Transport in Animals

Question 1

Circulatory system

Answer 1

a system of blood vessels with a pump and valves to ensure one-way flow of blood

Question 2

Single and double circulatory system

Answer 2

• Fish have single circulatory system, where the blood passes through the heart once per circuit
• Mammals have double circulatory system where the blood passes through the heart twice per circuit.

Question 3

Advantages of double circulatory system

Answer 3

-Double circulatory system can maintain high blood pressure, which increases speed at which blood flows. Thus nutrients can be delivered faster and waste can be removed quickly.

Question 4

Blood pumped in Arteries and veins

Answer 4

blood is pumped away from the heart into arteries and returns to the heart in veins

Question 5

Thickness of the muscle wall of the left and right

ventricles

Answer 5

-The right ventricle pumps blood to the lungs (a shorter distance), the left ventricle pumps blood all around the body (a further distance), thus left ventricles have thicker walls as blood needs to be under high pressure

Question 6

Thickness of the muscle wall of the atria compared to that of the ventricles

Answer 6

The ventricles of the heart have thicker muscular walls than the atria. This is because blood is pumped out of the heart at greater pressure from these chambers compared to the atria.

Question 7

Importance of the septum in separating oxygenated and deoxygenated blood

Answer 7

The septum separates oxygenated and deoxygenated blood thus prevents mixing of oxygenated and deoxygenated blood.

Question 8

functioning of the heart in terms of the contraction of muscles of the atria and ventricles and the action of the valves

Answer 8

1. Deoxygenated blood enters the heart through the vena cava into the right atrium
2. Right atrium contacts and blood moves through tricuspid valve into right ventricle
3. Right ventricle contacts and blood exits through the semilunar valve to the lungs via pulmonary artery
4. Blood becomes oxygenated in lungs and returned to the heart in the left atrium through the pulmonary vein.
5. Left atrium contracts, blood moves through bicuspid valve into left ventricle
6. Left ventricle contracts, oxygenated blood exits through aorta, travels around body becoming deoxygenated.

Question 9

activity of the heart monitored by…

Answer 9

• ECG
• Pulse rate
• Listening to sounds of valves closing

Question 10

Valves in the heart

Answer 10

-Valves are present in the heart to prevent back flow of blood. Bicuspid and Tricuspid valves are known as Atrioventricular valves, as they prevent back flow of blood between ventricles and atria. Thus not present in Arteries as there is enough high pressure so back flow does not occur.

Question 11

Activity of the heart monitored by…

Answer 11

• ECG
• Pulse rate
• Listening to sounds of valves closing

Question 12

Effect of physical activity on the heart rate

Answer 12

• When physical activity is carried out, muscles respire to produce energy for movement. Aerobic respiration requires oxygen, thus heart rate increases so blood is pumped around the body more quickly allowing more oxygen to be delivered to repairing tissues.

Question 13

Roles of diet and exercise in the prevention of coronary heart disease

Answer 13

• It lowers blood pressure

Question 14

effect of physical activity on the pulse rate

Answer 14

-Exercise causes an increase in pulse rate (heart rate).

Question 15

ways in which coronary heart disease may be treated

Answer 15

-Drug treatment with aspirin, Aspirin thins the blood and makes platelets less likely to clump together to block the artery, also helps reduce high blood pressure.
Surgery:
-Stents: Small tube inserted into artery, to keep it open allowing blood to flow
-Angioplasty: Tiny ballon inserted into a collapsed artery, inflated with water and pushes artery open.
-Coronary bypass: Blocked or severely damaged artery replaced with a length of blood vessel.

Question 16

Coronary heart disease

Answer 16

Build up of cholesterol in the coronary artery, which narrows artery thus limiting blood flow to the heart. Risk factors include: diet, stress, smoking, genetic predisposition, age and gender

Question 17

structure and functions of arteries, veins and capillaries

Answer 17

-Arteries: Carry oxygenated blood away from the heart.
Has a thick outer wall of muscles and elastic fibers, and has a small lumen to maintain high blood pressure.
-Capillaries: Flow close to tissues for exchange (take nutrients to cells in the body and waste material way). they have very small lumen and has walls made up of single layer cell.
-Veins: Carry blood towards the heart, they have a large lumen as blood under low pressure, valves to prevent back flow, thin layer of muscle and elastic fibers and thin outer wall.

Question 18

function of arterioles, venules and shunt vessels

Answer 18

• Arterioles: Arteries branch into arterioles, they bring oxygen and nutrients from the heart to the organs and tissues.
• Venules: Small veins formed by group of capillary vessels, they carry deoxygenated blood back to the heart.
• Shunt vessels: Connect arteries to veins, without blood traveling through capillaries. They dilate and constrict like arteries to control blood flow, They dilate in cold conditions to reduce heat loss.

Question 19

blood vessels to and from the:

Answer 19

– heart: Vena cava, aorta, pulmonary
artery and pulmonary vein
– lungs: Pulmonary artery and pulmonary vein
– kidney: Renal artery and renal vein

Question 20

lymphatic system

Answer 20

-lymphatic system consists of lymphatic vessels and
lymph nodes.
-Capillaries exchange substances with cells producing tissue fluid. The walls of the capillaries are so thin that water, dissolved solutes and dissolved gases easily leak out of them / pass through the walls from the plasma into the tissue fluid surrounding the cells
-Cells exchange materials (such as water, oxygen, glucose, carbon dioxide, mineral ions) across their cell membranes with the tissue fluid surrounding them by diffusion, osmosis or active transport
-More fluid leaks out of the capillaries than is returned to them, and this excess of leaked fluid surrounding the capillaries then passes into the lymphatic system, becoming lymph fluid

Question 21

function of the lymphatic system in the circulation of body fluids and the protection of the body from infection

Answer 21

-Lymph nodes are small clusters of lymphatic tissue found throughout the lymphatic system, especially in the neck and armpits
-Large numbers of lymphocytes are found in lymph nodes
Tissues associated with the lymphatic system, such as bone marrow, produce these lymphocytes
-Lymphocytes play an important role in defending the body against infection
-And Helps maintain fluid balance in the body by collecting excess fluid from tissues and depositing them in the bloodstream.

Question 22

components of blood

Answer 22

• Red blood cells: Transports oxygen, Contain Haemoglobin that binds to oxygen, allowing it to be transported around the body to cells.
• White blood cells: Ingesting pathogens (phagocytosis) and producing antibodies
• Platelets: Involved in blood clotting
• Plasma: Liquid in blood vessels that contains blood cells, ions, soluble nutrients, hormones, and CO2

Question 23

Identify lymphocyte and phagocyte white blood cells

Answer 23

lymphocyte and phagocyte are types of white blood cells

Question 24

Function of lymphocytes and phagocytes

Answer 24

– lymphocytes: antibody production
– phagocytes: phagocytosis
Phagocytosis:
1. Phagocyte recognizes and attaches to a foreign pathogen
2. Membrane of the phagocyte envelops the pathogen and folds inwards, trapping the pathogen inside the phagocyte.
3. Phagocyte releases enzymes which break down the pathogen, killing it.

Question 25

roles of blood clotting as preventing blood loss and preventing the entry of pathogens

Answer 25

• In blood clotting, Platelets are key. When cut, platelets bump into rough edges of the cut and react by releasing chemicals. Fibrinogen in the blood plasma is converted into fibrin, when chemicals released by platelets and damages tissues, set off a chemical reaction it forms a mesh across wound. RBC and platelets get trapped in the wound. Forming blood clots.
• This prevents pathogens entering through the cut, and prevents excessive blood loss