Transcript Urinary System - Booklet 2

7.2 The Urinary System
• Components of urinary system are:
– 2 kidneys
– 2 ureters
– Urinary bladder
– urethra
• Kidneys supplied by renal arteries , drained by
renal veins
• The kidneys remove waste from the blood
through excretion of urine. The urine is
transported passively to the ureters, urine
carried down the ureters to urinary bladder by
peristalisis and gravitational forces.
Anatomy of the Kidney
• Surrounded in a packing of fat – for protection
• Located against posterior wall of abdominal
cavity
• Functional unit of the Kidney is called the
nephron, ~1,000,000 per Kidney.
• Micturition = urination – the process of
eliminating urine from the body
• Cap like structures called Adrenal Glands sit
on top of each Kidney
Functions of Kidney in greater detail
1. Elimination of Nitrogenous Wastes
2. Regulation of fluid/electrolytes – also called
osmoregulation
3. pH regulation
4. Blood chemical composition (ex. Sugar)
– Hyperglycemia – condition which can result if
BSL (blood sugar level) is TOO high
– Hypoglycemia – when BSL is TOO LOW – causes
weakness, fainting, or unconsciousness
5. Regulation of RBCs
6. Regulation of Blood Pressure
Comparison of Nitrogenous Wastes
• Ammonia, Uric Acid, Urea
• Nitrogenous wastes are produced from
catabolism (breakdown) of proteins
• Proteins  Amino Acids Ammonia
(hydrolysis or digestion) Deamination (type of break down)
NH3
• Ammonia
– Highly toxic
– Large amounts of water needed to dilute
ammonia – so it can be safely excreted
– Very soluble in water
– Excreted by: fish
– Can be converted into either uric acid or urea
• Uric Acid
– Produced from ammonia – requires energy to
make
– Is white, insoluble in water, crystals
– Minimal water required for excretion
– Excreted by birds and reptiles - bird pee = white
paste
– The least toxic forms of Nitrogenous wastes
• Urea
– Main nitrogenous waste
– Produced in liver from ammonia (NH3)
– Highly soluble in water
– Travels in blood into the kidneys – filtered
out to make urine
– Excreted: by mammals
– Medium toxicity
– Needs medium amount of water to dilute
so it can safely move through the excretory
organs for disposal
2 NH3 + CO2
H-N–H
|
H
Most Complex
Least Complex
LEAST
MOST
MOST
LEAST
Assignment
• Compare and Contrast – Three nitrogenous
waste products – Ammonia – Uric Acid – Urea
• Q 1- 4 p 302 of Text Book