mass transport in animals Flashcards
define mass transport
bulk movement of substances due to pressure difference
why do large, active, multicellular organisms need a blood transport system
- diffusion is too slow
- the blood and dissolved substances are transported by mass flow
draw and label a double circulatory system
name the blood vessels entering and leaving the heart
entering heart:
- vena cava
- pulmonary vein
leaving heart:
- pulmonary artery
- aorta
name the blood vessels entering and leaving the liver
entering liver:
- hepatic vein
- hepatic portal vein
leaving liver:
- hepatic artery
name the blood vessels entering and leaving the kidneys
entering kidney:
- renal vein
leaving kidney;
- renal artery
describe the structure of the artery and explain how each feature relates to its function
- 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
describe the structure of the arterioles and explain how each feature relates to its function
thick layer of smooth muscle: contracts and relaxes to regulate blood flow.
describe the structure of the veins and explain how each feature relates to its function
- wide lumen: reduces resistance to flow under low pressure
- contains valves: prevent back flow of blood under low pressure
describe the structure of the capillary and explain how each feature relates to its function
- 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.
describe the role of skeletal muscle valves in the one way flow of blood through a vein carrying blood up the leg
- skeletal muscle contracts
- vein above muscle builds pressure
-valve opens - pressure decreases
- valve shuts to prevent backflow
what is tissue fluid
- fluid that surrounds cells
- formed by blood plasma
- where the exchange of substances happens between blood and cells
- contains water and small molecules
describe how tissue fluids formed and returned back to the blood
- 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.
explain the role the heart plays in the formation o tissue fluid
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.
what are the 3 functions of the lymphatic system
- drains excess tissue fluid
-absorbs lipids from the small intestine - part of the immune system
how are lymph vessels adapted for blood flow.
- contain valves
- contraction of skeletal muscle pump.
what is the evidence that haemoglobin has a quaternary structure
made up of 4 polypeptide chains
what is made when haemoglobin combines with oxygen
oxyhaemoglobin
explain the term partial pressure
a measure of the concentration of a certain substance present in tissues
where Is the partial pressure highest in the body
- in the lungs
- haemoglobin has a high. affinity for oxygen
- soo haemoblobin becomes saturated with oxygen
why is the partial pressure of oxygen lowest in the tissues
- haemoglobin has a low affinity for oxygen so haemoglobin becomes unsaturated with oxygen
explain why the oxygen dissociation curve has a sigmoid shape
- 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
sketch a curve to show Bohr shift
explain what is meant by bohr shift and explain the benefits of this
- 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.
