Download Digestive and Excretory Systems

Excretory and Digestive Systems
7th grade Science
Knox Junior High
The Excretory
System
The main function of the
Excretory System is to
remove body wastes
through the skin and
through the digestive,
circulatory and urinary
systems.
WORK ALSO IN
PROGRESS
The Excretory
System
The Urinary System gets
rid of cell wastes which
accumulate in the blood
and controls blood
volume.
The Excretory
System
The part of the brain
called the hypothalamus
regulates the amount of
water in the blood.
•
•
If too much water, hormones
from the hypothalamus tell
kidneys to increase the
amount of urine and return
less water to the blood.
If too little water, hormones
tell kidneys to decrease
amount of urine and return
more water to the blood.
The Excretory
System
Organs of the urinary
system.
•
•
•
Two kidneys pass the
blood through the filtering
units called nephrons.
Urine drains from the
kidneys to the bladder
through tubes called
ureters.
The urethra passes urine
out of the body.
The Excretory
System
Other organs of
excretionThe liver produces a
chemical called urea
which ends up in urine.
Liver fast facts:
The liver supports almost every organ in
the body and is vital for survival. Because
of its strategic location and
multidimensional functions, the liver is
also prone to many diseases.
Adult-to-adult liver transplantation has
been done using 60 % of the donor's liver.
Due to the ability of the liver to regenerate,
both the donor and recipient end up with
normal liver function if all goes well.
The Excretory
System
Urinary diseases and
disorders.
• Infections often occur in
the bladder but then
spread to the kidneys.
• Ureters and urethra can
become blocked,
interrupting the flow of
urine and damaging the
kidneys.
• Urine tests can detect
urinary tract disorders and
other health problems.
The Excretory
System
Kidney Failure
•
•
A person with one kidney
can live normally.
If both kidneys fail, the
person might need a
dialysis machine to filter
blood.
The Digestive
System
Digestion- breaks food
down into small
molecules that can be
absorbed by blood.
•
•
Mechanical digestion food is chewed, mixed and
churned.
Chemical digestion chemical reactions break
down food.
The Digestive
System
Enzymes
•
•
Type of protein that speeds
up the rate of a chemical
reaction in your body.
Many enzymes are involved
in the digestion of
carbohydrates, proteins and
fats.
The Digestive
System
Organs of the digestive
system can be divided
into two categories:
• Accessory organs
• Digestive tract
The Digestive
System
Accessory organs - food
does not pass through
them.
• Include the tongue,
teeth, salivary glands,
liver, gallbladder and
pancreas.
The Digestive
System
Digestive tract
1. Mouth- here, your
tongue, teeth and
saliva change food
into a soft mass.
2. Esophagusmuscular tube that
moves food to the
stomach using
peristalsis, or
waves of muscle
contractions.
The Digestive
System
Digestive tract
3. Stomach- here, food is
digested mechanically by
peristalsis and chemically
by digestive solutions with
the help of enzymes. Food
becomes a thin, watery
liquid called chyme.
4. Small intestine- villi
increase the surface area to
help absorption. Blood
transports the absorbed
nutrients to cells.
Villi of small intestine
The Digestive
System
Digestive tract
5. Large intestine- absorbs
water from undigested
chime. Peristalsis slows
down so chime can be in the
large intestine as long as
three days. The rectum and
anus control the release of
solid waste from the body.
The Digestive
System
Bacteria live in many of
the organs of your
digestive tract and make
vitamins your body
needs.