Download Excretory System

Excretory System
Dialysis Patient
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Symptoms
Blood pressure abnormally high
190/110 mmHg
Tired, headache, nausea
Decrease in urine output
Blood test showed high levels of
creatine
Treatment
Dyalysis 3 times a week
3-4 hours each time
Change his diet to reduce the
amount of salt intake
Kidney transplant
Blood Components
RBC’s (Erythrocytes) –
transport Oxygen and
Carbon Dioxide
Plasma – transports
Nutrients and Waste
WBC’s – immune cells
Platelets – helps heal cuts
Important Points
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Excretory system: eliminates nonsolid wastes through
exhalation, sweat, and urine
Main parts:
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Lungs
Skin
Urinary System
 Lungs
Removes excess
(extra) carbon dioxide
from the blood
 We then breathe it out
 Keeps a balance of
oxygen and carbon
dioxide in our body
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 Skin
 Sweat
glands
release excess
water and salt
through skin pores
 Sweat also cools
the body to
maintain
homeostasis
 Kidney
 Removes
waste from
the blood, “cleans”
the blood
 Controls the amount
of water content in
the blood
 Maintains a balanced
pH in the blood
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3 Step Process: Filtration, Reabsorption, Excretion
Nephron
Filtration, Reabsorption, Excretion
Filtration
Excretion
Reabsorption
Filtration, Reabsorption, Excretion
Filtration
Blood enters kidney through
renal artery.
Blood then enters through a
network of capillaries known
as the glomerulus of each
nephron.
Filtration, Reabsorption, Excretion
During Reapsorption the materials in
the filtrate that the body needs are
reabsorbed into the bloodstream.
Reabsorption of glucose, amino acids,
vitamins, and ions involve active
transport from the filtrate back to
the blood.
Reabsorption
The amount of water reabsorbed
depends on the amount of water in
the blood. If the amount of water in
the blood is low, water is quickly
reabsorbed. If water is not low it
stays in the filtrate.
What are some instances when water
would be low in the blood?
Filtration, Reabsorption, Excretion
During excretion the nonreabsorbed filtrate is now called
urine and it continues to move
within the nephron in the
collecting duct.
Excretion
Excretory (Urinary) System
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Kidneys: filters that take the
waste out of the blood and make
urine
Ureters: tubes that carry the
urine to the bladder
Bladder: a bag that collects urine
Urethra: a tube that carries the
urine out of the body
http://kidshealth.org/kid/htbw/
Homeostasis
The circulatory, respiratory and excretory system all work together to
maintain homeostasis in the body.
They are responsible for the distribution of oxygen and nutrients to the body
and the removal of carbon dioxide and metabolic wastes from the body.
They seem to work automatically, however they are all under the control of
the nervous system.
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Renal Artery: Blood enters the kidneys here
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Glomerulus: capillary network, main FILTER of the
nephron. High pressure causes materials to diffuse out of
the blood here. FILTRATION
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Loop of Henle: U-shaped tubule surrounded by
capillaries, materials in the filtrate that the body needs are
diffused back into the blood here. REABSORPTION
Collecting Duct/Tubule: Liquid and waste not
absorbed by the blood enter here, called Urine, which
contains water, salts, glucose, amino acids, urea, vitamins,
and ions. EXCRETION
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Ureters: tubes that carry the urine to the bladder
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Urinary Bladder: a bag that collects the urine
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Urethra: a tube that carries the urine out of the body
Video
1. The functional unit of the kidney
that filters the blood of excess
waste products and water is the --.
a) Nephron
b) Ureter
c) Loop of Henle
d) Collecting tubule
3. Urine is excreted through a
pathway in the following order –
a) Kidney, ureter, urethra, urinary
bladder
b) Kidney, ureter, urinary bladder,
urethra
c) Ureter, kidney, urinary bladder,
urethra
d) Urethra, ureter, urinary bladder,
kidney
2. Filtration, reabsorption, and excretion
are three steps that occur in the –
a) Nephron, glomerulus, ureter
b) Ureter, urinary bladder, urethra
c) Glomerulus, loop of Henle,
collecting tubule
d) Kidney, heart, lungs
Kidney Facts
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The kidneys represent only 0.5% of the total weight of the body, but receive 20-25%
of the total arterial blood pumped by the heart.
The rate of filtration is approximately 125 ml/min. or 45 gallons (180 liters) per day.
Considering you have 7 to 8 liters of blood in your body, this means that your
entire blood volume gets filtered approximately 20-25 times a day.
Each kidney contains over a million nephrons
The right kidney is slightly lower than the left
Each kidney weighs about 113-170 grams and is about 11.4 cm long and 6 cm wide
and 2.5 cm thick.
The first workable artificial kidney was developed during World War II in 1944 by
Dr. William Kolff who was living in Holland.
According to the National Kidney Foundation, more than 370,000 Americans are
being treated with dialysis or kidney transplantation for kidney failure. Nearly 12
million Americans may be at risk for chronic kidney disease.
The use of a dialysis machine is suggested when a patient’s blood urea nitrogen
value exceeds 100 mg/dl (the normal value is 30 mg/dl)
Kidney Stones