2.3 Adaptations for Transport Flashcards
(47 cards)
What makes up an earthworm’s circulatory system?
Closed circulatory system
Blood under pressure
Organs not in direct contact with blood
Respiratory gasses transported in blood
What makes up the mammalian circulatory system?
Heart with two aorta and two ventricles
Closed, double circulatory system
What makes up an insect’s circulatory system?
Fluid-filled blood cavity (haemocoel)
Open circulatory system
Dorsal tube-shaped heart
What are the major blood vessels of the heart?
Vena Cava Aorta Pulmonary vein Pulmonary artery Coronary arteries
What makes up the human heart?
Cardiac muscle
Valves
Varying thickness of walls
Own blood supply
What are the layers of large blood vessels like arteries?
Tough collagen
Elastic muscle to sustain pressure
Smooth endothelium to reduce friction
What makes up a vein?
Thinner muscle layer than arteries
Semi-lunar valves to prevent back flow of blood
Why do arteries have thick walls?
To resist pressure
How do arterioles adjust blood supply?
They adjust their diameter
Describe capillaries.
Small diameter
Walls only one cell thick
Friction with walls slows blood flow
There are many capillaries in a capillary bed meaning they have a large total cross-sectional surface area which slows blood flow
Low velocity and thin walls make it very easy to exchange materials with tissue fluid
What is the cardiac cycle?
Sinoatrial node is spontaneously active
Excitation makes the atria contract
Connective tissue stops excitation reaching the ventricles
The excitation travels along the atrioventricular node to the Bundle of His / His Bundle and along the Purkinje fibres in the ventricle walls
Excitation makes ventricles contract /after/ the atria
Changes in pressure withing the atria and ventricles causes the valves to open and close
When the blood leaves the heart, where is the highest pressure?
In the aorta and main arteries
What causes pressure changes inarterioles
Friction
Large total surface area and narrow bore
If they are contracted or dilated
How can blood pressure be increased when returning to the heart?
By the massaging effect of muscles
How is oxygen carried in the blood?
As oxyhaemoglobin in the haemoglobin
How can the functioning of different types of haemoglobin be demonstrated?
Plot an oxygen dissociation curve of mammalian haemoglobin against foetal haemoglobin
Draw an oxygen dissociation curve for mammalian, foetal, lugworm and llama haemoglobin.
Llama and lugworm are highest, foetal is in the middle and mammalian is the lowest.
Name a physiological adaptation for life in oxygen depleted conditions.
Myoglobin found in skeletal muscles
It increases haemoglobin’s affinity for oxygen
It holds oxygen in the muscles until it is needed
What is the Bohr effect?
Lowered pH caused by dissolved CO2 reduces the oxygen affinity of haemoglobin
Oxygen is released only when and where it is most required
The oxygen dissociation curve shifts to the right
What (aside from respiratory gasses) is transported in the blood?
Protein Digested food materials Hormones Ions Antibodies
How do water and small solutes pass into and out of capillaries?
Pass through the endothelium at the beginning of the capillary beds where the hydrostatic pressure (forcing liquid out) is greater than the osmosis pressure (drawing water in)
At the end of the capillary bed the hydrostatic pressure is lower and the water potential gradient causes an inward flow.
99% of the fluid that leaves the blood at the arteriole end of the capillary bed returns at the venous end.
The rest is returned via the lymphatic system.
Draw the structure of a dicotyledon root.
.
What are the root hairs for?
Absorption of water
- Provide a large surface area
- Freely permeable
What is the apoplast route?
Soil solution soaks into the walls of epidermal cells
Travels across the cortex through cell walls or through spaces between cells
Drawn by the transpiration stream
Water can also cross the plasma membrane by osmosis
