Download Chemical digestion - Mater Academy Charter Middle/ High

The Digestive System
Functions:
1. Takes food into the
body
2. Breaks down food
3. Absorbs digested
materials
Two types of Digestion:
Mechanical digestion: food is physically broken
down into smaller pieces.
Chemical digestion: chemicals in the body break
down the food molecules into smaller molecules.
Enzymes help these chemical reactions happen.
Even your saliva contains enzymes and begins the
process of chemical digestion in the mouth.
enzyme at work
Food’s path:
mouth
esophagus
stomach small intestines
large intestines
rectum
anus
Epiglottis: the flap of tissue that covers the windpipe when
you swallow
Esophagus: connects the mouth with the stomach.
Peristalsis: food goes down the esophagus pushed by the
wave motion of involuntary muscles.
Most mechanical digestion occurs in the stomach.
Small intestine: most chemical digestion takes place
here and most of the absorption of nutrients too.
Liver: this organ secrets bile into the small intestines
which helps digest fats.
Pancreas: organ that produces enzymes that help
break down nutrients in the small intestines.
Villi: structures in the small intestine that absorb the small
nutrient molecules to be used by the body to make energy.
Large intestine: here material that is not absorbed passes to
the large intestine then to the rectum and finally eliminated
through the anus.
Large intestine
The Respiratory System
This system moves oxygen from the outside
environment in to the body and removes carbon
dioxide from the body
Air moves through the nose or mouth to the
pharynx or throat.
Air moves from the
pharynx into the
trachea, or
windpipe
At the top of the
trachea is the larynx,
which contains the
vocal cords.
From the larynx, air
passes through the
trachea into two large
passageways called the
bronchi
At the very end of the bronchi you have tiny
structures called alveoli. Here blood passes
and the gas exchanges take place.
Passage of oxygen to blood
Mouth/nose
Pharynx
Trachea
Bronchi
throat
Alveoli
windpipe
To blood
There is one
for each lung
O2 and CO2
Gas exchange
to blood
vessel
Diaphragm: muscle that allows you to inhale and exhale.
When you inhale the diaphragm move
“down”
When you exhale it moves “up”
The Excretory System
This system collects waste products from your
cells and removes this waste from the body. This
process is called excretion.
Kidneys: two organs that
filter your blood and
remove wastes such as
urea and excess water.
The 2 million filters in the
kidneys are called
nephrons.
The waste and water are then sent to the 2 tubes
called the ureters to your bladder. When you need
to pee, the urine travels to the urethra and then out
of your body.
Now your blood
has been cleaned!
The Circulatory System
This system links all parts of
your body through its network
of blood vessels.
The system carries
needed substances to
cells and carries waste
products away from
cells.
Each time your heart beats it pushes blood
through the blood vessels.
When the heart muscle relaxes, it fills with blood,
when it contracts, it pushes blood forward.
Blood that has no O2
but a lot of CO2 enters
the heart in the right
atrium. Then it follows
this path:
right atrium
right ventricle
lungs
left atrium
left ventricle
heart pumping
Your body
Arteries: Blood vessels that carries blood away
from the heart
Veins:
Carry blood back towards the heart.
Capillaries: Tiny blood vessels that carry
blood to the cells of your body. Capillaries also
join the arteries to the veins.
You have different cells in your blood that have different
functions:
Red blood cells: carry O2 to all your other
cells and CO2 away from them.
White blood cells: these cells fight
harmful bacteria and viruses.
Platelets: form clots to injured
tissues. (scabs)
The lymphatic System
This system collects all the fluids
that leak out of the bloodstream
and puts it slowly back in the
blood. In this system you also
have “lymph nodes” that can help
catch harmful bacteria. Your
tonsils are lymph nodes.
The lymphatic system has no “pump” so liquids move
slowly and mainly by diffusion. The lymph vessels have
smooth muscle that help move the fluid along as well.