The Skeletal and Muscular Systems

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Organs and Functions Because of the way we

usually see bones, it’s easy to think of them as dry and lifeless.

The fact is they are neither dry nor lifeless

Bones are living organs made of several different tissues.

They are moist, supplied both blood and lymph vessels, as well as nerves, bones are as much organs as are the heart and brain.

Organs and Functions The average human

adult has 206 bones. Bones support and

protect parts of the body.

They work with your muscles so you can move.

They help you maintain homeostasis by storing minerals and making blood cells

Types of Bone Tissue Bones are made of

connective tissue and minerals.

There are two different kinds of bone tissue:

Compact bone: dense and rigid, does not have open spaces.

Spongy bone: many open spaces, provides most of the strength.

Bones also contain a tissue called marrow, which produces blood cells and stores fat

Parts of Bones When you were born, you

didn’t have much true bone. What you had was cartilage,

which is soft and rubbery. As you grew, most of the

cartilage was replaced by bone.

Most bones still have cartilage at the ends.

This cartilage cushions the areas where bones meet (joints)

The Skeletal System A place where two bones

meet is called a joint. Your joints allow you to

move when your muscles contract.

Some joints, like those in your skull allow for little or no movement.

Other joints, like those in your shoulder allow for many movements

Joints are held together by ligaments, which are strong bands of connective tissue

Joint Types

The Muscular System

EQ: How do organ systems work together to enable an organism to maintain homeostasis?

Skeletal and Muscular Interaction

Your skeletal system does not work alone!

Muscles connect to your skeleton and they contract and move the skeleton along (you use over 200 muscles each time you take a step!)

Organs and Functions Muscle is an organ that

contracts and expands, creating movement.

In your body there are more than 600 muscles.

Muscles not only help you move, they also give your body shape and produce heat in your body.

Organs and Functions Most of the meat on our

bones is muscle. There is so much of it, it

makes up about 40% of our total body weight.

Available in all shapes and sizes, muscles shorten on command, stretch when necessary, and then bounce back to their normal resting strength.

Types of Muscle There are two main

groups of muscle, voluntary and involuntary.

Voluntary muscles are muscles your control consciously (you have to think about how and when to move them)

Involuntary muscles are those that work automatically (you don’t have to think about them)

Muscle Tissue You have three types of muscle tissue in your body:

Skeletal Smooth Cardiac

Muscle Tissue – Skeletal Muscle

These muscles move bones.

They are attached to bones by tendons (thick bands of tissue)

They are voluntary muscles.

They are the most common type of muscle in your body.

They are striated (striped). They contract and expand

quickly.

Muscle Tissue---Smooth Muscle

Involuntary (work automatically)

Found in the walls of many of your organs, such as your intestines, blood vessels and skin.

They move the organs as needed.

They contract and relax slowly.

They are not striated They are thin muscles

Cardiac Muscle Only found in the

heart. It is involuntary It is striated. It contracts

nonstop all day and night for your entire lifetime!

Interactions with your nervous system

Your muscular system is very closely connected to the nervous system.

This makes sense because you usually do not have to think to keep your heart beating, your internal organs working or even before you move.

EQ SUMMARIZER What are the organs and functions of the skeletal and muscular systems?

How do the skeletal and muscular systems interact?