Connective Tissue
Download
Report
Transcript Connective Tissue
Chapter 3
Cell Types
&
Tissues
What are Tissues?
Tissues are groups of cells that
have similar function
There are 4 main tissue types:
Epithelial Tissue
Connective Tissue
Muscle Tissue
Nervous Tissue
Epithelial Tissue
Fit Closely together to form continuous
sheets
Cells are bound together via tight
junctions and proteins called
desmosomes
Always have 1 free surface: the apical
surface, exposed to the body exterior or
cavity of an organ
Lower surface rests on the basement
membrane – structureless material
secreted by the cells
Epithelial Tissue
Avascular – having no blood
supply
These tissues rely on diffusion of
materials through the capillaries
that lie in the connective tissue
Easily regenerated
Epithelial Tissue
Organized by shape and the number of layers
Shape
Squamous – Flat, Tile-like
Cuboidal – Cube Shape
Columnar – Column Shape
Layers
Simple – one layer
Stratified – multiple layers
Pseudostratified – columnar only, one layer of
cells with variable heights
Transitional – vary due to stretching – cuboidal
to columnar basal membrane
Simple Squamous Epithelia
Stratified Squamous
Connective Tissue
Stratified Squamous Epithelia
Stratified Squamous Epithelia
Simple Cuboidal Epithelia
Simple Columnar Epithelia
Pseudostratified Columnar
Glandular Tissue
Secrete various products
2 different types of glands
Endocrine – ductless, have lost their
connection to the surface
Secretions
diffuse into nearby
capillaries
Example: Thyroid
Exocrine – Retain their ducts and
empty secretion on epithelial surface
Examples:
Sweat and Oil glands, Liver,
and Pancreas
Connective Tissue
Most are highly vascularized
Tendons & Ligaments = Poor Blood Supply
Cartilage = Avascular
These
3 take a LONG time to heal because
of little/no blood
Made of living cells surrounded by a
non-living Extracellular Matrix (ECM)
ECM Gives the ability
to bear weight
to form a soft tissue around organs
to withstand stretching and other abuses
Connective Tissue
Types:
Bone – Osseous Tissue – Protects body
organs
Cartilage – flexible - 3 types
Hyaline – lots of collagen, ribs, larynx, joints, &
fetal skeleton
Fibrocartilage – highly compressible,
intervertebral disks
Elastic – flexible, outer ear & nose
Bone
Hyaline Cartilage
Stratified Squamous Epithelia
Hyaline Cartilage
Fibrocartilage
Elastic Cartilage
Connective Tissue
Loose – Fewer fibers, softer
Areolar – widely distributed, protective
wrapping of organs
Adipose – lots of fat cells, insulation and
cushioning
Reticular – LOTS of fibers, forms the
stroma of lymph organs to support free
blood cells – need special stain to see!
Dense – Lots of Fibers, very organized
Areolar
Adipose
Reticular Connective Tissue
Dense Regular Connective
Connective Tissue
BLOOD – made of cells
surrounded by a nonliving ECM
Contains fibers that remain invisible
until a vessel is broken
Then these fibers come together to
form a clot
Blood
Blood
Muscle Tissue
Specialized to contract, or shorten
Cells are elongated to provide better
contraction
Individual Cells are called fibers
There are 3 types:
Skeletal
Cardiac
Smooth
Skeletal Muscle Tissue
Fibers are organized into sheets that
form the organs, Skeletal Muscles
Attached to the Skeleton
Voluntary Muscles – can be consciously
controlled
Cells are
Long
Cylindrical
Multinucleate
Striated – Striped
Skeletal Muscle
Skeletal Muscle
Skeletal Muscle
Cardiac Muscle Tissue
Found only in the heart
Cells are
Uninucleate
Branching
Striated
Branches meet at junctions called
intercalated disks
Allow ions to move freely from cell to
cell – creates electrical impulse
Involuntary – not under conscious control
Cardiac Muscle
Smooth Muscle Tissue
Found in the walls of hollow organs and
vessels
Contraction causes the cavity of an organ to
either constrict or dilate
Contracts more slowly than the other 2
types of muscle
Ex: Peristalsis – wavelike motion that keeps
food moving through the digestive system
Cells are
Uninucleate
Spindle-shaped
Not Striated
Smooth Muscle
Connective Tissue
Nervous Tissue
Receive and conduct electrochemical
impulses
Cells have long extensions which allow
a single neuron to reach multiple sites
Along with numerous supporting
cells, they make up the nervous
system organs – spinal cord, brain, and
nerves
Nervous Tissue
Nervous Tissue
Tissue Repair
2 major processes
Regeneration
Replacement of cells with the same
kind of cells
Fibrosis
Replacement of cells with Dense
Connective Tissue, or scar tissue
Depends on type of cells damaged and
what type of injury took place
Tissue Repair
Damaged tissue brings a series of events
into motion:
Capillaries become permeable
Allows clotting proteins to enter
damaged area to stop blood loss and
‘wall off’ the damaged area
This prevents bacteria or other
harmful materials from entering
Tissue Repair
Granulation tissue forms
Delicate pink tissue, full of tiny
capillaries that bleed freely when
damaged (picking a scab)
Contains phagocytes to dispose
of the clot and collagen making
fibroblasts that synthesize scar
tissue to permanently fix the gap
Tissue Repair
Surface epithelium regenerates
Newly made epithelial cells grow just under
the scab, which will fall off
Leaves new surface over scar tissue.
Scar may be visible, as a white line, or
invisible depending on the wound severity
Which Tissues Repair Themselves?
Regenerate Well
Epithelial
Fibrous Connective & Bone
Smooth Muscle
Regenerate Poorly (surgical)
Skeletal Muscle
Cartilage
No Regeneration (all scar)
Nervous Tissue
Cardiac Muscle
Cancer
50% of Americans will have cancer at one point
in their life
20% of Americans will die from cancer
A group of >100 diseases
All involve uncontrolled proliferation of cells
The process begins with one cell that is mutated
and begins to grow uncontrollably
Each daughter cell produced will carry the same
trait for uncontrolled cell division
Cancer
These cells will form a tumor:
in situ – within the original tissue
invasive – within nearby tissue
Many in situ tumors are benign, not harmful,
and can be surgically removed.
All invasive tumors and some in situ tumors
are considered malignant, dangerous.
Malignant tumors are likely to
metastasize, spread to other parts of the
body and establish new tumors
Cancer Growth Model