Disorders Of Water And Electrolyte Metabolism Flashcards
Plasma osmolality
2x Na plasma in mmol
When is body in water balance
Water intake= water output
Homeostasis of water and electrolytes maintained by
Kidney
Water transport
Ion transport
Biochemical factors regulating water and electrolyte balance
Thirst mechanism Antidiuretic hormone RAAS system Aldosterone ANP Kinins
Thirst mechanism
Lack of water->increased comc or osmolarity of plasma->stimulation of thirst centre in hypothalamus->to drink water-> water in body regulated
ADH mechanism
Lack of water in body->release of ADH->works on collection duct-> increases its permeability to water-> reabsorption of water-> scanty concentrated urine
RAAS mechanism kick in?
When volume and pressure of blood is lost. Ie from hearmmorhage, vomiting, diarrheal . Mechanisms that lead to drop in BP
Where is vasopressin secreted from?
Posterior pituitary
RAAS mechanism?
Decreased BP->stimulation of receptors in juxtaglerular apparatus->release of renin->formation of angiotensin 2->contriction of afferent arteriole->restoration of BP as pressure increases.
Angiotensin 2 can also release aldosterone->causes reabsortiom of sodium amd water-> lowers irine output
Aldosterone
Increases k+ losses im urine
Hyperkalemia
Induces release of aldosterone
Aldosterone
Acts on distal comvoluted tubule
Adh and osmolality
Increased osmolality induces adh production
Thirst mechanism and adh mechanism
Are responses to increased osmolality and just water is enough to solve problems since electrolytes are present
What is atrial natriuretic peptide
Cardiac hormone released by right atrium in response ro increased bp
Anp and raas
Anp opposes raas system and suppresses renin aldosterone and adh
Anp stimulayes excretion of
Sodium and water
Anp
Causes vasodilation and decreased vascular resistance
Kinins
Proteins in blood that lowers bp.
Increases sodium and water excretion
Causes inflammation
Dehydration caused by
No water intake
Excessive loss of fluid
Water deficiency condition
Disturbance of body electrolytes
Types of dehydration
Primary
Seconday
Mixed
Primary dehydration
This is due to loss of water.