Download EXCRETION

EXCRETION
EXCRETION
- is the process of removing metabolic wastes
(metabolic means it has entered the body cells)
A. The metabolic activities of living organisms result in the
production of waste materials
Metabolic Activity
cellular respiration
dehydration synthesis
Wastes
carbon dioxide + water
water
certain metabolic processes
mineral salts
protein metabolism
nitrogenous
1. nitrogenous wastes
(come from the breakdown of amino acids) are produced
when excess amino acids are utilized in cellular
respiration.
2. nitrogenous wastes vary from the extremely toxic
ammonia to less toxic urea and the nontoxic uric acid.
3. excretion maintains homeostasis by regulating the
chemistry of body fluids and maintaining body temperature.
II. ORGANS of EXCRETION for HUMANS
A. Livermultipurpose organ which include functions of
1) making bile
2) detoxifies blood,
3) destroys red blood cells
4) makes urea from excess amino acids.
1. deamination
the amine group (NH2) + an extra Hydrogen are
removed from amino acids (a.a. can not be stored in the
body) and converted to ammonia which is later
converted into urea
2. cirrhosisinflammation of liver cells & surrounding tissues liver
cells don't function properly.
3. goutalso associated with diets containing increase levels of
specific organ compounds.
4. jaundice
a condition when bile is not excreted properly and metabolic
wastes are reabsorbed into the blood; this cause skin to look
yellow.
B. Urinary System
(organs of urinary system are: kidneys, ureters, urinary
bladder, urethra)
1. Kidneys
have two functions
a. remove metabolic wastes from the blood (make urine)
b. control the concentration of many substances in body tissue.
2. Ureter
•carries urine to bladder
3. Urinary Bladder
•stores urine
4. Urethra
•carries urine outside the body
C. Lungs
- excrete Carbon Dioxide, Water & Heat which are waste
products of cell respiration
D. Sweat Glands of Skin
Water, salts, and some urea diffuse from the blood into
the sweat glands and are subsequently excreted as
perspiration.
Respiration is only incidentally excretory, its primary
function being temperature regulation.
Evaporation of the sweat (98% water and 2%salts and
urea) occurs when heat is absorbed from skin cells.
This absorption of heat lowers body temperature.
Temperature regulations an example of homeostasis.
Skin has two layers the epidermis and the dermis.
The epidermis is the above layer while the dermis is the inner
layer.
epidermis:
•tightly packed epithelial cells.
•Tough, waterproof; protects the dermis
dermis:
•elastic connective tissue supports skin, binds it to muscles &
bones
•has blood vessels, lymph vessels nerves, sense
receptors, glands & hair follicles
•layer of fat (adipose tissue) below
•sebaceous glands which secrete oil
•sweat glands secrete Respiration (urea, water, salt)
Functions of the SKIN
1. Protection
2. Excretion
3. Sensory
4. Temperature Regulation
Why is urine yellow?
The liver has many functions. One of them is to
breakdown red blood cells. Within the red blood cell
is a protein structure called hemoglobin. When
hemoglobin breaks down it produces a pigment
called urochrome. This yellow pigment is constantly
filtered out of the blood as a waste product. Since
red blood cells are constantly being destroyed by
our liver, urochrome is continually being made. This
pigment makes our urine yellow.