The Musculoskeletal System

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The Musculoskeletal System

• Unit 7 Mr. Mundy

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Do Now March 9th

• Write down HW assignment in your Agenda
• Take out a sheet of lined paper and a pen/pencil
• Exam will begin shortly

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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.

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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.

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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.

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Functions of the Skeletal System

• Bones 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!

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Functions of the Skeletal System
Functions Examples
1. Protection -Rib cage protects our vital organs heart, lungs, liver -Skull protects your brain
2. Support Without our bones and muscles, our bodies would not have support.
3. Attachment points Bones in our legs, arms, neck, and chest give our bones places to attach.
4. Storage Skeletal system helps to store calcium phosphorus.
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Stop Check

• Write 2 things that you have just learned in this
  lesson so far.
• 1.________________________________________________
  __________________________________________________
  _______________________
• 2.________________________________________________
  __________________________________________________
  _______________________

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Bones Connect At Joints

• Because bones are hard, they cannot bend.
• However, our bodies can bend, twist, and spin.
• Soft tissue called joints, holds two bones
  together.

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• 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.

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• 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.

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Types of Joints
Description of Joint
Hinge Joints Allow bones to move back forth Examples fingers, elbows, and knees
2. Saddle Joints Allow bones to move back and forth and side to side, but have limited rotational ability. Example Thumbs
3. Ball-and-Socket Joints Allow bones to move and rotate in nearly all directions. Example hips and shoulders
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Description of Joint
4. Pivot Joint Allows bones to rotate Example Neck
5. Gliding Joint Allows bones to move side to side or front to back Examples ankles and wrists
6. Immovable Joint Allows very little or no movement Examples Skull
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The Muscular System

• Muscles 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.

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The Muscular System

• Muscles 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.

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The Muscular System

• Since 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.

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Muscle Contractions

• What do you think makes your muscles contract?
  ltwrite your response belowgt

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Muscle Contractions

• Muscle 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.

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Review

• Recall 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

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Types of Muscle
Type of Muscle Function
1. Skeletal Muscle Help cause movement of your body
2. Cardiac Muscle Found only in the heart
3. Smooth Muscle Found only in the organs of the body, such as your stomach and blood vessels.
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Interactions of the Musculo-skeletal System

• Our 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

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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.

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Opposing Muscle Groups

• The 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!

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Review

• What 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?

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Opposing Muscle Groups

• Muscle 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.

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Opposing Muscle Groups

• Arrangement of muscles is often in opposing
  groups
• This means that as one muscle flexes, the other
  is relaxing.
• Example Your Bicep/Tricep