INTRODUCTION TO BODY STRUCTURE

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INTRODUCTION TO BODY STRUCTURE
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BODY ORGANIZATION

• The levels of organization of the body
• cells- individual unit
• tissues- Similar cells that work together to
  perform a
• common function.
• organs- Combination of 2 or more tissues that
• work together to perform a
  common
• function
• organ system- Group of organs that work together
  to
• perform a
  specific function.

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BODY ORGANIZATION

• Maintaining homeostasis requires
• Bodys organs functioning together.
• Temperature regulation (endotherms)
• Adjusting metabolism
• Detecting and responding to stimuli
• Maintaining water and mineral balances

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IntegumentarySystem

• Consists of
• Skin, Hair, Nails

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Skin

• The largest organ in your body. Yes, skin is an
  organ.
• Functions of the Skin
• Protective barrier against pathogens
• Prevents water loss
• Offers body protection
• Regulates body temperature through sweating

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Four Tissues of the Integumentary System

• Epithelial- covers body surfaces
• Connective- provides support and protection
• Muscle body movement
• Nerve- forms bodys communication network

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3 layers of skin

• 1. Epidermis Top layer
• Constantly makes new skin cells to replace dead
  ones
• Contains keratin, which as a waterproof barrier
• Also contains melanin, a brown pigment that helps
  protect you from UV rays. (This is why people
  tan)

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3 layers of skin

• 2. Dermis The 2nd layer of skin
• Contains hair follicles (each follicle contains 1
  hair)
• Contains the sebaceous glands which produce an
  oil called sebum. This lubricates the skin and
  hair.
• Contains sweat glands. These release water and
  some wastes to cool the body and maintain
  homeostasis

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3 layers of skin

• 3. Subcutaneous tissue The 3rd layer
• Composed of fat cells
• This is used for insulation and an energy supply

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SKIN LAYER DIAGRAM
EPIDERMIS
SEBACEOUS GLAND
DERMIS
SUBCUTANEOUS TISSUE
SWEAT GLAND
HAIR FOLLICLE
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SKELETAL SYSTEM

• Functions of the skeleton
• Support the body
• Provide protection for the internal organs
• Enables movement

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SKELETAL SYSTEM

• There are 206 bones in the skeleton.
• The skeleton is divided into 2 parts
• axial- includes the skull, spine, ribs, and
• sternum
• 2. appendicular- includes shoulders, arms,
  
• hips, and legs

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SKELETAL SYSTEM

• Bone is made of hard compact bone
• surrounding porous bone.

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BONE MARROW

• RED makes all blood cells for body (RBC, WBC,
  platelets)
• YELLOW stores fat tissue

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SKELETAL SYSTEM

• Early in development, the skeleton is made mostly
  of hyaline cartilage.
• Bones hardens as calcium, phosphate and other
  mineral deposits build up.
• Osteoblasts make bone tissue.
• Bones thicken and elongate as development
  continues.

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SKELETAL SYSTEM

• JOINT where 2 bones meet.
• Three types of joints
• Immovable
• permits little or no movement.
• ex. skull joined by sutures.
• Slightly moveable
• ex. Spine and ribs
• Freely moveable joints
  (see table 2 p. 854)
• ex. knee

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SKELETAL SYSTEM

• Ligament Connects bone to bone
• Tendon Connects muscle to bone

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Osteogenesis Imperfecta
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MUSCULAR SYSTEM

• Functions Include
• Movement in body
• Generate Heat for Body Temperature

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MUSCLES

• Involuntary muscles not under conscious
  control.
• 1. Smooth muscles line internal organs
• blood vessels.
• a. Function of smooth muscle is to
• contract.
• b. Smooth muscle contractions are
• slow.

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MUSCLE

• 2. Cardiac muscle heart muscle.
• Adapted to conduct electrical
• impulse.

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MUSCLE

• Voluntary muscles under conscious
• control skeletal system.
• 3. Skeletal muscles attached
  
• to the bones skeletal system.
• a. Majority of muscles are skeletal
• b. Contractions are short strong

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MUSCLE

• Page skeletal muscle structure
• 1. Skeletal muscle are made up of
• bundles of muscle fibers.
• 2. Each muscle fiber is made up of
• myofibrils.

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MUSCLE

• 3. Myofibrils are made up of smaller
• proteins filaments.
• a. Myofibrils are striated or divided
• into sections called sarcomeres
• which are the functional units of
  the
• muscle

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MUSCLE

• 4. Two types of filaments
• a. Thick filaments are made up
• myosin.
• b. Thin filaments are made up of
• actin.

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MUSCLES

• Sliding Filament Theory
• 1. during contractions, actin filaments
• move towards one another from the
  pulls of myosin heads

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Muscular Dystrophy
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NERVOUS

• The function of the nervous system is allow an
  organism to think, learn, perceive, move, and
  express emotion.
• Neurons are specialized cells that transmit
  information thought the body by conducting
• electrical signals called nerve impulses.

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NERVOUS

• Structure of Neurons (see p. 944)
• Dendrites receive information from other cells.
• Cell body collects information from the
  dendrites, relays the information, and
• maintains the neuron.
• Axon conducts nerve impulses.
• Axon terminals Where neuron communicate with
  other cells.
• Nerves- bundles of axons

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NERVOUS

• Myelin sheath is a layer of
• insulation found
• on some neurons.
• Myelin sheaths causes nerve
• impulses to
• travel faster down the axon.
• Nodes of Ranvier gaps between
• the myelin sheath.

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NERVOUS - see p. 948

• Synapse where a neuron meets another
• cell.
• Neurotransmitters a chemical that transmits
• the electrical impulse across the synapse.

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NERVOUS

• The central nervous system
• consists of the brain and spinal cord
• controls the body
• responds to stimuli from the environment

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NERVOUS

• Peripheral nervous system contains
• Sensory neurons send information from sense
  organs to the CNS.
• Motor neurons send commands from the CNS to
  muscles and other organs.