Tissue: The Living Fabric

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Tissue The Living Fabric

• Part III Muscle and Nervous

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Muscle Tissue

• 3 types
• Skeletal muscle
• Cardiac muscle
• Smooth muscle

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Skeletal Muscle

• Description
• Long, cylindrical
• Multinucleated (2 nuclei)
• Striated (banded appearance)
• Function
• Muscles contract, pull on bones or skin ? cause
  body movements
• Location in the body
• Attached to skeleton
• Other features
• Voluntary control

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Cardiac Muscle

• Description
• Striated
• Uninucleate (1 nucleus)
• Branching cells fit at junctions called
  intercalated discs
• Function
• Propel blood through blood vessels to all parts
  of body
• Locations in the body
• Walls of the heart
• Other features
• Involuntary control
• Virtually no regenerative capacity
  differentiated terminally and lack stem cells for
  replacement purposes

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Smooth Muscle

• Description
• No visible striations
• Cells have 1 central nucleus
• Spindle-shaped (pointed ends)
• Cells arranged closely to form sheets
• Function
• Propel substances or objects through hollow
  organs
• Locations in the body
• Walls of organs (stomach, bladder, uterus, blood
  vessels)
• Other features
• Involuntary control
• Contracts slowly
• Peristalsis wavelike motion that moves food
  through SI

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Nervous Tissue

• Main component of nervous system
• Structure neuron dendrite cell body axon
• Function regulates and controls body functions
• Location in the body brain, spinal cord, nerves

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Nervous Tissue

• 2 Major Cell Types
• Neurons
• Respond to stimuli
• Transmit electrical impulses
• Glial Cells
• Support, insulate, protect neurons
• Provide nutrients and oxygen to neurons

• Neurons have VERY little to no regenerative
  capacity research is looking more into this.
• Neurons do not have centrioles, which
  orchestrate cell division in our cells
• Neurons connect at synapses when a neuron dies
  off it is essentially bypassed and new
  connections are made
• Glial cells DO regenerate

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A closer look.
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Tissue Repair

• Wound healing
• Two ways
• Regeneration replace destroyed tissue by same
  kind of cells
• Fibrosis form scar tissue (dense fibrous
  connective tissue)
• Depends on
• Type of tissue damaged
• Severity of injury

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Steps to Tissue Repair

• 1. Hemostasis (Blood Clotting )Phase
• Platelets begin to stick to the injured sites
• Chemical signals released by platelets to promote
  clotting
• Fibrin protein activated act as glue to stick
  platelets together
• Clot plugs the damaged blood vessels to slow the
  loss of blood

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Steps to Tissue Repair

• 2. Inflammation Phase
• Cells release inflammatory chemicals
• Capillaries become very permeable vasodilation
  occurs
• White blood cells and clotting proteins
  (platelets)seep into injured area
• WBCs (macrophages) begin to break down
  damaged/dead cells and stimulate healing

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Steps to Tissue Repair

• 3. Proliferation/Organization Phase
• Granulation tissue replaces blood clot
• Delicate pink tissue with new capillaries
• Fibroblasts of connective tissue produces
  collagen fibers
• Tissue contracts and pulls together the wound
  opening
• Macrophages consume original blood clot

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Steps to Tissue Repair

• 4. Regeneration Phase
• Surface epithelium begins to regenerate and
  thickens
• Epithelial cells multiply over granulation tissue
• Collagen realigned and cells that are no longer
  needed are removed by programmed cell death,
  or apoptosis
• Fibrous tissue matures forms scar tissue

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Regenerative Capacity of Different Tissues
Extremely Well Moderate Weak Virtually None (mostly scar tissue)
Skin epidermis Connective Blood Bones Smooth muscle Tendons, ligaments Skeletal muscle Cartilage Cardiac muscle Nervous tissue