cardiovascular system; heartbeat + cardiac cycle

Question 1

control of heartbeat

Answer 1

impulse that triggers the heart beat originates in heart itself

Question 2

sinoatrial node/ sa node

Answer 2

bundle of specialized tissue, that stimulates muscle fibers to contract and relax rythmically

Question 3

sa node location

Answer 3

in the wall of right atrium

Question 4

other node atria contracts

Answer 4

atrioventricular node/ av node

Question 5

signal of av node

Answer 5

delayed @ av node for 0.01 seconds while atria empties blood into ventricles, then gets activated and enters the bundle of his.

Question 6

bundle of his function

Answer 6

av bundle that are conducting fibers that distribute the electrical signals to the ventricles

Question 7

purkinje fibers

Answer 7

specialized conduction fibers that provide the heart’s conduction system to perform synchronized contractions of its ventricles

bundle of his contains purkinje tissue

Question 8

specialized muscle fibers function (general)

Answer 8

conduct signal to apex of heart + throughout ventricular heart

Question 9

specialized muscle fibers function cont

Answer 9

triggers ventricles contraction
drives blood from ventricles -> large arteries

Question 10

hormonal control of heart rate

Answer 10

when you’re relaxed your sa node fires regularly
70 times/minute

Question 11

heart rate when exercising

Answer 11

increased activity in your muscles produces a faster rate of cellular respiration
-> increase amount of CO2 in blood
-> receptors in blood vessels transmit this info to medulla
oblongata

Question 12

medulla oblongata -> nervous systems

Answer 12

medulla oblongata sends impulse along nervous system, causes release a chemical called nonadrenaline

Question 13

nonadrenaline -> sa node

Answer 13

fires more rapidly

Question 14

when finished exercising

Answer 14

heart rate gradually returns to resting heart rate
-> controlled by medulla oblongata

Question 15

heart rate that’s fast =

Answer 15

increase in blood pressure, blood being pumped more quickly through vessels

Question 16

fast heart rate sensed =

Answer 16

receptors in blood vessels sense increase in blood pressure
-> transmit info to medulla oblongata

Question 17

medulla oblongata -> nervous system path 2

Answer 17

medulla oblongata causes nervous system to release acetylcholine, slows firing of sa node

Question 18

reason heart beats faster when exercising?

Answer 18

heart needs to transport blood faster as body needs more oxygen

Question 19

cardiac cycle

Answer 19

sequence of events of a heartbeat (3 stages)

Question 20

cardiac cycle consists of

Answer 20

systole and diastole

Question 21

complete cardiac cycle

Answer 21

during a complete cycle, each chamber undergoes a systole and diastole

Question 22

stage one

Answer 22

atrial systole and ventricular filling
ventricles relax + blood flows into them from atria
70% blood flows passively, during last third of ventricular filling gets contracted by atria

Question 23

stage two

Answer 23

ventricular systole
atria relaxes, ventricles contract, blood pumped ventricles from aorta
-> pulmonary artery

Question 24

stage three (has split second of relaxation/ventricular diastole)

Answer 24

semilunar valves close to prevent backflow into the ventricles

cycle begins again.

Question 25

systole

Answer 25

contractions

Question 26

diastole

Answer 26

relaxation

Question 27

ECG - electrocardiogram

Answer 27

electrical impulse transmitted through the heart, generates electrical currents

Question 28

how to detect ECG

Answer 28

by placing metal electrode on body’s surface

can be recorded on a heart monitor as a trace/ electrocardiogram (ecg)

Question 29

ECG pattern is produced by

Answer 29

different impulses produced from each phase of cardiac cycle

Question 30

p wave

Answer 30

spread of impulse from SA node through atria, causing them to contract

Question 31

qrs complex

Answer 31

corresponds to the spread of the impulse through the ventricles which contract

Question 32

t wave

Answer 32

represents the recovery of electrical activity of the ventricles which are relaxed.