3.3.4.1 Mass transport in animals Flashcards
Name the tissue that capillaries are made from
Endothelium
Which layer is particularly thick (relative to their size) in arteries and arterioles and why?
Muscle with elastic fibres so can stretch and recoil to maintain high blood pressure
Describe three disadvantages of single circulatory systems as seen in fish
Blood pressure drops as blood passes through the gill capillaries; blood flows slowly through as it is under low pressure
Describe how haemoglobin loads and unloads oxygen in the body
Loading of oxygen at high pO2
In lungs haemoglobin has a high affinity for oxygen
Unloads oxygen at low pO2
In the tissues unloading as higher carbon dioxide concentration
How does an increase in respiration in tissues of mammals affect the oxygen dissociation curve of haemoglobin
Increase in carbon dioxide
The curve shifts to the right
The haemoglobin in one organism may have a different chemical structure for the haemoglobin in another organism. Describe how
Different primary structures
Explain how fluid leaves the capillary at the arterial end
Higher hydrostatic pressure than osmotic effect
Forcing small molecules/ fluid out
How is plasma different from tissue
Contains larger molecules (plasma proteins, platelets and red blood cells)
Blood pressure decreases along the length of the capillary explain why
Fluid is lost
High blood pressure leads to an accumulation of tissue fluid. Explain how
High blood pressure = high hydrostatic pressure
Increases outward pressure from arteriole end of capillary and reduces the inward pressure at the venule
More tissue fluid formed
Explain one advantage of capillaries being narrow
Short diffusion pathway so faster diffusion of gases
Water potential of the blood plasma is more negative at the venue end of the ca[illary than the arteriole end. Explain why
Water has left the blood plasma
Proteins are too large to leave through capillary
Increase concentration of blood proteins lowering water potential
Why are valves important
To ensure blood flow is unidirectional
What are the three stages of the cardiac cycle
Diastole
Atria systole
Ventricular systole
Describe the mechanism by which an arteriole regulates blood flow into the capillary
Smooth muscles in arteriole contract
This leads to the narrowing of the arteriole lumen
Give two ways in which directional flow is maintained in the heart
Valves
Pressure gradient moving from high to low
State how the structural features of the aorta allow it to be adapted to its function
Elastic tissue > stretching allows smooth blood flow, stretches when ventricle contracts
Muscle > contraction
Thick walls > withstand pressure
Smooth endothelium > reduce friction
Semi Lunar valve > prevents backflow
What causes the high pressure in the heart ?
The contractions
Binding of one oxygen to haemoglobin makes it’s easier for the second oxygen molecule to bind
Binding if the first O2 molecule changes the tertiary structure
This open another binding site for more O2 to bind = cooperative binding
Suggest how widening pf blood vessels can reduce vemticnlar blood pressure
Larger lumen
Reduces blood pressure in blood vessels
Less friction/resistance in blood vessels
In a healthy person blood flows in one direction as it passes through the heart. Give two ways this is achieved
Pressure gradient - moves from high to low pressure
Valves stop backflow
Haemoglobin is a protein with a quaternary structure. Describe what this means.
Haemoglobin is made of more than one polypeptide chain
The chains are joined together to form a functional protein
