H/E Lecture 11

Question 1

What stain is specifically used for basement membranes?

Answer 1

Periodic Acid Schiff.

Question 2

What two layers make up the basement membrane?

Answer 2

Basal Lamina

Reticular Lamina

Question 3

Components in the basal lamina are synthesized by ___?

Answer 3

Epithelial cell

Question 4

What are the major functions of the basal lamina?

Answer 4

Attachment of epithelium to CT
Regulation/filtration
Scaffolding for regeneration

Question 5

Reticular lamina components are synthesized and secreted by___?

Answer 5

Fibroblast cells (CT cells)

Question 6

What fibers are in the reticular lamina?

Answer 6

type III collagen

Question 7

What is the purpose of the reticular lamina?

Answer 7

anchor basal lamina to the CT

Question 8

What anchors the basal lamina to the reticular lamina?

Answer 8

anchoring fibrils and plaques

Question 9

What are the general functions of epithelium?

Answer 9

Protection (covers and lines)
Secretion
Absorption (intestines)
Transport along a surface (lungs)

Question 10

What are the three types of epithelium in regard to proliferation?

Answer 10

Permanent: no mitosis
Stable: normally no mitosis but can if needed
Labile: steadily renewable, stem cells present, very regulated

Question 11

What is neoplasia?

Answer 11

Uncontrolled proliferation of cells.

Question 12

What are the differences between benign and malignant tumors?

Answer 12

Benign: slow, no metastasis, called adenoma or papilloma
Malignant: fast, metastasis, carcinoma or adenocarcinoma

Question 13

Describe adherens junctions.

Answer 13

belt like or “zonula”
CAMs are E-cadherin
Linked to actin filaments inside the cell
Towards the apical side of the cells
Resists mechanical separation of the cells

Question 14

Describe desmosomes.

Answer 14

spot welds or “macula” adherens
CAMs are desmosomal cadherins, overlap to form cadherin zipper between cells
Keratin filaments (intermediate filaments) attach to the attachment plaque
All below the adherens junction belt
Very strong, resist tearing and shearing forces

Question 15

Describe hemidesmosomes.

Answer 15

bind epithelial cells to the basal lamina
CAMs are integrins which are linked to BL components
integrins attached to attachment plaques inside the cell
attachment plaque linked to keratin filaments
meant to be a strong attachment for the cells to the BL

Question 16

Describe focal adhesions.

Answer 16

CAMs are integrins which are attached to actin filaments
Function: adhesion and mechanosensitivity
junction between epithelial cells and the basal lamina

Question 17

What are the three domains of an epithelial cell?

Answer 17

apical domain
lateral domain
basal domain

Question 18

Describe tight junctions, where they are located, and what they do.

Answer 18

In the lateral domain above the adherens junction. Also called the zonula occludens. No CAMs are used, transmembrane proteins from each cell reach out to each other.
These establish polarity or functional domains in the cell. May prevent membrane proteins from migrating.

Question 19

What are gap junctions?

Answer 19

Transmembrane proteins that allow cells to communicate. Connection proteins are called connexons and they create central pores. Very regulated communication. Also called communication junctions or nexus. Located in lateral domain but under the adherens junction.