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Urinary SystemUrinary System

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FunctionsFunctions

11. . Excretion

2. Elimination

3. Homeostatic Regulation

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Urinary SystemUrinary System

Kidney regions:Kidney regions:

1.1. CortexCortex Direct filtrationDirect filtration cortical nephronscortical nephrons juxtamedullary nephronsjuxtamedullary nephrons

2. 2. Medulla Medulla Reabsorption, SecretionReabsorption, Secretion

3.3. PelvisPelvisexcretionexcretion

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Overview of Urinary SystemOverview of Urinary System Flow Flow

1. Filtration2. Reabsorption3. Secretion

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Glomerular FiltrationGlomerular Filtration

Filtration membraneFiltration membrane

Net Filtration Pressure:Net Filtration Pressure:

Glomerular hydrostatic pressure (HPg) Glomerular hydrostatic pressure (HPg) (GBHB)(GBHB)

Colloid osmotic pressure (OPg) (BCOP)Colloid osmotic pressure (OPg) (BCOP)

Capsular hydrostatic presure (HPg) Capsular hydrostatic presure (HPg) (CHP)(CHP)

Glomerular Filtration Rate (GFR)Glomerular Filtration Rate (GFR)

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Tubular ReabsorptionTubular Reabsorption

Molecule Reabsorption: glucose, aa, urea Ion Reabsorption: sodium, potassium, calcium, chloride, bicarbonate, phosphate

Water reabsorption: Obligatory Water Reabsorption

Processes of reabsorption:Diffusion, Osmosis, Active Transport

Transport MaximumTransport Maximum

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The mechanism for the tubular reabsorption of glucose can be likened to a conveyor belt running at constant speed. A, When the concentration of glucose in the filtrate is low, all is reabsorbed. B, When the glucose concentration in the filtrate has reached the transport maximum, all carrier sites for glucose are occupied. If the glucose rises further.C, as in the disease diabetes mellitus, some glucose escapes the carriers and appears in the urine.

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Tubular SecretionTubular Secretion

Disposes of unwanted solutes

What gets secreted into tubules?

You Tube Video about types of Diuretics http://www.youtube.com/watch?NR=1&feature=fvwp&v=FjdJdoZcbyA

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Maintaining Homeostasis

Balances:

Water/saltpHBlood pressure