Urinary system Designed by Pyeongsug Kim ©2010 [email protected]@att.net Picture from

Urinary system

Designed by Pyeongsug Kim ©2010 [email protected] Picture from http://www.treatbedwetting.info/

Physiology - iPhysiology - i

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Kidney FunctionKidney Function-Cleans the blood removes ____ and other nitrogen-containing wastes.

-Balance the blood in concentration Filtration Reabsorption Secretion

ions, nutrients, water content

-pH balnce by secretion of ___ or _____

-Urine formation

-Hormones Adrenal glands ~ adrenal medulla, adrenal cortex

urea

H+ HCO3

If need or decrease (reduce)

If excess

Almost everything except Protein & RBC

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Nephron

NephronNephron-Functional unit of the kidney-Regulate…. Blood pressure Electrolyte concentration pH, [H+]-Remove waste

A

B

A:B:

Bowman’s capsuleGlomerulus

Bowman’s capsule encases _________ . glomerulus



_________: A substance enters the glomerular ultrafiltrate.Filtration

_____________: A substance is transported from the filtrate, through

tubular cells, and into the blood.Reabsorption

_____________: A substance is transported from peritubular blood,

through tubular cells, and into the filtrate.Secretion

In the kidneyIn the kidney



Nephrons

Bowman’s capsule-Encloses a __________.-Filters the smaller blood molecules into the _________ ________= The selective passage of molecules

- Powered by _____________

-Form the renal corpuscle (the filter) ______= The liquid that passes from the blood into the nephron.

:water, ions, nutrients (glucose, amino acids, and vitamins), nitrogen-containing wastes (Urea)

glomerulus nephron

Filtrate

Filtration

blood pressure

Blood cells and blood proteins are too large to enter the nephron.

_________-FilterFilter the blood, -ReabsorbReabsorb solutes and water for balance. except waste(Urea) and excess water/solutes.

-FormForm the urine.



a:b:c:

A: B: C:D:E:

Adrenal cortexAdrenal medullaNephron

Glomerular capsuleProximal convoluted tubuleLoop of HenleDistal convoluted tubuleCollecting duct

E: F:

Glomerular capsuleGlomrulus

_______ : functional units of kidney responsible for the formation of urine.Nephron



_______________________ -The most reabsorption of solutes and water (except urea)

______________ -Loops down toward the medulla

then up again into the cortex -Specializes in _____________ reabsorption

___________________ -Can reabsorb water and all solutes (except urea)

Proximal convoluted tubule

Loop of Henle

NaCl and water

Distal convoluted tubule



Filtration Reabsorption Secretion

H2O Reabsorbtion

__________ is the portion of the nephron responsible for filtering the blood.___________________ contains microvilli increase the surface area for reabsorption of salt, water, etc.

_________________________ located in adrenal cortex.

GlomerularExcretion

Know the parts of the nephron. Be able to give examples of a molecule or ion that is reabsorbed in each part of the nephron (proximal convoluted tubule, descending loop, etc.)

Proximal convoluted tubule

Glomerular capsule, Proximal, distal convoluted tubule




____________ located in adrenal medulla.

____________ contains microvilli.

*Distal convoluted tubule contains few microvilli

relatively.

____________ has ADH receptors.; H2O

reabsorption occurs.

Loop of Henle

Collecting duct

Proximal, distal convoluted tubule

______________ is passively permeable water.

______________ is impermeable of water.; has Na/K+ pumps.

______________ is the place where secretion occurs.

Desending limb

Asending limbDistal convoluted tubule



In the proximal tubule-(Filtration/reabsorption/secretion)

-Active transports

:___________&__________

:K+ reabsrobed

-Passively follows Na+. :Cl- by electrical gradient.

:H2O by osmosis.

Na+/K+ pump

Glucose/Na+(coupled transport)

In the glomerular-(Filtration/reabsorption/secretion)

-Plasma water and solutes are

filtrated-except _______.protein



In the Descending limb-Passively permeable to water.-(Does/Does not) actively transport salt.

In the Ascending limb-(Permeable/impermeable) to water.-(Does/Does not) actively transport salt.-Na+/K+ pumps- Cl+ follows passively the (Na+/K+).





In the Distal convoluted tubule-(Filtration/reabsorption/secretion)-Impermeable to water; but last part is permeable.-(Does/Does not) actively transport salt. Cl+ follows passively the (Na+/K+). K+ secreted in the late distal tubule

In the Collecting duct-(Filtration/H2O reabsorption/secretion)-Passively permeable to water by ____.-(Does/Does not) actively transport salt. Cl+ follows passively the (Na+/K+). K+ secreted under __________

ADH

aldosterone




Think simple!

If something is TOO much in the body, .. kidneys throw away the too much things thru urine. SECRETION and EXCRETION!

If something is TOO little in the body, .. kidneys send the too little things back to body(the blood). REABSORPTION!


ADH(Antidiuretic hormone)

Plasma volume

Plasma osmolity

Osmotic pressure

Detected by osmoreceptors in_____________

_____ is released

Thirst

______reabsorption

Plasma volume

Urinehypothalamus

ADH H2O



Therefore, ADH decreases urine output(urine volume) but, increase the concentration in urine(Dark color in urine).


ADH hold the body water (increase water reabsorption) and increase blood volume.

ADH


-produced in the hypothalamus and stored in the posterior pituitary gland.-When blood osmolarity rises,(for example, dehydration) ADH is released increases water reabsorption in the distal tubule and collecting duct. increase blood volume but decrease urine volume.


ADH(cont’d)

Aquaporin - ADH-responsive water channel . -found in distal tubule and collecting duct!


Regulation of plasma volum Renin

-secreted by the _____________ cells.-Converts Angiotensinogen to____________

juxtaglomerular

Angiotensin I




Salt deficit, Low blood volume, or pressure

____________ is produced

Aldosterone secretion

Vasoconstriction

Na+, H2O retentionK+ secretion

↓Urine volume↑Blood pressure, ↑ Blood volume

Renin

ACE

*ACE: Angiotensin-

converting enzyme

angiotensin II


Therefore, Renin and aldosterone increase Na+ level and blood volume but, decreases urine output(urine volume).


Renin increases aldosterone. Aldosterone increase Na+ and water reabsorption.

Renin and Aldosterone



-Aldosterone produced in the adrenal cortex. When blood volume is low, aldosterone is increased at the distal tubules. ↑Na+ and Water reabsorption ↓K+ secretion

Renin and Aldosterone (cont’d)-Renin secreted in Juxtaglomerular cells. increases aldosterone production. leads angiotensinII production. Vasoconstriction in Glomerus. decreases GFR(Glomerular Filtration Rate)

leads to increased blood volume and pressure!!Decreases Urine output!



ADH acts on the distal tubule and collecting duct. Aldosterone acts on the distal tubule.


CO=SV x HR

↑HR



Sympathetic Nerves(Vasodilation/vasoconstriction) in kidneys (↓)GFR:Glomerular Filtration Rate (↓) Urine output (↑) Blood volume

ADHH2O retention (↓) Urine output

AldosteroneNa+, H2O retention, K+ secreted(↓) Urine output

ReninAngiotensinII (Vasoconstriction/vasodilation)(↓) GFR (↓) Urine output


In the Distal convoluted tubule-(Filtration/reabsorption/secretion)-Impermeable to water; but last part is permeable.-(Does/Does not) actively transport salt. Cl+ follows passively the (Na+/K+). K+ secreted in the late distal tubule

In the Collecting duct-(Filtration/H2O reabsorption/secretion)-Passively permeable to water by ____.-(Does/Does not) actively transport salt. Cl+ follows passively the (Na+/K+). K+ secreted under __________-Permeable to urea

ADH

aldosterone

OK! Look at this slide again!!


Aldosterone -stimulates the secretion of ___ & ____ at DCT(distal convoluted tubule).

↑pH in bloodK+ H+

Regulate blood pH by kidney-Normally, kidneys reabsorb HCO3- and excrete H+. so, urine usually acidic(low pH, high H+).


Think simple!If high pH(low H+) … Kidneys keep H+. (↓H+ secretion).

If low pH(high H+) … Kidneys throw away H+. (↑H+ secretion).

Aldosterone (cont’d)-stimulates the secretion of ___ & ____.-Cause ↑ K+ secretion but, ↓H+ secretion high H+(↓ pH) in blood

K+ H+


K+/ H+-Secreted in the late of distal tubule and ___________________.-High H+ may decrease K+ secretion and increase H+ secretion.

cortical collecting duct

During alkalosis(↑pH, low H+)-↓ H+ secretion-↓ HCO3- reabsorption-↑H+(↓pH) in blood


Remember!!!Normally, kidneys reabsorb HCO3- and excrete H+.

Kidneys try to keep H+.

Acidosis(↓pH; ↑H+)↑H+ secretion ↓K+ secretion ↓H+ /↑K+ in the blood __________may occur.

Hyperkalemia(↑K+)↑K+ secretion by ↑aldosterone ↓H+ secretion↑H+ /↓K+ in the blood________ may occur.

Hyperkalemia

Acidosis

*High K+ in the blood stimulates directly release of aldosterone(w/o renin or angiotensin I).


In Acidosis, Kidneys try to throw away H+.

Kidneys try to throw away K+.

Urea-Waste product of amino acid metabolism-Filtrated in the glomerular -Diffuse… into the asending limb out of collecting duct trapped in the interstitial fluid high osmolality in the medulla H2O reabsorbed. urine concentrated!

H2O reabsoption occur in the collecting duct.


Diuretic drugs-inhibit the reabsorption of water increase urine volume. lower blood volume.-for congestive heart failure, hypertension, edema- Lasix (furosemide), mannitol (osmotic diuretics)


Lasix (Furosemide)-Diuretic drug-act on thick ascending limbs. -inhibit Na+ transport. ↓Na+ reabsorption. (followed by Water) ↓Water reabsorption. increase urine volume. decrease blood volume.


Mannitol (Osmotic diuretics)-Diuretic drug-act on Last part of distal tubule and cortical collecting duct. -reduces osmotic reabsorption of water by reducing osmotic gradient. pull water to the nephron.(↑water secretion) increase urine volume. decrease blood volume.


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