Physiology of the Kidney

Physiology of the Kidney

Urine FormationUrine Formation

FiltrationFiltration

Occurs in the glomerulus

Renal artery branches off into tiny capillaries upon entering the kidney = increased pressure, which drives filtration

Occurs in the glomerulus

Renal artery branches off into tiny capillaries upon entering the kidney = increased pressure, which drives filtration

FiltrationFiltration

Plasma is filtered through capillary walls and passes into the Bowman’s capsule

Size determines what will be filtered; anything small enough is forced out by the filtration process

Plasma is filtered through capillary walls and passes into the Bowman’s capsule

Size determines what will be filtered; anything small enough is forced out by the filtration process

FiltrationFiltration

Examples: water, salts, glucose, amino

acids, urea, some drugs,

etc.

• Blood cells & plasma proteins are too large to be forced out of capillaries - move into efferent vessel which contains very concentrated blood

Examples: water, salts, glucose, amino

acids, urea, some drugs,

etc.

• Blood cells & plasma proteins are too large to be forced out of capillaries - move into efferent vessel which contains very concentrated blood

ReabsorptionReabsorption

Occurs primarily in the PCT (~80%) but some occurs in the DCT & Collecting Duct

Prevents the loss of nutrients by reabsorbing useful substances from the filtrate back into the bloodstream

Occurs primarily in the PCT (~80%) but some occurs in the DCT & Collecting Duct

Prevents the loss of nutrients by reabsorbing useful substances from the filtrate back into the bloodstream

ReabsorptionReabsorption

Passive transport occurs naturally & allows substances such as water & urea back into the bloodstream (urea is a waste product but kidneys aren’t 100% efficient at removing it so some is reabsorbed)

Passive transport occurs naturally & allows substances such as water & urea back into the bloodstream (urea is a waste product but kidneys aren’t 100% efficient at removing it so some is reabsorbed)

ReabsorptionReabsorption

Active transport is when the body expends energy to get desired substances back from the filtrate such as glucose or amino acids

Active transport is when the body expends energy to get desired substances back from the filtrate such as glucose or amino acids

SecretionSecretion

Occurs mainly in the DCT & Collecting Tubule

Substances move from the blood into the kidney tubules to be excreted in the urine

Occurs mainly in the DCT & Collecting Tubule

Substances move from the blood into the kidney tubules to be excreted in the urine

SecretionSecretion

Examples of substances secreted: urea, creatinine, hydrogen, bicarbonate, & hormones

Purpose is to eliminate waste products not already present in the filatrate & to maintain proper pH, fluid, & electrolyte balance

Examples of substances secreted: urea, creatinine, hydrogen, bicarbonate, & hormones

Purpose is to eliminate waste products not already present in the filatrate & to maintain proper pH, fluid, & electrolyte balance

SecretionSecretion Hormones involved in Secretion:-ADH (anti diuretic hormone)

+helps regulate water balance

+secreted by pituitary gland when blood pressure too high (too much

salt)

Hormones involved in Secretion:-ADH (anti diuretic hormone)

+helps regulate water balance

+secreted by pituitary gland when blood pressure too high (too much

salt)

SecretionSecretion Hormones involved in Secretion:-ADH (anti diuretic hormone)

+prevents excessive water loss by

causing collecting tubules to reabsorb

water back into the blood stream

Hormones involved in Secretion:-ADH (anti diuretic hormone)

+prevents excessive water loss by

causing collecting tubules to reabsorb

water back into the blood stream

SecretionSecretion Hormones involved in Secretion:-ADH (anti diuretic hormone)

+results in more concentrated urine & a smaller volume of urine

*Diuretic = a substance that inactivates ADH & increases the amount of urine produced

Ex: water, milk, coffee, tea, alcohol,

pop, etc.

Hormones involved in Secretion:-ADH (anti diuretic hormone)

+results in more concentrated urine & a smaller volume of urine

*Diuretic = a substance that inactivates ADH & increases the amount of urine produced

Ex: water, milk, coffee, tea, alcohol,

pop, etc.

SecretionSecretion Hormones involved in Secretion:- Aldosterone (salt & water hormone)

+helps regulate electrolyte & fluid

balance

+secreted by adrenal glands when blood pressure low (not enough salt)

= “Dilute Blood”

Hormones involved in Secretion:- Aldosterone (salt & water hormone)

+helps regulate electrolyte & fluid

balance

+secreted by adrenal glands when blood pressure low (not enough salt)

= “Dilute Blood”

SecretionSecretion Hormones involved in Secretion:- Aldosterone (salt & water hormone)

+Retains more sodium than normal & excretes more potassium than normal; also results in water retention because “water follows

salt”

Hormones involved in Secretion:- Aldosterone (salt & water hormone)

+Retains more sodium than normal & excretes more potassium than normal; also results in water retention because “water follows

salt”

SecretionSecretion Hormones involved in Secretion:- Aldosterone (salt & water hormone)

+Addison’s disease (aldosterone deficiency) = fatigue, loss of appetite, weight loss, low blood pressure, nausea, vomiting, diarrhea, muscle spasms & weakness, emotional changes such as irritability & depression, salt cravings, & “bronzing” of the skin

Hormones involved in Secretion:- Aldosterone (salt & water hormone)

+Addison’s disease (aldosterone deficiency) = fatigue, loss of appetite, weight loss, low blood pressure, nausea, vomiting, diarrhea, muscle spasms & weakness, emotional changes such as irritability & depression, salt cravings, & “bronzing” of the skin

End.End.