Mass Transport Flashcards
(21 cards)
What are the blood vessels and their functions
Arteries - carry blood away from the heart at high pressures
Arterioles - Carry blood from arteries into the capillaries
Capillaries - Site of diffusion between blood and body tissues
Venues - carry blood from capillaries into veins
Veins - Return blood to the heart
Name and explain the adaptions of arteries
- Collagen provides strength to prevent the vessels from bursting and to maintain the vessel shape
- Elastic fibres contain elastin that allows them to stretch and recoil to minimise changes in pressure
- Thick smooth muscle layer - Contracts/relaxes to constrict/dilate the lumen and control blood flow
Describe arterioles
They are smaller than arteries but have a larger Lumen.
Smoother wall muscles
Less elastin as they don’t need to withstand high pressure
How do smooth muscles control blood flow
Through vasoconstriction and vasodilation
What is vasoconstriction
When the smooth muscle constricts blood vessel and decreases blood flow
Describe the adaptions of capillaries
Narrow lumen to allow red blood cells to be close to body cells
Thin walls to shorten diffusion distance
Highly branched to provide a large surface area for diffusion
What is vasodilation
Smooth muscle relax
Blood vesssel dilates
Increases blood flow
Describe the adaptions of veins
Collagen - to provide strength, prevents bursting & maintains shape
Little smooth muscle and elastic fibre due to low blood pressure
Pocket Valves - prevents backflow of blood when veins are squeezed around skeletal muscle
What’s the difference between heart valves and pocket valves
Pocket valves are controlled by skeletal muscle
Describe venules
Smaller than veins
Very little smooth muscles
Have valves
What is haemoglobin and what is it’s role in the transport of oxygen
Haemoglobin is a protein with a quaternary structure found in red blood cells.
Haemoglobin binds to oxygen and carries its blood from lungs to tissues where it’s needed then releases the oxygen for cell use
What does the cooperative nature of oxygen binding mean
This means that the binding of the first oxygen makes it easier for the subsequent molecules to bind
Compare the partial pressures of oxygen in lungs and in respiring tissues
In lungs partial pressure of oxygen is high so haemoglobin binds to oxygen
In respiring tissues partial pressure is low so haemoglobin unloads oxygen
What is the Bohr effect
The Bohr effect or Bohr shift is when an oxygen disassociation curve shifts towards the left. This happens due to an increase in carbon dioxide, the CO2 makes the haemoglobin release more oxygen in areas where it’s needed most.
What is the oxygen disassociation curve
A graph showing how the saturation of haemoglobin with oxygen changes when the partial pressure of oxygen changes
What is the significance for different affinities for oxygen in fetal and adult haemoglobin
Fetal haemoglobin has a higher affinity for oxygen than adult haemoglobin allowing it to draw oxygen from it’s mothers blood supply
