Lecture 12: Epithelial Tissue

Question 1

Regular Cell

1. What are the properties of the apical surface?
2. What are the properties of the basal​ surface?
3. What are the properties of the lateral​ surface?

Answer 1

1. What are the properties of the apical surface?

Faces exterior surface/lumen and participates in molecular filtering

2. What are the properties of the basal​ surface?

Rests on basement membrane and anchors cell to underlying connetctive tissue

3. What are the properties of the lateral​ surface?

Communicates and attaches to adjacent cells while maintaining integrity

Question 2

Tight/Occluding Junctions

1. What are their properties?
2. Where do you normally find them?

Answer 2

1. What are their properties?

They are impermeable and acts as a barrier

2. Where do you normally find them?

Normally at apical surface

Question 3

Gap/Communication Junctions

1. What are their properties?
2. Where do you normally find them?

Answer 3

• 1. What are their properties?*
• Mediate communication with adjacent cells
• Uses Connexin to create a pore for fluid and ions to pass through
• 2. Where do you normally find them?*

Lateral Side of Cells

Question 4

Anchoring Junctions

1. What is the function?
2. What types of anchoring junctions are there?

Answer 4

1. What is the function?

Link a cell to the cytoskeleton of adjacent cells

2. What types of anchoring junctions are there?

Adherins: Cadherins that interact with actin filaments on the apical surface

Desmosomes: Cadherins that interact with intermediate filaments on the lateral surface

Hemidesomosomes: Basal adhesions that interact with integrins and intermediate filaments that anchor to basal lamina

Question 5

What is the basement membrane?

Answer 5

Extracellular material where basal surface of cell rests on

-Permits diffusion of nutrients

Question 6

What are the three types of Apical Specializations?

Answer 6

1. Microvilli
2. Stereocilia
3. Cilia

Question 7

Microvilli

What is their function?

What makes up the core of each Microvillus?

Answer 7

Function: Specialized for Absorption

Composition: Actin core

Question 8

Stereocilia

1. What is its function?
2. What is its composition?
3. Where is it found?

Answer 8

Function: Absorption and Secretion

Composition: Acting core and longer than usual microvilli (has less movement)

Location: Epididymis and the Sensory Cells of the Inner Ear

Question 9

Cilia

1. What is its function?
2. What is its composition?
3. Where is it found?

Answer 9

Function: Propel substances across tissue (to remove debris) and plays role in embryonic L/R axis determination

Composition: Internal arrays of microtubules (axoneme)

Location: Respiratory Tract

Question 10

What are the three types of Cilia and their functions?

Answer 10

Motile: Beat in a wave like fashion to move substances

Primary: Immobile, but function as chemo-/osmo-/mechano- sensors

Nodal: Embryonic, help determine left/right axis

Question 11

Where might you find Simple Squamous Epithelium?

Answer 11

Lining the Blood and Lymph Vessels (Endothelium)

Lining of Serous Membranes (Mesothelium)

-reduce friction

Lining Alveoli, Loop of Henle, Ducts

Question 12

Where might you find Simple Cuboidal Epithelium?

Answer 12

Kidney Tubules, Glands, and Associated Ducts.

Terminal Bronchioles

Covering of the Ovary

Question 13

Where might you find Simple Columnar Epithelium?

Answer 13

Auditory Tubes

Uterus

Oviducts

Stomach

Small / Large Intestines

Gallbladder

Question 14

Where might you find Pseudostratified Columnar Ciliated Epithelium?

Answer 14

Lining of the Nasal Cavity

Pharynx

Trachea

Bronchi

(Respiratory System except the Terminal Bronchioles)

Looks like many layers but it is just one

Question 15

Where might you find Urothelium?

Answer 15

Urinary Bladder

Ureters

Urethra

Multiple layers but doesn’t follow 3 shape rule

Question 16

What is the special function of the Urothelium?

Answer 16

It is distensible

Question 17

Where might you find Nonkeratinized Stratified Squamous Epithelium?

Answer 17

Oral Cavity

Portions of the Pharynx

Esophagus

Anus

Vagina

Urethra

Cornea

Apical cells have nuclei!

Question 18

What is special about the Apical Layer of Keratinized Stratified Squamous Epithelium?

Answer 18

The cells there do not have Nuclei

Question 19

Where might you find Stratified Cuboidal Epithelium?

Answer 19

Sweat Glands and Ducts

Ovarian Follicles

Salivary Gland Ducts

Release Products and very similar looking to Stratified Columnar

Question 20

What function does a Goblet Cell perform?

Answer 20

Secretes mucus into the GI tract.

Simple Columnar Cells

Question 21

What kind of membranes are the Peritoneum, Pericardium, and Pleura?

Answer 21

Serous Membranes (Mesothelium)

Question 22

What is the example given for a Unicellular Gland?

Answer 22

Goblet Cell

Question 23

What is the method of secretion for a Merocrine Gland?

Answer 23

Secretory products are wrapped in membrane bound vesicles to the apical surface and released via exocytosis.

Example: Salivary Gland

Question 24

What is the method of secretion for an Holocrine gland?

Answer 24

Secretory product builds up inside of a cell, causing apoptosis

Cell ruptures and releases product along with cell debris

Example: Sebaceous Gland

Question 25

What is the method of secretion for an Apocrine gland?

Answer 25

Secretory product released with the apical portion of cell

• Secretory product is surrounded by cytoplasm within the plasma membrane
• Example: Mammary Glands*

Question 26

What is the secretory portion of a multicellular gland called?

Answer 26

The Acinus

In Exocrine Glands

Question 27

What sort of secretions are formed in the Parotid Gland?

Answer 27

Serous

Question 28

What sort of secretions are formed in the Sublingual Gland?

Answer 28

Mucous

Question 29

What kind of secretions are formed in the Submandibular Gland?

Answer 29

Both Serous and Mucous