blood physiology Flashcards
Haematocrit
- Everything that isn’t plasma
- Buffy coat and red plot cells
plasma made up of
- Water
- Plasma proteins (7% by mass)
- Salts (mainly Na, Cl, buffers HCO3-
- Nutrients (eg. Glucose, amino acids
- Wastes eg. Urea, uric acid, bilirubin
- Dissolved gases (eg. Oxygen, cardon dioxide
plasma does
○ Maintenance of the internal environment
○ Rapid transport system: nutrients, wastes, hormones, heat
plasma protein functions
§ Colloidal osmotic pressure (especially albumin)
§ pH buffering
§ Transport eg. Lipid binding proteins, hormone binding proteins
§ Immunity eg. Antibodies
§ Blood coagulation - fibrinogen -> fibrin
- Granulocytes
○ Neutrophils
○ Eosinophils
○ Basophils
- Agranulocytes
○ Lymphocytes
○ Monocytes
○ Neutrophils
§ Anti bacterial cells - eat bacteria
§ Rapid to infection site to form pus
○ Eosinophils
§ Destroy parasites extracellularly - release enzymes, oxidants
§ Also weaking phagocytes (of allergens)
○ Basophils
§ Activate other WBCs during inflammation and allergic reactions - release histamine
○ Monocytes
§ Become macrophages - powerful phagocytes
Lymphocytes
- respond to foreign substances/cells
B and T cells
§ B lymphocytes
□ 20% of circulating lymphocytes
□ Proliferate and become plasma cells that produce antibodies (humeral immunity)
§ T lymphocytes
□ 80% of circulating lymphocytes
□ Proliferate and become activated t cells(cell-mediated immunity) that kill foreign invading cells or altered cells
erythrocytes consist of membrane enclosing
○ Water
○ Electrolytes
○ Haemoglobin
○ Metabolic enzymes
haemoglobin consists of
§ Globin (polypeptide chains
§ HbA: 2x a-globin and 2x B globin
§ Haem unit: (1x Fe and 1x protoporphyrin molecule)
- O2 disassociation curve
○ Local conditions alter how tightly Hb binds O2
○ Hb dumps more O2 in metabolically active tissues
§ Acidosis, high temp, high PCO2 (Bohr effect)
- CO2
○ More soluble - 22x in plasma/cytoplasm than O2
○ Can increase transport efficiency if loaded into RBCs
carbon dioxide transport 3 ways
§ Carbonic anhydrase in RBC catalyses the reaction CO2 +H2O H2CO3 H+ + HCO3-
§ Hb in RBC (and proteins in plasma) bind CO2 forming carbamino compounds
- dissolves in blood
RBC destruction
- no nucleus therefore cant repair
- Life span 120 days
- Old cells removed by spleen, liver and bone marrow
red blood cells are removed due to
○ Reduced flexibility
○ Rupture
RBC being phagocytosed by macrophages
○ Fe recycles
○ Rest disposed of - bilirubin
causes of hypoxia
§ Haemorrhage/increased RBC destruction
§ Insufficient haemoglobin eg. Iron deficiency
§ Reduced O2 availability eg. High altitudes
§ Insufficient B vitamins (B12 and folic acid)
red cell count
- 0 x 10^12 cells/L (males)
4. 8 x 10^12 cells/L (females)
haemoglobin
150 g/L (M)
135 g/L (f)
haematocrit / packed cell volume
- 45 (M)
0. 42 (F)
