URINE CONCENTRATION
AND DILUTION.
Role Of ADH (Vasopressin)
,Dilute urine and Role Of ADH Concentrated Urine and Role Of AD
• When there is excess water in the body and body • when there is a deficit of water and
fluid osmolarity is reduced, the kidney can excrete extracellular fluid osmolarity is high, t
urine with an osmolarity as low as 50 mOsm/L. kidney can excrete urine with a conce
of 1200 to 1400 mOsm/L.
• ROLE OF ADH
• When there is excess water in the body and • ROLE OF ADH
extracellular fluid osmolarity is reduced, the
secretion of ADH by the posterior pituitary • When osmolarity of the body fluids in
decreases, thereby reducing the permeability of the above normal (that is, the solutes in t
distal tubule and collecting ducts to water, which fluids become too concentrated), the
causes large amounts of dilute urine to be excreted. pituitary gland secretes more ADH, w
Thus, the rate of ADH secretion determines, to a increases the permeability of the dist
large extent, whether the kidney excretes a dilute or and collecting ducts to water, this allo
a concentrated urine. amounts of water to be reabsorbed a
decreases urine volume but does not
• OSMOLARITY: Amount of solute alter the rate of renal excretion of the
________________
Volume of ECF
, Mechanism of forming dilute urine
• After ingestion of excess water, the kidney rids the body of the excess w
but does not excrete excess amounts of solutes.
• When the glomerular filtrate is initially formed, its osmolarity is about th
same as that of plasma (300 mOsm/L). To excrete excess water, it is nec
to dilute the filtrate as it passes along the tubule. This is achieved by
reabsorbing solutes to a greater extent than water, but this occurs only
certain segments of the tubular system as follows.
AND DILUTION.
Role Of ADH (Vasopressin)
,Dilute urine and Role Of ADH Concentrated Urine and Role Of AD
• When there is excess water in the body and body • when there is a deficit of water and
fluid osmolarity is reduced, the kidney can excrete extracellular fluid osmolarity is high, t
urine with an osmolarity as low as 50 mOsm/L. kidney can excrete urine with a conce
of 1200 to 1400 mOsm/L.
• ROLE OF ADH
• When there is excess water in the body and • ROLE OF ADH
extracellular fluid osmolarity is reduced, the
secretion of ADH by the posterior pituitary • When osmolarity of the body fluids in
decreases, thereby reducing the permeability of the above normal (that is, the solutes in t
distal tubule and collecting ducts to water, which fluids become too concentrated), the
causes large amounts of dilute urine to be excreted. pituitary gland secretes more ADH, w
Thus, the rate of ADH secretion determines, to a increases the permeability of the dist
large extent, whether the kidney excretes a dilute or and collecting ducts to water, this allo
a concentrated urine. amounts of water to be reabsorbed a
decreases urine volume but does not
• OSMOLARITY: Amount of solute alter the rate of renal excretion of the
________________
Volume of ECF
, Mechanism of forming dilute urine
• After ingestion of excess water, the kidney rids the body of the excess w
but does not excrete excess amounts of solutes.
• When the glomerular filtrate is initially formed, its osmolarity is about th
same as that of plasma (300 mOsm/L). To excrete excess water, it is nec
to dilute the filtrate as it passes along the tubule. This is achieved by
reabsorbing solutes to a greater extent than water, but this occurs only
certain segments of the tubular system as follows.
