Histo Lec M4 - Epithelial Tissues

Question 1

is a group of connected cells from the same origin that have a similar function within an organism.

Answer 1

tissue

Question 2

form the boundary between external environment and body tissues. They cover body surfaces (e.g., the epidermis of the skin) and line the lumens of internal organs that open to the exterior of the body.

Answer 2

Epithelial tissues

Question 3

composed of a basal lamina and a reticular lamina

Answer 3

The basement membrane

Question 4

by the epithelial cells and consists of the lamina lucida and the lamina densa.

Answer 4

basal lamina

Question 5

secreted by fibroblasts located in the underlying connective tissue.

Answer 5

reticular lamina

Question 6

Functions of the basement membrane

Answer 6

1. Provides support and attachment for the epithelial cells
2. Selective diffusion barrier

Question 7

Cells are much wider than tall, resembling a “fried egg.” Nucleus is highly flattened.

Answer 7

Squamous

Question 8

Cells are of equal height and width.
2.
Nucleus is spherical.

Answer 8

Cuboidal

Question 9

Cells are much taller than they are wide.
2.
Nucleus is oval shaped, generally located toward the base of the cell.

Answer 9

Columnar

Question 10

One cell layer thick.
2.
All cells rest on the basement membrane (basal surface) and all cells face the free surface.

Answer 10

Simple epithelium

Question 11

Cells are of various heights. All cells rest on the basement membrane, but only the tallest cells reach the free surface. Variation in height of the cells and the location of nuclei give the appearance of a stratified epithelium. Frequently ciliated.

Answer 11

Pseudostratified (One cell layer thick)

Question 12

More than one cell layer thick.
2.
Only the deepest layer of cells has contact the basement membrane and only the superficial‐most cells have a free surface.

Answer 12

Stratified epithelium

Question 13

Protects from physical abrasion and prevents desiccation

Answer 13

Stratified squamous

Question 14

Lining of wet cavities, including the mouth, esophagus, rectum, and anal canal; surface cells are nucleated and living.

Answer 14

Nonkeratinized (moist).

Question 15

Epidermis of the skin; surface cells are nonliving

Answer 15

Keratinized

Question 16

Lines the larger ducts of exocrine glands

Answer 16

Stratified cuboidal/columnar

Question 17

Protective function; constructed to expand with distension of the hollow organs it lines. Unique to the urinary system; lines the urinary bladder and ureter

Answer 17

Transitional

Question 18

Large, nonmotile; not cilia Contain a core of actin microfilaments

Present on cells lining the epididymis and ductus deferens in the male reproductive tract

Answer 18

Stereocilia

Question 18

Finger‐like extensions from the free surface of the cell, about 1 micron in height Are present in large numbers on each cell and, collectively, are called a brush or striated border

Prominent on cells lining the digestive tract and proximal tubules in the kidney

Answer 18

Microvilli

Question 19

Multiple hair‐like extensions from free surface of the cell; 7–10 microns in height. Highly motile; beat in a wave‐like motion

(e.g., in the respiratory system and the oviduct of the female reproductive system)

Answer 19

Cilia

Question 20

Specialized structures of the plasma membrane that:
* Attach and anchor cells
* Establish apical and basolateral membrane domains by sealing adjacent plasma membranes
* Provide channels for ionic and metabolic coupling

Answer 20

Cell Junctions

Question 21

Belt‐like, barrier junction around apex of the cell
* Provides close apposition of adjacent plasma membranes and occludes the intercellular space

Answer 21

Tight junction (zonula occludens)

Question 22

Prevents diffusion of material between the intercellular space and the lumen of the organ
*
Establishes apical and basolateral membrane domains in the cell by preventing the lateral migration of proteins in plasma membrane

Answer 22

Tight junction

Question 23

Attach cells to each other and anchor them to the basal lamina; no fusion of the plasma membrane

Answer 23

Adherent junctions

Question 24

junction that encircles the apex of the cell like a barrel strap and is located immediately beneath the zonula occludens; serves to attach adjacent cells together; associated with actin filaments.

Answer 24

Belt desmosome (zonula adherens

Question 25

Disk‐like junctions scattered over the surface of the cell, which are paired with similar structures in adjacent cells; associated with intermediate filaments (e.g., keratin filaments in epithelial cells).

Answer 25

Spot desmosome (macula adherens).

Question 26

Represent a “half desmosome”; these junctions anchor the basal surface of the cell to basal lamina

Answer 26

Hemidesmosome

Question 27

Consists of the zonula occludens, zonula adherens, and desmosomes; because these structures cannot be resolved as separate structures at the light microscopic level, they appear as a single, bar‐ shaped, dark region at the apical corners of adjacent cells

Answer 27

Junctional complex

Question 28

consist of connexons (also known as a connexin hemichannel), six transmembrane proteins clustered in a rosette that defines a central pore.

Answer 28

Gap junction.