THE MUSCULOSKELETAL SYSTEMUnit 7 Mr. Mundy

Do Now March 9thWrite down HW assignment in your Agenda

Take out a sheet of lined paper and a pen/pencil

Exam will begin shortly

What is the Musculoskeletal System?The hard structures within our bodies are part of the skeletal system.

The Skeletal System provides support, protection, and movement for our bodies.

Press down on your wrist and you will feel bones and muscles.

What is the Musculoskeletal System?A bone is a hard tissue made mostly of cells, collagen, and calcium.

Collagen is a protein that forms strong fibers in the bone.

Calcium is a mineral that adds strength to the collagen fibers.

What is the Musculoskeletal system?The human body has over 200 bones that make up the skeleton.

Diets rich in calcium and Vitamin D help to maintain strong teeth and bones.

Functions of the Skeletal SystemBones in the skeletal are not all smooth, have different sizes, rough spots, pits, and holes where blood vessels and nerves enter and leave.

The bones in our bodies have blood vessels and nerves to deliver nutrients and signals.

This is why breaking a bone is SO PAINFUL!

Functions of the Skeletal System

FunctionsExamples1. Protection-Rib cage protects our vital organs: heart, lungs, liver-Skull protects your brain2. SupportWithout our bones and muscles, our bodies would not have support. 3. Attachment pointsBones in our legs, arms, neck, and chest give our bones places to attach.4. StorageSkeletal system helps to store calcium & phosphorus.

Stop & CheckWrite 2 things that you have just learned in this lesson so far.1._________________________________________________________________________________________________________________________2._________________________________________________________________________________________________________________________

Bones Connect At JointsBecause bones are hard, they cannot bend.However, our bodies can bend, twist, and spin.

Soft tissue called joints, holds two bones together.

Ligaments connect bones.

They are similar to a strong rubber-band because they stretch when we move.

Cartilage is a strong, yet flexible tissue that reduces friction and increases flexibility in our bones.

Try twisting your LOWER ARM without moving your upper arm!

Can you do the same with your leg?

The structure of the joint determines its movement.

Types of Joints

Description of JointHinge Joints Allow bones to move back & forthExamples: fingers, elbows, and knees2. Saddle Joints Allow bones to move back and forth and side to side, but have limited rotational ability.Example: Thumbs3. Ball-and-Socket JointsAllow bones to move and rotate in nearly all directions.Example: hips and shoulders

Description of Joint4. Pivot JointAllows bones to rotateExample: Neck5. Gliding JointAllows bones to move side to side or front to backExamples: ankles and wrists6. Immovable JointAllows very little or no movementExamples: Skull

The Muscular SystemMuscles are parts of the body that help our bodies move.

Muscle: is a tissue made of long cells that contract

There are more than 620 muscles in the human body.

The Muscular SystemMuscles are made of bundles of muscle cells called muscle fibers.

Muscle fibers contain hundreds of nuclei and mitochondria

Muscle fibers are arranged length-wise and usually overlap other muscle fibers.

The Muscular SystemSince Muscle fibers overlap each other, during muscle contractions the filaments move closer to each other.

When muscle fibers contract, the fibers become shorter.

Contraction is a shortening of muscle fibers in the body.

Muscle ContractionsWhat do you think makes your muscles contract?

Muscle ContractionsMuscle cells have nerve cells that start a chemical reaction in the muscle cell.

This chemical reaction causes muscle fibers to shorten and the muscle will contract.

Muscles require lots of energy and oxygen to contract.

ReviewRecall that cells form tissues, tissues form organs, organs form organ systems, and organ systems form an organism.

Muscles work the same way!

Muscle cells form tissue. There are 3 different types of muscle tissue in our bodies

Types of Muscle

Type of MuscleFunction1. Skeletal MuscleHelp cause movement of your body2. Cardiac MuscleFound only in the heart3. Smooth MuscleFound only in the organs of the body, such as your stomach and blood vessels.

Interactions of the Musculo-skeletal SystemOur bones alone cannot move our bodies.

Similarly, muscle contraction is only part of movement

In order for us to move, the muscular system must work with the skeletal system.

Our skeleton provides support for our muscles

How Do You Move?Usually, a muscle is connected to at least 2 different bones.

Tendons: connect bones to muscles

Cartilage and ligaments are 2 other types of connective tissue.

Opposing Muscle GroupsThe bicep muscle causes your arm to bend.

Flexion is the bending of a limb that decreases the angle between the bones of a limb.

Just think when someone asks you flex your arms, you make your arm bend!

ReviewWhat type of muscle do we use in our arm? (voluntary? Involuntary? Cardiac?)

Also, are the muscles in our arm shortening? Or becoming longer when we flex our biceps?

Opposing Muscle GroupsMuscle can contract and become shorter, but they CANNOT actively lengthen.

Extension is the straightening of a limb.When you straighten your limb, the angle of between the bone increases.

Opposing Muscle GroupsArrangement of muscles is often in opposing groupsThis means that as one muscle flexes, the other is relaxing.

Example: Your Bicep/Tricep