BIO2104 The Tissue Level Of Organization
I. Definition
A.
groups
of closely associated cells that are similar in structure and perform a common
function
B.
Tissues
are organized into organs
C.
Histology
– study of tissues
II.Types
A.
epithelial tissue
1.covering
and linings
2.glands
B.connective
tissue
1.support
C.muscle
tissue
1.movement
D.nervous
tissue
1.control
III.Epithelium
A.Characteristics
1.close
cells
2.avascular
a.no
blood vessels
b.depends
on underlying tissue for nutrients
3.very
little extracellular matrix
4.intercellular
junctions to hold cells together
a.
tight
or gap junctions –transmembrane proteins
b.
adherens
– transmembrane proteins communicate with cytoskeleton
c.
desmosomes
– most stable, with tension
5.apical
or luminal surface
a.free
side or top of cells
b.faces
outside of body or inside cavity (lumen)
c.microvilli
(brush border)
d.cilia
6.can
renew and repair
7.basement
membrane
a.attaches
and supports base of cell
b.basal
lamina
(1)glycoprotein
secreted by the cells
c.reticular
lamina
(1)collagenous
fibers
(a)secreted
by connective tissue cells
d.defines
the boundary for epithelial cells
(1)cancerous
cells can invade
B.Classification
1.structural
a.layers
(1)monolayer
= simple
(2)multiple
layers = straitified
b.shape
(1)cuboidal
=cube
(2)columnar
=height>width
(3)squamous
=flattened (fried eggs)
2.Simple
epithelium
a.simple
squamous
(1)interdigitating
cells
(2)on
basement membrane
(3)Type
(a)mesothelium
i)serosal
lining
a)pleural
serosa
b)pericardial
serosa
c)peritoneal
serosa
(b)endothelium
i)lines
lumen
a)blood
vessels
b)heart
c)lymphatic
vessels
b.simple
cuboidal
(1)secretory
portions of glands
(2)lines
gland ducts
(3)lines
kidney tubules and ducts
c.simple
columnar
(1)nuclei
may be close to basal surface
(2)lines
uterus,oviducts
(3)central
canal of the spinal cord
(4)digestive
tract
3.Stratified
epithelium
a.basal
cell layer anchored to basement membrane, to cells above,
and
adjacent cells
b.In
thick layers of cells the top layer of cells is far away from
nutrients
and may be malnourished and die.
c.Lower
layer undergoes mitosis and cells move up.
d.stratified
squamous epithelium
(1)mixture
of cell shapes
(2)superficial
layers are squamous
(3)basal
layers more columnar
(4)middle
layers more cuboidal shape
(5)basal
and middle layers undergo mitosis
(6)noncornified
stratified squamous
epithelium
(a)superficial
cells remain active until
lost
by friction
(b)loss
of cells stimulates deeper
layers
to divide
(c)lining
of
i)oral
cavity
ii)esophagus
iii)anus,vagina
(7)cornified
stratified squamous epithelium
(a)superficial
cells lack nuclei
(b)dehydrated
due to exposure to air
(c)far
from capillary bed
(d)become
hardened (cornified)
(e)protection
(f)skin
e.stratified
cuboidal epithelium
(1)rare
(2)ducts
of sweat glands
f.stratified
columnar epithelium
(1)rare
(2)areas
in the larynx
g.pseudostratified
columnar epithelium
(1)nuclei
appear at various levels
(2)almost
every cell is anchored
(3)located
(a)large
excretory ducts of glands
(b)urethra
(c)cilia
on cells in respiratory and uterine tubes
h.Transitional
epithelium
(1)transition
between stratified squamous and stratified
columnar
(2)urinary
bladder
(3)very
thin basement membrane
4.Glandular
Epithelium
a.gland
(1)one
or more cells that make and secrete a
product
(2)endocrine
(a)secrete
to blood stream
(b)product
is a hormone
(3)exocrine
(a)secrete
to a surface
(b)unicellular
i)mucin
a)mucin
in water=mucus
(adjective
=mucous)
b)goblet
cell secretion
(c)multicellular
i)duct
to surface
ii)secretory
cells
iii)simple
or compound shape
iv)secretory
parts
a)tubular
b)alveolar
=acinar
c)tubuloalveolar
(4)exocrine
classed by secretion
(a)merocrine
i)
exocytosis
ii)
sweat, salivary glands
(b)holocrine
i)rupture
ii)sebaceous
(c)apocrine
i)apex
of cell pinches off
IV.Connective Tissue (CT)
A.General
1.Living
cells surrounded by a matrix
a.cells+extracellular
matrix (ECM)=stroma
b.structural
framework
2.most
abundant tissue in body
3.functions
in
a.binding
and support
b.protection
c.insulation
B.Characteristics
1.derived
from mesenchyme (mesoderm)
2.generally
vascular
a.except
cartilage
3.ECM
C.Composition
1.
cells
a.fibroblast
(1)CT
proper
b.chondroblast
(1)cartilage
c.osteoblast
(1)bone
d.hemocytoblast
(1)blood
e.NOTE
"blast"
(1)mitotic
cells
(2)indicates
cell secretes ECM
(3)matures
to "cyte"1.ECM more than glue
2.
matrix
a.macromolecules
b.tissue
fluid like plasma
c.organized
lattice
d.cells
migrate within and interact
e.varies
in composition among CT
(1)ground
substances (fills EC space)
(a)noncollagenous
proteins
(b)proteoglycans
- glue
i)hyaluronic
acid
© fibronectin –
adhesion protein to link ground substances together
(2)fibers
(a)collagen
- strength;types I-XII
(b)elastin - stretch
(c)reticular
- fine collagen fibers
2.cells
D.Types
1.CT
Proper (fibroblasts)
a.loose
(1)areola
(a)packing
between tissues
(b)separates
muscles
(c)absorbs
fluid
i)edema
(2)adipose
(a)adipocyte - cell filled
with oil
(b)pushes
nucleus to side
(3)reticular
(a)reticular
cell = fibroblast
(b)supports
tissue - stroma
(c)fine
network
b.dense
(1)regular
(a)tendons
i)connects
muscles/bones
(b)ligaments
i)bone/bone
(c)aponeuroses
i)sheet
connects muscle/muscle or muscle/bone
(2)irregular
(a)dermis
(b)organ
covering
c.elastic
(1)vocal
cords
(2)ligamentum
flava connects vertebrae
(3)walls
of aorta
2.cartilage
a.hyaline
(1)embryonic
skeleton
(2)ends
of bones
(3)trachea
b.elastic
cartilage
(1)more
elastin
(2)external
ear
c.fibrocartilage
(1)more
collagen
(2)intervertebral
discs
(3)knee
d.characteristics
of cartilage
(a)avascular
(b)covered
with vascular perichondrium
i)dense
irregular CT membrane
(c)chondrocytes
i)mature
chondroblasts
ii)located
in lacunae(cavities)
3.Bone
a.osseous
tissue
b.deposits
of inorganic calcium salts
(1)strength
c.osteoblasts
-> osteocytes
d.More
in later chapter
4.Blood
a.cells
in liquid matrix (plasma)
b.Red
blood cells and white blood cells
(1)produced
from hemocytoblast
V.Epithelial Membranes
A.mucous
membranes
1.lines
cavities that open to outside
2.absorption
and secretion
3.epithelial
sheet with lamina propria
a.loose
CT deep to basement membrane
B.Serous
membranes
1.lines
internal ventral body vavity
a.parietal
b.visceral
2.pleural
3.peritoneum
4.pericardium
VI.Muscle tissue
A.elongated
cells
1.fibers
2.myofilaments
a.contraction
b.proteins
(1)actin
(2)myosin
B.Types
1.skeletal
muscle
a.packaged
by CT
b.attach
to bones
c.contraction
moves bones
d.voluntary
muscle
2.cardiac
muscle
a.walls
of the heart
b.pumps
blood
c.intercalated
discs
(1)join
branched fibers
d.striations
e.involuntary
muscle
3.smooth
muscle
a.no
striations
b.one
central nuclei
c.involuntary
muscle
VII.Nervous
A.neurons
1.specialized
cells to conduct nerve impulses
2.located
in brain, spinal cord and nerves to and from organs
3.cell
body and long extensions
VIII.Tissue Repair
A.Parenchyma
1.functioning
cells
B.Stroma
1.supporting
cells
C.Regeneration
1.replace
tissue
D.Fibrosis
1.scar
tissue
a.nonfunctioning
if this is in parenchyma
E.Damage
initiates the inflammatory response
1.histamine
a.
agent released from mast cells
b.increases
blood flow to damage site
2.white
cells migrate to injury
a.clean
up crew
3.blood
clots
4.clot
replaced by granulation tissue
a.becomes
scar tissue
b.collagen
fiber with few cells
F.Tissues
vary in ability to repair
1.easy
a.epithelium,bone,
skin, mucous membranes
2.difficult
a.skeletal
muscle, cartilage
3.very
little repair
a.cardiac
muscle, nervous
IX.Primary Germ Layers
A.three
layer embryo
1.ectoderm
(outer)
a.nervous
tissue
b.epithelium
(skin)
2.mesoderm(middle)
a.muscle
b.connective
tissue
c.endothelium(epithelium)
3.endoderm
(inner)
a.mucosae(epithelium)
B.Tissue
Growth
1.Epithelium
and Connective tissue continue dividing (mitosis) as adults