Chapter Three: Intro and Epithelial Tissue

What are the main tissue types (4)

Epithelial, connective, muscular, and nervous

What is the function of epithelial tissue?

Covers body surfaces, lines hollow organs, cavities. and ducts, forms glands

What are cell junctions?

What are the types?

Contact points between the plasma membranes of tissue cells

Tight, anchoring, and gap

What are tight junctions?

Are fluid tight seals, inhibits the passage of substances between cells and prevents content from organs from leaking

What are anchoring junctions?

What are the type of anchoring junctions?

Structural components use filaments and contain the protein, plaque

Adherens, desmosomes, hemidesmosomes

(AJ) Adherens, where are they on the PM and plaque, and what is their function?

Are on both sides of the PM, linking adjacent cells, and elongating the plaque

Helps epithelial surfaces resist separation

(AJ) Desmosomes, where are they on the PM, and the plaque, and what is their function?

Plaque is on each side of the PM, linking adjacent cells with spot-weld junctions

Contributes to the stability of the cells and tissue

(AJ) Hemidesmosomes, what is the difference, what is their function?

Does not link adjacent cells, but links cells to their own PM

(AJ) What are the proteins of the gap junction, and what do they form, what do they pass, and what is their function

The membrane protein: connexins forms tunnels: connexons, connecting neighboring cells

What do the proteins of gap junctions pass?

What is their function?

through the connexons, ions, and small molecules pass

allows for fast cellular communication

What are the general functions of epithelial tissues?

Protection, filtration, secretion, absorption, and excretion.

What are the general functions of epithelial tissues?

How are the cells arranged? What are the surfaces? Epithelial cells are X? Have a good supply of what? And what does it do easily?

The cells are arranged in continuous sheets, either single or stratified

They have apical and basal surface

Epithelial cells are avascular

Have a good nerve supply

Regenerates easily

What does apical mean?

What may it contain?

A “free” surface, faces body surfaces, cavity (lumen)

Cilia or microvilli

What is the basal surface?

What does it adhere to?

The deepest layer of epithelial cells

Adheres to the basement membrane

Epithelial cells are avascular what do they rely on?

Epithelial cells have no blood supply on their own so they rely on underlying connective tissue

Epithelial cells regenerate easily because?

They have a high rate of cell division.

What are the types of simple epithelium?

• What may some of them contain or not?

Simple squamous

Simple cuboidal

Pseudostratified

• cilia

Simple Columnar

• microvilli or cilia

What are the types of stratified epithelium?

Stratified squamous

Stratified cuboidal

Stratified columnar

Transitional

What are membranes?

What are the type of membranes?

Flat sheets of pliable tissue that cover or line the body

Mucous, serous, cutaneous, and synovial membrane

What are mucous membranes?

Lines a body cavity that OPENS directly into the exterior

What are mucous membranes lined up of?

Lined by nonkeratinized stratified squamous epithelium

Where are mucous membranes located?

What is their function?

Located in the entire digestive, respiratory, and reproductive tract

Important defense mechanism

What are serous membranes?

What are they made up of?

Location and function?

Lines a body cavity that does NOT open directly into exterior

Single layer of squamous

Covers organs within the cavities

Cutaneous membrane is the?

Skin

What does the synovial membrane lack?

What is their function?

Lacks epithelium

Lubricates movable joints

What is the difference between endocrine and exocrine glands

Endocrine glands secrete hormones into the blood stream

Exocrine glands use ducts to secrete substances onto the body surface or cavity