Transcript The Human Body: The Excretory System - Holding

The Human Body:
The Excretory System
Textbook Chapter 34
Review Topic 1
Function
• Removes toxins and wastes which build up
in the body as a result of metabolism
• Regulates the amount of fluid and salts in
the body and maintains pH of the blood
• Helps regulate homeostasis
Parts
• Lungs
• Excretes carbon dioxide
• Skin
• Excretes water and salts contained in sweat
• Kidneys
• Major excretory organ in the body
Kidneys
• Bean-shaped
• Filters out wastes, water and salts from the
blood
• Two regions
• Renal cortex ~ outer region
• Renal medulla ~ inner region
• Contains microscopic tubules and blood
vessels
• Renal pelvis ~ center of kidney where these
filters are found
• Nephron filtration
• Each kidney has 1 million filtering units called
nephrons
• Blood enters each Nephron through a long tube
surrounded by capillaries called a glomerulus
• Surrounded by the Bowman’s capsule
• Renal artery transports nutrients and
wastes to the kidney
• Branches into smaller blood vessels forming
the glomerulus
• Blood vessel walls are thin and under high
pressure
• Urea ~ nitrogenous waste product containing
water and substances dissolved in water
• Pushed through capillary walls into the
Bowman’s capsule
• Red blood cells and proteins are too large
and remain in the blood stream
• Reabsorption/formation of urine
• Filtrate collects in the Bowman’s capsule and
flows through renal tubules (loop of Henle and
collecting tubule)
• Most water and useful substances (ex. glucose,
minerals) are reabsorbed back into blood stream
(reabsorption)
• Excess fluids and toxic substances are collected
to form urine
• Leaves the kidneys through ducts called ureters
• Urine is stored in the urinary bladder
• Exits the body through the urethra
• Each kidney filters 180 L of blood a day in
adults to produce 1.5 L of urine
• Process requires large amounts of energy
• Use 20-25% of your body’s oxygen intake for their
internal energy requirements!
• Controls pH balance by absorbing or filtering
out acids or bases to regulate pH of the blood
• Urinary System BrainPop
Kidney Disorders
• Infections
• Start as bladder infections which spread to kidney
• Fever, chills, mid-/lower-back pain
• Can be caused by blockages
• If untreated, kidneys can scar causing a loss in function
• Can be treated with antibiotics
• Nephritis
• Inflammation (painful swelling) of the
glomeruli
• Cause by blockages
• Blood in urine, swelling of body tissues, protein
in urine
• Can improve on its own but may require a
special diet or prescription drugs to treat the
infection
• Kidney Stones
• Crystallized solid (calcium compound) which
forms in the kidney
• Small stones can be passed out in urine
• Larger stones are broken up using ultrasonic
sound waves or removed using surgery
• Diabetes/High Blood Pressure
• Causes reduced kidney function or kidney
failure
• Illegal/Prescription Drugs
• Can cause kidney damage
Treatments
• Dialysis
• An artificial
kidney machine
filters out wastes
and toxins from
a patient’s blood
• Two types
• Blood is passed through the machine
temporarily to be filtered and cleaned, then
returned (3-4 hours/3 days week)
• Membrane lining the abdomen acts as an
artificial kidney by injecting it with a special
fluid through a small tube attached to the
patients body to collect draining wastes (3040 min/daily)