Download RENAL SYSTEM

Topic: Excretion
AIM: How does the process of
Excretion aid in the maintenance
of Homeostasis?
• Do Now: Define & write an Acrostic
Poem for the word EXCRETION
Homework: TEXT BOOK
Read Pages 595-599 Page 599
Questions 1-5
What is the Function or Purpose
of the Excretory System?
• To Rid the body of METABOLIC
WASTES!!
• Alternate wording: To Rid the body of
CELLULAR WASTES!!
What are METABOLIC
WASTES?
 Metabolic wastes are chemical products
which are of no use to the body.
 In fact, some of them may prove detrimental
to health, and accumulation of these waste
products can even be fatal.
 They are produced by different cellular
activities.
• Can you name some Metabolic wastes?
Metabolic Wastes
•
•
•
•
Carbon Dioxide
Sweat
Ammonia
Urine
What are the Components of
the EXCRETORY SYSTEM




Kidneys
Skin
Lungs
Liver
Explain the processes that
produce these Metabolic Wastes.
• CO2: Produced from the process of
Cellular Respiration
• Ammonia: The breakdown of excess
Amino Acids in the Liver.
(DEAMINATION)
• Urea: The breakdown of excess of Amino
Acids in the Liver. (DEAMINATION)
• Sweat: Diffusion of excess urea, salts, and
water.
How Do the Lungs function in
Excretion?
• By removing Carbon Dioxide from the
body
HOW?
Explain the process
How Does the liver function in
Excretion?
• Liver DETOXIFIES THE BLOOD
How Does the Skin function in
Excretion?
• Sweat is excreted through tiny openings
called pores.
SWEAT GLANDS
 There are approximately 2 million sweat glands
all over the skin.
 They are tiny, coil shaped tubes.
 They extend from the deepest layer of the skin to
the surface.
 These glands help to regulate the body
temperature and also contribute to the excretion
of water and salt from the body.
 Sweat contains about 98-99% of water.
 Certain inorganic salts – specially sodium
chloride along with small make up the remaining
1-2%.
SKIN STRUCTURE
SWEAT GLAND
How do the Kidneys function in
Excretion?
• FILTER the blood
• Kidneys are part of the Urinary System
• Functional unit of Kidneys is the Nephron.
• Kidneys and the urinary system including
Nephrons
URINARY SYSTEM
URINARY SYSTEM
KIDNEY
1. The Glomerulus is a ball of capillaries
found inside Bowmans Capsule.
2. The blood is filtered in Bowmans Capsule.
3. The Filtrate moves down into the loop of
Henle where the reabsorption of some
substances occurs.
4. Whatever is not reabsorbed is now urine
and goes to a collecting tubule.
5. Collecting tubules empty into the ureters
which lead to the bladder.
6. Urine exits through the urethra.
URETERS
 There are 2 muscular tubes, 25 to 30 cm in
length, with a very small inner diameter of about
3 mm.
 They convey urine from the kidneys to the
bladder.
URINARY BLADDER
 Pear shaped organ, which lies in the pelvis.
 Though the 2 ureters, the bladder receives waste
products, including urea from the kidneys.
 The average capacity of the bladder is up to 400
or 500 mL.
 The need to pass urine is usually felt when the
bladder is filled to about 280 mL.
 Sometimes up to 500 mL can be tolerated.
 Filling above 500 mL leads to pain.
URETHRA
 Is a passage way through which urine is
discharged from the bladder.
 In men the urethra is longer than in females.
 It passes through the penis, and also has a
passage for the discharge of semen.
 In women the shorter urethra opens immediately
in front of the vagina.
 It serves solely for the discharge of urine.
URINE
 The average daily output of urine is 1.0 to 1.5
liters/day.
 Apart from excess water, urine contains
nitrogenous substances (chiefly urea) –
approximately 32 g and mineral salts containing
sodium, chloride, phosphorus, and potassium.
 Urea and other nitrogen containing substances
are derived from protein.
 These compounds undergo further changes in
the liver before passing to the kidneys to be
excreted in the urine.