Histology Topic 2: Epithelial Tissue

Question 1

What are the general functions of Elithelial Tissue?

Answer 1

1. Protection
2. Secretion
3. Selective
4. Absorption
5. Excretion
6. Trans-cellular
7. Transport/diffusion
8. Sense organ

Question 2

What is the general structure of Epithelial Tissue?

Answer 2

• Polarised with an apical surface that faces
  the lumen. Basal surface is located interior
  -Thin sheets of cells tightly packed

Question 3

What is Simple Epithelial Tissue?

Answer 3

A single-layered epithelium that is adapted for diffusion

Question 4

What is Stratified Epithelial Tissue?

Answer 4

A multi-layered epithelium adapted for protection

Question 5

What resources the shapes of Epithelial Tissue?

Answer 5

1. Squamous
2. Cuboidal
3. Columnar

Question 6

What is pseudostratified epithelium?

Answer 6

A single layer of epithelium that has a stratified appearance due to the difference in size of the nuclei of the adjacent cells.

Question 7

What is the Basement Membrane and what is its function?

Answer 7

• Noncellular layer directly beneath epithelial tissue
• Composed of proteins secreted by epithelial cells and
  connective tissue
• Function: Provides structural support to overlying cells.
  Attaches epithelial layer to underlying tissues

Question 8

Where is Simple Squamous Epithelium found in the body?

Answer 8

▪︎Air sacs of lungs
▪︎lining of heart (mesothelium), blood vessels (endothelium) and lymph vessels
▪︎major cavities

Question 9

What is the function of Simple Squamous Epithelium?

Answer 9

▪︎To allow materials to pass through by diffusion and filtration
▪︎To secrete lubricating substances

Question 10

Where is Simple Cuboidal Epithelium found in the body?

Answer 10

▪︎ In ducts and secretary portions of small ducts

▪︎ In the kidney tubules

Question 11

What is the function of Simple Cuboidal Epithelium?

Answer 11

▪︎ To secrete and absorb

▪︎sensory reception (nose, ears and taste buds)

Question 12

Where is Simpler Columnar Epithelium found in the body?

Answer 12

▪︎Ciliated: bronchi, uterine tubes, uterus

▪︎Smooth/ Non-ciliated: Digestive tract and bladder

Question 13

What is the function of Simple Columnar Epithelium?

Answer 13

▪︎Absorbs

▪︎Secretes mucus and enzymes

Question 14

Where is Pseudostratified Columnar Epithelium found in the body?

Answer 14

Ciliated pseudostratified elithelium lines the trachea and much of the upper respiratory tract

Question 15

What is the function of Pseudostratified Columnar Epithelium?

Answer 15

▪︎Secretes mucous

▪︎Cilia moves mucous

Question 16

Where is Stratified Squamous Epithelium found in the body?

Answer 16

▪︎lines esophagus, mouth and vagina

Question 17

What is the function of Stratified Squamous Epithelium?

Answer 17

▪︎protects against abrasion

Question 18

Where is Stratified Cuboidal Epithelium found in the body?

Answer 18

▪︎Sweat glands, Salivary glands and Mammary glands

Question 19

What is the function of Stratified Cuboidal Epithelium?

Answer 19

▪︎protective tissue

Question 20

What is the function of Stratified Columnar Epithelium?

Answer 20

▪︎Secretes and protects

Question 21

Where is Stratified Columnar Epithelium found in the body?

Answer 21

▪︎urethra

▪︎ducts of some glands

Question 22

Where is Transitional Epthelium (Urothelium) found in the body?

Answer 22

▪︎lines bladder, urethra and ureters

Question 23

What is the function Transitional Epithelium (Urothelium)?

Answer 23

▪︎allows Urinary organs to stretch and expand

Question 24

What is the difference between Stratified Epithelium and Urothelium?

Answer 24

▪︎Urothelium has less layers than Stratified Epithelium

▪︎Urothelium is more stretchy

Question 25

What is Keratinized Epithelia?

Answer 25

Epithelia composed of numerous dead squamous cells at the most apical surfaces, adapted to be waterproof and prevent evaporation

Question 26

How does Keratinized Epithelia arise?

Answer 26

Dead squamous cells at the most apical layers of the Epithelium loses their nuclei and cytoplasms and contain a tough protein, keratin.

Question 27

What is the structure of Transitional Epithelia?

Answer 27

▪︎stretchy ▪︎looks stratified cuboidal when NOT stretched ▪︎looks stratified squamous when it IS stretched

Question 28

What is Glandular Epithelium?

Answer 28

▪︎A group of tissues, other than the covering and lining epithelium that are specialized for the production and secretion of various macromolecules ▪︎a.k.a secretory epithelium

Question 29

What is a gland?

Answer 29

▪︎Epithelium that secretes substances into ducts (tubes), onto a surface, or eventually into the blood in the absence of ducts.

Question 30

What is an Exocrine Gland?

Answer 30

▪︎Glands that secrete their products into ducts that release the secretions onto the surface of organs—>the skin surface or the lumen of a hollow organ. ▪︎Remain connected to the covering epithelium via tubular ducts —>lined with lining epithelium and carry the secreted products into the site of action.

Question 31

What is an Endocrine Gland?

Answer 31

▪︎Group of glands that do not have a duct system—>release their secretions directly into the bloodstream. ▪︎The secretions—>hormones, enter the interstitial fluid and then diffuse into the bloodstream without flowing through a duct. ▪︎Endocrine secretions have far-reaching effects—>distributed throughout the body by the bloodstream.

Question 32

Where are Goblet Cells found and what are they function?

Answer 32

▪︎they are found in Columnar Epithelium ▪︎Function: -Protection and lubrication of epithelial surfaces (respiratory and digestive tract where it needs to produce mucus and other substances)

Question 33

How to identify squamous

Answer 33

▪︎elliptical nucleus | ▪︎flat cells

Question 34

How to identify Cuboidal Epithelium?

Answer 34

▪︎circular nucleus | ▪︎cube-shaped cells

Question 35

How to identify Columnar Epithelium?

Answer 35

1. Oval-shaped nucleus | 2. Rectangular-shaped cells

Question 36

How to identify Transitional Epithelium?

Answer 36

▪︎dome-shaped apical cells

Question 37

How to identify pseudostratified epithelia?

Answer 37

▪︎different shapes of nuclei | ▪︎varying height of cells (if visible)

Question 38

What are the common diseases and disorders relating to Epithelium Tissue?

Answer 38

Acne, dermatitis, impetigo (bacterial skin infection), psoriasis (red, itchy, scaly patches on skin), sunburn, sweating disorders, yeast infections of the mucous membranes, leprosy -Sunburn: radiation causes damage to DNA (directly or via free radical excitement) >Melanocytes produce melanin → distribute to keratinocytes (common type of skin epithelium). >When exposed to sun, melanocytes increase production of melanin to protect cell. >Once cells are damaged → signal molecules generated → body mounts an inflammatory response → results in “burn” from sun → blood flows to area to repair damage.