General Biochemistry Flashcards
Osmolality definition
Number of particles in 1kg of solvent
Osmolality unit
mOsm/kg
Osmolarity definition
Number of particles in 1L of solution
Vasopressin
ADH
ADH synthesis and secretion site
Synthesised - Hypothalamus
Secreted - Posterior pituitary
Triggers for ADH secretion
Stress - pain, nausea
Hypovolaemia by 10%
Drugs - analgesics, antidepressants
Action of ADH
Increased water permeability in distal tubule
Water reabsorption
Triggers for renin secretion
Reduced NaCl delivery
Increased catecholamines
Hypotension
Renin-angiotensin-aldosterone-system
Angiotensinogen (liver) –renin –>Angiotensin I
Angiotensin I –ACE (lungs)–> angiotensin II
Angiotensin II – peptidase (plasma) –> angiotensin III (inactive)
Actions of Angiotensin II
Vasoconstriction
Thirst
Increased Na absorption
Aldosterone release
Aldosterone secretion site
Adrenal cortex
Aldosterone actions
Water retention
Sodium retention
Hormones secreted by kidney
Hydroxylated Vit D
Renin
Erythropoietin
Factors contributing to GFR
Pre-renal: HTN
Renal: Glomerular function
Post-renal: Tubular luminal pressure (eg. BPH)
GFR definition
Glomerular filtrate formed per minute in all nephrons of both kidneys
Factors affecting serum creatinine
Renal function
Muscle mass
Transudate
Fluid
Low protein
Filtration across capillary endothelium
Due to oncotic pressure
Exudate
Fluid
High protein
Increased permeability
Due to inflammatory process
Lights criteria
Fluid Albumin : Serum Albumin > 0.5
Then fluid = exudate
Causes of protein uria
Nephrotic syndrome Glomerulonephritis Tubular damage Overflow UTI
Causes of tubular damage
Heavy metals
Renotoxic drugs
Chronic pyelonephritis
Fanconi syndrome
Acute phase proteins which increase
CRP Ferritin Alpha 1 antitrypsin Fibrinogen Caeruloplasmin Serum Amyloid A
Acute phase proteins which decrease
Albumin
Transferrin
Haptoglobulin
Binds free Hb from haemolysis
Taken up by reticuloendothelial system
Low Haptoglobulin
Haemolytic anaemia
Sepsis
Caeruloplasmin
Copper carrying protein
Low in Wilson’s disease
Sources of ALP
Liver
Biliary tree
Bone
Placenta
Role of α-1 antitrypsin
- α-1 protease inhibitor
- Normally controls proteolytic enzymes from macrophages
α-1 antitrypsin deficiency associations
Liver cirrhosis
Early COPD