The Excretory System

1
The Excretory System
2
1
The Urinary System And Excretion
2
Vena cava
3
1. Renal vein
4
2. Vena cava
7
3. Kidney
4. Ureter
5. Urinary bladder
6. Urethra
5
7. Aorta
6
3
Waste Products of Metabolism
1. Amino acids
Protein Amino Acids Ammonia Ammonia
Uric Acid
Urea (Fish) (Insects, Reptiles,
Birds) (Mammals)
2. Ammonia
3. Uric acid
1
4. Urea
2
4
3
4
1

• Pyramid the pyramid
• is a group of collecting
• ducts

2

• Renal artery this artery
• branches off the aorta

• Renal vein this vein
• dumps its blood into
• the vena cava

3

• Renal pelvis Urine
• collects in this hollow
• area of the kidney

4
5

• Ureter this tube
• transports urine to
• the urinary bladder

5
1. Bowmans (Nephron) capsule
3. Peritubular capillary
5. Collecting duct
2. Proximal tubule
4. Loop of Henle (Nephron Loop)
6. Renal cortex the outer part
of the kidney
6
7. Renal medulla the middle
part of the kidney
7
1
2
3
4
5
6
3
6
Peritubular Capillary
Distil Tubule
4
Proximal Tubule
2
Glomerulus
Cortex
------- ---- ----
-------------------
1
Medulla
Renal Artery
Gradient of Increasing Sodium Concentration
Collecting Duct
Bowmans(Nephron) Capsule
7
8
Loop of Henle (Nephron Loop)
5
7
Cortex
------- ---- ----
-------------------
Medulla
Gradient of Increasing Sodium Concentration
8

• The Three Process In
• Urine Formation
• Glomerular filtration
• Small substances are
• forced by blood pressure
• through the glomerulus
• into the nephron capsule
• Tubular Reabsorption
• Water, salt, and glucose
• are reabsorbed into the
• blood stream. Most of
• the reabsorption takes
• place in the proximal
• tubule
• Tubular Secretion
• Substances are secreted

Glomerulus
9
The Three Steps of Urine Formation

• What is the site of glomerular filtration?
• What is the primary site of reabsorption?
• What is the primary site of secretion?

Substances are filtered from the blood through
the walls of the glomerulus into the nephron
capsule
The proximal tubule is where most water, all
glucose, and most salts are reabsorbed from the
nephron back into the blood stream
Drugs (legal and illegal), hydrogen ions,
antibiotic, are secreted from the blood stream
into the distil tubule. These substances end up
in the urine. This is why testing the urine for
recently used drugs works