tissues epithelial

Chapter 5 Tissues

Each tissue contains several different cell types that have differentiated (specialized) to perform a specific series of functions.

Histology4 primary tissue types 1. epithelial 2. connective 3. muscle 4. neural

Epithelium Forms a superficial covering or an internal

lining of a body cavity or vessel Cells form a barrier It is avascular Attached to an underlying basement

membrane Has a free surface Cells are in close contact with one another

Types of Epithelia Simple - Stratified - Pseudo-stratified - Squamous - Cuboidal - Columnar -

all pictures are from the University of Delaware all pictures are from the University of Delaware Histology webpageHistology webpage

1. Simple squamous

thin and flat, look like fried eggsthin and flat, look like fried eggs function - function - locations - locations -

2. Simple cuboidal

resemble little boxes. Nuclei in a neat row, close to the center of each cell

function - location -

3. Simple columnar

tall and slender, nuclei are crowded into narrow band close to the basement membrane

microvilli goblet cells function - location -

4. Pseudostratified columnar

nuclei are several rows deep instead of in a nuclei are several rows deep instead of in a neat line, but still only one row of cellsneat line, but still only one row of cells

ciliatedciliated goblet cellsgoblet cells function - function - location - location -

5. Stratified squamous

many layers, relatively thick keratinized keratinized – tough, dry dead outer layer (skin)– tough, dry dead outer layer (skin) nonkeratinizednonkeratinized – moist, live throughout, – moist, live throughout,

(everywhere else)(everywhere else) function - location -

6. Transitional

Shape of surface cells vary from squamous to cuboidal depending on the amount of distention (stretch) of the bladder

function - location -

Gland cells

Gland cells may exist as individuals or as part of a multi-cellular gland.

exocrine ducts

endocrine hormones

Methods of Secretion (exocrine)

merocrinemerocrine apocrineapocrine

holocrineholocrine

Tumors and Cancer

Tumor - Tumor - Benign - Benign - Malignant - Malignant - Cancer - Cancer - PathologistPathologist OncologistOncologist

Carcinogens Hereditary factorsHereditary factors Exposure to radiationExposure to radiation Exposure to certain electrolytesExposure to certain electrolytes Exposure to carcinogenic compoundsExposure to carcinogenic compounds Chronic sublethal tissue damageChronic sublethal tissue damage Viral infectionsViral infections AgeAge SexSex

Treatments

Kill the cancer cellsKill the cancer cells surgerysurgery radiationradiation heat heat freezingfreezing

Prevent new tumors from growingPrevent new tumors from growing chemotherapychemotherapy immunotherapyimmunotherapy