4.3 Flashcards
what are erythrocytes
RED BLOOD CELLS
Erythrocytes are adapted for transporting oxygen.
They contain haemoglobin, a protein which carries the oxygen and gives them the red colour.
The blood also carries away carbon dioxide produced during respiration by cells
what is heamaglobin
Haemoglobin is made up of:
1. 4 polypeptide chains
2. each polypeptide chain contains a haem group which contains an iron ion
Each haem can pick up 4 molecules of oxygen
what is the reaction of heamaglobin and oxygen
Hb + 4O2 ⇌ HbO8
Haemoglobin + oxygen = oxyhaemoglobin
This is reversible.
Oxyhaemoglobin is formed in the lungs, then when oxygen unloads (leaves) oxyhaemoglobin in the body tissues it turns back to haemoglobin.
Once one O2 molecule loads it makes it easier for other O2 molecules to then load. But as it becomes saturated it becomes harder for more to load.
what is partial pressure
pO2
the concentration of oxygen
when does oxygen load onto haem
when the pO2 is high
when it is low it unloads
what is the graph
shape
labels
ADD GRAPH
sigmoidal shape - 4 molecules
1st harder
2+3 easier
4 hard
never 100% as there is always blood moving
bohr shift to right
curve to the left
high affinity for oxygen
loads oxygen easily.
Releases it less readily.
Found in organisms that live in environments with little oxygen (i.e. low PPO2).
E.g. lugworms.
These organism must have a low metabolic rate.
I.e. respire or use oxygen slowly.
So the slow unloading of oxygen into the tissues is not a problem.
For these organisms it is more important to have a Hb that loads oxygen rapidly than unloads it.
curve to the right
low afinity to oxygen
loads oxygen less readily.
unloads more readily.
Found in organisms with that live in environments with plenty of oxygen (i.e. high PPO2)
E.g. humans.
These organisms have a high metabolic rate.
I.e. respire and use oxygen readily.
So rapid release of oxygen to the tissues replaces that used (in metabolism).
For these organisms it is more important to have a Hb that unloads oxygen more rapidly than load.
feotal haemoglobin
Has a different quaternary structure to adult Hb.
Has a higher affinity for O2 at the same P02 as adult Hb.( shifts to the left)
Loads/associates at a PO2 at which the adult Hb dissociates.
Maintains a diffusion gradient across the placenta.
myoglobin
Has a higher affinity for O2 than adult and fetal Hb.
(shifts a lot to the left) - different shape
Stores O2 in the muscle – extending aerobic respiration.
Only unloads/dissociates when the PO2 is very low/CO2 high.
Found in human (muscles) and diving organisms e.g. seals -areas where contractions are sustained.
erythrocytes
red blood cell
contain haeomoglobin
no nucleus
transport oxygen from the lungs to the cells
biconcave disc shape ( large surface area to volume ratio)
leucocytes
larger than erythrocytes
defend the body against infection
nucleus and cytoplasm
granulocytes
leucocytes
granuals in the cytopasm to stain them
lobed nuclei
neutrophils
type of granulocyte
non specific immune system
engulf and digest pathogens by phagocytosis
multi lobed nuclei
eosinophils
type of granulocyte
non specific immune system
stained red
important in non specific immune response against parasites in allergic reactions and inflamation
basophils
type of granulocyte
non specific immune system
two lobed nucleus
produce histamines in allergic reaction and inflammation
agranulocyte
leucocytes do not have granules
unlobed nuclei
monocyte
agranulocyte
specific immune system
largest leucocyte
move out of the blood and into tissues to form macrophages
engulf pathogens by phagocytosis
lymphocytes
type of white blood cell
small leucocytes with very large nuclei that are vitally important in specific immune response of the body
platelets
tiny fragments of large cells called megakaryocytes
involved in clotting of the blood
vein
cary blood back towards the heart
most cary deoxgyenated
except
-pulmonary
-umbilical
thin layer of muscle and few fibres
large lumen
adaptation of veins
hold large volumes of blood
low pressure
semilunar valves to prevent backflow of blood
during physical activity the muscles squeeze the veins forcing the blood back to the heart
capillaries
branch between cells so
substances can diffuse between cells and the blood quickly
diameter is small encouraging more diffusion
thin walls
oxygen out of blood
co2 and waste products in
walls are partially permeable