Adaptions for transport in animals Flashcards
open circulatory systems
blood does not move around the body in blood vessels but it bathes the tissues directly while held in a cavity the haemocoel
insects-open blood system
long dorsal (top) tube shaped heart, running the length of the body.
pumps blood out at low pressure into the haemocoel, where materials are exchanged between the blood and body cells
blood returns slowly to the heart and the open circulation starts again
oxygen- open blood system in insects
oxygen diffuses to the tissues from the tracheoles so the blood does not transport oxygen and has no respiratory pigment
closed circulatory systems
the blood move in blood vessels
single circulation
double circulation
single circulation
the blood moves through the heart once in its passage around the body
single circulation in fish
ventricle of the heart pumps deoxygenated blood to the gills, where the well developed capillary network reduces its pressure.
oxygenated blood is carried to the tissues and from there, deoxygenated blood returns to the atrium of the heart
blood moves to the ventricle and the circulation starts again
single circulation- earthworm
blood moves forward in the dorsal vessel, and back in the ventral vessel
five pairs of ‘pseudohearts’, thickened,muscular blood vessels, pump the blood from the dorsal to the ventral vessel and keep it moving
double circulation
blood passes through the heart twice in its circuit around the body eg. mammals
double circulation in mammals
blood is pumped by a muscular heart at high pressure , giving rapid flow through blood vessels
blood pressure is reduced in the capilliaries of the lungs and and its pressure would be too low to make the circulation effiicent in the rest of the body
instead blood is returned to the heart, which raises its pressure again, to pump it tii the rest of the body
materials are then delivered quickly to the body cells
insect
earthworm
fish
mammal
circulation type
closed
closed, single
closed, single
closed,double
respiratory pigment
none
yes
yes
yes
heart
Dorsal tube shaped
Pseudohearts
1 atrium and 1 ventricle
2 atria and 2 ventircles
pulmonary circulation
serves the lungs
right side of hearty pumps deoxygenated blood to the lungs
oxygenated blood returns from the lungs to the left side of the heart
systemic circulation
serves the body tissues
left side of the heart pumps the oxygentaed blood to the tissues
deoxygentaed blood from the body returns to the right side of the heart
in each circuit
the blood passes through heart twice, once through the right side and once through the left side
double circulation of mammal is more efficient than the single circulation of a fish as the oxygenated blood can be pumped around the body at a higher pressure
blood contents
made up of cells (45%)
and plasma (55%)
plasma
pale yellow liquid
fluid component of the blood comprising water and solutes
blood - cells
affinity
degree to which two molecules are attracted to each other
cooperative binding
the increasing ease with which heamoglobin binds its second and third oxygen molecules, as the conformation of the heamogloblin molecule changes
allows haemogoblin to pick up oxygen very rapidly in the lungs
oxygen dissociation curve
Hb binds
haemoglobin binds oxygen in the lungs, and realeases it in the respiring tissue
Oxygen + Haemoglobin = oxyhaemoglobin
4O2 + Hb = HbO8
red blood cells
Erythocytes
red- contain pigment called haemoglobin
transports oxygen from the lungs to the respiring tissue
made in bone marrow, destroyed in the liver
red blood cells- structure
biconcave discs- surface area is larger so more oxygen diffuses across the membrane
thin centre makes them look paler in the middle- reduces the diffusion distance making gas exchange faster
red blood cells- no nucleus
more room for haemoglobin, maximising oxygen that can be carried
to transport oxygen efficiently
haemoglobin must associate readily with oxygen where gas exchange takes place eg. alveoli and readily disassociate with oxygen at the respiring tissues eg. muscle
haemogoblin- 4 haem groups
each haem contains an ion of iron (Fe2+)
one oxygen can bind to each iron
first oxygen molecule that attaches changes the shape of Hb molecule- easier for the second molecules to attach
2nd oxygen molecule attaching changes shape again - easier 3rd
cooperative binding
3rd molecule doesnt change shape so it takes up a large increase in oxygen partial pressure to bind the fourth oxygen molecule.
partial pressure of a gas
the pressure it would exert if it were only one present
oxygen dissociation curve
O2 affinity of haemogoblin is high at high partial pressures of oxygen and oxyhaemogoblin does not release its oxygen
oxygen affinity reduces as the partial ;pressure of oxygen decreases, and oxygen is readily released, meeting respiratory demands
very small decrease in the oxygen partial pressure leads to lot of oxygen dissociating from haemogoblin
if relationship between oxygen partial pressure and % saturation of haemogoblin with oxygen were linear
HIGHER
At higher partial pressure of oxygen, haemogoblin oxygen affinity would be too low and so oxygen would be readily released and would not reach the respiring tissues
if relationship between oxygen partial pressure and % saturation of haemogoblin with oxygen were linear
LOWER
at lower partial pressure of oxygen, haemogoblins oxygen affinity would be too high and oxygen would not be released in respiring tissues, even at a low oxygen partial pressure
Disassociation in the tissues
In the tissues the partial pressure of oxygen is about 2~4 kPa.
At these low partial pressures of oxygen, haemoglobin has a lower affinity for oxygen.
The haemoglobin offloads oxygen to the tissues.
Dissociation in the lungs
In the lungs the partial pressure of oxygen is about 11 kPa.
At these high partial pressures of oxygen, haemoglobin has a higher affinity for oxygen.
The haemoglobin becomes saturated with oxygen.
Disassociation of mother
In the placental tissues the partial pressure of oxygen is about 2~4 kPa.
The mothers haemoglobin has a low affinity for oxygen.
The haemoglobin more readily offloads oxygen to the tissues.
Disassociation of foetus
At the same partial pressure of oxygen, about 2~4 kPa.
The fetal haemoglobin has a higher affinity for oxygen.
The fetal haemoglobin picks up the oxygen offloaded by the mother.
Transport of oxygen in other animals
Dissociation curve is to the left of an adults
The haemoglobin has a higher affinity for oxygen than adult human.
This means it loads or saturates with oxygen very readily at very low partial pressures of oxygen.
They then release the oxygen as extremely low p.p. of oxygen.
lugworm
In the sand the partial pressure of oxygen is very low, about 2~4 kPa.
The lugworm has haemoglobin/mogloblin which has an even higher affinity for oxygen than normal human haemoglobin.
The haemoglobin more readily saturates with oxygen to the tissues.
llama
lives in an area of high altitude of 2-4kPa where the O2 partial pressure is very low
It’s haemoglobin has a high affinity for oxygen at all oxygen partial pressure than humans
loads oxygen more readily in the lungs and releases oxygen when oxygen partial pressure is low
Bohr effect
The movement of oxygen dissociation curve to the right at a higher partial pressure of carbon dioxide, because at a given oxygen partial pressure, haemoglobin has a lower affinity for oxygen
Accounts for the unloading of oxygen from oxyhemoglobin in respiring tissues where partial pressure carbon dioxide is high and oxygen is needed
Effects of carbon dioxide concentration
If the carbon dioxide concentration increases, haemoglobin releases oxygen more readily
At any oxygen partial pressure the haemoglobin is less saturated with oxygen so the data points on the dissociation curve are lower
CO2 curve- tissues
In the tissues the partial pressure of oxygen is about 2~4 kPa. The p.p. of carbon dioxide is high due to tissue respiration.
The haemoglobin more readily offloads oxygen to the tissues.
summary of CO2 curve
When the partial pressure of carbon dioxide is high haemoglobin has a lower affinity for oxygen so it is less efficient at loading oxygen and more efficient at unloading it
transport of Carbon dioxide
Transported in:
- in solution in the plasma (aprox 5 percent)
- in HCO3- (aprox 85)
- Bound to haemoglobin as carbamino haemoglobin (aprox 10)
Reactions in red blood cell
1- transport of CO2
Carbon dioxide in the blood diffuses into the red blood cell