Epithelial Tissues

Question 1

Macroscopic vs microscopic anatomy

Answer 1

Macroscopic: (gross anatomy)-study of structures that can be seen with the naked eye. Learning the names, locations of muscles, bone, arteries, veins, and nerves
Microanatomy: Study of microscopic structures and organs - AKA Histology

Question 2

Tissue types

Answer 2

epithelial, connective, nervous, muscle

Question 3

Epi tissue is composed of

Answer 3

cells that cover and line other tissues (bladder, mouth, blood vessels, and thorax [all body cavities])

Question 4

Epi acts as

Answer 4

interface layer that separates and defines the beginning and ending of different tissues

Question 5

Epi provides _____, has _________ aspects, and _________ things

Answer 5

-Provides protection - often acts as a biochemical filter (skin) and can be absorptive (GI epi - nutrients)
-Has sensory aspect (tongue, eyes, nasal passages) - Touch, temp, and taste
-Secrets things - Glandular epi

Question 6

Individual glandular epi cells

Answer 6

Goblet cells - found in the intestines (lubrication)(colon mucous)

Question 7

Grouped glandular epi cells

Answer 7

Pancreas
Make important substances (hormones, enzymes, milk, sweat, and musk)

Question 8

Excretions vs secretions

Answer 8

Excretions are waste
Secretions are products of that cell (needed by the body)

Question 9

Characteristics of epi

Answer 9

The size and shape of cells are based on it’s location and function in the body, but all are:
Polar, have junctional complexes, are avascular, and are innervated

Question 10

Polar

Answer 10

Have a sense of direction
Apical surface - side of the cell that faces the lumen (innermost section of a hollow organ)
Basal Surface - Side of the cell that faces the underlying CT (concretes the organ to its location)

Question 11

Junctional Complexes

Answer 11

Bring cells into close apposition to one another (close together)
Leave little to no room for extracellular matrix, if one does exist, it is very small

Question 12

Avascular

Answer 12

No blood supply to the cells
They rely on underlying CT to provide O2 and nutrients

Question 13

Innervated

Answer 13

Some epi lack nerves (Stomach, intestines, cervix)
Most are innervated (has nerves) and provide valuable sensory input

Question 14

Basement Membrane (BM): AKA basal lamina

Answer 14

-Foundation of the epi cell - a nonliving meshwork of fiber - acts as cement to the underlying CT (strong and elastic)
-Made and laid down by epi cells in varying degrees of thickness
-Nutrients and excremet diffuse across the BM to either be absorbed & used by epi (nutrients) or excreted in the blood stream for waste disposal (excrement)

Question 15

Surface specializations :

Answer 15

Vary depending on location and role it plays
Some have a smooth surface
Others have an irregular surface

Question 16

Smooth Surface

Answer 16

Blood vessels
Allow for easy passage of red blood cells (prevents clots)

Question 17

Irregular surfaces

Answer 17

Microvilli
Cilia

Question 18

Microvilli

Answer 18

Fingerlike projections
Brush border
-The surface area of the cell is covered in microvilli
-Greatly increases SA (20X)
-Increase absorptive ability of the cell (involved with secretions or absorptions)
-Found in intestines and urinary tracts

Question 19

Cilia

Answer 19

Thousands of tiny hairs
Found on the free surface (apical surface) of cells
-Resp tract - Trachea - Propel mucus and debris away from lungs
-Urogenital tract (repro) - Oviduct (infundibulum) - Cilia gently move new ova into the oviduct

Question 20

Classify Epi based on 3 criteria

Answer 20

Number of cell layers
Shape of the cells
Presence of surface specialization

Question 21

Single layer of cells

Answer 21

Simple
Provides little protection to the underlying CT
Found in protected areas of the body (Ducts, vessels etc.)

Question 22

Miltiple layers of cells

Answer 22

Stratified
Thicker and stronger
Found in areas that undergo mechanical and chemical stress

Question 23

Shapes of cells

Answer 23

Squamous, Cuboidal, and Columnar
In stratified epi - Many diff shapes are visible within the same tissue
Classified based on the shape of the luminal surface

Question 24

Simple Squamous Epi

Answer 24

-Delicate and thin
-Lining surfaces involved with the passage of gas or liquids - the inner lining of lungs (O2/CO2 exchange)- Filtration membrane of kidneys (Water and molecules excreted as urine)
- Flat and smooth - Reduces friction (blood vessels and lymphatics)
-Special named depending on location - Mesothelium (lines the pleural, pericardial, and peritoneal) - Endothelium (Line vessels and lymphatics)

Question 25

Simple cuboidal

Answer 25

Single layer of cubic cells
Dark nuclei are in a single row (Like a string of pearls)
Little protection
Secretion and absorption - Ovary surface, thyroid gland, ducts (of liver, pancreas, kidney [has microvilli], and salivary glands)

Question 26

Simple Columnar epi

Answer 26

-Elongated and tightly packed - Makes them tougher than simple squamous or cuboidal
-Nucleus at the base of the cell near the basement membrane
-Found in the GI tract - From stomach to the rectum - Associated w/ absorption and secretion - found in many excretory ducts
- Two types of cells make up gut lining - Absorptive (Most numerous, apical surface, dense microvilli) - Goblet (Wine glass shape, make and store mucus)
- Simple Ciliated columnar - uterine tubes, resp tract

Question 27

Stratified Squamous Epi (Stratified Squamous Keratinized Epi)

Answer 27

Various cell layer
in areas that undergo chemical and mechanical stress - Mouth, esophagus, vagina, rectum
Outer layer always being worn or shed off - replace at an equal rate from deeper layer

** Stratified Squamous Keratinized Epi is found on skin **

Question 28

Stratified Cuboidal Epi

Answer 28

Salivary ducts/glands and mouth

Question 29

Stratified Columnar Epi

Answer 29

Rare
Found in repro, resp, digestive, excretory ducts

Question 30

Pseudostratified Ciliated Columnar Epithelium

Answer 30

False Stratified - nuclei area found at diff levels across length of tissue layer - not all cells reach lumen (Appears to have multiple layers ) - all are attached to the BM
-is considered a simple epi
-Most ciliated - resp, some in male repro

Question 31

Transitional Epi

Answer 31

-Stretches
-Found in areas that need to expand and contract - Urinary tract (bladder, ureters, urethra)
- Can change the appearance of the cells - Empty urinary bladder (Thick, multilayers, domelike on the luminal surface) - Filled urinary bladder (go from 6 layers to 3 layers) - Forms a leak-proof membrane that prevents diffusion (Don’t want urine in the abdomen)