TISSUE: THE
LIVING FABRIC
Part III: Muscle and Nervous
Muscle Tissue

3 types:
Skeletal muscle
Cardiac muscle
Smooth muscle
Skeletal Muscle

Description:
Long, cylindrical
 Multinucleated (2+
nuclei)
 Striated (banded
appearance)


Function:


Location in the body:


Muscles contract, pull on
bones or skin  cause
body movements
Attached to skeleton
Other features:

Voluntary control
Cardiac Muscle

Description:




Function:


Propel blood through blood vessels to
all parts of body
Locations in the body:


Striated
Uninucleate (1 nucleus)
Branching cells – fit at junctions
called intercalated discs
Walls of the heart
Other features:


Involuntary control
Virtually no regenerative capacity –
differentiated terminally and lack
stem cells for replacement purposes
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
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
Nervous Tissue
2 Major Cell Types:
• Neurons have VERY little 
toNeurons
no regenerative
capacity; research is looking more
intotothis.
 Respond
stimuli
• Neurons do not have centrioles,
which
 Transmit
electrical
orchestrate cell division in ourimpulses
cells
 Glial
Cells
• Neurons connect at synapses;
when
a
 Support,
insulate,
neuron dies off it is essentially
bypassed
and
protect neurons
new connections are made
 Provide nutrients
• Glial cells DO regenerate
and oxygen to
neurons

A closer look….
Tissue Repair
Wound healing
 Two ways:
1. Regeneration: replace destroyed tissue by
same kind of cells
2. Fibrosis: form scar tissue (dense fibrous
connective tissue)

Depends on:
 Type of tissue damaged
 Severity of injury

Steps to Tissue
Repair
1. Inflammation Phase
Injured cells release inflammatory chemicals
Capillaries become very permeable




WBC’s and clotting proteins seep into injured area
Clot factors in plasma prevent loss of blood
(surface dries, forms a scab)
Steps to Tissue
Repair
2.
Organization Phase
Granulation tissue replaces blood clot




Delicate pink tissue with new capillaries
Fibroblasts of connective tissue produces
collagen fibers
Macrophages consume original blood clot
Steps to Tissue Repair
3.
Regeneration Phase
Surface epithelium begins to regenerate and
thickens



Epithelial cells multiply over granulation tissue
Fibrous tissue matures – forms scar tissue
Regenerative Capacity of
Different Tissues
Extremely
Well
• Skin
epidermis
• Connective
• Blood
• Bones
Moderate
Weak
Virtually
None
(mostly scar tissue)
• Smooth
muscle
• Tendons,
ligaments
• Skeletal
muscle
• Cartilage
•Cardiac muscle
•Nervous tissue