HISTOLOGY
Lecture one
DR. ASHRAF SAID
Start
Of this lecture
TISSUES
TISSUE: A
DEFINITION
A group of connected
and interdependent cells
that cooperate to perform
a specific function
Categories of Tissue
1. Epithelial Tissue
2. Connective Tissue
3. Muscle Tissue
4. Nervous Tissue
Epithelial Tissues
• General Features
Cellular Layer +
Basement
Membrane
Epithelial Tissues
• General Features
Cellular Layer + Basement Membrane
No Direct Circulation/Blood Supply
Touch Each Other
Rapid Rate of Cell Reproduction
• Structural Classification
Cell Shapes
EPITHELIAL
TISSUES
Squamous
Cuboidal
Columnar
Epithelial Tissues
• Structural Classification
Cell Shapes
Cell Layers
Simple
Stratified
Epithelial Tissues
• Major Types
Simple Squamous Epithelium
Simple Squamous Epithelium
Function: Exchange
Sample Locations:
Alveoli, capillaries
Stratified Squamous
Epithelium
Stratified Squamous Epithelium
Function: Protection
Sample Locations: Skin, Mouth, Repro tracts
Simple Cuboidal Epithelium
Function: Absorption or Secretion
Sample Locations: Kidney, Hormone Glands
Simple Columnar Epithelium
Function: Absorption (or Secretion)
Sample Location: Digestive Tract
Microvilli
Simple Columnar
Note goblet cells
Pseudostratified Columnar Epithelium
Note cilia
Pseudostratified Columnar Epithelium
Pseudostratified Columnar Epithelium
Function: Absorption, Secretion, Movement
Sample Locations: Respiratory & Repro Ducts
Transitional Epithelium
Function: Stretchability
Sample Location: Urinary Bladder
What kind of tissue is this?
Epithelium cont.
 Epithelium that lines cavities sits on lamina
propria.
– Supports epithelium
– Binds epithelium to other tissue
– Provides nutrition
 Sides of cells are named
– Basal
– Apical (free)
– Lateral
Basal Lamina-Lamina Propria
Specializations of Cell
Surface
 Microvilli
– Found mainly on absorptive cells
– Brush border, 1m high
 Cilia / flagella
– Cylindrical, motile structures, 5-10m high
– Contain microtubules
– Basal bodies
Microvilli
Apical region of an intestinal epithelial cell seen with TEM. Filaments
that constitute the core of the microvilli are clearly seen. An extracellular
cell coat (glycocalyx) is bound to the plasmalemma of the microvilli.
x45,000.
Cilia
Concept 1
To study cells, biologists
use microscopes and the
tools of biochemistry
Isolating Organelles by Cell
Fractionation
 Cell fractionation
– Takes cells apart and separates the major
organelles from one another
 The centrifuge
– Is used to fractionate cells into their
component parts
Epithelium
 Epithelium that lines cavities sits on lamina
propria.
– Supports epithelium
– Binds epithelium to other tissue
– Provides nutrition
 Sides of cells are named
– Basal
– Apical (free)
– Lateral
Basal Lamina-Lamina Propria
Specializations of Cell
Surface
 Microvilli
– Found mainly on absorptive cells
– Brush border, 1m high
 Cilia / flagella
– Cylindrical, motile structures, 5-10m high
– Contain microtubules
– Basal bodies
Microvilli
Apical region of an intestinal epithelial cell seen with TEM. Filaments
that constitute the core of the microvilli are clearly seen. An extracellular
cell coat (glycocalyx) is bound to the plasmalemma of the microvilli.
x45,000.
Microvilli (Cs)
Actin filaments can
be seen inside the
structure.
Cilia
Simple Squamous Epithelium
(endothelium)
Simple cuboid epithelium
Simple squamous epithelium
(mesothelium)
Lines a body cavity
Such as abdominal
cavity.
Simple columnar epithelium
Stratified squamous epithelium
(non-keratinized)
Transitional epithelium
Pseudostratified epithelium