Fall 2013 Nur 0012
Chapter 4: Histology
1. What are the major characteristics of epithelial tissue?
2. Know the structure, functions, and locations of the epithelial tissues we discussed
in class (squamous, cuboidal, columnar, transitional, pseudostratified).
Know examples of
Simple squamous, Simple cuboidal, Simple columnar, Pseudostratified
Stratified squamous, Stratified cuboidal, Transitional
3. Know what functions simple and stratified epithelium serve in the body.
4. Name the 3 characteristics of all connective tissues
The cell types found in different connective tissues.
Know the three types of proteins found in connective tissue.
Know the different ground substances we discussed.
5. Know the structure, function and location of the different types of fibrous
Know examples of
The loose connective tissues – adipose, areolar
The dense connective tissues – regular and irregular.
6. Know the different types of cartilage and what their structure, functions, and
Hyaline, elastic, and fibrocartilage
Cartilages are avascular
Know the purpose of Proteoglycans (hyaluronic acid, chondroitins)
7. Know the basic properties of bone and blood, and how all connective tissues are related.
8. Know the basic properties of both muscle and nervous tissue.
9. The three embryonic tissues and what they become.
10. The three epithelial membranes: mucous, serous, and cutaneous.
Think of where they are found.
11. Tissue Repair – Go over the 3 steps from my powerpoints.
1 Chapter 4: Histology
Tissues are composed of groups of specialized cells working together to perform specific
Tissues are grouped into 4 categories Epithelial, Connective, Muscular, and Nervous.
Structure and function of tissues are closely related.
All Tissues arise from 3 primary germ layers in the developing embryo
1. Ectoderm – Epidermis and nervous system
2. Mesoderm – Muscle, bone, blood
3. Endoderm – Linings of digestive and respiratory tracts.
Longtitudinal: down the middle in half
Cross Section: across, horizontal, luman: inside of cut
Oblique: cut through at an odd angle
II. Epithelial : has basement membrane: attaches epithelium to underlying
tissue, thin layer of connective tissue glues epithelia tissue to another type of
Tight junctions keep it together
Usually have free surface: exposed side
1. Cellularity – very cellular, easy to distinguish between cells, very close to one
another, like a quilt
2. Special cell contacts –supported by connective tissue
3. Polarity –
4. Supported by connective tissue –
5. Avascular but innervated – don’t have good blood supply, nerve endings
All gases and nutrients carried in the blood must reach the cells by diffusing
across the basement membrane.
In cells with many layers, the most active cells are nearest the basement
6. Regeneration – replace itself every 1-2 days deep layers
7. Where it’s found – stomach, digestive tract, mouth, olfactory epithelium (between
the eyebrows), covers surfaces, skin, outside of tubing, can form glands when clumped
B. Classification of Epithelium
1. Classification based on number of cell layers
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Simple - one cell layer, with each cell extending from basement membrane to
Stratified - more than one layer of cells with only one layer that is adjacent to
the basement membrane
Pseudostratified - all cells are attached to basement membrane, but only
some of the cells reach the free surface, and the folding of the others gives the
appearance of stratification.
Transitional - a special type of stratified epithelium found only in the bladder,
2. Classification based on cell shape
Squamous – flat, or sheet-like, thin
Cuboidal - cube-like, same height and width. Rounded edged squares
Columnar - tall and thin., nucleus at bottom,
* hexagonal most surface area*
C. Functions of Epithelium
1. Based on cell layers
Simple - found in organs whose principle functions are:
diffusion, filtration, secretion, absorption
Since simple is only one cell layer thick it is ideally adapted to areas in which
substances must be able to move easily across cell membranes.
Stratified - found in areas where protection is important
Stratified is well adapted to protection because as outer layers are damaged,
new layers are being produced to replace it.
2. Based on Cell Shape
Squamous - are thin and flat and therefore allow substances to diffuse through
them or act as filters.
Cuboidal or Columnar - are generally cells that secrete or absorb substances
because they have a greater cytoplasmic volume than squamous cells.
D. Types of Epithelia
Simple Squamous: has to be thin so things can be diffused easily
Structure - flat or oval with central nucleus.
Location - places with little wear and tear and also in places where
substances are diffused and filtered.
Function - diffusion, filtration, secretion
Body – alveoli, kidney capillaries, lining of heart and blood vessels ( when torn,
causes blood clotting)
Simple Cuboidal: often form tubes or ducts
Structure - cube shaped with a central nucleus.
Location - in tubules where they can reabsorb substances.
Function - mainly absorption, active transport, secretion
Body – kidney tubules, liver, thyroid,
3 Simple Columnar
Structure - nucleus near bottom of column shaped cells.
Location - inside lining of digestive tract, also contain goblet cells.
Function - secretion of mucous, absorption.
Body – begin in stomach, line digestive tract
Pseudostratified: not multiple layers, all attached to basement membrabe, all
Structure - all cells touch basement membrane but not all reach the
Location - respiratory tract
Function - specialized goblet cells release mucous that coat
Body - lower respiratory tract
Stratified Squamous : cells get flatter as you move closer to surface, layers
darker are more active
Structure - many layers with outermost layer being flat and scale –
like. Underlying layers are more cuboidal or columnar.
Location - anywhere the outer layers can be abraded and generally
wherever protection is needed.
Function - protection against abrasion. In epidermis the keratin also
acts as a waterproofing agent to fight water loss.
Body – epidermis,
Keratin impregnantes into cells Nonkeratinized wet stratified, lines esophagus,
retum, vaginal v. keratinized: dry
Stratified Cuboidal - rare
Structure - Cuboidal cells, but in layers.
Location - wherever protection is needed.
Function - protection and secretion.
Body – sweat glands, ovarian follicles( secretes estrogen and progesteron) ,
Stratified Columnar - rare
Structure - layers of columns - only outer layer is columnar.
Location- male urethra.
Function - protection and secretions.
Transitional 4 or 5 layers of cubes
Structure - looks like stacks of cuboidal cells when in relaxed state, layers closest
to apical surface can distend as bladder fills.
Location - bladder, urethra, ureters
Function - allows stretching of urinary bladder as it fills.
Body - bladder, urethra
E. Glands and membranes formed by epithelial cells in clumps
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1. Endocrine - Have no ducts. Ducts were separated during development. Secrete
hormones directly into blo