3. DEFINITION:
The excretory system consists of the
organs that remove metabolic wastes
from the body.
In humans, this includes the removal of
liquid nitrogenous waste in the form of
urine and solid wastes especially from
the breakdown of hemoglobin.
The removal of urine is accomplished by
the urinary tract, while solid wastes are
expelled through egestion from the large
intestine.
4. • 20% of blood of each heart-beat flows
to kidneys
• Total Blood flows into Kidneys 12
times/hour
• Out of 125ml/min of fluid absorbed out
of blood in filters, 124ml/min gets
returned i.e. 1ml/min Urine is made
• Blood enters into Kidneys through
Renal artery and leaves through Renal
veins
5.
6. 1.Kidneys
The kidneys are paired, bean-shaped organs
located in the abdomen, on either side of
the spine, under the diaphragm. Renal
artery supplies blood to each Kidney (10X5
cm)
They are made of a large number of
structural and functional sub-units called
nephrons (1million/Kidney). These nephrons
perform the primary task of filtering blood
and removing waste products.
7. Each Nephron snakes between the outer
cortex of the kidney and the inner
medulla, with different activities
occurring at each site. Urine gets
collected in Urinary Bladder through
Ureter (25–30 cm (10–12 in) long). Finally
ejected out through Urethra.
URINARY BLADDER
1.Hollow, muscular, distensible organ at
Pelvic floor, stores urine coming via
ureter, excretes through urethra, outlet
at the bottom.
8. Function of Nephrons: Filtration, selective
absorption and secretion. Peritubular
capillaries.
After birth, none is produced thr’out life.
Loss of nephrons is irreversible
FLOW DIAGRAM:
Efferent artery Glomerulus
Bowman’s capsule (filter unit) primary food
(recollected by the blood) & wastes to renal
pelvis ureter U.bladder
urethra Exit.
9.
10.
11.
12.
13. 2. Liver
he liver, the largest organ is the main
detoxifying organ of the body, especially
for nitrogenous wastes.
The cells of the liver play host to
biochemical processes that create
ammonia from amino acids. Since
ammonia is extremely toxic, it is quickly
converted to urea before being
transported in the blood towards the
kidney.
Other poisons are also synthesized in
Liver and removed from the body
14. FUNCTIONS
1. Purification/Detoxification of Blood
2. Regulate bp and electrolytes bal.
3. Stimulates RBC production
4. Increases Calcium absorption
5. Osmoregulation: water-solute bal.
6. Maintains salt level in the body
7. Amino acid/Nucleic acid converted to
Nitrogenous waste products(urea, uric
acid, Ammonia, Creatinine
8. Ammonia Liver Urea (less toxic)
HOMEOSTASIS
15. 3. Lungs: diffusion of gaseous waste –
CO2 etc.
4. Eccrine glans in forehead, bottom
of the feet, palms & other area
removes excess water, regulates
temp.
5. Skin
The skin is a secondary excretory organ
since sweat glands in the dermis can
remove salts and some excess water.
The skin also has sebaceous Glands that
can secrete waxy lipids.