Unit 2.6 Animal Transport

Question 1

Circulatory system

Answer 1

Used to transport materials around the body.

There are 3 parts - a fluid to carry materials (blood), tubes to carry it in (blood vessels) and a pump (heart).

Question 2

Blood

Answer 2

A tissue made of red and white blood cells suspended in a fluid called plasma.

It transports nutrients (from the small intestine) oxygen (from the lungs) and carbon dioxide (from body tissues back to the lungs).

Question 3

Red blood cells

Answer 3

Cells that are specialised for the transport of oxygen.

They are tiny, biconcave and have no nucleus.

They are flexible, able to squeeze through tiny blood vessels and have a large surface area for absorbing oxygen.

Question 4

Haemoglobin

Answer 4

A protein found in red blood cells, which combines with oxygen to form oxyhaemoglobin.

This allows efficient transport of oxygen in the blood.

Question 5

White blood cells

Answer 5

Part of the immune system, that protects the body from pathogens (disease causing organisms) by destroying them.

There are 2 main types - lymphocytes and phagocytes.

Question 6

Phagocytes

Answer 6

White blood cells that destroy microbes by engulfing them and digesting them with enzymes.

Question 7

Lymphocytes

Answer 7

White blood cells that release proteins known as antibodies that bind to invading microbes and stop them attacking cells.

Since antibodies are specific, they bind to one type of pathogen only.

Question 8

Blood vessels

Answer 8

Tubes that carry blood around the body.

There are 3 types - arteries, veins and capillaries.

Question 9

Arteries

Answer 9

Blood vessels with a thick muscular wall, made of several layers and a narrow channel (lumen) down the middle.

Carry oxygen rich blood away from the heart at high pressure.

Question 10

Veins

Answer 10

Blood vessels with thin walls made of several layers, and a wide channel (lumen).

Contain valves to prevent backflow of blood.

Carry deoxygenated blood at low pressure back to the heart.

Question 11

Capillaries

Answer 11

Blood vessels made of a single layer of cells only.

They are very thin walled and are permeable (they leak) allowing rapid diffusion and exchange of materials with body tissues.

They connect arteries to veins.

Question 12

Capillary networks

Answer 12

Made from branching capillaries, and link arterioles (small arteries) to venules (small veins).

They run between the cells of the body, leaking fluids and allowing exchange of materials. eg. glucose, oxygen.

They form a large surface area for efficient exchange.

Question 13

Double circulation

Answer 13

Blood travels to every part of the body, visiting the heart twice on each circuit.

One circuit travels to the lungs, the other to the body tissues.

Oxygen is collected from the lungs, returned to the heart, and is then pumped to the tissues.

Carbon dioxide is collected from the tissues, returned to the heart, and is then pumped back to the lungs.

Question 14

Atria

Answer 14

The 2 thin walled upper chambers of the heart - left and right atrium.

Receive blood from the lungs/body and push it down into the ventricles, through valves.

Question 15

Ventricles

Answer 15

The 2 thick walled chambers at the bottom of the heart.

The left ventricle has more muscle, as it has to push the blood further (around the body).

The right ventricle has less muscle, as it only has to return blood to the lungs.

Question 16

Oxygenated blood

Answer 16

Blood containing oxygen, that is delivered to the left side of the heart from the lungs.

It is then pumped out to the body tissues.

Question 17

Deoxygenated blood

Answer 17

Blood that has had its oxygen removed by respiring cells in the tissues.

Deoxygenated blood returns from the body tissues to the right side of the heart, and is pumped back to the lungs.

Question 18

Septum

Answer 18

A strip of muscle tissue that separates the left and right sides of the heart.

This prevents oxygenated and deoxygenated blood from mixing, increasing the efficiency of oxygen delivery.

Question 19

Heart valves

Answer 19

Found between the atria and ventricles on both sides, and at the exits from the heart (aorta and pulmonary artery).

Prevent backflow of blood into heart chambers.

Question 20

Heart blood vessels

Answer 20

Left side - pulmonary vein in, aorta out (oxygenated blood)

Right side - vena cava in, pulmonary artery out (deoxygenated blood)

Question 21

Action of the heart

Answer 21

Both atria fill at the same time, as the heart muscles relax.

Blood is pulled in from the pulmonary vein (L) and vena cava (R).

The atria contract together, pushing the blood into the 2 ventricles, via valves to stop backflow.

Both ventricles contract together, pushing the blood up and out of the heart, via valves into the aorta (L) and pulmonary artery (R).

Question 22

Pathway of blood

Answer 22

Pulmonary vein, L atrium, L ventricle, aorta, arteries, capillaries in body tissues. (oxygenated blood)

Veins, vena cava, R atrium, R ventricle, pulmonary artery, lung capillaries (deoxygenated blood)

Oxygen is collected in the lung capillaries, then the pathway starts again with the pulmonary vein…

Question 23

Coronary arteries

Answer 23

Arteries that branch off the aorta, divide into capillaries and provide the heart muscle with blood containing oxygen and nutrients.

Capillaries rejoin to form coronary veins that return deoxygenated blood to the vena cava.

Question 24

Cause of a heart attack

Answer 24

Coronary arteries become blocked, due to fatty deposits resulting from an unhealthy lifestyle.

The heart muscle is deprived of oxygen and nutrients and stops working.