The structure and function of the heart

Where is the AV valve located?

between atria and ventricles

Where is the SL valve located?

Right is located between the right ventricle and pulmonary artery. The left is between the left ventricle and aorta

Why does the heart contain valves?

prevent back flow of blood

What is a heart rate?

number of beats per minute

What is a stroke volume?

The volume of blood pumped out by each ventricle during contraction.

What is the cardiac output?

The volume of blood pumped through each ventricle per minute.

What is the cardiac cycle?

It refers to the lattern of contraction and relaxation of the heart during one complete heartbeat.

What are the three parts of the cardiac cycle?

Diastole, atrial systole, ventricle systole

Where does the blood go during diastole?

Blood returning to the attia flows into the ventricles

What happens to the atrial and ventricles during diastole?

They are relaxed

What happens to the vales during diastole?

The AV valves are open and SL valves are closed due to the higher pressure in the arteries

What happens to the atria and ventricles during atrial systole?

The atria contracts and ventricles relax

Where does the blood go in atrial systole?

The remander of the blood in the atrium is transfered theough the open AV valves to the ventricles

What happens to the AV and SL valves during atrial systole?

AV valves are open and SL valves are closed

What happens to the AV and SL valves during ventricular systole?

AV valves close and pumps the blood out through the open SL valves ti the aorta and pulmonary artery

What is the SAN also known as?

Pacemaker

Where is the auto rhythmic cells of the SAN located?

In the wall of the right atrium

What do the auto rhythmic cells of the SAN do?

Sets the rate with which the heart contracts

What is the timing of the cardiac muscle cell contraction controlled by?

Impulsed in the SAN spreading through the atria causing atrial systole

Where do the impulses travel after causing atrial systole?

The AVN node

Where is the AVN located?

In the centre of the heart

Where do impulses from the AVN travel?

Down fibres in the central wall of the heart and then uo through the walls of the ventricles

What does the medulla regulate?

The rate of the SAN through the antagonistic action of the autonomic nervous system

What does the sympathetic nerves release?

Noradrenaline (epinephrine) which increases heart rate

What does the parasympathetic nerves release?

Acetylcholine which decreases the heart rate

What releases adrenaline and why?

The sympathetic nervous system causes the adrenal glands to release adrenaline inder circumstances like stress or exercise

What does adrenaline do?

It travels in the blood to act on the SAN increasing heart rate

What detects impulses in the heart?

Electocardiograms (ECG)

What causes blood pressure?

The contraction of the ventricles

Why does the blood need to be pressured?

So it can travel through the body and for pressure filtration

When does blood pressure increase and decrease?

Increases during ventricular systole and decreases during diastole

How is blood pressure measured?

By using a sphygmomanometer