Science - Chapter 2 Test: Grade 7

Good luck :D!

Vertebrae

A total of 26 small bones that make up your backbone.

Joint

A place where two bones come together

Ligament

Strong connective tissue that hold together the bones in movable joints.

Marrow

Soft connective tissue which the bone has two types of.

Cartilage

A strong connective tissue that is more flexible than bone. As you grow, most of this is replaced with bone.

Involuntary muscle

Muscles that are __***NOT***__ under your conscious control.

Voluntary muscle

Muscles under your conscious control.

Tendon

A strong connective tissue that attaches the muscle to a bone.

Epidermis

The outer layer of your skin, which protects your skin/body.

Melanin

A pigment that colors the skin which is produced by some cells deep in the epidermis.

Dermis

The inner layer of your skin, and is located above a layer of fat.

Pore

Openings that allow sweat to reach the surface.

Follicles

Strands of hair that grow within the dermis.

Cancer

A disease in which some cells divide uncontrollably.

Osteoporosis

A condition in which bones become weak and break easily. Mineral loss can lead to this, usually as you grow older.

Name the three types of muscle tissues describing them and where they are.

### The three types of muscle tissues are __***skeletal, smooth, and cardiac.***__

__***Skeletal muscles***__ provide the force that moves your bones, and they are voluntary. They can be found in your leg, face, etc. It is striated and reacts quickly but also tires quickly.

__***Smooth muscles***__ are involuntary muscles that work to control certain movements inside your body. It can be found in your internal body organs such as blood vessels and the stomach. Reacts and tires slowly.

__***Cardiac muscle***__ is found only in your heart and is involuntary. They are striated but do not tire and contract repeatedly.

Name 5 functions of the skin

1. Regulates body temperature
2. Eliminates waste
3. Gathers information about the environment
4. Produces vitamin D
5. Protects the body

What does the dermis layer consist of?

Nerves, blood vessels, sweat glands, and oil glands.

Name 4 types of joints

1. __***Hinge joint***__ - allows forward or backward motion. Ex: Elbow & knees
2. __***Ball-and-Socket joint***__ - Allows the greatest range of motion. Ex: Hip & shoulder
3. __***Pivot joint***__ - Allows one bone to rotate over another bone. Ex: Neck
4. __***Gliding joint***__ - Allows one bone to slide over another. Ex: Ankles & wrists

Difference between Involuntary and Voluntary muscles + Examples

Involuntary muscles are muscles that are __***NOT***__ under your conscious control. Voluntary muscles are ones under your conscious control.

__***Involuntary***__ ex: Your lungs, your heart, and your stomach.

__***Voluntary***__ ex: Your legs, arms, and fingers.

How can you have healthy skin?

## With three healthy habits:

__***Eat a healthy diet***__ (Provides energy and raw materials needed for the growth and replacement of skin cells),

__***keep your skin clean,***__ (Mild soap gets rid of dirt and harmful bacteria, and controls oiliness.

__***and limit your time in the sun***__. (Too much sunlight will cause cancer.)

How do you get healthy bones?

__***A balanced diet***__ (Foods that contain enough calcium and phosphorus to keep your bones strong while they’re growing.)

__***Regular exercise***__ (Helps build and maintain strong bones.)

> Wear proper equipment to prevent injuries!