The Urinary System Components: 2 kidneys 2 ureters urinary bladder urethra

The Kidneys Excrete metabolic wastes Maintain homeostasis (6 ways) Supplied by renal arteries , drained by renal veins The kidneys remove waste from the blood, then excrete them as 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 Located on the back wall of the abdominal cavity Surrounded by fat for protection (they easily bruise); caps on top are the adrenal glands Ribs protect the upper half of the kidneys Filter/clean blood with structures called nephrons (functional units) There are ~ 1 million nephrons per kidney

Urination The process of eliminating urine from the body ADD THESE NOTES TO THE BOTTOM OF YOUR PAGE: The process of eliminating urine from the body Also known as Micturation A sphincter muscle controls the opening to the bladder Is under nervous control

THE NEPHRON

Excretion The Removal of waste products from the body

What types of wastes does the Human Body produce? Primary Metabolic Wastes incl: Carbon Dioxide Water Ammonia Mineral Salts The Main Excretory Organs are the lungs, kidneys, rectum and skin Primary metabolic waste – means:

Some Major Organs and their waste products Primary Waste Secondary Waste Kidney Urine through water, N2 wastes, salts Carbon dioxide, Heat Rectum Food wastes, bacteria Feces Carbon dioxide, heat, water, salts, and methane! Lungs Carbon dioxide Water vapor Skin Sweat = urea, water, salt Look up the deal on methane

Consequences if Fluid Intake is not equal to Fluid output High fluid output can occur due to many reasons: Consumption of diuretics or kidney malfunction (examples of diuretics….? Write them down) Large amounts of perspiration (sweating) Increased exhalation (exercise) Prolonged bouts of diarrhea These conditions along with low fluid intake can lead to ? Dehydration

Dehydration When body’s fluid output is greater than fluid input – body attempts to restore homeostasis: If output exceeds intake by (% of dehydration occurring or % of total body mass) 1% : thirst sensation to get lost fluids replaced 5%: pain and collapse to conserve water, exhalation is reduced 10%: death!!

Roles of the Liver in Excretion Transforms toxins (ex. Alcohol and heavy metals) into soluble compounds Transforms hazardous products of protein metabolism into safer products Ammonia is converted to urea, and also: ketones Look up heavy metals, and ketones

TWO Major Roles of the Kidney 1. Excretion of Nitrogenous and other wastes – making and releasing urine 2. Maintaining Homeostasis – by many different ways (see other handout)

Composition of Urine Water – 95% - from food and drinks PLUS N – Urea – 2% - from detoxified ammonia N – Uric Acid – broken down nucleic acids (DNA) N – Creatinine – 1.5% - from muscles as they work (involved with ATP being used) Excess salt ions – 1.4% - from food and drinks N – Ammonia – 0.05% from breaking down proteins (amino acids  ammonia) Detoxified means – liver converting ammonia into urea

Composition of Urine N – Ammonia – 0.05% from breaking down proteins (amino acids  ammonia) N – Ketones – .03% - from broken down body fat (higher in diabetics and ppl losing body fat) N – Urochrome – .02% - from broken down red blood cells – is what gives urine its yellow color

Fluid Balance

How The Kidney Maintains Homeostasis 6 ways Read the page Fun quiz afterwards! ??

T/F ?? The Kidneys clean blood by filtering it  2. T/F ?? The Kidneys can put sugar into urine if there’s too much sugar in the blood   3. T/F ?? The kidneys make more urine when the blood doesn’t have enough water 4. T/F ?? The kidneys can put more salt in the urine if the blood is too salty 5. Osmoregulation is  a) Regulation of the water content of the blood b) Regulation of the salt content of the blood c) Regulation of the water content in the urine d) Regulation of the salt content in the urine e) All of the above

6. T/F ?? [OH –] ions are acid ions 7. What kind of ions will the urine contain after a person eats lemons and oranges? (Acid or Base??)   Y/N ?? Can the kidney control how many red blood cells are in the blood? 9. How does the kidney do this? 10. T/F ?? The kidneys help to balance the composition of blood by adding or subtracting things to the urine.

T/F ?? The Kidneys clean blood by filtering it  True T/F ?? The Kidneys can put sugar into urine if there’s too much sugar in the blood   T/F ?? The kidneys make more urine when the blood doesn’t have enough water False T/F ?? The kidneys can put more salt in the urine if the blood is too salty 5. Osmoregulation is  e) All of the above

T/F ?? [OH –] ions are acid ions False What kind of ions will the urine contain after a person eats lemons and oranges? (Acid or Base??) Acid   Y/N ?? Can the kidney control how many red blood cells are in the blood? Yes How does the kidney do this? By releasing the hormone Erythroprotein which tells the bone marrow to make more rbc’s T/F ?? The kidneys help to balance the composition of blood by adding or subtracting things to the urine. True