Transcript Slide 1

The Urinary System
Components:
1.
2.
3.
4.
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
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
Some Major Organs and their waste
products
Organ
Primary Waste
Secondary Waste
Kidney
Carbon dioxide,
Heat
Lungs
Urine through
water,
N2 wastes, salts
Food wastes,
bacteria
Feces
Carbon dioxide
Skin
Heat
Sweat = urea,
water, salt
Rectum
Carbon dioxide,
heat, water, salts,
and methane!
Water vapor
Heat
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
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)
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!
??
1.
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??)
8.
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.
1.
T/F ??
The Kidneys clean blood by filtering it
True
2.
T/F ??
The Kidneys can put sugar into urine if there’s too much sugar
in the blood
True
3.
T/F ??
The kidneys make more urine when the blood doesn’t have
enough water
False
4.
T/F ??
The kidneys can put more salt in the urine if the blood is too
salty
True
5. Osmoregulation is
e) All of the above
6.
T/F ??
[OH –] ions are acid ions
False
7.
What kind of ions will the urine contain after a person eats lemons and
oranges? (Acid or Base??)
Acid
8.
Y/N ??
Can the kidney control how many red blood cells are in the
blood?
Yes
9.
How does the kidney do this?
By releasing the hormone Erythroprotein
which tells the bone marrow to make more rbc’s
10. T/F ??
The kidneys help to balance the composition of blood by
adding or subtracting things to the urine.
True