Download Tissues

Tissues
Anatomy and Physiology
Four tissue types
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Epithelium
Connective
Muscle
Nervous
Epithelium
• Functions: protection,
secretes, absorbs,
excretes
• Location: covers body
surfaces, lines internal
organs, glands
• Is found anywhere the
body has an outside
link
Epithelium
• Is anchored to
connective tissue
• Does not contain
blood vessels
• How, then, would
epithelium get needed
materials?
Epithelium
• Reproduces rapidly
• Heals quickly
• Tightly packed
Epithelium
• Classified by cell
shape and layers
• Three general groups:
simple—one layer of
cells
stratified—layered
glands—produce
and secrete substances
Epithelium
• Three shapes or forms:
1. squamous: flat cells
• May be simple or
stratified (usually simple)
Simple squamous
Epithelium
• Shape 2: cuboidal
• Cube shaped, but may
have rounded edges
• May be simple or
stratified
Epithelium
• Shape 3: columnar
• Longer, oval or
rectangular, tall cells
• May be simple or
stratified
Connective Tissue
• Very diverse
• Functions include: to bind, support, store
fat, blood and immune cells
• Though they appear to unrelated, they have
the same structure microscopically
Structure
Good blood
supply (must
support
epithelium)
Cells farther apart than
epithelium
Have fibers in between the cells
Background of either fluid, solid
or semi-solid
Structure
• Solid background:
bone
• Semi-solid
background: cartilage,
loose connective
• Fluid background:
blood
Major Cell Types
• Fibroblasts: produce 3
types of connective
fibers
1. collagenous (made
from collagen); a
tough white fiber as in
tendons
Fibroblasts produce
• 2. Elastic fibers: most
abundant, appear
yellow, made from
elastin, are weaker,
can stretch.
• Found in vocal chords
and walls of blood
vessels
Fibroblasts produce
• 3. Reticular: found in
lymph organs,
digestive and
respiratory passages
Major Cell Types
• Macrophages
(engulfers)
• Mast Cells: produce
heparin, which
prevents blood clotting
and histamine, which
reacts in allergies and
inflammation
Examples of Connective
• Loose fibrous
connective: binds
epithelium to
under layers
Examples of Connective
• Adipose: fat
storing
• Cells get larger
as fat is added
Examples of Connective
• Dense fibrous
connective:
closely packed
fibers
• Ligaments
Examples of Connective
• Bone: most rigid
• Made in
concentric circles
Examples of Connective
• Blood: consists of
plasma, red blood
cells, white blood
cells, many
dissolved
substances and
fibers
Examples of Connective
• Cartilage: fibers and
background make it
flexible;
• 3 types of cartilage
Muscle Tissue
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•
•
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Three types:
1. Skeletal
2. Smooth
3. Cardiac
• Can contract
Skeletal Muscle
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•
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Voluntary
Attaches to bone
Long threadlike fibers
Striated (appears
striped)
• Each cell has many
nuclei
Smooth Muscle
• Involuntary
• Not striated (smooth)
• Spindle shaped cells
with one large
nucleus
• Found in walls of
internal organs and
blood vessels
Cardiac Muscle
•
•
•
•
Only in the heart
Involuntary
Striated
Special branches to
interconnect cells
• This makes the message to
contract reach all cells at
about the same time
• Cell to cell
communication proteins
help with this also
Nervous Tissue
• Found in brain, spinal
cord, and nerves
• Basic cell is the
neuron
• Neurons can respond
to a stimulus and send
an impulse
Neuron
Nervous Tissue
• Mixed in with the
neurons are support
cells called Neuroglial
cells
• They support, bind,
and contain the blood
supply
• Neuroglial cells do
not receive and send
impulses
The purple are axons from
neurons; the pink cells are
neuroglial cells