The KidneyThe KidneyControl of urine volume and Control of urine volume and

concentrationconcentration

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an pressure produces an ultrfiltrate free of plama ultrfiltrate free of plama proteins and cellular elements proteins and cellular elements of the bloodof the blood

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosis

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosisReabsorbtion of solutes such as Na+, K+, Cl-, HCO3-, aa and glucose by a mixture of active and passive processes

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosisReabsorbtion of solutes such as Na+, K+, Cl-, HCO3-, aa and glucose by a mixture of active and passive processes

Loop of HenleLoop of Henle

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosisReabsorbtion of solutes such as Na+, K+, Cl-, HCO3-, aa and glucose by a mixture of active and passive processes

Loop of HenleLoop of Henle Active secretion of Active secretion of chloride ions from chloride ions from ultrafiltrate inascending ultrafiltrate inascending limblimb

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosisReabsorbtion of solutes such as Na+, K+, Cl-, HCO3-, aa and glucose by a mixture of active and passive processes

Loop of HenleLoop of Henle Active secretion of chloride ions from Active secretion of chloride ions from ultrafiltrate inascending limbultrafiltrate inascending limb

Second Second convoluted convoluted tubuletubule

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosisReabsorbtion of solutes such as Na+, K+, Cl-, HCO3-, aa and glucose by a mixture of active and passive processes

Loop of HenleLoop of Henle Active secretion of chloride ions from Active secretion of chloride ions from ultrafiltrate inascending limbultrafiltrate inascending limb

Second Second convoluted convoluted tubuletubule

Reabsorption of NaReabsorption of Na++

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosisReabsorbtion of solutes such as Na+, K+, Cl-, HCO3-, aa and glucose by a mixture of active and passive processes

Loop of HenleLoop of Henle Active secretion of chloride ions from Active secretion of chloride ions from ultrafiltrate inascending limbultrafiltrate inascending limb

Second convoluted Second convoluted tubuletubule

Reabsorption of NaReabsorption of Na++

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosisReabsorbtion of solutes such as Na+, K+, Cl-, HCO3-, aa and glucose by a mixture of active and passive processes

Loop of HenleLoop of Henle Active secretion of chloride ions from Active secretion of chloride ions from ultrafiltrate inascending limbultrafiltrate inascending limb

Second convoluted Second convoluted tubuletubule

Reabsorption of NaReabsorption of Na++

Faculative reabsorbtion of water under control Faculative reabsorbtion of water under control

ofof ADHADH

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosisReabsorbtion of solutes such as Na+, K+, Cl-, HCO3-, aa and glucose by a mixture of active and passive processes

Loop of HenleLoop of Henle Active secretion of chloride ions from Active secretion of chloride ions from ultrafiltrate inascending limbultrafiltrate inascending limb

Second convoluted Second convoluted tubuletubule

Reabsorption of NaReabsorption of Na++

Faculative reabsorbtion of water under control ofFaculative reabsorbtion of water under control of ADH ADH

Secretion of HSecretion of H++, NH4, NH4++, , urea,creatinine and some drugsurea,creatinine and some drugs

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosisReabsorbtion of solutes such as Na+, K+, Cl-, HCO3-, aa and glucose by a mixture of active and passive processes

Loop of HenleLoop of Henle Active secretion of chloride ions from Active secretion of chloride ions from ultrafiltrate inascending limbultrafiltrate inascending limb

Second convoluted Second convoluted tubuletubule

Reabsorption of NaReabsorption of Na++

Faculative reabsorbtion of water under control ofFaculative reabsorbtion of water under control of ADH ADHSecretion of HSecretion of H++, NH4, NH4++, urea,creatinine , urea,creatinine and some drugsand some drugs

Collecting ductCollecting duct

Region of Region of nephronnephron

ActivityActivity

Bowman’s capsuleBowman’s capsule Ultrafiltration of blood in the Ultrafiltration of blood in the glomerulus under hydrostatic glomerulus under hydrostatic pressure produces an ultrfiltrate free pressure produces an ultrfiltrate free of plama proteins and cellular of plama proteins and cellular elements of the bloodelements of the blood

First convoluted First convoluted tubuletubule

reabsorbtion of water by osmosisReabsorbtion of solutes such as Na+, K+, Cl-, HCO3-, aa and glucose by a mixture of active and passive processes

Loop of HenleLoop of Henle Active secretion of chloride ions from Active secretion of chloride ions from ultrafiltrate inascending limbultrafiltrate inascending limb

Second convoluted Second convoluted tubuletubule

Reabsorption of NaReabsorption of Na++

Faculative reabsorbtion of water under control ofFaculative reabsorbtion of water under control of ADH ADHSecretion of HSecretion of H++, NH4, NH4++, urea,creatinine , urea,creatinine and some drugsand some drugs

Collecting ductCollecting duct Faculative reabsorbtion of Faculative reabsorbtion of water under control of water under control of ADHADH

Control of water Control of water reabsorbtion by ADHreabsorbtion by ADH

• The permeability of the walls of the The permeability of the walls of the second convoluted tubule and collecting second convoluted tubule and collecting duct is increased by duct is increased by antidiuretic antidiuretic hormone (ADH)hormone (ADH)

• ADH is produced by the hypothalamus but ADH is produced by the hypothalamus but secreted by the pituitary.secreted by the pituitary.

• A rise in blood concentration (i.e. its water A rise in blood concentration (i.e. its water potential becomes more negative) is potential becomes more negative) is detected by osmoreceptors in the detected by osmoreceptors in the hypothalamushypothalamus

normal water potential

of blood

normal water potential

of blood

receptors in

hypothalamus

becomes less negative

normal water potential

of blood

receptors in

hypothalamus

second convoluted tubule

and collecting ducts

becomes less negative

less ADHproduced

normal water potential

of blood

receptors in

hypothalamus

second convoluted tubule

and collecting ducts

less water

reabsorbed

becomes less negative

less ADHproduced

normal water potential

of blood

receptors in

hypothalamus

second convoluted tubule

and collecting ducts

less water

reabsorbed

becomes less negative

less ADHproduced

normal water potential

of blood

receptors in

hypothalamus

second convoluted tubule

and collecting ducts

less water

reabsorbed

blood water potential becomes more negative becomes

less negative

less ADHproduced

normal water potential

of blood

receptors in

hypothalamus

second convoluted tubule

and collecting ducts

less water

reabsorbed

blood water potential becomes more negative becomes

less negative

less ADHproduced

becomes more negative

normal water potential

of blood

receptors in

hypothalamus

second convoluted tubule

and collecting ducts

less water

reabsorbed

blood water potential becomes more negative becomes

less negative

less ADHproduced

becomes more negative

more ADH released

normal water potential

of blood

receptors in

hypothalamus

second convoluted tubule

and collecting ducts

less water

reabsorbed

blood water potential becomes more negative becomes

less negative

less ADHproduced

becomes more negative

more ADH released

more water

reabsorbed

normal water potential

of blood

receptors in

hypothalamus

second convoluted tubule

and collecting ducts

less water

reabsorbed

blood water potential becomes more negative becomes

less negative

less ADHproduced

becomes more negative

more ADH released

more water

reabsorbed

blood water potential becomes less negative

Control of water Control of water reabsorbtion by ADHreabsorbtion by ADH

• When ADH is produced more water When ADH is produced more water is reabsorbedis reabsorbed

• A more concentrated (hypertonic) A more concentrated (hypertonic) urine is producedurine is produced

Control of water Control of water reabsorbtion by ADHreabsorbtion by ADH

• A fall in blood concentration inhibits A fall in blood concentration inhibits the release of ADH – the walls of the the release of ADH – the walls of the second convoluted tubule and second convoluted tubule and collecting duct become impermeable collecting duct become impermeable to waterto water

• Less water is reabsorbed and a Less water is reabsorbed and a hypotonic urine is producedhypotonic urine is produced

Control of water Control of water reabsorbtion by ADHreabsorbtion by ADH

Another example of negative Another example of negative feedback!feedback!