heart pt.4

Question 1

The period of one heartbeat and the beginning of the next. The heart consists of four pumps working in pairs. The atria pump together followed by the ventricles pumping together

Answer 1

cardiac cycle

Question 2

all four chambers are relaxed (diastole; ventricles are passively refilling)

Answer 2

cardiac cycle begins. 1st

Question 3

atria contract; finish filling ventricles

Answer 3

atrial systole. 2nd

Question 4

continues until start of next cardiac cycle (through ventricular systole)

Answer 4

atrial diastole. 3rd

Question 5

Contracting ventricles push AV valves closed but not enough pressure to open semilunar valves

Answer 5

ventricular systole first phase. 4th

Question 6

no volume change and all valves closed. during first phase of ventricular systole

Answer 6

isovolumetric contraction

Question 7

Increasing pressure opens semilunar valves; blood leaves ventricle. aka Ventricular ejection

Answer 7

ventricular systole second phase. 5th

Question 8

Ventricles relax and their pressure drops; blood in aorta and pulmonary trunk backflows, closes semilunar valves

Answer 8

​early ventricular diastole. 6th

Question 9

All valves closed; no volume change; blood passively filling atria

Answer 9

isovolumetric relaxation. 7th

Question 10

ventricles passively fill to 70%. all chambers relaxed. AV valves are open

Answer 10

late ventricular diastole. 8th (last step)

Question 11

a prominent and distinctive feature of the pressure waveform in the central arteries (aortic elastic walls recoil)

Answer 11

dicrotic notch

Question 12

first heart sound in cardiac cycle. occurs when ____ valves close. marks start of ventricular contraction

Answer 12

Lubb. AV

Question 13

second heart sound in cardiac cycle. occurs when ______ close.

Answer 13

Dupp. semilunar

Question 14

sound 3 is blood flowing into _____ and sound 4 is _____ contraction. these are very faint sounds. Rarely heard in adults

Answer 14

ventricles, atrial

Question 15

The heart is controlled indirectly by signals from the brain and by hormones, mostly in form of adjusting

Answer 15

heart rate

Question 16

each heartbeat begins with an action potential from this node. This is also known as the “pacemaker.”

Answer 16

sinoatrial (SA) node

Question 17

Node located In posterior wall of right atrium, near superior vena cava

Answer 17

SA node aka pacemaker

Question 18

conduct APs to atria as it continues toward the ventricles. transmits from SA node to AV node

Answer 18

internodal pathways

Question 19

contains pacemaker cells, but does not generally affect heart rate. Can take over for SA if it fails, though it only generates beats at 40-60 a second.

Answer 19

atrioventricular (AV) node

Question 20

Conducting cells transmit signal from AV node down through interventricular septum. Usually only electrical connection between atria & ventricles

Answer 20

AV bundle

Question 21

stems off AV bundle. has right and left. ___ side is larger because left ventricle needs more. Conducting cells transmit signal to apex of heart, then spreading out in ventricular walls

Answer 21

bundle branches, left

Question 22

ascends off bundle branches into ventricle wall. important role in cardiac conduction

Answer 22

purkinje fibers

Question 23

This node stimulates the depolarization of atria immediately and contraction quickly follows. Impulse moves to AV node, where it delays the action potential for 100ms, allowing ventricles to fill. During the delay, atrial systole is occurring.

Answer 23

SA node

Question 24

after AP reaches AV bundle, signal travels quickly through left and right bundle branches in the interventricular septum, reaching the Purkinje fibers located the ventricular wall. Causes depolarization and contraction of both ventricles almost simultaneously. Ventricular systole begins in the ____ of the heart and moves toward _____

Answer 24

apex, atria

Question 25

Cardiac pacemaker cells have ______ resting membrane potentials. Slow ___ channels are open and __ channels are closed which causes gradual depolarization.

Answer 25

unstable, Na+, K+