The Cardiovascular System In Action

Question 1

What is cardiac output ?

Answer 1

The volume of blood pumped through each ventricle (out of the heart) per minute
It is measured in litres/ minute

Question 2

What do the left and right ventricles pump the same volume of blood through?

Answer 2

The aorta and pulmonary artery

Question 3

What is stroke volume ?

Answer 3

The volume of blood pumped out of the heart with each heartbeat

Question 4

What does the pulse rate correspond to?

Answer 4

The heart rate

Question 5

What is cardiac output determined by?

Answer 5

Heart rate and stroke volume

Question 6

How is an individuals cardiac output calculated ?

Answer 6

CO = HR X SV

Question 7

How many chambers does the heart have ?

Answer 7

4

Question 8

What does the right side of the heart do?

Answer 8

Collects blood from the body and pumps it to the lungs to collect oxygen

Question 9

What does the left side of the heart do?

Answer 9

Collects oxygenated blood from the lungs and pumps it to the body

Question 10

What are the walls of the heart made of and what can this do?

Answer 10

Cardiac muscle

It can contract rapidly without fatigue for a life time

Question 11

During atrial diastole what fills the right atrium ?

Answer 11

Deoxygenated blood returning from the body via the vena cava

Question 12

What does a build up of pressure in the right side of the heart do?

Answer 12

Forces open the atrioventricular valve (tricuspid) and blood flows into the right ventricle, at this point the atrium contracts forcing all the blood into the ventricle (atrial systole)

Question 13

Once full what happens to the right ventricles muscular walls and what does this cause ?

Answer 13

They contract (ventricular systole) closing the tricuspid (av valve) and forcing the blood up through the semi lunar valve and in to the pulmonary artery to the lungs

Question 14

During atrial diastole what fills the left atrium?

Answer 14

Oxygenated blood retiring from the lungs via the pulmonary vein

Question 15

What does a build up of pressure in the left side of the heart do?

Answer 15

Forces open the atrioventricular valve (bicuspid) and blood flows into the left ventricle, at this point the atrium contracts forcing all the blood into the ventricle (atrial systole)

Question 16

Once full what happens to the left ventricles muscular walls and what does this cause?

Answer 16

They contract (ventricular systole) closing the bicuspid valve (AV valve) and forces the blood up through the Semj lunar valves and on through the aorta to the body’s organs

Question 17

What are the opening and closing of the AV and SL valves responsible for?

Answer 17

The heart sounds heard with a stethoscope

Question 18

Where does the heart beat originate and how is it regulated ?

Answer 18

The heart

By both nervous and hormonal control

Question 19

What are the muscle cells of the heart known as due to them being able to contract spontaneously?

Answer 19

Myogenic

Question 20

Where is the sinoatrial node(SAN) or pacemaker situated ?

Answer 20

In the wall of the right atrium

Question 21

What does the SAN ensure?

Answer 21

That both atria contract simultaneously by sending out a wave of excitation (electrical impulses) which are carried through the muscular walls

Question 22

What happens once the impulse from the SAN reach the atrioventricular node(AVN) located near the base of the atria?

Answer 22

Sends out impulses unto a bundle of conducting fibres which cause the ventricles to contract simultaneously after the atria

Question 23

What initiates each heart beat and how can the heart rate be altered?

Answer 23

The pacemaker initiates i

It can be altered by nervous and hormonal activity

Question 24

How can the pacemaker(SAN) responds to situations?

Answer 24

Because it is connected to a part of the brain called the medulla

Question 25

How does the medulla regulates the rate of the SAN?

Answer 25

Regulates the rate of the SAN through the antagonistic action if the automatic nervous system (ANS)

Question 26

What do sympathetic accelerator nerves release and what does it cause?

Answer 26

Noradrenaline (norepinephrine) Causes an increase in heart rate

Question 27

What do parasympathetic nerves release and what does it cause ?

Answer 27

Acetylcholine Causes a decrease in heart rate

Question 28

What happens to the sympathetic nervous system under certain circumstances such as stress or exercise?

Answer 28

Causes the adrenal glands to release adrenaline (epinephrine) which results in an increase in heart rate

Question 29

What do the auto rhythmic cells of the SAN do?

Answer 29

Sets the rate at which the cardiac muscle cells contract

Question 30

What is the timing of the cardiac cells contracting controlled by?

Answer 30

The impulse from the SAN spreading through the atria and then travelling to the atrioventricular node (AVN) and then through the ventricles.

Question 31

What do impulses from the SAN to the AVN generate?

Answer 31

Currents that can be detected by an electrocardiogram (ECG)

Question 32

Where is blood pressure highest?

Answer 32

In the large elastic arteries (aorta and pulmonary artery)

Question 33

Where is blood pressure lowest ?

Answer 33

In the vena cava

Question 34

What is blood pressure generated by ?

Answer 34

The contraction of the ventricles

Question 35

What happens as the heart goes through systole and diastole during each cardiac cycle?

Answer 35

The arterial pressure rises and falls

Question 36

When is blood pressure at its maximum ?

Answer 36

During ventricular systole (120mmHg)

Question 37

When is blood pressure at its minimum?

Answer 37

During ventricular diastole (80mmHg)

Question 38

What is a typical blood pressure reading for a young adult?

Answer 38

120/70 mmHg

Question 39

How is blood pressure measured?

Answer 39

Sphygmomanometer The inflatable cuff stops blood flow and deflated gradually. The blood starts to flow (detected by a pulse) at systolic pressure. The blood flows freely through the artery ( and a pulse is not detected) at diastolic pressure when at rest

Question 40

What is hypertension ?

Answer 40

High blood pressure | It is the prolonged elevation of blood pressure when at rest

Question 41

What is a major risk factor for many disease in later life such as corona heart disease and strokes?

Answer 41

Hypertension (high blood pressure)