happens in a heart attack?

Answer 15

death to area of myocardium due to lack of oxygenated blood flow to a specific region - pointers at areas where death would interfere with either impulse conduction or muscle contraction

ex. damage to SA node

Damage to left ventricle

damage to bundle branch

Question 16

what veins are used for a coronary artery bypass?

Answer 16

autologous saphenous vein or the radial or thoracic artery

Question 17

pressure difference between pulmonary and systemic circuit?

Answer 17

pulmonary low

systemic high

Question 18

for blood to flow from left brachial vein to left brachial artery it must pass through

Answer 18

left subclavian vein
superior vena cava
lungs and heart

Question 19

Venous return:

characteristics of veins:

Answer 19

vein pressure is low

vein valves: one way open –> towards heart