Chapter 4 - Summary Questions

Question 1

What prevents the backflow of blood in the circulatory system?

Answer 1

Valves.

Question 2

List the tissues found in a leaf.

Answer 2

Epidermal tissue, palisade mesophyll, spongy mesophyll, xylem, phloem.

Question 3

What is the function of phloem?

Answer 3

Transport of food.

Question 4

What type of blood vessel carries blood to the heart?

Answer 4

Veins.

Question 5

a) List the types of cells found in the blood.

b) Name the liquid that transports them.

Answer 5

a) Red blood cells, white blood cells, platelets.

b) Plasma

Question 6

State two differences in the structure of arteries and veins.

Answer 6

Arteries have thick muscular walls and veins have thin muscular walls; arteries do not have valves and veins have valves.

Question 7

a) Where is the natural pacemaker found in the heart?

b) What is the function of the pacemaker?

Answer 7

a) In the right atrium (Wall)

b) It controls the resting rate (rhythm) of the heart.

Question 8

Explain why the left ventricle can generate more force than the right ventricle.

Answer 8

It has a thicker muscular wall.

Question 9

What features of an alveolus make it an efficient exchange surface?

Answer 9

Three from: large surface area, thin walls / in close contact with blood capillaries (short diffusion path); well supplied with blood capillaries (for transport); to maintain a steep diffusion gradient.

Question 10

List the route the blood would take when travelling from the body to the lungs and back to the body. Include the names of all the blood vessels and heart chambers.

Answer 10

Vena cava —-> right atrium —-> right ventricle —-> pulmonary artery —-> lungs —-> pulmonary vein —-> left atrium —-> left ventricle —-> aorta

Question 11

Explain why plants wilt.

Answer 11

If the cells lose a lot of water they became flaccid; to reduce water loss the stomata close and the leaves wilt, which reduces their surface area, so less water evaporates and diffuses out of the leaf.

Question 12

Describe and explain the sequence of events that draws air into the lungs.

Answer 12

The intercostal muscles contract and the diaphragm contracts; the ribcage moves up and out and the diaphragm flattens; this increases the volume inside the thorax and decreases the pressure (so air is forced into the lungs).