mass transport in animals

Question 1

define mass transport

Answer 1

bulk movement of substances due to pressure difference

Question 2

why do large, active, multicellular organisms need a blood transport system

Answer 2

• diffusion is too slow
• the blood and dissolved substances are transported by mass flow

Question 3

draw and label a double circulatory system

Answer 3

Question 4

name the blood vessels entering and leaving the heart

Answer 4

entering heart:
- vena cava
- pulmonary vein

leaving heart:
- pulmonary artery
- aorta

Question 5

name the blood vessels entering and leaving the liver

Answer 5

entering liver:
- hepatic vein
- hepatic portal vein

leaving liver:
- hepatic artery

Question 6

name the blood vessels entering and leaving the kidneys

Answer 6

entering kidney:
- renal vein

leaving kidney;
- renal artery

Question 7

describe the structure of the artery and explain how each feature relates to its function

Answer 7

• thick muscle layer: prevents bursting under high pressure
• thick elastic tissue layer: elastic tissue stretches hen ventricles contract and recoil when ventricles relax to maintain blood pressure
• smooth endothelium: reduces friction to allow blood flow

Question 8

describe the structure of the arterioles and explain how each feature relates to its function

Answer 8

thick layer of smooth muscle: contracts and relaxes to regulate blood flow.

Question 9

describe the structure of the veins and explain how each feature relates to its function

Answer 9

• wide lumen: reduces resistance to flow under low pressure
• contains valves: prevent back flow of blood under low pressure

Question 10

describe the structure of the capillary and explain how each feature relates to its function

Answer 10

• endothelium is only one cell thick: short diffusion pathway for exchange of materials
• flattened cells: short diffusion pathway
• many of them: slow food flow so more time for diffusion
• narrow lumen (only one blood cell wide): large surface area.

Question 11

describe the role of skeletal muscle valves in the one way flow of blood through a vein carrying blood up the leg

Answer 11

• skeletal muscle contracts
• vein above muscle builds pressure
  -valve opens
• pressure decreases
• valve shuts to prevent backflow

Question 12

what is tissue fluid

Answer 12

• fluid that surrounds cells
• formed by blood plasma
• where the exchange of substances happens between blood and cells
• contains water and small molecules

Question 13

describe how tissue fluids formed and returned back to the blood

Answer 13

• there isa high hydrostatic blood pressure at the arteriole end
• this forces water and other small molecules out of the capillary. cells and proteins stay in the blood as they are. too big.
  -exchange of nutrients between tissue fluid and cells
• at the venue end water re-enters the capillary by osmosis from a high water potential to a low water potential down and water potential gradient due to the proteins in the blood. there’s a lower hydrostatic pressure n the blood.
• excess tissue fluid drains into lymph vessels and back into the blood.

Question 14

explain the role the heart plays in the formation o tissue fluid

Answer 14

the left ventricle contacts to create a high hydrostatic pressure in the arterioles so water and small molecules are forced out to form tissue fluid.

Question 15

what are the 3 functions of the lymphatic system

Answer 15

• drains excess tissue fluid
  -absorbs lipids from the small intestine
• part of the immune system

Question 16

how are lymph vessels adapted for blood flow.

Answer 16

• contain valves
• contraction of skeletal muscle pump.

Question 17

what is the evidence that haemoglobin has a quaternary structure

Answer 17

made up of 4 polypeptide chains

Question 18

what is made when haemoglobin combines with oxygen

Answer 18

oxyhaemoglobin

Question 19

explain the term partial pressure

Answer 19

a measure of the concentration of a certain substance present in tissues

Question 20

where Is the partial pressure highest in the body

Answer 20

• in the lungs
• haemoglobin has a high. affinity for oxygen
• soo haemoblobin becomes saturated with oxygen

Question 21

why is the partial pressure of oxygen lowest in the tissues

Answer 21

• • haemoglobin has a low affinity for oxygen so haemoglobin becomes unsaturated with oxygen

Question 22

explain why the oxygen dissociation curve has a sigmoid shape

Answer 22

• the binding of the first molecule of oxygen to haemoglobin canoes the tertiary and quaternary structure of the haemoglobin
• this uncovers another ham group for oxygen to bind to
• so as oxygen binds to haemoglobin it makes it easier for the next oxygen to bind

Question 23

sketch a curve to show Bohr shift

Answer 23

Question 24

explain what is meant by bohr shift and explain the benefits of this

Answer 24

• in the presence of carbon dioxide the oxygen dissociation curve shifts to the right
• because the affinity of haemoglobin for oxygen is reduced
• so at the partial pressures of oxygen found at the tissues, haemoglobin is less saturated
• oxygen unloads more readily to be used for aerobic respiration at the tissues.
• this delays inset of anaerobic respiration at the tissues so less lactic acid is produced
• this happens because the carbon dioxide lowers the pH of the blood which alters the tertiary structure if haemoglobin.

Question 25

draw an oxygen dissociation curve showing an organism living at sea level

Answer 25

blue line

Question 26

draw an oxygen dissociation curve showing an organism living at sea level

Answer 26

green line

Question 27

draw an oxygen dissociation curve showing an organism with a high met bloc rate

Answer 27

red line

Question 28

label a diagram of the heart including chambers, blood vessels and valves

Answer 28

Question 29

state function of atrioventricular valves

Answer 29

prevent back flow of blood into atria

Question 30

state function of semilunar valves

Answer 30

prevent back flow into the ventricles