Ch. 4 Connective Tissue
Muscle Tissue
Figure 4-18 Muscle Tissue
Skeletal Muscle Tissue
Cells are long, cylindrical,
striated, and multinucleate.
Nuclei
LOCATIONS: Combined
with connective tissues
and neural tissue in
skeletal muscles
FUNCTIONS: Moves or
stabilizes the position of
the skeleton; guards
entrances and exits to
the digestive,
respiratory, and urinary
tracts; generates heat;
protects internal organs
Muscle
fiber
Striations
LM  180
Skeletal muscle
Cardiac Muscle Tissue
Nucleus
Cells are short, branched,
and striated, usually with a
single nucleus; cells are
interconnected by
intercalated discs.
LM  180
Cardiac
muscle
cells
LOCATION: Heart
FUNCTIONS:
Circulates blood;
maintains blood
(hydrostatic) pressure
Intercalated
discs
Striations
LM  450
Cardiac muscle
Smooth Muscle Tissue
Cells are short, spindle-shaped, and
nonstriated, with a single, central
nucleus.
LOCATIONS: Found in
the walls of blood vessels
and in digestive, respiratory,
urinary, and reproductive organs
Nucleus
FUNCTIONS: Moves food,
urine, and reproductive tract
secretions; controls
diameter of respiratory
passageways; regulates
diameter of blood vessels
Smooth
muscle
cell
Smooth muscle
LM  235
Three types of muscle
 Skeletal, smooth and cardiac muscle
 Epithelia – lined outside and inside of body and cavities
 Connective – supported and connected parts
 Major function of many organs and organ systems involves
MOVEMENT; either of a substance (digestive system and
circulatory system) or of the body (skelato-muscular)
 Muscle cells – distinct organelles and properties
 Muscle cells and muscle tissue are specialized to
CONTRACT
Skeletal Muscle
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Very long, very slender muscle cells called muscle fibers
Multinucleate
Can divide
Muscle usually grows because satellite stem cells called myosatellite cells
divide
Can repair after injury
Fibers made of proteins called actin and myosin
Contractile
Appear banded or “striated”
Voluntary
Most predominant form of tissue in human body
Held together by elastin and collagen and blended with tendons
Which are attached to bones, contraction moves bone at joint ( think
hinge)
Figure 4-18a Muscle Tissue
Skeletal Muscle Tissue
Cells are long, cylindrical,
striated, and multinucleate.
Nuclei
LOCATIONS: Combined
with connective tissues
and neural tissue in
skeletal muscles
FUNCTIONS: Moves or
stabilizes the position of
the skeleton; guards
entrances and exits to
the digestive,
respiratory, and urinary
tracts; generates heat;
protects internal organs
Muscle
fiber
Striations
Skeletal muscle
LM  180
Cardiac Muscle
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Located only in the heart
Cardiocytes
Most with one nucleus
Prominent striations
Branching – highly interconnected; fan out of message to contract
= heart beat
Connections are called intercalated discs and contain desmosomes,
proteoglycans and gap junctions = cells are locked tight together
and ions responsible for beat can flow through
Limited ability to repair damaged/dead cells
“pace maker” cells vs nerve cells
Striated INVOLUNTARY
Figure 4-18b Muscle Tissue
Cardiac Muscle Tissue
Nucleus
Cells are short, branched,
and striated, usually with a
single nucleus; cells are
interconnected by
intercalated discs.
Cardiac
muscle
cells
LOCATION: Heart
FUNCTIONS:
Circulates blood;
maintains blood
(hydrostatic) pressure
Intercalated
discs
Striations
Cardiac muscle
LM  450
Smooth Muscle
 Located in walls of blood vessels and hollow organs like
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intestine and bladder
Often in layers
Smaller cells; tapered at each end with oval nucleus
Because of nuclei, they can regenerate after injury
Actin and myosin arranged differently – no striations
Under nervous control, but not conscious control = 8 m of
intestine and miles of blood vessels would be a lot to think
about!
Non-striated, involuntary
Figure 4-18c Muscle Tissue
Smooth Muscle Tissue
Cells are short, spindle-shaped, and
nonstriated, with a single, central
nucleus.
LOCATIONS: Found in
the walls of blood vessels
and in digestive, respiratory,
urinary, and reproductive organs
Nucleus
FUNCTIONS: Moves food,
urine, and reproductive tract
secretions; controls
diameter of respiratory
passageways; regulates
diameter of blood vessels
Smooth
muscle
cell
Smooth muscle
LM  235
Nervous Tissue
Neural or Nervous Tissue
 Conducting electrical impulses
 98% within brain and spinal cord (CNS)
 Neurons = nerve cells
 Many without nuclei
 Very limited ability to repair
 Neuroglia = supporting cells; connective tissue; “glue”
 Support
 Supply nutrients
 Some repair
 Electrical impulses are “transmembrane potentials”
Figure 4-19 Neural Tissue
NEURONS
NEUROGLIA (supporting cells)
Nuclei of neuroglia
• Maintain physical structure
of tissues
• Repair tissue framework
after injury
• Perform phagocytosis
• Provide nutrients to neurons
• Regulate the composition of the
interstitial fluid surrounding neurons
Cell body
Axon
Dendrites
LM  600
Nucleolus
Nucleus
of neuron
Dendrites
(contacted by
other neurons)
Mitochondrion
Nucleus
Axon (conducts
information to
other cells)
Microfibrils and
microtubules
Nucleolus
Contact with
other cells
Cell body (contains nucleus
and major organelles)
A representative neuron
(sizes and shapes vary widely)
Transmembrane Potential
 Cell membranes have an associated electrical potential
 This means that the ion concentrations of the cytoplasm and
the extracellular fluid are slightly different and there is a
charge difference from one side of the CM to the other side
 Long, thin wires = rapid conduction
 Measured in millivolts (1/1000 th of a volt)
 mV / microsecond
( 10-6 or 1/1000th of a millisecond)
 Nerve impulses temporarily reverse this charge or polarity
 Na, K, Ca, Cl
 Must be restored before it can refire - tonus/ spasm