chapter 9: transport in animals

Question 1

describe the circulatory system

Answer 1

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

Question 2

describe the circulatory system of a fish

Answer 2

• fish have a two chambered heart
• for every one circuit of the body, blood passes through the heart only once
• they have a single circulation system

Question 3

describe the circulatory system of a mammal

Answer 3

• they have a 4 chambered heart
• for every one circuit of the body, blood passes through the heart twice
• they have a double circulation system
• right side: receives deoxygenated blood to be sent to the lungs (pulmonary circulation)
• left side: receives oxygenated blood to be sent to the body (systemic circulation)

Question 4

outline the advantages of a double circulatory system

Answer 4

• maintains a higher blood pressure to the body for more efficiency
• supports faster metabolism as there is more oxygen for metabolically active tissues
• allows a lower pressure to lungs which allows more time for gas exchange

Question 5

how can heart activity be monitored

Answer 5

• ECG/measuring pulse rate/stethoscope to losten to the sounds of valves closing

Question 6

what is the effect of physical activity on heart rate and breath rate?

Answer 6

• increased physical activity = increased heart and breath rate
• this is to provide muscles with enough nutrients and oxygen for increased respiration and remove waste products at a faster rate
  —
• heart rate remains high then gradual decrease
• remains high at first to ensure all excess waste products are removed and to deliver oxygen to muscle cells to pay off the oxygen debt and breakdown lactic acid in the liver

Question 7

what is the purpose of coronary arteries

Answer 7

• to provide the muscle cells of the heart with their own supply of blood and provide nutrients and remove waste products

Question 8

describe coronary heart disease

Answer 8

• when the coronary arteries become completely or partially blocked by fatty deposits called plaques (formed from mainly cholesterol and some wbc)
• the coronary arteries are no longer as elastic as they should be and cannot stretch to accomodate the flow of blood
• partial = angina (severe chest pains)
• completely = heart attack

Question 9

state the possible risk factors of coronary heart disease

Answer 9

• poor diet: eating saturated fat = higher cholesterol levels
• lack of exercise: increases blood pressure and cholesterol levels
• stress: hormones produced can increase blood pressure
• smoking: nicotine makes blood vessels narrower and thus increases blood pressure
• genetic predisposition: history of disease in family makes it more likely for younger generation to get it
• age: chances of getting disease increases when older
• gender: more likely in males

Question 10

outline ways to reduce the risk of coronary heart disease

Answer 10

• don’t smoke
• reduce animal fats, eat veggies and fruits
• exercise regularly to help with weight loss, decrease blood pressure and reduce stress

Question 11

explain the relative thickness of the muscle walls of the left and right ventricles

Answer 11

• ventricles have thicker walls because they are pumping blood out of the heart so more pressure is needed, thick walls help to withstand the high pressure
• left ventricle has a thicker muscle wall as it needs more pressure to pump blood to the rest of the body

Question 12

explain the importance of the septum

Answer 12

• separates the oxygenated and deoxygenated blood
• if there is a problem with the septum not enough oxygenated blood can be pumped out of the heart

Question 13

what is the basic function of valves

Answer 13

to prevent blood from flowing backwards

Question 14

how do the atrioventricular valves work

Answer 14

• when the atria contracts, they open to let blood flow into the ventricle
• when the ventricle contracts, they close so blood doesn’t flow back into the atria

Question 15

why is the pulmonary artery and aorta unusual?

Answer 15

they are the only arteries in the body with valves

Question 16

how do the semilunar valves work?

Answer 16

• when the ventricle contracts, they open to let blood flow
• when the blood flows out they close to avoid blood flowing back into the ventricle

Question 17

outline the functioning of the heart

Answer 17

1. deoxygenated blood from the body flows to the right atrium via the vena cava
2. blood is pushed past the tricuspid valve into the right ventricle
3. ventricle walls contract, pushing the blood out of the heart via the pulmonary artery through the semilunar valve
4. blood travels to lungs via and through capillaries to the alveoli where has exchange takes place
5. oxygenated blood travels to the left atrium via the pulmonary vein
6. oxygenated blood goes to the left ventricle past the bicuspid valve
7. ventricle walls contract and push blood out of the heart and to the rest of the body via the aorta past the semilunary valve

Question 18

compare arteries and veins

Answer 18

• arteries have a thicker wall to withstand the pressure of the blood they are sending to the rest of the body after they recoil
• arteries have smaller lumen to maintain the high blood pressure
• arteries have no valves as blood is flowing at high pressure

Question 19

describe capillaries

Answer 19

• carry blood to the cells of the tissues
• one cell thick for easy diffusion
• contain gaps to allow fluid to leak out
• small lumen to increase the surface area to volume ratio for efficient diffusion

Question 21

list the components of blood

Answer 21

• plasma (55%): transport of blood cells, nutrients and waste, hormones and heat energy
• rbc: transport oxygen
• wbc: defend the body against infection by doing phagocytosis and produce antibodies
• platelets: blood clot

Question 23

describe blood clotting

Answer 23

• prevents blood loss and the entry of pathogens
• platelets clump together to seal off the wound, trapping blood cells
• soluble fibrinogen converts to insoluble fibrin, which creates a meshwork to hold together the platelets

Question 24

state the function of a lymphocyte

Answer 24

• produces antibodies to destroy/mark pathogens

Question 25

state the function of a phagocyte

Answer 25

- carries out phagocytosis by engulfing and digesting pathogens - their sensitive cell membrane allows them to detect chemicals produced by pathogenic cells - they release digestive enzymes to digest it

Question 26

state the differences between a phagocyte and a lymphocyte

Answer 26

- a phagocyte has a granular cytoplasm - a phagocyte has a multi-lobed nucleus, lymphocytes have a large round nucleus