Topic 6.2: The Blood System

Question 1

What are the four chambers of the human heart?

Answer 1

two atria and two ventricles

Question 2

What is the purpose of the atria?

Answer 2

The atria act as reserviors, by which blood returning to the heart is collected via veins (and passed on to ventricles)

Question 3

What is the purpose of the ventricles?

Answer 3

The ventricles act as pumps, expelling the blood from the heart at high pressure via arteries

Question 4

What does the left side of the heart pump?

Answer 4

The left side of the heart pumps oxygenated blood around the body (systemic circulation)

Question 5

What does the right side of the heart pump?

Answer 5

The right side of the heart pumps deoxygenated blood to the lungs (pulmonary circulation)

Question 6

What is the function of arteries?

Answer 6

Arteries convey blood at high pressure from the ventricles to the tissues of the body

Question 7

What is the structure of arteries?

Answer 7

Arteries have muscle cells and elastic fibres in their walls

Question 8

How do muscle fibers help in blood flow?

Answer 8

The muscle fibres help to form a rigid arterial wall that is capable of withstanding the high blood pressure without rupturing

Question 9

How do elastic fibers help in blood flow?

Answer 9

The elastic fibres allow the arterial wall to stretch and expand upon the flow of a pulse through the lumen

Question 10

What is the structure and function of capillaries?

Answer 10

Capillaries have permeable walls that allow exchange of material between cells in tissues and blood in capillaries

Question 11

What is the function of veins?

Answer 11

The function of veins is to collect the blood from the tissues and convey it at low pressure to the atria of the heart

Question 12

What is the purpose of valves in veins?

Answer 12

Valves in veins and the heart ensure circulation of blood by preventing backflow

Question 13

Describe the walls of arteries

Answer 13

Arteries have thick walls and narrow lumens because they transport blood at high pressure

Question 14

Describe the walls of capillaries

Answer 14

Capillaries have walls that are only a single cell thick because they exchange materials between blood and tissue

Question 15

Describe the walls of veins

Answer 15

Veins have thin walls with wide lumens and valves because they transport blood at low pressure

Question 16

Describe the two atria in terms of heart structure

Answer 16

Two atria (singular = atrium) – smaller chambers near top of heart that collect blood from body and lungs

Question 17

Describe the two ventricles in terms of heart structure

Answer 17

Two ventricles – larger chambers near bottom of heart that pump blood to body and lungs

Question 18

Describe the atrioventricular valves in terms of heart structure

Answer 18

Atrioventricular valves (between atria and ventricles) – bicuspid valve on left side ; tricuspid valve on right side

Question 19

Describe the semilunar valves in terms of heart structure

Answer 19

Semilunar valves (between ventricles and arteries) – aortic valve on left side ; pulmonary valve on right side

Question 20

Describe the vena cava in terms of heart structure

Answer 20

Vena cava (inferior and superior) feeds into the right atrium and returns deoxygenated blood from the body

Question 21

Describe the pulmonary artery in terms of heart structure

Answer 21

Pulmonary artery connects to the right ventricle and sends deoxygenated blood to the lungs

Question 22

Describe the pulmonary vein in terms of heart structure

Answer 22

Pulmonary vein feeds into the left atrium and returns oxygenated blood from the lungs

Question 23

Describe the aorta in terms of heart structure

Answer 23

Aorta extends from the left ventricle and sends oxygenated blood around the body

Question 24

Define myogenic in terms of heart contraction

Answer 24

The contraction of the heart is myogenic – meaning that the signal for cardiac compression arises within the heart tissue itself

Question 25

Define sinoatrial node

Answer 25

Within the wall of the right atrium are a specialised cluster of cardiomyocytes which direct the contraction of heart muscle tissue

This cluster of cells are collectively called the sinoatrial node (SA node or SAN)

Question 26

What is the first step of the electrical conduction of a heart beat?

Answer 26

The sinoatrial node sends out an electrical impulse that stimulates contraction of the myocardium (heart muscle tissue)

Question 27

After The sinoatrial node sends out an electrical impulse that stimulates contraction of the myocardium (heart muscle tissue) what is the next step of the electrical conduction of a heart beat?

Answer 27

This impulse directly causes the atria to contract and stimulates another node at the junction between the atrium and ventricle

Question 28

After This impulse directly causes the atria to contract and stimulates another node at the junction between the atrium and ventricle what is the next step of the electrical conduction of a heart beat?

Answer 28

This second node – the atrioventricular node (AV node) – sends signals down the septum via a nerve bundle (Bundle of His)

Question 29

After This second node – the atrioventricular node (AV node) – sends signals down the septum via a nerve bundle (Bundle of His) what is the lastt step of the electrical conduction of a heart beat?

Answer 29

The Bundle of His innervates nerve fibres (Purkinje fibres) in the ventricular wall, causing ventricular contraction

Question 30

Define coronary arteries

Answer 30

Coronary arteries are the blood vessels that surround the heart and nourish the cardiac tissue to keep the heart working

Question 31

Define atherosclerosis

Answer 31

Atherosclerosis is the hardening and narrowing of the arteries due to the deposition of cholesterol