Lecture 2; types of epithelium and glands

Question 1

What are the two different types of epithelia tissue?

Answer 1

1) Covering and lining epithelia (outer coverings of skin and internal organs and lining epithelia of blood vessels, ducts, body cavities, interior of respiratory, urinary, digestive and repro systems)
2) Glandular epithelia (secretory portion of glands)

Question 2

epithelial tissue and their subcategories

Answer 2

1) epithelia (outer covering and inner lining)

2) Glandular epithelium (exocrine and endocrine glands)

Question 3

How are covering and lining epithelia classified?

Answer 3

according to their arrangement (simple, stratified, pseudostratified) and their shape (squamous, cuboidal, columnar, transitional)

Question 4

Simple squamous epithelium features

Answer 4

most delicate epithelium, found where filtration (kidneys), diffusion (lungs) and secretion where slippery surface is needed (outer layer of serous membranes)

Question 5

simple squamous epithelium appearance

Answer 5

thin, flat, somewhat irregular shape, cells look like “fried eggs”

Question 6

simple squamous specialised subtypes

Answer 6

mesothelium (lines pericardial, pleural, peritoneal cavities) and endothelium (lines inside of the heart, blood and lymphatic vessels)

Question 7

give examples of simple squamous epithelium locations

Answer 7

• Bowman’s capsule
• lines cardiovascular and lymphatic systems
• found inside the eye
• alveoli of the lungs
• visceral cavity linings
• inside blood vessels and inside heart

Question 8

Simple cuboidal epithelium features

Answer 8

-where there is secretion and absorption

Question 9

Appearance of simple cuboidal epithelium

Answer 9

-cuboidal or hexagonal boxes, distance between adjacent nuclei is approximately the height of the epithelium

Question 10

simple cuboidal epithelium location

Answer 10

• pancreas ducts
• parts of kidney tubules
• smaller ducts of many glands
• secretory chambers of thyroid
• anterior surface of lense
• pigmented epithelium
• secretory part of some glands like thyroid

Question 11

simple columnar epithelium features

Answer 11

more cytoplasm so more organelles; comes in two major subtypes; non-ciliated and ciliated simple columnar epithelium

Question 12

simple columnar epithelium appearance

Answer 12

rectangular, often hexagonal but taller and more slender than cuboidal, nuclei often elongated and near the base of the cell, height of cell several times the distance between adjacent nuclei

Question 13

Features, examples and function of nonciliated simple columnar epithelium

Answer 13

-features:
single layer, microvilli can be present on apical surface (ie. intestines), have goblet cells interspersed
-location examples:
lines gut mucosa from stomach to anus, ducts of many glands and gallbladder
-Function
secretion, lubrication (due to goblet cells) and absorption.

Question 14

Features, examples and function of Ciliated columnar epithelium

Answer 14

Features
-single layer, have goblet cells if it has cilia

Examples
-some bronchioles, uterine tubes, paranasal sinuses, central canal of SC, ventricles of the brain

Function
-synchronous movement assists motility of mucus and foreign objects or oocytes

Question 15

Stratified squamous epithelium features

Answer 15

located where mechanical and chemical stresses are severe; all forms protect against microbes; in places where mechanical stress and dehydration are a major issue apical cells pack with keratin making the surface tough and waterproof.
specialized subtypes; keratinised and non-keratinised

Question 16

appearance of stratified squamous

Answer 16

cells form layers; lower layers may be cuboidal or columnar; cells furthest away from nutrition are thinner and less active

Question 17

examples of each subtype of stratified squamous

Answer 17

keratinised - skin (makes surface tough and waterproof)
non-keratinised- mouth, throat, tongue, oesophagus, anus and vagina (protection from abrasion, defence from microbes, require secretions from glands)

Question 18

Features of stratified cuboidal epithelium

Answer 18

2 or more layers of cells; cells in apical layer cuboidal

Question 19

location examples of stratified cuboidal

Answer 19

ducts of adult sweat glands, esophageal glands, male urethra

Question 20

Function of stratified cuboidal epithelium

Answer 20

protection, limited secretion and absorption

Question 21

stratified columnar epithelium description

Answer 21

basal layers usually consist of shortened, irregularly shaped cells, only apical layer has columnar cells, uncommon

Question 22

Location of stratified columnar epithelium

Answer 22

lines part of urethra, large secretory ducts of some glands, small areas in anus and mucus membrane, part of the conjunctiva of the eye

Question 23

Function of stratified columnar epithelium

Answer 23

protection and secretion

Question 24

Transitional epithelium description

Answer 24

has variable appearance; relaxed/ unstretched state looks like stratified cuboidal cells but larger and rounded. As tissue is stretched, cells become flattened.

Question 25

location and function of transitional epithelium

Answer 25

urinary bladder, portions of urethra and ureters; allows urinary organs to stretch and maintain protective lining holding variable amounts of fluid without rapturing

Question 26

Pseudostratified epithelium features

Answer 26

All cells are in contact with the BM but not all reach the apical surface; actually a simple epithelium. has specialised subtypes; pseudostratified ciliated and nonciliated columnar epithelium.

Question 27

Appearance of pseudostratified columnar epithelium

Answer 27

nuclei at different levels, appears to have several level;s but only one

Question 28

Pseudostratified columnar epithelium description, example and function

Answer 28

• cilia on some cells and has goblet cells
• most upper airways
• secretes mucus and moves it

Question 29

Pseudostratified nonciliated columnar epithelium description, location and function

Answer 29

• no cilia and lacks goblet cells
• larger ducts of glands, epididymis, part of male urethra
• absorption and protection

Question 30

Endocrine glands, secretion pathway and examples

Answer 30

secrete directly into the blood usually by traversing interstitial fluid.
Pituitary, pineal, thyroid, parathyroid glands; generally distant strong effectors

Question 31

Exocrine glands, secretion pathway and examples

Answer 31

secrete into ducts that empty onto the surface of a covering or lining epithelium
sweat and salivary glands, oil glands, wax glands, pancreas; generally local effects