BIOL 211 – CELLULAR AND ORGANISMAL BIOLOGY

Lecture Outline for April 6, 2005

 

Topic: water balance in animals

Chapter 38 sections 38.2 through 38.5

Figures used in lecture: 38.7, 38.13, 38.14, 38.15, 38.16, 38.17, 38.18

Additional Resources

            The Kidney – anatomy and function

Human Excretory System

 

Water Balance in Animals

Define/explain: osmoregulation, osmotic stress, kidney, cortex, medulla, ureter, nephron, Bowman's capsule, proximal tubule, loop of Henle, distal tubule, collecting duct,

 

You should be able to:

1.  Discuss the ways in which water balance differs for fresh water aquatic animals, marine animals, and terrestrial animals.

2.  Discuss kidney function as an organ of osmoregulation in terrestrial animals.  This discussion should include the functions of the following components of the kidney:

            Bowman's capsule

            proximal tubule

            loop of Henle

            distal tubule

            collecting duct

 

Today’s Lecture (4-6-05)

 

Different Habitats Present Different Challenges

            freshwater organisms -

 

            marine organisms -

 

            terrestrial organisms -

 

 

Kidney Structure and Function

Renal artery –

 

Renal vein –

 

Ureter

 

nephron -

 

Components of the nephron:

            Bowman’s capsule –

 

 

            proximal tubule

 

            loop of Henle

 

            distal tubule

 

            collecting duct –

 

 

 

Glomerular filtrate contains:

 

Proximal tubule is a recycling center

 

 

Control of Kidney Function

Control often involves hormones

Site of control = distal tubule and collecting duct

 

Control of kidney function During dehydration:

 

 

 

A question…

The filtrate leaving the Bowman’s capsule contains water, nutrients, and waste products.

The water and nutrients must be reabsorbed

Why not filter out the wastes only?