1. Chapter 4: The Tissue Level of Organization

2. 4 Tissues of the Human Body
1.) Epithelial
2.) Connective
3.) Muscle
4.) Neural

3. What is a tissue?
Tissues are collections of cells and cell products that perform specific, but limited functions.
Histology- the study of tissues and their functions.

4. Epithelial Tissue Covers exposed surfaces Lines internal passageways
Forms glands

5. Functions of Epithelial Tissue
Provide physical protection
Control permeability (absorption)
Provide sensation
Produce specialized secretions

6. Characteristics of Epithelia
Cellularity (cell junctions)
Polarity (apical and basal surfaces)
Attachment (basal lamina)
Avascularity (lack blood vessels)
Regeneration (short life)

7. Look at how they are organized close together
Epithelia Classes
Look at how they are organized close together

8. Simple Squamous Epithelium
Areas Found-
1.) Mesothelia lining of body cavities.
2.) Endothelia lining of heart and blood vessels.
3.) Portions kidney tubules.
4.) Inner lining of cornea and alveoli.
Function- Reduces friction in the cavity, increases permeability, performs secretion and absorption.
Thin, Flat and Irregular in Shape
Alveoli Sacs in the lungs

9. Simple Cuboidal Epithelium
Found in- Ovaries, Testes, Kidney tubules, ducts in the pancreas, Liver, Salivary Glands.
Used for- Secretions, Absorption and Filtration.
Hexagonal boxes

10. Long, thin and rectangular in shape
Found in- Lining of the stomach, intestines, gallbladder, uterine tubules and collecting ducts of the kidney.
Function- Protection, secretion, and absorption.

11. Stratified Squamous Epithelium
Found in:
  outer layer of the skin. 
  oral cavity,
  throat,
  vagina,
  anal canal
Stratified Cuboidal Epithelium
Found in:
  mammary glands
   sweat glands
   pancreas
  ovarian follicles
Stratified Columnar Epithelium
Found in:
   vas-deferens,
  male urethra
  parts of the pharynx
Stratified Epithelium is generally located in areas that need protection from mechanical or chemical stresses like the lining of the mouth or skin

12. Glandular Epithelia
Release secretions in the Endocrine or Exocrine Glands.
Composed of glands for specific excretions.
Example:Sweat, Intestines, mammary.

13. Exocytosis-Merocrine secretion
Most common mode of secretion
Apocrine secretion-partial loss of cell for secretion
Holocrine secretion- cells is lost for secretion

14. Glandular Epithelium Types
Endocrine/Ductless glands- release their secretions directly into interstitial fluid like the blood, stomach, intestines etc.
Secretions- normally called hormones and initiate the start of something.
Examples- pancreas, pituitary, hypothalamus, thalamus, thyroid, or adrenal.

15. Glandular Epithelium Types
Exocrine/ Glands with a duct- These glands secrete contents to a duct that will then empty onto the surface of the skin or on the lining of a tract.
Secretions- milk from mammary glands, sweat for the skin, tears for the eyes, or enzymes for the digestive tract.
Examples- Salivary, Mammary, Sweat, Tear, Gall bladder, Pancreas.

16. Classification of Ducts
Simple- Tubular or Alveolar (straight or is it round like a bulb)
Simple branched or alveolar
Compound- More than one attached to the same opening.
Compound tubular or compound alveolar
Tubuloalveolar- Gland that possesses both tubular and alveolar ducts.

18. Secretion Methods
Merocrine- most common way for secretions in the body. Secretions are completed through exocytosis of a vesicle.
Apocrine- Portion of the cell is pinched off and lost through secretion (breast milk)
Holocrine- Mature cell grows with secretion amounts and burst during the secreting. Cell dies and is replaced.

20. Epithelial Tissue Identification Lab
Receive a slide from Mr. Quinn
Place the slide on your microscope
Use the best magnification for best view
Compare view to drawings done on epithelial tissue
Identify Epithelial tissue type
Explain features in view that support your answer.
Label those features in your drawings.
Also take a picture with your phone.