12. Osmoregulation & Excretion - Animal...

Zoology 430: Animal Physiology

12. Osmoregulation & Excretion

1Zoology 430: Animal Physiology

12. Osmoregulation & Excretion

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Zoology 430: Animal Physiology

Water flows freely through cell membranes

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Aquaporin is a channel protein: Big pukas letting H2O through (image below)Channels do not require/use any energy equivalents (ATP)Ions have a harder time getting through membrane (Semi permeable membrane)

In general: Ions “trapped” in cells, water flows through to balance concentration gradient

Aquaporin

Zoology 430: Animal Physiology

Body Solids and Fluids

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Zoology 430: Animal Physiology

Extracellular and Intracellular Ions

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Zoology 430: Animal Physiology

Osmoregulatory strategies

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Free ride? No - must maintain intracellular function - balance.

Expensive?Yes - done by active transport= ATP!, but maintains stable internal environment

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Freshwater 10-50

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Zoology 430: Animal Physiology

Intracellular Ions

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Intracellular solutes - K+ and organic solutes

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Too little water, has to drink salty water

Too much water, has to absorb salt

Zoology 430: Animal Physiology

Tubular Excretion

Blood Flow

Renal Tubule (e.g., Nephron)

Renal Blood Supply

RPF [P]

[P] Renal Plasma Flow

Filtrate

[F] Glomerular Filtration Rate

GFR [F]

Secretion Reabsorption

[U] Urine Flow Rate

UrineUFR [U]

Osmo-conentration

(e.g., glomerulus & Bowman’s Capsule)

(proximal tubule)

(distal tubule)

(collecting duct)

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