Mass transport Flashcards
What is mass transport
the net movement of mass from one location to another
Explain why haemoglobin has a quaternary structure
they are made up of 4 polypeptides that can combine with a single oxygen molecule, therefore haemoglobin can carry lots of oxygen to respiring cells
What is association of oxygen and where does take place
high affinity for oxygen in the lungs at high oxygen concentration and low carbon dioxide concentration
What is dissociation of oxygen and where does take place
low affinity for oxygen thus releasing oxygen at respiring tissues at low oxygen concentration and high carbon dioxide concentration
Why do different species have differently shaped haemoglobins
the structure of haemoglobin can change due to its high or low affinity for oxygen e.g. organisms living at high altitudes have high affinity for oxygen at low partial pressures which is a shift to the left
What is the Bohr effect
a shift to the right where there is a lower affinity for oxygen so oxygen is released more easily
What is a shift to the left
haemoglobin has a higher affinity for oxygen so oxygen is loaded readily but unloads less easily
What effect does carbon dioxide have on haemoglobin
it lowers pH thus haemoglobin has lower affinity for oxygen and more readily releases oxygen e.g. Bohr effect
Why do large organisms require a large circulatory sustem
increasing size increases surface area to volume ratio to a point where the needs of the organism cannot be reached
Why do mammals have a closed, double circulatory system
- to pump deoxygenated blood through the pulmonary artery to the lungs
- to pump oxygenated blood through the aorta and around the boddy
How does blood enter the heart
- oxygenated blood enters the left atrium by the pulmonary vein from the lungs
- deoxygenated blood enters the right atrium by the vena cava after circulating around the body
- the two sides are separated by the septum
How does the blood reach the kidney’s and lower limbs
- oxygenated blood get to the kidney’s and lower limbs by the renal arteries and release the oxygen
- the deoxygenated blood flows back towards the vena cava through the renal veins
Which blood vessel supplies the heart muscle
coronary artery
What causes myocardial infarction
the blockage of the coronary arteries thus the heart muscle is deprived of blood and therefore oxygen and the muscle cells can no longer respire aerobically
Why is the left side of the heart 3x thicker than the right
for a stronger contraction to pump blood around the body
What is diastole
- semi luna valves are closed
- AV valves are open
- atria and ventricles relax
- blood passively flows into the atria from arteries
What is atrial systole
- atria contract
- blood forced into ventricles
- semi luna valves stay shut
What is ventricular systole
- ventricles contract
- pressure closes AV valves, preventing back flow of blood into the atria
- semi luna valves open and blood forced out into arteries (pulmonary artery and aorta)
How do you calculate cardiac output
heart rate X stroke volume
What is the structure of a artery related to function
- thin inner lining - endothelium to reduce friction and allow diffusion
- thick muscle layer - can be constricted and dilated to control volume of blood passing through
- thick elastic layer - stretch and recoil to maintain high pressure and smooth out pressure surges from the heart beating
- overall thick wall - resists bursting under pressure
- no valves - blood is under constant pressure
What is the structure of a vein related to function
- thin inner lining - endothelium to reduce friction and allow diffusion
- thin muscle layer - can be constricted and dilated to control volume of blood passing through
- thin elastic layer - stretch and recoil to maintain high pressure and smooth out pressure surges from the heart beating
- overall thin wall - under less pressure than arteries
- valves at intervals - to prevent back flow of blood at low pressures and making sure blood goes in one direction, towards the heart
What is the structure of a capillary related to function
- consist of endothelial cells - short diffusion distance for diffusion
- they are numerous and highly branched - increases the surface area for efficient diffusion
- narrow lumen - short diffusion distance and red blood cells are slowed down to allow more time for oxygen to be released
- spaces between the endothelial cells for white blood cells to escape from to deal with infection
How is tissue fluid formed
- when the hydrostatic blood pressure at the arterial end of capillary is higher than the osmotic pressure thus tissue fluid moves out the blood plasma
- at the venous end of the capillary the osmotic pressure is high than the hydrostatic pressure thus tissue fluid moves back into the blood plasma
- any excess products e.g. water and carbon dioxide moves into the lymphatic capillary
How is the structure of the xylem related to its function
-very thin - short diffusion distance
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