WEEK 3: Epithelial Tissues (Lecture)

Question 1

composed of closely aggregated polyhedral cells adhering strongly to one another and to a thin layer (small amount) of ECM, forming cellular sheets that line the cavities of organs and cover the body surface.

Answer 1

Epithelial Tissues

Question 2

The principal functions of the epithelial tissues include the following: CAS

Answer 2

Covering, lining and protecting surfaces
Absorption
Secretion

Question 3

All epithelial cells don’t have veins or also called ______

Answer 3

avascular

Question 4

All epithelial cells undergo _____. Under certain abnormal conditions, one type of epithelial tissue may undergo transformation into another type in another reversible process called _____.

Answer 4

metaplasia

Question 5

Epithelial Cell Junction.

Function: Seals adjacent cells to one another, controlling passage of molecules between them; separates apical and basolateral membrane domains.

Junctional protein: Occludins, claudins and ZO proteins

Answer 5

Tight Junction (Zonula Occludens)

Question 6

Epithelial Cell Junction.

Function: Provides points linking the cytoskeletons of adjacent cells; strengthens and stabilizes nearby tight junctions.

Junctional Proteins: E-cadherin, catenin complexes

Answer 6

Adherens Junction (Zonula Adherens)

Question 7

Epithelial Cell Junction.

Function: Provides points of strong intermediate filament coupling between adjacent cells, strengthening the tissue

Junctional Protein: Desmogleins and Desmocollin

Answer 7

Desmosomes

Question 8

Epithelial Cell Junction.

Function: Anchors cytoskeleton to the basal lamina

Junctional Proteins: Integrins

Answer 8

Hemidesmosomes

Question 9

Epithelial Cell Junction.

Function: Allow direct transfer of small molecules and ions from one cell to another.

Junctional Protein: Connexins (1 connexons: 6 connexins)

Answer 9

Gap Junctions or Communicating Junction (Nexus)

Question 10

Morphology. Thin and flat cells

Answer 10

Squamous

Question 11

Morphology. Cell width and thickness roughly similar. Square

Answer 11

Cuboidal

Question 12

Morphology. Cells taller than they are wide. Rectangular

Answer 12

Columnar

Question 13

One cell layer

Answer 13

Simple epithelia

Question 14

Two or more cell layers

Answer 14

Stratified epithelia

Question 15

Surface Modifications. Are long, highly motile apical structures, larger than microvilli, and containing internal arrays of microtubules not microfilaments.

Answer 15

Cilia

Question 16

Surface Modifications. Specialized for absorption usually of uniform length. In cells such as those lining the small intestine, densely packed _____ are visible as a brush or striated border projecting into the lumen.

Answer 16

Microvilli

Question 17

Surface Modifications. Are a much less common type of apical process best seen on the absorptive epithelial cells lining the male reproductive system. Increase the cells’ surface area, facilitating absorption. Important components of inner ear sensory cells.

Answer 17

Stereocilia

Question 18

A layer of flat cells derived from the mesoderm. It lines the coelom (the body cavity of the embryo) and forms the simple squamous epithelium covering true serous membranes such as the peritoneum, pericardium, and pleura

Answer 18

Mesothelium

Question 19

Another type of simple squamous epithelium that lines the inner surface of blood vessels, including arteries, veins and capillaries

Answer 19

Endothelium

Question 20

These cells are found in glandular tissue. They have contractile properties and surround secretory cells in glands, assisting in the release of glandular products.

Answer 20

Myoepithelium

Question 21

Lines the inner surface of the uterus. It undergoes cyclic changes during the menstrual cycle and plays a vital role in implantation and pregnancy.

Answer 21

Endometrium

Question 22

A misnomer. Historically believed to be the source of germ cells or gametes (eggs and sperm) in the gonads. However, the actual site of germ cell production is the ovarian follicles and seminiferous tubules.

Answer 22

Germinal Epithelium

Question 23

Also known as glandular tissue, produces and release various secretory products. These include sweat, saliva, breast milk, digestive enzymes, and hormones, among others.

Answer 23

Glandular Epithelium