The Skeletal System s2

Name ______The Skeletal System

The skeleton is the name given to the collection of bones that holds our body together. BIG IDEA: The skeleton has 3 major jobs.

1. It protects our vital organs such as the brain, the heart and the lungs.

2. It gives us the shape that we have. Without our skeleton, we would be a blob of blood and tissue on the floor.

3. It allows us to move. Our muscles are attached to our bones, so when our muscles move, they move the bones, we move. This is called ______.

When you were born, your skeleton had around ______bones. By the time you become an adult, you will only have around ______bones. This is because as you grow, some of the bones join together to form one bone.

Bones don’t work alone!! Bones join together to form a ______. A tough, smooth, shiny, substance called ______covers the end of each bone. The cartilage- coated ends of the

2 bones are kept apart by a thin film of slippery fluid that works like oil in a car. All of this is so your bones won’t scratch and bump against each other when you move. Strong stretchy bands called ______hold our bones together.

Inside a Bone

In the body, bones are very much alive! They have their own nerves and blood vessels, and they do many jobs, such as storing ______.

A typical bone has an outer layer of hard or compact bone, which is very strong, dense and tough. Inside this is a layer of spongy bone, which looks like a honeycomb. In the middle of some bones is jelly like substance called ______, where new cells are constantly being produced for the blood. What kind of new cells?  Red blood cells – deliver oxygen to all parts of your body  White blood cells – fight germs and disease

3 Muscular System

Almost half the body’s weight is muscle.

What percent of our body is muscle? ______

Big Idea: What does the muscular system do?

1. Muscles are the part of our body that allows us to move!

What are muscles made of?

 They are made up of special ______that can

contract or shorten, when they receive a ______

from the ______. (That’s the nervous system)

 The muscles are attached to bones by stretchy tissue called

______. When the muscles contract, they pull on the

tendons, which pull on the bones and cause our limbs to move. So that

means the muscular system works with the ______

system to make us move!

Did You Know?

There are more than ______muscles and they DO NOT work alone! How do muscles work?

Most muscles are arranged in opposing teams. Think Tug of War!

What does this mean?

4  When one muscle flexes (let’s call this team A), it pulls the body

part in that direction. The other muscle (team B) is relaxing. Then

they switch and the body moves back.

 As each team flexes or tightens, the other relaxes and becomes

loose. The body part moves back and forth.

 It takes three of our body systems to work together in order

for our us to move:

1. ______- send a signal to the muscle

2. ______- contract and pull

3. ______- bone attached to the muscle

Are there different types of muscles?

Yes, there are two different types of muscles.

1. ______muscles, such as your arms and legs can

be controlled by your thoughts.

a. All this muscle action is controlled by your ______,

which sends and receives signals through your

______system.

2. ______muscles, such as the heart, diaphragm,

and intestines, are automatically controlled by the brain.

a. You don’t have to think about making them work (Whew!) For

example, your heart beats between 60 and 80 beats per minute

without you having to think about it.

5 ** Some muscles can be both voluntary and involuntary – an

example is ______! Nervous System

The nervous system is the most ______and delicate of all the body systems. It consists of: 1. ______2. ______3. ______

Big Idea: The job of the nervous system is to allow the brain to communicate with every part of the body.

How does it work?

1. The brain is the command center of the body. It tells the body where to go, what to think, if it is hungry, cold, tired, excited, and more. 2. ______are transmitted to and from the brain through a network of ______. There are ______of microscopic nerves inside your body.

6 3. The brain passes the message to the spinal cord, which then passes it onto smaller and smaller nerve networks until the message reaches its final destination. Nerves ______information as electrical ______from one area of the body to another. Are all nerves the same?

No, nerves are separated based on two main jobs: 1. ______nerves carry information from the five senses to the brain. This allows us to see, smell, hear, taste, and touch. 2. ______nerves carry messages from the brain to the muscles. This control’s our body’s ______.

Did you Know?

Many drugs, such as alcohol and cigarettes, affect the way that our nerves work. This can result in us not being able to control our body as well as we should.

7 Digestive System

The digestive system breaks down food in nutrients. The nutrients are needed by the body for ______.

Big Idea: The digestive system breaks down large food molecules into smaller molecules for the body to use as energy.

How does it work?

Your teeth chop up the food into small pieces. Then

______mixes with the food in the mouth. Then the food travels down the ______into the stomach. The food slides down the esophagus automatically through a process called ______. The stomach has ______or digestive juices that help to break the food down even more.

In the ______the vitamins and nutrients from the food pass through the linings of the intestines into the bloodstream. The last stop, the ______

______, is where water is absorbed form the left

8 over food that is of no use to the body. It is stored here until it is eliminated through the rectum. How can I keep my digestive system healthy?

Eating foods high in ______and drinking at least eight

8-ounce glasses of ______a day will help keep it healthy.

There are other important organs in the digestive system!

 The ______stores nutrients, removes harmful

substances from the blood, filters old blood cells and

processes nutrients.

 ______is produced in the

______. Insulin is a chemical that helps take

up sugar from the blood. The pancreas also secretes

______, which helps digest food.

 The ______stores bile from the liver. Bile

helps break down fats.

9 Circulatory System

A typical person has around ______liters of blood. That is like 2 1/2 bottles of soda! I heard blood carries stuff. Is that true? YES!!!  The blood is the ______system by which ______and ______reach the body’s cells and waste materials are carried away.  Blood also carries: ______, which control the body processes ______, which fight invading germs

Big Idea: The circulatory system transports needed material to the cells and carries wastes away from the cells.  It consists of the heart, veins and arteries.

What about the heart?

10 The heart, a ______, positioned behind the ribcage and between the ______, is the pump that keeps this system moving. Your heart is about the size of a clenched fist. How does it work? The blood that needs oxygen (has a bluish color) to deliver to the body enters the heart through ______. The veins bring the blood through capillaries deep in the lungs where it receives fresh supplies of oxygen (giving it the red color).

Then the blood leaves the heart through ______, which divide into smaller and smaller networks called ______. In the capillaries,  nutrients and oxygen are released into the body’s cells AND  carbon dioxide and other waste products are returned to the blood. This way the blood can transport the waste back to the heart and lungs, where they can leave the body.

11 Then the process starts over! Whew! That is exhausting!

Respiratory System

The respiratory system is the system of the body that deals with ______. When we breathe, the body takes in the

______that it needs and removes the ______that it doesn’t need.

Big Idea: The respiratory system is responsible for exchanging the gases between the blood and the environment.

This takes place in the lungs.

How does it work?

1. First, the body breathes in air through the ______or

_____ and down through the ______or windpipe.

2. The trachea is a pipe shaped by rings of ______. It

divides into two tubes called ______. These carry air

into each lung.

12 3. Inside the ______, the tubes divide into smaller and

smaller tubes called ______. At the end of each of

these tubes are small air sacs called ______.

a. Capillaries, (from the circulatory system) which are

microscopic ______with thin walls, are

wrapped around these alveoli.

So, how does the oxygen get from the lungs to the rest of the body?

1. The walls of the alveoli are so thin and close to each other

that things can pass right through them! Two things

happen:

i. The ______seeps into the bloodstream

where it can be distributed to the body cells

that need it

ii. ______leaves the bloodstream and

enters the alveoli, where it is eliminated from

the body when we breathe out.

**So, the respiratory system and the circulatory system work together!

2. The ______is the muscle that controls the breathing process. As the diaphragm flattens it causes the chest to expand

13 and the air is sucked into the lungs. When the diaphragm relaxes, the chest collapses and the air is forced out.

Other Important Systems

The Endocrine System - Glands produce chemicals called hormones that regulate, coordinate, and control many of your body’s functions What are some examples?  When you feel hungry or full  How you sleep  Your body temperature – too cold, too, hot or just right!  How you break down and use food’s nutrients  Whether your body is fat or thin  How much adrenaline you have in certain situations  When and how fast you grow

Excretory System - Responsible for removing liquid and gaseous wastes from the body  Made up of the kidneys, sweat glands, lungs and rectum What do they do? Kidneys – remove waste from the blood Sweat glands – give off perspiration (excess water and mineral salts your body no longer needs) through the skin Lungs – Remove carbon dioxide from the blood Rectum/ Urethra – Removes liquid and solid waste from the body

14 The Reproductive System – the ability for animals and human to produce offspring, or babies

Do people ever tell you that you look just like your dad or you have your mom’s eyes?

 The DNA, or genetic make-up of each offspring is

exactly 50% of the mother and 50% of the father