Zusammenfassung der Ressource
Oral Histology andEmbryology: Tissues
- Tissues: a group of cells with similar
characteristics of form and function
- Tissue Properties
- Regeneration: The natural
renewal of tissue by the growth
of new tissue to replace the old
- Tooth enamel doesn't regenerate
- Turn over time: the time it takes for new
cells to differentiate and replace old tissue
- Varies between tissue types
- Basic Tissue Types
- Epithelial: Tissue type
covering and lining all internal
and external body surfaces
- Histology of epithelial tissue:
- Can be derived from any of
the three embryonic layers:
1) ectoderm- epidermis and
oral regions 2) mesoderm- 3)
endoderm
- Capable of rapid
regeneration
because there is
only one cell type
- Avascular
(Receives blood
supply from the
CT below
- ALWAYS has a
basement
membrane
between any
epithelium
and it's
underlying CT
- Function
- Serves as a protective
covering but is also
involved itissue absorption,
secretioin, sensory, and
specialized functions
- Classification:
- Arrangement
- Simple: One layer of cells
- Stratified: More than one layer of cells
- Pseudostratified: One layer of
cells that all attach to the
basement membrane, and
appears to be multiple layers.
This is due to the nuclei being
at different levels.
- Shape
- Squamous: Platelike and flattened. Height is less
than width
- Cuboidal: Cube shaped. Equal height and width
- Columnar: Rectangles with height greater than their width
- Most of the
epithelial
tissues in the
body are
stratified
squamous
- Muscle
- Types of muscle tissue
- Skeletal muscle
- Voluntary, and
typically attach
to bone. Ex.
muscles in the
pharynx,
tongue,
esophagus, and
for facial
expression and
mastication
- Histology: Striped or
striated. Muscle --> Muscle
bundle (fascicle) --> muscle
cells (myofibers) -->
myofibrils --> myofilaments
(actin and myosin)
- Smooth muscle
- Involuntary, and under
the control of the ANS.
Contractions are slow
and can be maintained
over time
- Cardiac muscle
- Has characteristics of smooth
muscle and striated muscle.
Only muscle tissue that has
Purkinje fibers or a Bundle of
His
- Function: Movement, support, etc.
- Nerve Tissue
- Function: Carry impulses
based on electric
potentials. Results in
movement of muscles,
stimulation of glands,
regulations of systems,
perceptions of sensations
like pain, touch, taste,
and smell
- Histology of nerve tissue
(derived from
neuroectoderm)
- Neuron: the functional
cellular component of the
nervous system
- Neuron Components
- Cell body
- Cytoplasmic components:
- Axon: A long,
thin, singular
cablelike
process that
conducts
impulses
away from
the neuron
- Dendrite: a
threadllke
process, usually
with multiple
branches that
receives impulses
travelling to the
neuron
- Nerve: A bundle of neural
processes in the PNS (not in
CNS)
- Afferent
Nerves:
Sensory.
BODY
TO
BRAIN
- Efferent
Nerves:
Motor.
BRAIN
TO
BODY
- Divisions of nervous system
- Central nervous system: CNS: Brain and spine
- Peripheral Nervous System: Spinal and cranial nerves
- Autonomic Nervous system: Operates without
conscious control and is responsible for the
sympathetic (fight or flight) response and the
parasympathetic (rest and digest) response.
- Somatic
Nervous
System: Voluntary skeletal movement
- Connective Tissue
- Function: support, attachment,
packing, insulation,storage,
transport, repair and defense
- Properties: By weight the most abundant type of basic
tissue --> Lots of matrix (which is intercellular
substance and fibers
- Fibroblast: Most common cell
in CT- long flat and
elongated- Fixed-
Differentiate into all CT cell
types
- Protein FIbers
- Elastic Fibers:
Have the ability to
stretch and return
to their original
shape. Composed
microfilaments
embedded in
elastin
- Reticular Fibers:
Prominent in embryonic
tissues, and only in the
spleen and lymph nodes in
adults. Very fine hairlike
fibers composed of
reticulin
- Collagen Fibers: Main fibers in
CT- about twelve common
types- types 1-4 most
- CT Classification:
- Soft
- CT Proper
- Loose CT
- Dense CT
- Specialized
- Adipose Tissue
- Elastic Tissue
- Reticular Tissue
- Firm: Cartilage-
- Function: Forms temporary
skeleton of embryo, and is
present in articulate surfaces
of movable joints
- Cell Types:
- Chondroblasts-
Lie internal to the
perichondrium
and PRODUCE the
cartilage matrix
- Appositional Growth-
chondroblasts on external surface
replace damaged tissue by building
layers upon preexisting cartilage
- Chondrocytes-
Mature
chondroblasts
these
MAINTAIN the
cartilage matrix
- Interstitial Growth- chondrocytes undergo
mitosis inside of the lacuna and expand
from the inside out
- Types of
Cartilage:
- Elastic cartilage: Has
numerous elastic fibers in
addition to collagen fibers
- Fibrocartilage: Never found alone.
Transitional type between hyaline cartilage
and dense CT. No true perichondrium.
- Hyaline cartilage: Most common
type of cartilage, all cartilage starts
out as this. Only collagen fibers
- Repair- As cartilage
ages it becomes less
cellular and the
chondrocytes die.
Fibers become firm
and repair is slow
because it is
avascular
- Avascular and no nerve supply.
Surrounded by the
perichondrium which is a
fibrous CT sheath containing
blood vessels
- Rigid: Bone-
- Functions: Protection and
structural support for soft
tissues, attachment mechanism,
movement, manufactures blood
cells through bone marrow,
stores calcium and other
minerals
- Anatomy (superficial-deep)
- Periosteum:
Double layered
dense CT sheath
covering bone.
The outer layer
contains blood
vessels and
nerves and the
inner layer has
cells that form
osteoblasts.
- Compact bone:
- Cancellous bone
- Endosteum- similar to
the periosteum
however it lines the
inside of the bone
- Bone marrow: location of blood stem cells
- Development
- Intramembranous Ossification
- Endochondral ossification
- Repair
- Fluid
- Function
- Components
- Plasma
- Formed Elements
- Thrombocytes
- Erythrocytes
- Leukocytes
- Granulocytes
- Eosinophils
- Basophils
- Neutrophill
- Agranulocytes
- Lymphocytes
- B Cells
- T cells
- Natural killer cells
- Monocytes