1. Excretion – The process by which
metabolic wastes are eliminated
Excretory Organs:
Skin
Lungs
Kidneys

2. Roles of the Kidneys:
maintaining blood pH
removing waste products from the
blood
regulating water content of the blood
controlling blood volume

4. Nephrons are the functioning units of the kidneys.
A ball of capillaries called the glomerulus is surrounded by a structure called Bowman’s capsule.
Filtration occurs as blood pressure
forces fluid from the blood in the glomerulus into Bowman’s capsule.

5. The filtrate contains water, urea,
salts, amino acids, and vitamins.
Reabsorption (at Bowman’s Capsule)
-materials that are reabsorbed
include amino acids, fats, water,
and glucose

6. The Loop of Henle reabsorbs water in
the descending loop and NaCl enters the interstitial fluid in the ascending
loop.
Urine flows into the collecting duct
and includes salts, water, and urea,
produced by the liver.

7. Kidney Structure
collecting
ducts lead
to the:
inside
outside

8. Nephron
Structure

9. Figure 44.21 The human excretory system at four size scales

10. The nephron and collecting duct: regional functions of the transport epithelium
reabsorbed
NaCl conc
increases

11. Human Endocrine Glands The adrenal glands secrete ADH which
promotes reabsorption of Na+ and excretion of K+
in the kidneys.

12. Excretory System Animations:
Intro to the Nephron:
Bowman’s Capsule:
Loop of Henle:
Collecting Duct:
Effect of ADH:

13. Excretory System Animations:
Bozeman Science: