Anatomy Tissue
Group of cells with similar structure
and function, plus the extracellular substance
surrounding them.
tissue
study of tissue
histology
four tissue types in the human body:
1.Epithelial – a covering or lining tissue
2. Connective – a diverse primary tissue type
that makes up part of every organ in the body
3. Muscle – a tissue that contracts or shortens,
making movement possible
4. Nervous – responsible for coordinating and
controlling many body activities
4 types of tissue
epithelial
connective
muscular
nervous
covers and
protects surfaces, both outside and inside the
body.
epithelium or epithelial tissue
Included under the classification of epithelial tissue are the
exocrine and endocrine glands
Epithelial Tissue Characteristics
1. Mostly composed of cells
2. Covers body surfaces
3. Distinct cell surfaces
4. Cell and matrix connections
5. Nonvascular
6. Capable of regeneration
Functions of Epithelial Tissues
1. Protects underlying structures
2. Acts as a barrier
3. Permits passage of substances
4. Secretes substances
5. Absorption of substances
Classification of Epithelia
simple
stratified
pseudostratified
consists of a single layer of
cells, with each cell extending from the
basement membrane to the free surface.
simple epithelium
consists of more than one
layer of cells, but only the basal layer attaches
the deepest layer to the basement membrane.
stratified epithelium
special type of simple epithelium, that appears
to be falsely stratified.
It consists of one layer of cells, with all the cells
attached to the basement membrane.
Due to variations in the shape of the cells, the
epithelia appears stratified.
pseudostratified columnar epithelium
three types of epithelium based on
idealized shapes of the epithelial cells:
squamous cell
cuboidal cell
columnar cell
1. flat or scalelike.
2. cube-shaped—about as
wide as they are tall.
3.tend to be taller than they are
wide.
1.squamous cell
2.cuboidal cell
3.columnar cell
There are two types of stratified squamous epithelia:
keratinized stratified squamous and
nonkeratinized stratified squamous epithelia.
cell structures do three things:
1.mechanically bind
the cells together.
2. help form a permeability barrier.
3. provide a mechanism for intercellular
communication
Desmosomes - are mechanical links that bind cells
together.
Hemidesmosomes - are half desmosomes that
anchor cells to the basement membrane.
Tight junctions - prevent the passage of
materials between epithelial cells.
Gap junctions - are small channels that allow
small molecules and ions to pass from one
epithelial cell to an adjacent one.
dosmosomes
hemidesmosomes
tight junctions
gap junctions
secretory organs that secrete substances onto a surface, into a cavity, or into the bloodstream.
glands
COMPOSED PRIMARILY OF EPITHELIUM, with a supporting network of connective tissue
glands
Glands with ducts are called
exocrine glands.
are ductless glands; they secrete their products (termed hormones) into the bloodstream.
endocrine glands
have a single, non-branched duct,
some have branched ducts.
simple glands
MOST EXOCRINE GLANDS are MULTICELLULAR,
comprised of many cells.
SOME EXOCRINE GLANDS are composed of a SINGLE
cell, like Goblet Cells, That Secrete Mucus.
MULTICELLULAR EXOCRINE GLANDS can be classified
according to the structure of their ducts and
secretory regions.
glands
exocrine glands have multiple,
branched ducts.
compound
Glands with secretory regions shaped as tubules
(Small Tubes) are called TUBULAR, whereas those
shaped in SACLIKE STRUCTURES are called ACINAR OR
ALVEOLAR
Glands with a Combination of the TWO are called
TUBULOACINAR OR TUBULOALVEOLAR
glands
Exocrine glands can also be classified according
to how products leave the cell.
MEROCRINE SECRETION involves the release of
secretory products by exocytosis.
APOCRINE SECRETION involves the release of
secretory products as pinched-off fragments of
the gland cells.
HOLOCRINE SECRETION involves the shedding of
entire cells.
- diverse in both structure and
function
-diverse primary tissue type
that makes up part of every organ in the body.
- comprised of cells, protein
fibers, and an extracellular matrix
connective tissue
Functions of Connective Tissue
1. Enclose and separate other tissues
2. Connecting tissues to one another
3. Supporting and moving parts of the body
4. Storing compounds
5. Cushioning and insulating
6. Transporting
7. Protecting
the name of cell identifies cell function
OSTEOBLASTS - Form Bone, osteocytes maintain it,
and osteoclasts break it down.
FIBROBLASTS - are cells that form Fibrous
Connective Tissue, and fibrocytes maintain it.
CHONDROBLASTS - Form Cartilage and chondrocytes
maintain it.
MACROPHAGES - are large cells that are Capable Of
Moving About and ingesting foreign substances,
including microorganisms in the connective
tissue.
MAST CELLS - are nonmotile cells that Release
Chemicals, Such As Histamine, that promote
inflammation.
GROUND SUBSTANCE - Consists Of Non-fibrous
Protein and other molecules.
connective tissue
extracellular matrix of connective tissue has three major components:
1. protein fibers,
2. ground
substance,
3. fluid
connectives tissue
1. osteoblast
2. fibroblast
3. chondroblasts
4. macrophages
5. mast cell
6. ground substance
Three types of protein fibers:
1. collagen
2 reticular
3. elastic
matrix protein fiber
COLLAGEN FIBERS, which resemble microscopic
ropes, are Very Flexible but resist stretching.
RETICULAR FIBERS are Very Fine, Short Collagen fibers
that branch to form a supporting network.
ELASTIC FIBERS have the ability to return to their
original shape after Being Stretched or
compressed, giving tissue an elastic quality.
trap large quantities of water
between the polysaccharides, which allows
them to return to their original shape when
compressed or deformed.
proteoglycans
two main types of connective tissue are:
embryonic and adult connective tissue
consists of relatively Few
Protein Fibers that Form A Lacy Network, with
numerous spaces filled with ground substance
and fluid.
loose connective tissue
Three subdivisions of loose connective tissue are:
1.areolar,
2. adipose,
3. reticular
AREOLAR connective tissue primarily Consists Of
Collagen Fibers and a few elastic fibers.
The most Common cells in Loose Connective
tissue are the Fibroblasts.
ADIPOSE tissue Consists Of Adipocytes, or fat
cells, which contain large amounts of lipid for
energy storage.
ADIPOSE tissue pads and protects parts of the
body and Acts As A Thermal Insulator.
RETICULAR tissue Forms The Framework Of
Lymphatic Tissue, such as in the spleen and
lymph nodes, as well as in bone marrow and the
liver.
connective
two major subcategories of dense
connective tissue:
collagenous and elastic.
it has a relatively large
number of protein fibers that form thick bundles
and fill nearly all of the extracellular space.
Dense connective tissue
connective tissue has abundant
elastic fibers among its collagen fibers.
Dense elastic
it gaves cartilage flexibility and strength
collagen
- provides support, but if bent or slightly
compressed, it resumes its original shape.
- is composed of chondrocytes, located
in spaces called lacunae within an extensive
matrix.
Cartilage
There are three types of cartilage:
1.hyaline,
2.fibrocartilage,
3.elastic cartilage.
the most abundant type of cartilage and has many functions, such as covering the ends of bones, where they form joints.
hyaline cartilage
has more collagen than does hyaline
cartilage and is able to withstand compression and
resist tearing or pulling.
- is found in the INTERVERTEBRAL DISKS.
fibrocartilage
contains elastic fibers in addition
to collagen and proteoglycans.
elastic cartilage
Two types of bone tissue exist:
spongy bone and compact bone.
has spaces between trabeculae or plates, of bone and therefore resembles a sponge.
sponge bone
is more solid, with almost no
space between many thin layers of mineralized
matrix.
compact bone
The three types of muscle tissue are:
1.skeletal,
2.cardiac
3. smooth
muscle attaches to the skeleton and
enables the body to move
skeletal
is the muscle of the heart; it is
responsible for pumping blood.
cardiac muscle
forms the walls of hollow
organs; it is also found in the skin and the eyes.
smooth muscle
responsible for a number of
functions, such as moving food through the
digestive tract and emptying the urinary
bladder.
smooth muscle
Nervous tissue forms the
brain, spinal cord, and
nerves.
It is responsible for coordinating and controlling many body activities
nervous tissue