Theremoval of metabolic
wastes from an organism.
(I) Human Excretory Organs
Ridthe body of CO2 and excess
H2O from the blood during
exhalation (breathing out).
Largest internal organ
Major function is the removal of
toxins (poisons) from the blood.
This process is know as
detoxification and therefore, the
liver helps in purifying the blood.
Produces bile which is used for the
breakdown of fats (emulsification) in
the small intestine.
The coronary ligament of the liver refers to parts of the peritoneal reflections that hold the
liver to the inferior surface of the diaphragm.
The falciform ligament is a broad and thin antero-posterior peritoneal fold, falciform (Latin
"sickle-shaped") in shape, its base being directed downward and backward, its apex upward
Is a remnant of the ventral mesentery of the fetus.
Largest external organ of the
In contact with the external
Composed of two layers:
outer layer of
the skin used
layer of the skin
Consist of tiny coiled tubes that
open to the surface of the skin
Perspiration (sweat) is excreted
by these glands.
Perspiration consists mostly of
water (98%), salts, and urea.
Function of Skin
1. Protects internal tissue of the body from injury
and the entrance of foreign materials and
2. Excretes a small amount of urea and salt in the
form of perspiration.
3. Nerve endings in the skin detects stimuli like
heat, and pain.
4. The skin is also involved in the regulation of
body temperature (homeostasis).
- sweating cools the body
A Closer look
Liver and Skin
Sweat glands secrete wastes in the
form of water, urea, and salt
These wastes pass by diffusion from
capillaries and into sweat glands and
then through ducts that transport
the waste to the pores in the surface
of the skin.
A) Detoxification- removal of toxins
from the blood.
B) Urea- is formed in the liver from
the breakdown of amino acids in a
process known as Deamination.
-urea then diffuses into the blood
and is transported to the kidneys
and excreted in the form of urine.
A group of organs whose sole purpose is
to perform excretion.
The urinary system consists of:
Bean-shaped organs located below and
toward the back of the diaphragm.
Perform two major functions:
1. Remove wastes from blood.
2. Controls the concentration of
various substances in the body.
The functional units of the kidneys are
known as nephrons.
Cross section of a human kidney
Each kidney contains approximately
1.25 million nephrons.
The nephron begins with a cluster of
capillaries called the glomerulus.
The glomerulus is surrounded by a
cup-like structure called Bowman’s
The way the nephron works:
1. Blood is carried to each kidney by the
2. The renal artery subdivides into smaller
arterioles and then subdivides into a ball
of capillaries known as the glomerulus.
3. Each glomerulus is part of the nephron.
4. Through diffusion (passive
transport), wastes are filtered out
(urea, water, and salt) and enter the
5. From the Bowman’s capsule, the
filtrate (waste) passes through a long
tubule surrounded by capillaries.
6. Through active transport, useful
substances are reabsorbed into the
capillaries from the Loop of Henle.
7. The remaining liquid, called urine,
pass into the collecting tubule and
then pass out of the kidney and into
8. Urine is composed of urea, water,
9. Urine then travels down the ureter,
into the urinary bladder, and out of
the body through the urethra.
Structurethat carries urine from
the kidneys and into the urinary
Temporarily store urine.
Urine is excreted from the
bladder, through the urethra and
out of the body.
(III) Diseases of the Kidneys
Diseases of the kidneys affects the
ability of the body to eliminate
normal amounts of metabolic
develop in the
urinary system .
Produces symptoms similar to
Caused by deposits of uric acid in
Victims of gout suffer severe pain
and stiffness in the joints.