The Excretory System
1
Vena2cava
3
The Urinary System
And
Excretion
1. Renal vein
4
2. Vena cava
7
3. Kidney
4. Ureter
5. Urinary bladder
6. Urethra
5
6
7. Aorta
Waste Products of Metabolism
1. Amino acids
2. Ammonia
3. Uric acid
Protein
Amino1 Acids
4. Urea
Ammonia
2
Ammonia
(Fish)
Uric3Acid
(Insects, Reptiles, Birds)
4
Urea
(Mammals)
1
1.
2
Pyramid – the pyramid
is a group of collecting
ducts
2.
Renal artery – this artery
branches off the aorta
3.
Renal vein – this vein
dumps its blood into
the vena cava
4.
Renal pelvis – Urine
collects in this hollow
area of the kidney
5.
Ureter – this tube
transports urine to
the urinary bladder
3
4
5
1. Bowman’s (Nephron) capsule 3. Peritubular capillary
2. Proximal tubule
5. Collecting duct
4. Loop of Henle (Nephron Loop)
6. Renal cortex – the outer part
of the kidney
7. Renal medulla – the middle
part of the kidney
6
7
1
2
3
4
5
3
6
Peritubular Capillary
Distil Tubule
4
Proximal Tubule
2
-------
1
----
----
Renal Artery
Cortex
------------------Medulla
Collecting Duct
Bowman’s(Nephron) Capsule
7
8
Loop of Henle (Nephron Loop)
5
Gradient of Increasing Sodium Concentration
Glomerulus
----
----
Cortex
------------------Medulla
Gradient of Increasing Sodium Concentration
-------
The Three Process In
Urine Formation
1. Glomerular filtration
•
Small substances are
forced by blood pressure
through the glomerulus
into the nephron capsule
2. Tubular Reabsorption
Glomerulus
•
Water, salt, and glucose
are reabsorbed into the
blood stream. Most of
the reabsorption takes
place in the proximal
tubule
3. Tubular Secretion
•
Substances are secreted
from the bloodstream
into the distil tubule
The Three Steps of Urine
Formation
• What is the site of glomerular filtration?
Substances are filtered from the blood through the walls of the
glomerulus into the nephron capsule
• What is the primary site of reabsorption?
The proximal tubule is where most water, all glucose, and most salts
are reabsorbed from the nephron back into the blood stream
• What is the primary site of secretion?
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