MCM 2-25 Microanatomy of Epithelial Tissue

Question 1

Define “tissue”

Answer 1

tissues consist of groups of cells with varying amounts of extracellular matrix that perform specific functions

Question 2

organs

Answer 2

two or more tissues combine to form larger functional units called organs

Question 3

organs may be divided into 2 components

Answer 3

parenchyma - cells responsible for the main organ function

Stroma - supporting elements or matrix of the organ

Question 4

4 basic types of tissues

Answer 4

epithelial, connective, muscular, nervous

Question 5

Basic steps in preparing tissue for light microscopy

Answer 5

1. fixation - prevents structural organization, formalin cross-links proteins to each other, osmium fixes lipids. prevents post-mortem changes
2. sectioning - steel blade on rotary microtone, cuts 3-10um sections of specimen embedded in parafin. Paraffin removed prior to staining after section is mounted on glass slide

3. Staining - used to localize/distinguish cell and tissue components. Acidic Eosin (-) binds cytoplasmic structures and components .
basic strain (+) (hemotoxylin) binds structures such as nucleic acids. H&E stain distinguishes nucleus from cytoplasm

Question 6

describe epithelium

Answer 6

closely coherent cells that form cellular sheets that cover and line many surfaces and lumens of the body. one can distinguish between covering epithelia and glandular epithelia

Question 7

functions of epithelia (4)

Answer 7

covers surfaces, provides protection, secretes/adsorbs various substances, transports particles

Question 8

types of epithelia

Answer 8

simple, pseudostratified, stratified

Question 9

what is the basal lamina?

Answer 9

structure composed of Type IV collagen, laminin, enactin, and proteoglycans that separates epithelial cells from connective tissue.

Question 10

what connects the basal lamina to connective tissue?

Answer 10

anchoring fibrils made of type 7 collagen

Question 11

epithelial classifications

Answer 11

1. number of cell layers (simple, pseudostratified, stratified)
2. shape of cells at most superficial layer furthest from basal lamina (squamous, cuboidal, or columnar)
3. If the free surface has cilia or keratin (or neither)

Question 12

where is pseudostratified epithelium generally found?

Answer 12

respiratory tract