Tissues - Epithelial (Ch. 4)

Front 1

Extracellular Matrix

Back 1

Produced by the cell to surround it. Epithelial, muscle and nervous tissue cells have very little. Composed of varying amounts of water, protein fibers, and dissolved macromolecules.

Front 2

Characteristics of Epithelial Tissue

Back 2

All Elithelia exhibit several common characteristics:
Cellularity (made of cells), Polarity (opposite sides with distinct differences), Attachment (must be attached to connective tissue), Avascularity (no blood vessels), Innervation 9has nerves), High Regeneration Capacity(stem cells replace dead cells and make up for damaged ones).

Front 3

Three Primary tissue "layers" during fetal development

Back 3

1. ectoderm, 2. mesoderm, 3. endoderm

Front 4

Apical Surface

Back 4

Epithelial top surface. Being exposed to the outside environment or some internal body space.

Front 5

Lateral Surface

Back 5

Between Apical and basal surfaces - containing intercellular junctions.

Front 6

Basal Surface

Back 6

Epithelial Base surface - connects to underlying connective tissue.

Front 7

Functions of Epithelial Tissue

Back 7

Physical protection, Selective Permeability, Secretions, Sensations

Front 8

Basement Membrane

Back 8

This extracellular layer between the Epithelial and connective tissue. Consists of two parts: Basal Lamina & Reticular Lamina which provides physical support for the epithelium, anchors the the epithelium to the connective tissue and acts as a barrier to regulate molecule movement between the epithelium and connective layers. Also uses Heparan sulfate to prevent clots which would inhibit nutirents reaching the epithelial.

Front 9

Basal Lamina

Back 9

Secreted by the Epethelial Layer - contains collagen fibers and specific proteins and carbohydrates.

Front 10

Reticular Lamina

Back 10

Secreted by the Connective layer - Contains specific proteins and carbohydrates.

Front 11

Four Types of Intercellular Junctions

Back 11

Tight, Adhering, Desmosome, Gap

Front 12

Tight intercellular junction

Back 12

Completely encircles and connects epithelial cells together.

Front 13

Adhering intercellular junction

Back 13

Encircles the cell and is made of microfilament.

Front 14

Desmosomes Junction

Back 14

Act as "buttons" between two epithelial cells to resist mechanical stress as potential weak points.

Front 15

Hemidesmosomes Junction

Back 15

SImilar to Desmosome in purpose. Is formed by the Basal layer to connect to strengthen connection to Basement membrane.

Front 16

Gap Junction

Back 16

Tiny fluid-filled tunnels (pores) that connect neighboring cells to allow the exchange of certain small molecules.

Front 17

Glands

Back 17

- Either individual cells or multicellular organs composed predominantly of epithelial tissue.
- Create secretory sudstances for use throughout the body, (Mucus, hormones, enzymes and waste products)

Front 18

Endocrine Gland

Back 18

Lacks ducts and therefore secretes their products directly into the interstitial fluid or blood stream.

Front 19

Exocrine Gland

Back 19

Usually maintain contact with epithelial surface by means of a duct. Secretes their products onto epithelial surface.

Front 20

Three Types of Exocrine Glands

Back 20

Merocrine (packages secretions for delivery), Holocrine (cells in the gland disintegrate and create the secretory substance), Apocrine (Secretory substance builds up in the apical portion of the gland cells and is pintched off and delivered to the epithelial surface)

Front 21

simple sqaumous epithelium

Back 21

- single layer of flat cells
- specialized for diffusion, osmosis and filtration of molecules.
-found only in protected moist areas away from friction and abrasion

Located:

aveoli of the lungs, lumen of blood and lymph vessels, heart chambers(endothelium), lines body cavities (mesothelium; part of the perietal membranes)and organ surfaces (mesothelium; part of the viceral membranes).

Front 22

endothelium

Back 22

the simple squamous epithelium lining the lumen of blood and lymph vessels as well as the chambers of the heart.

Front 23

mesothelium

Back 23

simple squamous epithelium that makes up the perietal and viceral membranes that coat body linings and the outer surfaces of organs.

Front 24

simple cuboidal epithelium

Back 24

- single layer of cells that are as tall as they are wide.
- specialized for absorbing fluids and other substances through its apical membrane and to secrete specific molecules.

Located:

kidney tubules (reabsorbtion of nutrients, ions and water out of blood), forms ducts of exocrine glands (secretes materials), covers surface of ovary and lines follicles of the thyroid gland.

Front 25

simple columnar epithelium

Back 25

- single layer of tall narrow cells.
- active movement of molecules occurs across these cells by absorption of secretion.
- two types: ciliated or nonciliated.

Nonciliated: often have microvili (to increase surface area for secretion) and goblet cells (to produce mucus for lubrication)

Front 26

nonciliated simple columnar epithelium

Back 26

often have microvili (to increase surface area for secretion) and goblet cells (to produce mucus for lubrication)

Loacted:

Lines most of the digestive tract from the stomach to the anal canal.

Front 27

ciliated simple columnar epithelium

Back 27

- cilia project from the apical surface and "beat" together in a direction to move along mucous.
- goblet cells are interspersed throughout this epithelium and produces the mucous.

Located:

Lines luminal surface of the uterine tubes (to help move along oocytes) and also is present in the bronchioles of the lungs.

Front 28

stratified squamous epithelium

Back 28

- multiple cell layers
- the basal layer has polyhedral shaped cells, however, the apical layer has sqaumous cells which defines this epithelium
- adapted to protect underlying tissues from damage from friction and abrasion.
- stem cells in the basal layer divide to replace cells at the apical surface that are lost.
- two types: keratinized and nonkeritinized

Front 29

keratinized stratified squamous epithelium

Back 29

- apical surface is composed of cells that are dead and filled with strong protective keratin.

Located:

The epidermis

Front 30

nonkeratinized stratified squamous epithelium

Back 30

- kept moist with secretions (mucous, saliva)

Located:

oral cavity, part of the pharynx (throat), the esophagus, the vagina and the anus

Front 31

stratified cuboidal epithelium

Back 31

- contains two or more layers of cells and tend to be as tall as wide.

Located:

most walls of larger ducts of most exocrine glands (sweat).

Front 32

stratified columnar epithelium

Back 32

- rare in the body
- two or more layers of columnar cells

Located:

ducts of salivary glands and in part of the male urethra.

Front 33

psuedostratified columnar epithelium

Back 33

- appears to be made up of multiple layers of cells, however, all cells are connected to the masemnet membrane
- two types: ciliated, nonciliated.

Located:

nasal cavity, pharynx, larynx, trachea and bronchi.

Front 34

transitional epithelium

Back 34

- varies in appearance depending on if it is stretched or relaxed.
- transitional because in different states the cells appear squamous, cuboidal or columnar.