1. The Excretory System

2. The functions of the excretory system:
– the removal of metabolic waste from the body
To maintain homeostasis by regulating the chemical composition of the blood

3. Excretory system consists of the:
1.Kidneys
2.Urinary tract[ureters, bladder, and urethra]
3.skin
4.Liver

4. The Kidneys
It maintains the proper levels of both salts and water in the body
The “cleansing system” of the body; it carefully selects the chemical wastes for removal while keeping useful nutrients in the body

5. The most important part of the excretory system
There are 2 kidneys located in the lower rear portion of the abdominal cavity

6. Different parts of the kidney:
Renal artery: large blood vessels that bring blood to the kidney from the body
Renal vein: returns newly cleansed blood to the body as it leaves the kidney
The inner portion of the kidney is hollow and this is where the urine is collected
The outer portion consist of the medulla and cortex

7. Nephrons:
 Tiny tubule structures located in the cortex that extend into the medulla
 The structural unit of the kidney
filtering units of the kidneys
 where the blood is cleansed
where water balance is maintained

8. Bowman’s capsule: where the reabsorption of water, minerals, and end products occur
Glomerulus: ball of capillaries that drain to the Bowman’s; substances are filtered here

9. As blood passes through the Nephrons in the kidneys
metabolic wastes are removed
The correct balance of salt and water in the blood is maintained
Urine is produced through the exchange of materials between the capillaries and the nephrons in the kidney

10. The result of all this activity in the kidneys is that:
The blood returns through the veins to the body, cleansed of wastes and properly balanced with salts and water
Urine, which contains wastes, urea, salts and water, is collected and removed from the body

13. The Urinary Tract
the correct pathway for the removal of urine from the body is:
Kidneyureterbladderurethra

16. The Urinary Tract Ureter connects each kidney to the urinary bladder
transports urine from the kidney and empties to the urinary bladder

17. temporarily stores urine holds up to 1 pint of urine
Urinary bladder:
temporarily stores urine
holds up to 1 pint of urine
after reabsorption in nephrons is completed, the fluid that is left in the tubules is transported here

18. Urethra:
urine leaves the body through the urethra
as urine is excreted, muscle contractions of the urinary bladder will cause the urine to pass into the urethra

19. Skin Largest organ of the body
This organ surrounds and protects the body
Has 2 separate layers
1.Epidermis: outer layer
2.Dermis: inner layer

20. The outer layer of skin:Epidermis
A very thin layer where new skin cells push their way toward the surface, replacing the dead skin cells there
The skin cells are tough and form a protective layer that prevents bacteria and harmful chemicals from entering, and water from leaving the body

21. Beneath the outer layer are cells that produce the pigments that give skin its colour
The inner layer{the Dermis} is a thick layer that contains a variety of structures that help maintain homeostasis

22. The structures within the inner layer of skin: Dermis
Nerve endings that can detect temperature and touch
Hair roots
Capillaries that help regulate body temperature
Sebaceous glands that keep skin and hair soft by releasing oils

23. Sweat glands
Perspiration from sweat glands contains some nitrogenous wastes
The main role of perspiration is to assist in regulating temperature by cooling the body through evaporation

27. Liver The largest internal organ in the body
It produces urea by breaking down amino acids[deamination]
Removes poisons from the blood

28. Stores extra sugar in the form of glycogen
Changes glycogen into glucose and secretes it back to the bloodstream when the body needs energy

29. Diseases of the excretory system:
Nephritis: Inflammation of the kidneys
kidney stones: A small, hard deposit that forms in the kidneys and is often painful when passed

30. Gout: A condition caused by high levels of nitrogenous wastes in the blood, produces severe pain in the joints
uremia: It occurs when urea and other waste products build up in the body because the kidneys are unable to eliminate them.

31. Cirrhosis: Chronic liver damage from a variety of causes leading to scarring and liver failure
hepatitis: A distinct disease that affects the liver and has different types, symptoms and treatments