3.2 Flashcards
(5 cards)
Exchange in the capillaries
Blood plasma:
High hydrostatic pressure More negative oncontic pressure Red blood cells,neutrophils and lymphocytes Plasma proteins Fats are transported in lipoproteins
Tissue fluid:
Formation - blood fluid is pushed out the capillaries. The fluid that leaves consists of plasma wig dissolved nutrients and oxygen. The fluid surrounds body cells so exchange can occur across plasma membranes .
Low hydrostatic pressure Less negative oncontic pressure Some neutrophils Few proteins Few fats
Lymph:
Low hydrostatic pressure Less negative oncontic pressure Lymphocytes Few proteins More fats especially near the digestive system
Movement of fluids:
Hydrostatic pressure of the blood tends to push fluid into the tissues
Hydrostatic pressure of the tissues tends to push fluid into the capillaries
Oncontic pressure of blood tends to pull water back into the blood
Oncontic pressure of the tissue fluid pulls water into the tissue fluid
Pressure changes in the heart
Study cardiac cycle
Pressure in blood vessels
Artery walls close to heart have lots of elastic tissue
When blood leaves the walls stretch
Aortic pressure begins to drop
Elastic recoil to maintain aortic pressure
Further blood flows along the arteries pressure drops
Study blood pressure graph
Transport of oxygen
Oxyhemoglobin
Haemoglobin has a high affinity for oxygen
Reversible reaction
pO2 is a measure of oxygen concentration
Oxygen loads when there is a high pO2
Oxygen unloads when there is a low pO2
Transporting carbon dioxide
5% dissolved in plasma
10% carbaminohaemoglobin
85% hydrogencarbonate ions (HCO3-)
CO2 diffuses into rbc where it combines with water to form carbonic acid. This reaction is catalysed is by carbonic anhydrase
CO2 + H2O ➡️ H2CO3
This acid disassociates to release hydrogen ions and hydrogencarbonate ions
H2CO3 ➡️ HCO3- + H+
Hydrogencarbonate ions diffuse out of rbc into plasma. Chloride shift maintains charge in rbc
Hydrogen ion building up in the rbc cause the rbc to be acidic. To prevent this hydrogen ions are removed producing haemoglobinic acid
Bohr effect: the effect that extra carbon dioxide has on the haemoglobin, explaining the release of more oxygen
