Transcript Urinary System Notes

Chapter 16
Kidneys and the
Urinary System
When protein is broken down
in the body, it results in
nitrogenous waste that must
be eliminated from the body
Examples
of Amino
Acids
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
All 20 amino acids have a nitrogen group (NH2).
When broken down for energy, the nitrogen group
is converted to ammonia (NH3). which is toxic to
the body
Circulatory
System
Ammonia is
converted into urea
by the liver. Urea is
then transported in
the blood to the
kidneys where the
urea is removed
from the blood.
Based on: Mader, S., Inquiry Into Life
Formation of Urine
Amino acids in protein are broken down,
resulting in production of ammonia
Ammonia is converted to urea in liver
Urea travels in blood to kidneys, where
removed from blood and incorporated
into urine
Major organs of
the system
1. Kidneys (2)
2. Ureters(2)
3. Bladder (1)
4. Urethra(1)
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
Functions of the Urinary System
• Kidneys excrete nitrogenous waste , such as
urea, uric acid, creatine and ammonium
• Maintain blood volume by regulating the
amount of water excreted
• Monitor blood composition by regulating
electrolyte excretion- sodium the most
significant; potassium; bicarbonate and
calcium among others
Functions of the Urinary System
• Monitor blood ph chiefly by regulating the
secretion of certain ions such as hydrogen
• Secretion of the enzyme Renin, which helps
maintain blood pressure
• Secretion of the growth factor erythropoietin
which stimulates the production of RBC.
Kidneys
•Lie in depressions against
deep muscles of the backbehind peritoneum
•Connective & adipose tissue
adhere to each kidney
•Renal capsule- fibrous
connective tissue
•Hilus- depresssion on
concave side where renal
blood vessels & ureters exit
•Renal cortex- outer
granulated layer
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
Urine Formation by Nephron
Blood pressure forces water, glucose,
amino acids and urea from capillaries into
nephron
Glucose and amino acids are reabsorbed
into blood from nephron
Some water is reabsorbed into blood
Urine is urea and salt concentrated in water
Nephron
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
Urine moves from the
collecting ducts through the
renal pelvis to the ureter
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
Urine moves from the kidneys,
through the ureters to the bladder
and finally through the urethra
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
Regulation of Water Balance
Brain monitors water content of blood
If low water content, pituitary releases ADH
ADH travels in blood to nephron
ADH causes more water to move from urine
back into blood
Alcohol consumption
suppresses the production of
ADH by the pituitary.
Why would this result in
dehydration and a hangover?
Alcohol Effects
Alcohol suppresses ADH
production by the pituitary
Without ADH, higher amounts of
water stay in the urine
Urine with high concentrations of
water leaves the body
Incontinence (urine leakage)
• More than 10 million Americans experience
incontinence
• Most do not seek treatment
• Treatment can improve or eliminate the
problem 90% of the time
Causes of Incontinence
Stress incontinence: leaking small amounts
of urine when coughing, lifting, or exercising
Urge incontinence: the bladder suddenly and
unexpectedly contracts and expels urine
Overflow incontinence: bladder cannot
completely empty so urine dribbles
Kidney stones form in the kidney
pelvis. There are 4 types of stones.
•Calcium stones
(most common)
•Uric acid stones
•Bacteria caused stones
•Cystein stones
Based on Mayo Clinic Health Letter
Kidney stones cause pain when
they pass down the ureters to the
bladder and urethra
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
Treatments for Kidney Stones
• Small stones may pass with no pain
• Larger stones may pass but cause extreme of
pain, requiring a lot pain medication
• Stones that are too large to pass may require
surgical treatment including:
– using a ureteroscope to go up and snare the
stone
– using a nephroscope to crush the stone and
retrieve it
– using shock wave lithotripsy where a person
is submerged in water containing shock
waves to pulverize the stones
Urinary Tract Infection (UTI)
• Second most common infection following
respiratory infections
• UTI occur when bacteria (E. coli) from the
digestive tract get into the opening of the
urinary tract and multiply
• Bacteria first infect the urethra, then move to
the bladder and finally to the kidneys
• UTI tend to occur more in women than men
Women may have more UTIs than men because:
1) they have a shorter urethra, allowing quicker
access to the bladder
2) the urethral opening is nearer the anus
3) intercourse may result in UTIs in women
Based on: Harvard Medical School Family Health Guide
Symptoms of UTIs
• Urge to urinate but only small
amount of urine produced
• Pain and burning sensation in
bladder
• Fever
• Blood in urine