The document describes several body systems - respiratory, nervous, skeletal, and digestive. It provides details on key parts of each system and their functions. The respiratory system brings oxygen into the body and removes carbon dioxide. It includes the lungs, trachea, bronchi, and diaphragm. The nervous system controls and coordinates the body using neurons, brain, and spinal cord. The skeletal system provides structure with bones, cartilage, tendons, and ligaments. The digestive system breaks down food into nutrients that can be absorbed and used, moving food through the esophagus, stomach, small intestine, and large intestine.

2. Systems of Human Body
• Respiratory System
• Nervous System
• Skeletal System
• Digestive System

4. Parts of Respiratory System
• Lung
• Trachea
• Bronchi
• Diaphragm

5. What is Respiratory System?
• Your respiratory system is made up
of the organs in your body that
help you to breathe. Remember,
that Respiration = Breathing. The
goal of breathing is to deliver
oxygen to the body and to take
away carbon dioxide.

6. What are Lungs?
• The lungs are the main organs of the respiratory
system. In the lungs oxygen is taken into the
body and carbon dioxide is breathed out. The
red blood cells are responsible for picking up the
oxygen in the lungs and carrying the oxygen to
all the body cells that need it. The red blood cells
drop off the oxygen to the body cells, then pick
up the carbon dioxide which is a waste gas
product produced by our cells. The red blood
cells transport the carbon dioxide back to the
lungs and we breathe it out when we exhale.

7. What is Trachea?
• The trachea is sometimes called
the windpipe. The trachea filters
the air we breathe and branches
into the bronchi.

8. What is Bronchi?
• The bronchi are two air tubes
that branch off of the trachea
and carry air directly into the
lungs.

9. What is Diaphragm?
• Breathing starts with a dome-shaped muscle at the
bottom of the lungs called the diaphragm. When
you breathe in, the diaphragm contracts. When it
contracts it flattens out and pulls downward. This
movement enlarges the space that the lungs are in.
This larger space pulls air into the lungs. When you
breathe out, the diaphragm expands reducing the
amount of space for the lungs and forcing air out.
The diaphragm is the main muscle used in
breathing.

12. Parts of Nervous System
• Brain
• Spinal Cord
• Neurons

13. What is Nervous System?
• The cells that make up the
nervous system are called
neurons. Long, stringy neurons
are perfect for carrying the
electrical messages that are the
"language" of the nervous
system.

14. What is Brain?
• The brain is the command center of your entire body. The
brain is the body's main information center. It is made of
billions of neurons. The brain helps the body respond to
the information it receives from the senses. The brain also
processes thoughts. When you think, neurons in your brain
are working.
• The brain has three main parts. The largest is the
cerebrum, which controls vision, touch, and other senses.
It also handles movements you have control over. Thinking
takes place in the cerebrum. The cerebellum is another
section of the brain. The cerebellum helps control balance
and coordination. Another part of the brain is called the
brain stem. The brain stem is the link to the spinal cord
and it also controls digestion, breathing, and heartbeat.

15. What is Spinal Cord?
• The spinal cord is a tube of neurons that
runs up the spine and attaches to the
brain stem. Information from nerves
that branch out to the rest of the body
goes to the spinal cord. Some messages
are processed by the spinal cord but
most information is sent on to the brain.

16. What are Neurons?
• The cells that make up the nervous
system are called neurons. Long,
stringy neurons are perfect for
carrying the electrical messages
that are the "language" of the
nervous system.

19. Parts of Skeletal System
• Vertebrae
• Cranium
• Tendon
• Ligament
• Bone Marrow
• Cartilage

20. What is Skeletal System?
• Your Skeletal system is all of the bones in the
body and the tissues such as tendons,
ligaments and cartilage that connect them.
Your teeth are also considered part of your
skeletal system but they are not counted as
bones. Your teeth are made of enamel and
dentin. Enamel is the strongest substance in
your body.

23. Parts of Digestive System?
• Esophagus
• Stomach
• Small Intestine
• Large Intestine

24. What is Digestion?
• Digestion is the breaking down of food
into forms that our bodies can use. Our
bodies use food as fuel to provide
energy for work, play and growth. Your
digestive system is responsible for
converting the food we eat into energy
for our bodies to use.

25. Where does the food go when we
swallow?
• When we swallow the food goes into a
tube called the esophagus. The
esophagus is a muscular tube that is
connected to the stomach. The muscles
that surround the esophagus help to
squeeze and push the food into the
stomach.

26. Can we swallow if we are upside
down?
• Yes, you can swallow upside down
because the muscles around the
esophagus are strong enough to push
the food up to your stomach. I do not,
however, recommend you try this
anytime soon.

27. What about the stomach?
• The stomach is a sack that receives the food
from the esophagus. Your stomach is located
just below the heart. The stomach makes
digestive juices (acids and enzymes) that help
to break our food down into a thick liquid or
paste. This thick liquid or paste is called
chyme. Your stomach is a muscular organ
that is able to move in order to mix the food
with digestive juices. Food usually remains in
the stomach for about two hours.

28. Where does the food go after it
leaves the stomach?
• After leaving the stomach the food enters the
small intestine. Your small intestine is a 20-25
foot tube that is coiled up in your abdomen. The
center of your small intestine is right behind
your belly button. The most important part of
digestion takes place in the small intestine. As
the thick liquid food paste travels through your
small intestine the nutrients (vitamins, minerals,
proteins, carbohydrates and fats) are absorbed
by millions of tiny finger-like objects called villi
and sent into your bloodstream where the
nutrients can travel to all your body cells.

29. Does the body use all the food we
eat?
• No, the body does not digest all the food that
we eat. The undigested food leaves the small
intestine and then enters the large intestine.
The large intestine is about five feet long so it
is shorter than the small intestine. The large
intestine is however thicker or wider than the
small intestine and that is why it is called the
large intestine. I know, it doesn't make a
whole lot of sense to me either.

30. So what does the large intestine
do to the undigested food?
• The undigested food enters the large
intestine as a liquid paste. In the large
intestine water is removed from the liquid
paste turning what is left into solid waste.
Remember, liquid paste to solid waste. The
solid waste then collects in the rectum at the
end of the large intestine and will finally
leave the body through an opening called the
anus.