The Human Heart Structure

Question 1

What is the heart made out of?

Answer 1

Cardiac muscle

Question 2

Where is the cardiac muscle found?

Answer 2

The cardiac muscle is found in the layers of the wall of the heart

Question 3

Describe the appearance of the layers of the cardiac muscle:

Answer 3

The layer of the cardiac muscle is thick and muscular

Question 4

What are the unique properties of the cardiac muscle?

Answer 4

Cardiac muscle is myogenic and does not fatigue

Question 5

What is meant when it is said the cardiac muscle is “myogenic”?

Answer 5

This means the cardiac muscle can contract/relax without nervous/hormonal stimulation

Question 6

What is meant when it is said the cardiac muscle “does not fatigue”?

Answer 6

This means as long as the cardiac muscle has a supply of oxygen and glucose, it will never fatigue

Question 7

What are coronary arteries and what do the coronary arteries surround?

Answer 7

They are blood vessels that surround the heart

Question 8

What is the role of the coronary arteries?

Answer 8

The coronary arteries supply the cardiac muscle with oxygenated blood

Question 9

Where do coronary arteries branch off from?

Answer 9

Coronary arteries branch off the aorta

Question 10

What cause a heart attack (myocardial infarction)?

Answer 10

A heart attack is caused by the coronary arteries becoming blocked. This prevent the cardiac muscle from receiving oxygen, which leads to the cells being unable to respire and eventually dying. This results in the heart attack (myocardial infarction).

Question 11

What are the four chambers of the heart?

Answer 11

There are two atrias (left and right atrium) and the two ventricles (left and right ventricle)

Question 12

What are the features of the atria?

Answer 12

• The muscular walls are thinner
• The walls are elastic and stretch when the blood enters
• The walls are thinner as they do not need to contract as hard since blood is not being pumped far (only to the ventricles)

Question 13

What are the feature of ventricles?

Answer 13

1. the muscular walls are thicker to enable for bigger contraction
2. has a higher blood pressure that enables blood to flow longer distances (to the lungs and then the rest of the body)

Question 14

Describe the right ventricle: (wall+pressure)

Answer 14

The right ventricle has a thinner muscular wall and a lower pressure level.

Question 15

Why does the right ventricle have a thinner muscular wall?

Answer 15

The right ventricle has a thinner muscular wall since it pumps blood to the lungs

Question 16

Why does the right ventricle have a lower pressure level?

Answer 16

1. To prevent damage to capillaries in the lungs
2. To allow blood to flow slowly to allow time for gas exchange

Question 17

Describe the left ventricle:
(wall + pressure)

Answer 17

1. The left ventricle has a thicker muscular wall
2. The left ventricle has a higher pressure

Question 18

Why does the left ventricle have a higher pressure level?

Answer 18

The higher pressure is needed to ensure blood reaches to all the cells in the body

Question 19

Why does the left ventricle have a thicker muscular wall?

Answer 19

The left ventricle has a thicker muscular wall to enable large contractions of the muscle to create a higher pressure

Question 20

How many veins are there in the hearts?

Answer 20

There are two veins in the human heart

Question 21

What do veins do in the heart?

Answer 21

Veins carry blood into the heart

Question 22

What are the two veins in the heart?

Answer 22

The vena cava and the pulmonary vein

Question 23

What is the function of the vena cava?

Answer 23

The vena cava carries deoxygenated blood from the body into the right atrium

Question 24

What is the function of the pulmonary vein?

Answer 24

The pulmonary vein carries oxygenated blood from the lungs to the left atrium

Question 25

What does the word “pulmonary” always refer to?

Answer 25

The lungs

Question 26

How many arteries are there in the human heart?

Answer 26

There are two arteries

Question 27

What is the function of the artery?

Answer 27

The arteries carry blood away from the heart

Question 28

What are the two arteries?

Answer 28

The pulmonary artery and the aorta

Question 29

What is the function of the pulmonary artery?

Answer 29

Pulmonary artery carries deoxygenated blood from the right ventricles to the lunges to become oxygenated

Question 30

What is the function of the aorta?

Answer 30

The aorta carries oxygenated blood from the left ventricles to the rest of the body

Question 31

What are the two valves?

Answer 31

The semi-lunar valves and the atrioventricular valves

Question 32

Where are the semi lunar valves found?

Answer 32

They are found in the aorta and pulmonary arteries

Question 33

Where are the atrioventricular valves found?

Answer 33

They are found in between the atrias and ventricles

Question 34

What are the atrioventricular valves sometimes called?

Answer 34

They are sometimes called bicuspid/tricuspid

Question 35

What does the “bicuspid/tricuspid” names refer to?

Answer 35

The names refers to numbers of flaps that make up the valve

Question 36

What is the function of the valves?

Answer 36

The valves ensure blood flow is one directional, preventing back flow of blood

Question 37

How do valves open and close?

Answer 37

Valves open when the pressure is higher, behind the valve and then proceed to close when pressure is higher, in front of the valve

Question 38

What is the function of the septum?

Answer 38

The septum separates oxygenated and deoxygenated blood, ensuring oxygenated blood is not diluted by deoxygenated blood.

Question 39

What does the septum allow to have maintained in the human heart?

Answer 39

The septum maintain a high concentration of oxygen in oxygenated blood to maintain concentration gradient which enables diffusion amongst respiring cells