Ch.44 Controlling the Internal

Environment

I. ThermoregulationII. Osmoregulation

III. Excretion

Thermoregulation

Heat exchange review Fig 44.1

Ectothermy example: Endothermy example:

Thermoregulation p.871Feedback mechanisms (Fig 44.8)

Hypothalamus control (Ch 48)

Responses to high body temp?Responses to low body temp?

Acclimatization (some mammalian cell proteins)

Torpor (hibernation, estivation)

Water Balance & Waste Disposal

p. 873

Nitrogenous wastes:Ammonia, urea, uric acid (fig44.10)

Osmoregulation: (fig 44.11)

Stenohaline, euryhaline

Anhydrobiosis (water bears p. 879)

Salt water fish Fresh water fish

Fig 44.18, anatomy terms

Excretory Systems p.879

Excretory Systems p.879

What is the function of the kidneys?1. Filtration

NEPHRONS of the kidneys

Blood pressure forces blood into the glomerulus; water,urea, small solutes are forced through the filter.

Nonselective filtration

Excretory Systemsin the NephronProximal tubuleLoop of HenleyDistal tubule (collecting duct)

99% of water is reabsorbed back into the body

Excretory Systems: in the Nephron

ReabsorptionSugar, vitamins, nutrients, waterSome salts

Excretory SystemsFeedback circuits:

ADH, hypothalamusRAAS (renin-angiotensin-aldosterone system)ANF (atrial natriuretic factor)

Excretory Systems