Mass Transport Flashcards
What are the structures of haemoglobin?
- Amino acid chain
- A-helix
- Folded into precise shape
- All 4 polypeptides linked together
What is loading oxygen?
Haemoglobin associating with oxygen
what is unloading oxygen?
Haemoglobin associating with oxygen
What must haemoglobin do to efficiently transport oxygen?
— readily associate with oxygen at the surface where gas exchange takes place
— readily dissociate from oxygen at this tissues requiring it
Why are there different haemoglobins?
Different properties needed for different ways to take up and release haemoglobin in different organisms
Explain the reasons for the shape of the oxygen dissociation curve
— the shape of the haemoglobin molecules makes it difficult for the first oxygen molecule to bind
— binding of 1st molecule changes shape of haemoglobin so easier to join more
— small increase in partial pressure to bind 2nd molecules
— after binding third molecule forth molecule is harder to bind du3e to probability
Why does behaviour of haemoglobin change in different regions of the body?
— at gas-exchange surface CO2 conc is low so affinity of haemoglobin for oxygen is increased. So oxygen is readily loaded
— in rapidly respiring tissues conc of CO2 is high so affinity of haemoglobin for oxygen is reduced
Describe the process of loading, transport and unloading of oxygen
— at the g-exchange surface CO2 is coantly being removed
— pH is slightly raised due to the low concentration of carbon dioxide
— higher pH changes shape of haemoglobin so it can load oxygen readily
— this shape also increases the affinity of haemoglobin for oxygen, so not released during transport
— in tissues, CO2 is produced in respiring cells
— CO2 is acidic in solution, so the pH of the blood within the tissues is lowered
— Lower pH changes the shape of haemoglobin into one with a lower affinity for oxygen
— haemoglobin releases its oxygen into the respiring tissues
why do large organisms have a transport system?
— the surface are to volume ration
— how active the organisms is
what are the common features of transport systems?
— a suitable medium in which to carry materials
— a form of mass transport in which the transport medium is moved around in bulk over large distances
— a closed system of tubular vessels that contains the transport medium
— a mechanisms for moving the transport medium within vessels
What is the order of blood flow of oxygenated blood around the heart?
— pulmonary vein
— left atrium
— left ventricle
— aorta
— round body
what is the order of flow of deoxygenated blood around the heart?
— vena cava
— right atrium
— right ventricle
—pulmonary artery
— lungs
what’s the process of relaxation of the heart (diastole)
– blood enters atria from pulmonary vein and the vena cava
– as atria fill pressure in it raises
– when pressure in atria is higher than in the ventricles, atrioventricular valves open allowing blood to pass through
– atria and ventricle walls both relaxed
– relaxation of ventricle walls reduce pressure within the ventricle. this causes the pressure to be lower than in the aorta and pulmonary artery so semi-lunar valves close
what is the process of the contraction of the atria (atria systole)
– contraction of atrial walls forces remaining blood into the ventricles from the atria.
– muscles of ventricle walls remain relaxed
describe the process or the contraction of the ventricles (ventricular systole)
– when ventricles fill with blood, their walls contract simultaneously
– increases blood pressure forcing shut the atrioventricular valve preventing back flow of blood
– pressure in ventricles rises
– blood forced into aorta and pulmonary artery
what is the cardiac output?
volume of blood pumped by one ventricle of the heart in one minute
what is the equation for cardiac output
heart rate x stroke volume
what is the structure of the arteries?
– lumen
– lining layer
– elastic layer
– muscle layer
– tough outer layer
what is the structure of the vein?
– lumen
– lining layer
– elastic layer
– muscle layer
– tough outer layer
what is the structure of capillaries?
– lumen
– lining layer
what are the structures of the arteries related to their function?
– the muscle layer is thick compared to veins so smaller arteries can be constricted and dilated
– elastic layer is thicker than veins
because blood pressure in arteries need to be high to reach all parts of body.
– the overall thickness of wall is great so resists the blood vessel bursting under pressure.
– there are no valves as blood is under constant high pressure due to the heart pumping blood into arteries
what is the functions of arterioles related to its function?
– muscle layer is relatively thicker than in arteries so the contraction of this muscle layer allows construction if the lumen of the arteriole
– the elastic layer is relatively thinner than in arteries because blood pressure is lower
what is the structure of veins related to it’s function?
– muscle layer is relatively thin as veins carry blood away from tissue so dilation cannot control flow of blood
– the elastic layer is relatively thin as low pressure
the overall thickness of the wall is small due to little pressure
– there are valves at intervals throughout to ensure no backflow of blood
what is the structure of capillaries related to it’s function
– walls consist mostly of the lining layer making them extremely thin
– they are numerous and highly branched providing a large surface area for exchange
– they have a narrow diameter so no cell cell is far from capillary
– their lumen is narrow so RBC are flat against the wall
– there are spaces between the lining cells
