Histology 1.Epithelial tissues 2.Connective tissues 3.Muscle tissues 4.Nervous tissues.
Tissues: The living fabric Ch 4 c Nervous and Muscle Tissues.
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Transcript of Tissues: The living fabric Ch 4 c Nervous and Muscle Tissues.
Tissues: Tissues: The living The living
fabricfabricCh 4 c
Nervous and Muscle Tissues
Nervous Nervous TissueTissue
Nervous Tissue
• Consists of branched neurons with long cellular processes and supporting cells
• Supporting cells are nonconducting cells that support, insulate, and protect the delicate neurons.
Nervous Tissue
• Neurons transmits electrical signals from sensory receptors to effectors
• Found in the brain, spinal cord, and peripheral nerves
Nervous Tissue
Figure 4.10
Muscle Tissue
Muscle Tissue
•Highly cellular
•Well-vascularized
•3 types–Skeletal–Cardiac–smooth
Skeletal Muscle•Long, cylindrical cells, also
called muscle fibers
•Multinucleated with obvious striations (bands)
•Initiates and controls voluntary movement
•Found in skeletal muscles that attach to bones or skin
Skeletal muscle tissue
Figure 4.11a
• Long, cylindrical, multinucleate cells with obvious striations
• Initiates and controls voluntary movement
• Found in skeletal muscles that attach to bones or skin
Cardiac Muscle Tissue
•Branching, striated, uninucleate cells interlocking at intercalated discs
•Propels blood into the circulation
•Found in the walls of the heart
Cardiac muscle
Figure 4.11b
• Branching, striated, uninucleate cells interdigitating at intercalated discs
• Propels blood into the circulation
• Found in the walls of the heart
Smooth Muscle Tissue
•Sheets of spindle-shaped cells with central nuclei and no striations
•Propels substances along internal passageways (by peristalsis)
•Found in the walls of hollow organs
Smooth Muscle Tissue
Figure 4.11c
Muscle Tissue
•Skeletal muscle is voluntary muscle
•Cardiac and Smooth muscles are involuntary muscles
Tissues: Tissues: The living The living
fabricfabricCh 4 d
Tissue Repair and Developmental
Aspects
What happens What happens when there is when there is
trauma to tissue?trauma to tissue?
Tissue Trauma
•Causes inflammation, characterized by:–Dilation of blood vessels–Increase in vessel permeability
–Redness, heat, swelling, and pain
Tissue Repair
Figure 4.12a
•Severed blood vessels bleed
•Inflammatory chemicals are released
Tissue Repair
Figure 4.12a
•Local blood vessels dilate and become more permeable
•This allows white blood cells and clotting proteins to invade injured site
Tissue Repair
Figure 4.12a
•Clotting proteins initiate clotting, surface dries and forms a scab
Tissue Repair
Figure 4.12b
•Granulation tissue is formed
•Capillary buds invade the clot, restoring vascular supply
Tissue Repair
Figure 4.12b
•Fibroblasts secrete collagen, which bridges the gap
•Macrophages phagocytize dead and dying cell debris
Tissue Repair
Figure 4.12b
•Surface epithelial cell divide and migrate over the granulation tissue
Tissue Repair
Figure 4.12c
•About one week later, the fibrosed area (scar) has contracted and regeneration of the epithelium is in progress
Tissue Repair
Figure 4.12c
•Results in a fully regenerated epithelium with underlying scar tissue
Regenerative Capacity
•Epithelial tissues, bone, areolar connective tissue, dense irregular connective tissue and blood-forming tissue regenerate extremely well
Regenerative Capacity
•Smooth muscle and dense regular connective tissue have a moderate capacity for regeneration
Regenerative Capacity
•Skeletal muscle and cartilage have a weak regenerative capacity
Regenerative Capacity
•Cardiac muscle and nervous tissue in the brain and spinal cord have NO functional regenerative capacity–They are replaced by scar tissue
Regenerative Capacity
•Scar tissue is strong, but lacks flexibility and elasticity of most normal tissues, nor can it perform the normal functions of the tissues it replaced
Developmental Developmental AspectsAspects
Developmental Aspects•Primary germ layers:
ectoderm, mesoderm, and endoderm
Figure 4.13
Developmental AspectsThese three layers of cells are formed early in embryonic development then specialize to form the four primary tissues
Figure 4.13
Developmental Aspects
•Nerve tissue arises from ectoderm (blue)
Figure 4.13
Developmental Aspects
•Muscle and connective tissue arise from mesoderm (red)
Figure 4.13
Developmental Aspects
•Most mucous membranes arise from endoderm (yellow)
Figure 4.13
Developmental Aspects
•Epithelial tissues arise from all three germ layers
Figure 4.13
Developmental Aspects
• By end of second month of development, all primary tissues have appeared
• Tissue cells remain mitotic and produce rapid growth until birth, except the division of nerve cells nearly stop during fetal period
Developmental Aspects
• After birth, most tissues divide until adult body size is achieved
• In adults only epithelia and blood-forming tissues are highly mitotic
Developmental Aspects
• With old age, the amount of collagen declines, making tissue repair less efficient
• With old age, bone, muscle, and nervous tissues begin to atrophy
QuizQuiz next time
Study guide check 16-21
MembranesMembranes
Cutaneous, Mucous, Cutaneous, Mucous, and Serous and Serous
Cutaneous, Mucous, and Serous Membranes
•Composed of epithelium tissue bound to connective tissue proper.
•Considered simple organs
Cutaneous Membranes
Figure 4.9a
•Skin
•Exposed to air, considered a dry membrane
Cutaneous Membranes
Figure 4.9a
• Consists of a keratinized stratified squamous epithelium (epidermis) firmly attached to a thick layer of dense irregular connective tissue (dermis)
Mucous Membranes
Figure 4.9b
•Lines body cavities open to the exterior
(digestive, respiratory, and urogenital tracts)
Mucous Membranes
Figure 4.9b
•Epithelial tissue upon a layer of loose connective tissue, then sometimes smooth muscle
Mucous Membranes
Figure 4.9b
•Considered Wet or moist membranes
Serous membranes
• Moist membranes found in closed ventral body cavities
• Simple squamous epithelium resting on a thin layer of loose connective areolar tissue
Serous membranes
• Serous fluid lubricates the facing surfaces of the parietal (wall) and visceral (organs).–Remember this is a double membrane with the serous fluid between the layers
Serous membranes
• Serous membranes named according to where they are and the organs they are associated with
Serous membranes
• Pleura – lining the thoracic wall and covering the lungs
• Pericardium – enclosing the heart• Peritoneums – abdominopelvic
cavity and visceral organs