Chapter 32 Notes: The Integumentary, Skeletal, and Muscular Systems

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Chapter 32 Notes The Integumentary, Skeletal,
and Muscular Systems
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The Integumentary System

• The integumentary system is the system of organs
  in the body that covers and protects the body.
• The main organ of this system is the skin.
• Skin is composed of four different types of
  tissues.
• Those four different types of tissues are the
  epithelial tissue, connective tissue, muscle
  tissue and the nerve tissue.

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Structure of the Skin
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The Structure of the Skin

• The upper most layer of the skin is called the
  epidermis.
• The epidermis is a layer of cells about 10 to 30
  cells thick that is made up of epithelial cells.
• The epidermis is about as thin as paper.
• The cells of the epidermis contain a protein
  substance called keratin, which waterproofs and
  protects the cells and tissues below it.

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The Epidermis
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The Epidermis

• The very top layer of cells of the epidermis are
  constantly being shed.
• In fact, a large portion of the dust in your
  house consists of dead skin cells from the
  epidermis.
• An entire layer of skin cells can be lost each
  month.
• The inner layer of epidermis contains cells that
  are continually dividing by mitosis.

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The Epidermis

• Cells that are found in the inner layer of the
  epidermis called melanocytes contain a protective
  pigment called melanin.
• Melanin is a pigment that absorbs (UV)
  ultraviolet radiation. The amount of melanin in
  a persons skin determines the color of the skin.
• Skin color is primarily determined by genes, but
  it can also be produced in response to bright
  sunlight when a person gets a suntan.

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Melanin
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Structure of the Skin

• Below the epidermis is another layer of skin
  called the dermis.
• The dermis is about 15 40 times thicker than
  the epidermis.
• The dermis consists mostly of connective tissue.
  The function of this connective tissue is to
  prevent the skin from tearing, and it makes the
  skin more elastic.
• Within the dermis there is also nerves, muscles,
  glands, and hair follicles.

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Structure of the Skin

• Below the dermis is the subcutaneous layer.
• The subcutaneous layer is also a layer of
  connective tissue that stores fat and insulates
  the body.
• Hair, fingernails and toenails are also part of
  the integumentary system that are made of keratin.

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Structure of the Skin

• Hair cells grow out of narrow cavities in the
  dermis called hair follicles.
• Most hair follicles have sebaceous glands or oil
  glands associated with them.
• Sebaceous glands lubricate the skin and hair.
• When the sebaceous glands and hair follicles get
  blocked, acne occurs.

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Hair Follicles and Sebaceous Glands
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Functions of the Integumentary System

• Temperature regulation insulating fat, arrector
  pili muscles, and sweat glands are just some of
  the ways that skin can regulate body temp. Blood
  vessels can also constrict and dilate to regulate
  body temp.
• Vitamin production skin responds to sunlight by
  producing vitamin D. Vitamin D increases
  absorption of calcium into the bloodstream for
  bone growth.
• Protection first line of defense against
  disease and foreign substances. Prevents water
  loss.

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Damage to the Skin

• Cuts and scrapes in minor cuts and scrapes only
  the epidermis is affected. When deep cuts
  occurs, blood clots must form a scab and white
  blood cells remove bacteria from the wound.
• Burns burns can be minor (first degree) and
  redness and swelling may occur, or severe (second
  and third degree) and blisters or loss of skin
  function may occur.

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Damage to the Skin

• Skin Cancer too much exposure to the sun or
  tanning beds is believed to cause skin cancer.
• Skin cancer is the most common form of cancer in
  the United States.
• There are two types of skin cancer melanoma and
  nonmelanoma. Melanoma begins in the melanocytes
  in the epidermis.
• Melanoma is the deadliest form of skin cancer.
• 1 person dies every hour from melanoma in the U.S.

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The Muscular System

• The human body has three different muscle
  tissues smooth, cardiac, and skeletal muscles.
• Smooth muscle involuntary (cannot be
  consciously controlled) muscles that control
  organs like the stomach and intestines. Not
  striped or striated.
• Cardiac muscle involuntary muscle that controls
  the heart. Less nuclei connected by gap
  junctions.
• The main structural difference between smooth and
  cardiac muscle is that cardiac muscle has
  striations and smooth muscle does not.

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The Muscular System

• Most muscles of the body are skeletal muscles.
• Skeletal muscles voluntary (can be consciously
  controlled) muscles that are attached to bones by
  tendons. Muscles striated and contain many
  nuclei.
• Skeletal muscles are responsible for movement.
• Tendons tough bands of connective tissue that
  connect skeletal muscles to bones.
• Skeletal muscles are striated like cardiac
  muscles.

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Muscle Types
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Skeletal Muscle Structure and Function

• Most muscles are arranged in opposing, or
  antagonistic pairs.
• A good example of this is your biceps and
  triceps. They work against each other.
• Skeletal muscles are arranged into fibers.
• Each fiber is arranged into smaller strands
  called myofibrils.
• Myofibrils are made up of small protein filaments
  called myosin and actin.

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Skeletal Muscle Structure and Function

• The myofibrils are arranged into different
  sections called sarcomeres.
• A sarcomere is the part of the muscle that
  contracts.
• The striations of skeletal muscles are the result
  of sarcomeres.
• When a nerve impulse is sent to a muscle, the
  actin filaments slide toward the myosin filaments
  in the center of the sarcomere.

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Skeletal Muscle Contraction
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Are you a long distance runner or a sprinter?

• Believe it or not, this probably has more to do
  with genetics than you may think.
• Slow-twitch muscles more endurance, resists
  fatigue, more mitochondria, more myoglobin which
  means more oxygen, darker colored.
• Fast-twitch muscles rapid burst of speed, more
  strength, muscles fatigues easily, less
  mitochondria available, less myoglobin which
  means less oxygen, more lactic acid, lighter
  colored, increased number of myofibrils,
  increased muscle size and diameter.

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The Structure of the Skeletal System

• The human body has 206 bones.
• The human skeleton is divided into two different
  divisions the axial skeleton and the
  appendicular skeleton.
• The axial skeleton includes the skull, the
  vertebral column, the ribs, and the sternum.
• The appendicular skeleton includes the bones of
  the shoulders, arms, hands, legs, and feet.

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The Axial and Appendicular Skeleton
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The Structure of Bone

• There are two types of bone tissue compact bone
  and spongy bone.
• Compact bone is dense and strong, and it provides
  strength and protection.
• The outer layer of all bones are composed of
  compact bone.
• Spongy bone is less dense, has many cavities that
  contain bone marrow, and is usually found in the
  center or the end of bones.

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Compact and Spongy Bone
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The Structure of Bone

• Running the length of compact bones are tube-like
  structures called osteons.
• Osteons contain blood vessels and nerves.
• The blood vessels provide oxygen and nutrients to
  living bone cells called osteocytes.
• There are two types of bone marrow red bone
  marrow and yellow bone marrow.
• Red blood cells, white blood cells and platelets
  are produced in the red bone marrow.
• Yellow bone marrow consists of stored fat.

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Compact Bone Structure
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Bone Formation and Maintenance

• During early fetal development, cartilage
  develops into bone forming cells.
• The process of bone formation from osteoblasts is
  called ossification.
• Osteoblasts are bone forming cells.
• Osteoblasts are responsible for bone growth and
  repair.
• Cells that are responsible for breaking down old,
  worn out bones are called osteoclasts.

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Joints and Ligaments

• Joints occur wherever two or more bones meet.
• Ball and socket hips and shoulders
• Pivot one example is the radius and ulna
• Hinge elbows and knees
• Gliding wrists, ankles, and some vertebrae
• Sutures immovable joints like the sutures that
  attach all of the bones of the skull.
• The bones connected at joints are held together
  by tough bands of connective tissue called
  ligaments.

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Functions of the Skeletal System

• Support legs, pelvis and vertebral column
  support the entire body.
• Protection Skull protects the brain, vertebrae
  protects the spinal cord, rib cage protects the
  vital organs (heart, lungs, liver).
• Formation of blood cells red bone marrow
  produces blood cells and platelets.
• Reservoir stores calcium and phosphorus.
• Movement attachment point for muscles.