mass transport in animals and heamoglobin Flashcards
what is the name of the blood vessels associated with the liver
hepatic artery/ vein
what is the name of the blood vessels associated with the kidneys
renal artery /vein
what are coronary arteries
blood vessels that deliver blood to the cardiac muscle of the heart
how does a heart attack occur
lack of glucose and oxygen being delivered to cardiac muscle via cornary arteries ( if the become blocled e.g. atheromas or blood clots )
what happens in the cardiac cycle
1) ATRIAL SYSTOLE ( atria contract )
volume of atria decreases, pressure increases. Blood is forced through the AV valves into ventricles
2) VENTRICULAR SYSTOLE ( atria relax, ventricles contract )
vol of ventricles decrease , pressure increases higher than that of atria , AV valves close and SLV open, blood flows into arteries
3) DIASTOLE ( ventricles relax )
SLV close, AV valves open as pressure decreases below that of the veins, so the heart fills with blood
what does it mean if the heart is myogenic
generates its own electrical impulses
what is the control of the cardiac cycle
1) wave of depolarisation is released by the SAN this causes 2 atria to contract - atrial systole
this pushes blood through the AVN into the ventricles
( layer of conductive tissue prevents it from passing straight down )
2) the depolarisation reaches the AVN where there is a short delay to allow the atria to fully empty
3) AV node sends depolarisation down the bundle of his in the septum of the heart, where it branches of and spreads the depolarisation up the walss of the two ventricles via purkinje fibres
4) this allows the ventricles to vontract from the base up pushing blood up and out of the heart via pulmonary artery and aorta
what is the structure of the aorta related to its function
- thick walls to withstand high pressure to prevent form bursting
- elastic tissue to allow stretch and coil during systole and diastole
- muscle tissue for contraction
- smooth endothelium layer next to the lumen to reduce friction to blood flow
- aortic valve prevents backlfow from aorta into ventrciules
what is the structure and function of arterioles
- smaller than arteries
- connect artery to capillary
- vessel diameter smaller so greater friction, causing fall in bp
- reduce blood flow to capillary by contracting the muscle layer which constricts the diameter of the lumen
what is the structure and function of the veins
- thinner wall as blood is transported at low pressure
- wider diameter of lumen to reduce resistance to blood flow
- valves to prevent backflow of blood
- walls have smaller amount of elastic protien fibres and smooth muscle as the pressure is very low
- smooth endothelium layer to reduce friction
what is the role of the capillaries
- thin, short diffusion distance
- numerous and branched , increases SA
- narrow diameter, ensures red blood cells are in contact wth wall
- pores between smooth endothelium, allow rapid formation of tissue fluid
what is tissue fluid
fluid that surrounds cells that allows for an exchange of substances
where is tissue fluid formed
at the arteriole end of the capillary due to contraction of the left ventricle
how is tissue fluid formed
high hydrostatic pressure caused by contraction of the left ventrcle, forces fluid and water/ dissolved substances to leave the capillary
large plasma protiens and red blood cells are too big to leave
water potential decreases
eater re enters the capillary down a water potential gradient by osmosis
excess tissue fluid enters the lymphastic system and is returned to circulation at the subclavian vein, if it is not reabsorbed by the venule end
how does high blood pressure (hypertension ) lead to an accumlation of tissue fluid (an oedema)
high bp means high hydrostatic pressure, this increases outward pressure from arteriole end and reduced pressure at the venule end. More tissue fluid is formed and less can be reabsorbed. The lymphatic system is not able to drain the excess fast enough.
what is an adaption of red blood cells
- boconncave shape
- large sa to vol ratio to enable oxygeb to diffuse into the cell more rapidly
- no nucleus to make more space for hemoglobin
what is heamoglobin
protien with a quaternery structure, composed of 4 sub units each containing a haem group
each haem group can combine with one molecule of oxygen, so a hb molcules can carry 4 o2
what is oxyheamoglobin
formed when hb associates with oxygen in area of higher pp02
oxyheamoglobin dissociates with 02 in area of lower pp02
what is partial pressure (pp)
the amount of a particular gas in a mixture of gases or a solution
what is loading in regards to hb
when oxygen is taken up by hb
what is unloading in regards to hb
when o2 is released/ given up by hb
what is affinity in regards
when hb loads oxygen as it has a high affinity to it.
what happens in the sigmoidal curve
in the lungs: at higher pp02, hb has a higher affintiy for oxygen and loads more readily, giving a higher percentage saturation of hb
at the tissues: at lower the pp02 hb has a lower affinity for oxygen and it unloads more readily, giving a lower % saturation of hb
what is coperative binding in hb
- binding of one molecule of o2 to hb makes it easier for a 2cnd to bind
- 1st o2 binds to hb causing a change in tertiary structure
- change allows more o2 to bind more easily as it uncovers another binding site ( containing the iron ion ) to bind to, so hb becomes more saturated with o2
how does the oxygen dissociation curve show coperative binding
- at low partial pressures of o2 there is little increase in the saturation of hb as oxygen increases. There is then a rapid rise as it gets easier for oxygen to bind
what is the bohr shift
increasing partial pressure of co2 in the blood plasma will result in a decrease in the pH. This will shift the oxygen dissociation curve to the right.
this means hb will have a lower affinity fro o2 and hb dissociayted more deadily and is unloaded ot the tissues.
how does the bohr shift happen
- more tissue cells respire, more co2 conc wil rise and cause a shift to the right
- hb now has lower affinity for o2 at the respiring cells
- more 02 is released from hb as it becomes less saturated
- this extra o2 is available for respiring cells
what is foetal hb
has a higher affinity for oxygen at lower partial pressures, this means o2 is more easily unloaded from adult hb where it diffuses across the placenta and is loaded by foetal hb. This o2 can be used by the foetus for aerbic respiration.
how does an animals hb change if they are more active
ODC shifted to the right
hb has lower affinity for o2
hb dissociates and loads more readily, releasing more o2 for respiration
