Epithelial Tissue

Question 1

Tight Junctions

Answer 1

Impermable junctions that prevent molecules from passing through the intercellular space

Ex: Blood-Brain barrier

Question 2

Desmosomes

Answer 2

Anchoring junctions bind adjacent cells together like a molecular “Velcro” and help form an internal tension-reducing network of fibers

Composed of Cadherin (Linker proteins), Plaque, and Keratine (intermediate filament)

Question 3

Gap Junction

Answer 3

Connexon proteins allow ions and small molecules to pass for intercellular comunication

Question 4

Which Intercellular junction is most likely to be found on a horizontal structure? Vertical structure?

Answer 4

Horizontal: Gap Junction
Vertical: Desmosomes

Gap on the Horizon, Spiders on a String

Question 5

Apical Surface

Answer 5

Upper Free; exposed to exterior of cavity

Question 6

Basal Surface

Answer 6

Lower attached;

Question 7

Stages of Tissue Repair

Answer 7

1. Inflammation Stage
2. Proliferation Stage
3. Regeneration Stage

Question 8

Describe the Inflammatory stage in Tissue Repair

Answer 8

• Severed blood vessels bleed
• Inflammatory chemicals are released
• Local blood vessels become more permeable, allowing WBC, Fluid, Clotting proteins, and other plasma proteins to seep into the injured areas
• Clotting occurs; surface dries and forms a scab

Question 9

Describe what happens during the Proliferation Stage of Tissue Repair

Answer 9

• The clot replaced by granulation tissue, which restores the vascular supply
• Fibroblast produce collagen fibers that bridge the gap
• Macrophages phagocytize dead and dying cells and other debris
• Surface epithelial cells multiply over the granulation tissue

Question 10

Describe what happens during the Regeneration Stage of Tissue Repair.

Answer 10

• The fibrosed area matures and contracts; the epithelium thickens
• A fully regenerated epithelium with an underlying are of scar tissue

Question 11

7 Epithelial Tissues

Answer 11

1. Simple columnar
2. Ciliated pseudostratified columnar with goblet cells
3. Simple cuboidal
4. Transitional
5. Simple squamous
6. Stratified squamous
   Keratinizing stratified squamous

Question 12

Simple Columnar E.T.

Answer 12

Singe layer of tall cells with round to oval nuclei; may have contain microvilli and/or goblet cells

Question 13

What is the Function of Simple Columnar?

Answer 13

Absorption; Secretion of mucus, enzymes, and other substances

Question 14

Where are Simple Columnar E.T. generally located?

Answer 14

Nonciliated types: lines most of the digestive tract (stomach to rectum), gallbladder, and excretory ducts of some glands

Ciliated types: line small bronchi, uterine tubes and some regions of the uterus

Question 15

Pseudostratified Columnar E.T.

Answer 15

Single layer of cells of differing heights, some not reaching the free surface; nuclei seem at different levels; may contain mucus-secreting cells and bear cilia

Question 16

What is the function of Pseudostratified Columnar E.T.?

Answer 16

Secrete substances, particularly mucus; propulsion of mucus by ciliary action

Question 17

Where are Pseudostratified Columnar E.T. Generally located?

Answer 17

Nonciliated type: in male’s sperm-carrying ducts and ducts of large glands
Ciliated types: Line the trachea, most of the upper respiratory tract

Question 18

Simple Cuboidal E.T.

Answer 18

Single layer of cube-like cells with large, spherical central nuclei.

Question 19

What is the function of Simple Cuboidal E.T.?

Answer 19

Secretion and absorption

Question 20

Where are Simple Cuboidal E.T. generally located?

Answer 20

Kidney tubules; ducts and secretory portions of small glands; ovary surface

Question 21

Transitional E.T.

Answer 21

Resembles both stratified squamous and stratified cuboidal; Basal cells cuboidal or columnsar; Surface cells dome shaped or squamous-like, depending on degree of organ stretch

Question 22

What is the function of Transitional E.T.?

Answer 22

Stretches readily, permits stored urine to distend urinary organ

Question 23

Where are Transitional E.T. generally found?

Answer 23

Lines the ureters, bladder, and part of the urethra

Question 24

Mesothelium (Simple Squamous E.T.)

Answer 24

Located: in the mesothelia lining ventral body cavity, endothelia lining heart and blood vessels and portions of kidney tubules, inner lining of the cornea and alveoli of lungs

Function: reduces fiction; controls vessel permeability; performs absorption and secreation

Question 25

Simple Squamous E.T.

Answer 25

Single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm; the simplest of the epithelia

Question 26

What is the Function of Simple Squamous E.T.?

Answer 26

Allows materials to pass by diffusion and filtration in sites where protection is not important; Secretes lubrication substances in serosae

Question 27

Where is Simple Squamous generally located?

Answer 27

Kidney glomeruil; air sacs of lungs; lining of hearts, blood vessels, and lymphatic vessels; lining of ventral body cavity (serosae)

Question 28

Stratified Squamous E.T,

Answer 28

Thich membrane composed of several cell layer; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers.

Question 29

What is the function of Stratified Squamous E.T.?

Answer 29

Protects underlying tissue in areas subjected to abrasion

Question 30

Where are Stratified Squamous E.T. generally located?

Answer 30

Nonkeratinized type forms the moist lining of the esophagus, mouth, and vagina

Keratinized type: forms the epidermis of the skin, a dry membrane

Question 31

Endocrine Glands

Answer 31

Ductless glands that internally secrete protein hormones or steroid hormones
ex: blood, Interstitial fluid, lymph