8 Transport in animals Flashcards
Why are specialised transport systems needed in animals (5)
-metabolic demands are higher
-smaller SA:V ratio
-molecules, hormones, enzymes are made in one place but needed in another
-food digested in one organ is needed all around the body
-waste products is cells need to be removed
features of a good transport system (5)
-fluid medium, carry nutrients + oxygen
-pump - create pressure to push fluid around
-exchange surfaces, specialised
-tubes or vessels to carry fluid
-two circuits one to collect oxygen, one to transport it
what systems are in place for circulatory (3)
-a liquid transport medium that circulates around the system (blood)
-they have vessels that carry the transport medium
-they have a pumping mechanism to move the fluid around the system
layers of the artery + use
-lumen
-endothelium
-elastic fibres (stretch)
-smooth muscle
-collagen fibres (strength)
-(transport) Thin lining of endothelium which is smooth to reduce friction
Layers of the vein + use
-lumen
-endothelium
-elastic fibres (stretch)
-smooth muscle
-collagen fibres (strength)
-(transport) have a thin lining of endothelium which is smooth to reduce friction.
Layers of the capillary + use
-lumen (small so blood flows slow)
-endothelium
-(exchange) have a thin layer of endothelium which is smooth to reduce friction
what sets the temp of the heartbeat + how it works
-SA node (pacemaker)
-generates electrical signals, that spread through both Atria making them contract simultaneously.
Where are these signals then delayed + time +what happens
-Au node
-for 0.1 seconds
-during which blood in the atria empties into the ventricles
What fibres then conduct the signals to the apex of the heart (2)
-Purkinjean fibres
-bundle branches (bundle of HIS)
What do the signals from the Purkinjean fibres (bundle of HIS) trigger
A powerful contraction of both ventricles from the apex towards the atria, driving blood into the large arteries.
Other name for Red blood cells
Erythrocytes
Other name for white blood cells
Leucocytes
Blood composition (4)
-Erythrocytes (RBC)
-Leucocytes (WBC)
-Platelets
-Plasma
What does plasma contain (10)
Dissolved:
-Co2,
-O2
-salt
-minerals
-glucose
-fatty acids
-amino acids
-hormones
-plasma proteins
-urea
How is tissue fluid formed (2)
-from plasma leaking from capillaries
-its in direct contact with cells + provides nutrients and oxygen
Haemoglobin info (3)
-4 subunits, different peptides, 2 alfa, 2 beta
-complex primary, ternary, quaternary structures
-prosthetic group = heme group
How does haemoglobin work (5 steps)
-oxygen is absorbed into the blood in the alveoli
-oxygen diffusing into blood plasma enters red blood cells
-oxygen associates with haemoglobin (reversibly binds)
-oxygen is taken out of solution
-removal of dissolved oxygen maintains a diffusion gradient allowing more oxygen to enter the cells
What does infinity mean for haemoglobin
When haemoglobin holds on to oxygen
Difference in foetal haemoglobin to normal (why)
-less partial pressure for more oxygen to be absorbed
(as when the umbilical cord passes the mothers blood it must have a higher infinity to take blood)
what does ODC stand for
oxygen dissociation curve
what is ODC (oxygen dissociation curve) (2)
When the percentage saturation haemoglobin in the blood is plotted against the partial pressure of oxygen (PO2)
ODC show the affinity of haemoglobin for oxygen
A change in what can make a significant difference to the saturation of oxygen
-a change in the partial pressure of oxygen
- once the first molecule becomes attached the change in the shape of the haemoglobin molecule means other oxygen molecules are added rapidly
what is the Bohr effect
As the partial pressure of carbon dioxide rises (at higher partial pressures of CO2) haemoglobin gives up oxygen more easily
Why is the Bohr effect so important (2)
-In active tissues with a high partial pressure of carbon dioxide, haemoglobin gives up its oxygen more readily.
-In the lungs the proportion of CO2 is low, it makes oxygen binding to haemoglobin are easily.
which 3 ways is CO2 transported + %
5% dissolved in plasma
10% combines with haemoglobin and forms carbonic haemoglobin
85% transported in form of hydrogen carbonate ions (HCO3-)
can haemoglobin acid hold oxygen
-no
-it removes it
what does chloride do
it balances the cell with the negative charge
There are 6 steps in knowing how Co2 is transported via HCO3- and they are (information card)
1
Some of the CO2 enters RBC and combines water forming carbonic acid (H2CO3)
2
Carbonic acid dissociates releasing negatively charged hydrogen carbonate ions and positively charged hydrogen ions
3
The hydrogen ions combine with haemoglobin (Hb) forming haemoglobin acid
4
This distorts the Hb molecule decreasing its affinity for oxygen so more oxygen is released to tissues (Bohr effect)
5
Hydrogen carbonate ions build up inside the RBC causing them to diffuse out into the plasma leaving the membrane positively charged
6
To balance the electrical charge, negatively charged chloride ions diffuse into the RBC from the plasma (Chloride Shift)
How does Hb act as a buffer
By removing H+ (acidity) so maintaining the pH of the blood
