6.2 The blood system

Question 1

What is the primary function of arteries?

Answer 1

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

Question 2

What are the characteristics of the walls of arteries?

Answer 2

Artery walls contain muscle cells and elastic fibres

Question 3

How do the muscle and elastic fibres in artery walls assist in blood circulation?

Answer 3

They assist in maintaining blood pressure between pump cycles

Question 4

How does blood flow through tissues?

Answer 4

Blood flows through tissues in capillaries

Question 5

What special feature do capillary walls have?

Answer 5

Capillary walls are permeable, allowing exchange of materials between cells in the tissue and the blood

Question 6

What is the role of veins in the circulatory system?

Answer 6

Veins collect blood at low pressure from the tissues of the body and return it to the atria of the heart

Question 7

How do veins ensure one-directional blood flow?

Answer 7

Valves in veins prevent backflow, ensuring circulation of blood

Question 8

How did William Harvey contribute to our understanding of circulation?

Answer 8

He discovered the circulation of the blood with the heart acting as the pump

Question 9

What is pulmonary circulation?

Answer 9

Pulmonary circulation is the separate circulation for the lungs, involving blood flow from the heart to the lungs and back

Question 10

Can you identify the chambers and valves of the heart?

Answer 10

Yes, by their structure and connection to blood vessels in diagrams or dissected hearts

Question 11

How is the heartbeat initiated?

Answer 11

By the sinoatrial node in the right atrium, acting as a pacemaker

Question 12

How does the sinoatrial node control the heartbeat?

Answer 12

It sends out an electrical signal that stimulates contractions, propagating through the atria and then the ventricles​

Question 13

How can heart rate be increased or decreased?

Answer 13

Through impulses brought to the heart by two nerves from the medulla of the brain​

Question 14

What effect does epinephrine have on the heart rate?

Answer 14

It increases the heart rate to prepare for vigorous physical activity

Question 15

What are the causes and consequences of coronary artery occlusion?

Answer 15

Causes include high LDL levels, diabetes, smoking, and high blood pressure. Consequences can be angina or myocardial infarction​

Question 16

How can you identify blood vessels as arteries, capillaries, or veins based on the structure of their walls?

Answer 16

Arteries have thick walls with muscle and elastic fibers, capillaries have walls one cell thick allowing for exchange, and veins have thinner walls with valves to prevent backflow

Question 17

Explain the pressure changes in the left atrium, left ventricle, and aorta during the cardiac cycle.

Answer 17

During the cardiac cycle, pressure increases in the left atrium during atrial systole, pushing blood into the left ventricle.

The left ventricle then contracts (ventricular systole), significantly increasing pressure to push blood into the aorta for systemic circulation.

During diastole, pressure drops, allowing the chambers to refill​