Transport In Animals Flashcards
Artistries - function and adaptations
Walls are very strong (3 layers) to withstand high pressure
Small lumen
Lots of collagen, elastic fibres to stretch and recoil and withstand pressure
Folded endothelium can unfold when artery stretches
Capillaries function and adaptations
Very thin walls- leaky walls
Single layer of endothelium
Narrow lumen
Large SĄ for diffusion as cross sectional area is larger than arteriole
Veins adaptations and function
Lower pressure so thin walls, not a lot of collagen elastic tissue or smooth muscle. Large lumen eases blood flow. Close to leg muscles
Why does pressure flactuate in artistes?
Due to rhythmic beating of the heart. Heart contacts - pressure in arteries increases (systolic)
Heart relaxes pressure decreases (diastole)
Why does pressure drop when it reaches capillaries
Stop damaging capillaries
Lack elasticity, delicate muscles
Allows time for exchange of surfaces
What is the heart made of
Myogenic cardiac muscle
Lymph - adaptations and function
Blind ending vessels (tiny valves)
Large enough for protein molecules to pass through as they do not fit in capillaries
Lymph gradually transported back to large vein
Move by contacting muscles and valves
Oncotic pressure
Tendency of water to move into blood by osmosis
Protein molecules decrease water potential (-3.3kPa)
What is a cardiac cycle
Sequence of events taking place during completion of 1 heartbeat
cardiac cycle
SAN generates a wave of excitation and spreads over the walls of both atria causing atrial systole
Wave reaches AVN and time delay of 0.1 seconds
Wave travels down Bundle of His and causes ventricles to contract from base upwards
Cardiac output
Stroke volume x heart rate
Haemoglobin in low p(o2)
Molecule js closed up within haem groups hidden in centre. Makes it difficult for O2 to associate.
When O2 binds to one haem group, there is a confrontational change and makes it easier for other O2 molecules to bind
Benefit of S curve (Haemoglobin)
In lungs (high partial pressure) Haemoglobin can easily become highly saturated
When it reaches lower partial pressure in tissue it can readily dissociate
Why does fetal Haemoglobin have higher affinity than adult?
Placenta has low partial pressure and maternal Haemoglobin dissociates from o2 and diffuses from Maternal into fetal blood.
More saturated
Transportation of CO2
- 5% dissolved into plasma
- 15% bind with Haemoglobin to form carbaminohaemoglobin
- Form hydrogen carbonate ions
Hydrogen carbonate ions - read port of co2
- react with h2o to form carbonic acid (catalysed by carbonic anhydrase)
- Carbonic acid dissociates into H+ and Hco3-.
H+ reacts with HbO2 to form HHb and O2.
HCO3- diffuses out down a concentration gradient, chlorine diffuses in (chlorine shift)
HCO3- reacts with NA+
Bohr affect
Shifts oxygen dissociation curve to the right.
Advantage- co2 makes Haemoglobin release oxygen. High levels of respiration, high partial pressure
