Cardiac Cycle

Question 1

What is the cardiac cycle

Answer 1

Sequence of events taking place during one heart beat

Question 2

What are the three phases of the cardiac cycle

Answer 2

Atrial systole

Ventricular systole

Diastole

Question 3

What is systole

Answer 3

Contracts

High blood pressure

Question 4

What is diastole

Answer 4

Relaxes

Low blood pressure

Question 5

What are the steps of the cardiac cycle in the left hand side

Answer 5

1. Blood drains from pulmonary veins in left atrium
2. Blood pressure rises in left atrium and forces bicuspid valve to open
3. Contraction of the left atrial muscle (atrial systole) forces the blood through the valve
4. As soon as left atrial systole is over, left ventricular muscle status to contract- ventricular systole
5. Forces the bicuspid valve to close and semilunar valve opens. Blood leaves left ventricle along aorta
6. Atrial diastole and ventricular diastole relaxes

Question 6

What are the steps of the heart beat

Answer 6

1. Muscle cells in the heart have slight electrical charge across the membrane- polarised
2. Charge changes, depolarised and causes them to contract
3. Depolarisation is initiated in region of heart called sinoatrial node- SAN- pacemaker- wall of right atrium

Question 7

What is the heartbeat

Answer 7

Regulation of the nervous system

Question 8

How is the cardiac cycle produced

Answer 8

1. Initiation at SA node by impulse, atria contracts and blood travels to vesicles
2. Travels to AV node
3. Travels and delayed by 0.1 seconds at atrioventricular node, slow spread of electrical impulses across the heart allowing atria to contract before ventricles
4. Bundle of his down middle of septum is where signals travel next
5. Signals travel to the purkinje fibres which are around heart and act like neurons
6. Travel around outer walls of ventricle to atria. Stimulates muscles to contract and ventricles to contract.

Question 9

Blood pressure:
What does baro mean

What does receptors mean

Answer 9

Pressure or stretch

Special nerve cells

Question 10

What do baroreceptors do

Answer 10

Dense blood pressure

Keep blood pressure balanced

Question 11

What happens if blood pressure is low

Answer 11

Heart beats faster

Question 12

What happens is blood pressure is high

Answer 12

Heat beats slows

Question 13

What is vasodilation

Answer 13

Dilation of veins

More room for blood

Less pressure

Question 14

What is vasoconstriction

Answer 14

Construction of the veins

Question 15

Barorrceptors are

Answer 15

Stretch receptors located in heart

Detect changes in pressure of blood filling atria

Send signals to CNS

Triggers vasodilation and reduces blood pressure

Question 16

What is sonatrial node

Answer 16

Causes impulse to travel through atria causing them to contract and force blood into ventricles

Sets heart rhythm and rate

Question 17

What is atrioventricular nose

Answer 17

Detect impulse travelling through atria and redirects impulse to bundle of his.

Delay slows spread of electrical impulse across heart and allowing atria to contract before vesicles

Question 18

Bundle of his

Answer 18

Group of fibres in septum which impulse travels through to base of ventricles

Question 19

Purkinje fibres

Answer 19

Act like neurons

Found on walls of ventricles

Impulse from his reaches fibres causing ventricles to contract

Question 20

The frequency of cardiac is monitored by

Answer 20

Heart rate which is recorded by number of beats per minute