Epithelial Tissues (Prof. Anyanwu)

Question 1

The nonliving portion of a tissue that supports cells is called …………………..

Answer 1

Extracellular matrix

Question 2

Mention the four major types of tissues

Answer 2

• Epithelial: protection, secretion, absorption
• Connective: support soft body parts and bind structures together
  – Muscle: for movement
  – Nervous: conducts impulses used to help control and coordinate body activities

Question 3

In one sentence, define epithelium.

Answer 3

An epithelium is a sheet of cells that covers a body surface or lines a cavity.

Question 4

Outline 6 characteristics of epithelia

Answer 4

■ Composed of closely packed cells with little extracellular material between.

■ Adjacent epithelial cells are bound together by specialized contacts such as desmosomes and tight junctions.

■ Exhibits polarity by having an apical surface (free) and a basal surface (attached).

■ Supported by the underlying connective tissue.

■ Innervated but avascular.

■ Has a high regeneration capacity.

Question 5

……………….. epithelium is common at sites of filteration, diffusion, osmosis.

Answer 5

Simple squamous

Question 6

……………. epithelium is common at sites of filtration, diffusion, osmosis; eg air sacs of the lungs, walls of capillaries, linings of blood and lymph vessels

Answer 6

Simple squamous

Question 7

…………………….epithelium is common at sites of filtration, diffusion, osmosis

Answer 7

Simple squamous

Question 8

……………… is referred to as germinal epithelium?

Answer 8

The simple cuboidal epithelium at the surface of the ovary

Question 9

…………… epithelium is found in the secretory portion of many glands

Answer 9

Simple cuboidal

Question 10

……………… epithelium is found in thyroid, mammary, and salivary glands

Answer 10

Simple cuboidal

Question 11

……………… epithelium is found in the kidney tubules

Answer 11

Simple cuboidal

Question 12

Where is the nucleus of the cells of simple culumnar epithelium located?

Answer 12

Near the basement membrane

Question 13

goblet cells secrete ………….

Answer 13

Mucus

Question 14

Simple columnar epithelium function in ……………….and are found in ……………..

Answer 14

Simple columnar epithelium function in absorption of nutrients; secretion of mucus and enzymes and they are found in the digestive tract.

Question 15

……………….. epithelium contains cells of varying heights giving the false impression of the presence of many layers

Answer 15

Pseudostratified columnar epithelium

Question 16

Where can pseudostratified epithelium be found?

Answer 16

■ Along the linings of the respiratory tract

Question 17

Pseudo stratified columnar epithelium is ciliated and includes goblet cells. True or false?

Answer 17

True

Question 18

Pseudo-stratified columnar epithelium is responsible for the ……………….. which protects the terminal airways and alveoli

Answer 18

“mucociliary elevator”

Question 19

Why does pseudostratified columnar epithelium give the false impression of the presence of many layers?

Answer 19

• contains cells of varying heights
• because nuclei are at 2 or more levels

Question 20

Why is pseudo-stratified columnar epithelium not said to be stratified, despite its appearance?

Answer 20

Because all cells touch basement membrane

Question 21

Pseudostratified columnar epithelium function in ……………….and are found in ……………..

Answer 21

Pseudostratified columnar epithelium function in protection, secretion, movement of mucus and are found in the linings of the respiratory tract

Question 22

What is the main function of stratified epithelia?

Answer 22

Protection

Question 23

cells on the free surface of stratified squamous epithelium are ………………….. while the underlying cells are ………………..in shape

Answer 23

Squamous shaped on the surface
and the underlying cells are cuboidal/columnar in shape

Question 24

Stratified squamous epithelium are found in ………………….

Answer 24

– Skin
– Mouth
– Esophagus
– Anal Canal
– Vagina

Question 25

…………….epithelium are found in locations subject to friction or attrition

Answer 25

Stratified squamous epithelium

Question 26

…………………epithelium is rare, found mostly in the ducts of some of the larger glands.

Answer 26

Stratified cuboidal epithelium

Question 27

What’s the distribution of stratified cuboidal epithelium

Answer 27

– Sweat glands – Developing ovarian follicles – Lining of larger ducts of mammary glands – Sweat glands – Salivary glands – Pancreas

Question 28

……………….epithelium is found in the pharynx, male urethra

Answer 28

Stratified columnar

Question 29

………………… epithelium forms the lining of the hollow organs of the urinary system that stretch as they fill

Answer 29

Transitional epithelium

Question 30

Transitional epithelium is found in …………………

Answer 30

renal pelvis, ureter, bladder, upper urethra

Question 31

…………. epithelium are stratified with dome shaped surface cells

Answer 31

Transitional epithelium

Question 32

What is the state of the of the transitional epithelium in the bladder: a. When the bladder is full b. When the bladder is empty

Answer 32

When the bladder is empty, the epithelium is at least 5-6 cells thick with rounded superficial cells that bulge into the lumen. When the bladder is full of urine the epithelium is stretched, the epithelium is only 3-4 cells thick and the superficial cells become more squamous in appearance

Question 33

State two features of transitional epithelium

Answer 33

■ they can stretch ■ distensibility, protection

Question 34

The basal surface of epithelial cells rests upon a …………….. which anchors the epithelium to the underlying connective tissue ………………..

Answer 34

basal lamina, lamina propia

Question 35

What is the basal lamina

Answer 35

The basal lamina is an organized sheet of organic molecules including collagen, most of which are synthesized by the epithelial cells.

Question 36

basement membrane for a thicker structure composed of …………………

Answer 36

the basal lamina and reticular lamina

Question 37

The reticular lamina refers to?

Answer 37

A layer of anchoring reticular fibers attaching the basal lamina to the underlying connective tissue.

Question 38

Name the apical surface modifications

Answer 38

Microvilli Cilia Sterocillia

Question 39

What are microvilli?

Answer 39

fingerlike projections of plasma membrane extending from the apical surface of epithelial cells into a lumen to increase surface area for absorption.

Question 40

Under light microscopy, the microvilli form a striated apical border referred to as a ……………..

Answer 40

“brush border”

Question 41

Name two common locations of the microvilli

Answer 41

simple cuboidal cells of some renal tubules and simple columnar cells of small intestine

Question 42

What are cilia?

Answer 42

Cylindrical structures on the apical surface of some epithelial cells that exhibit coordinated wavelike motion to propel a current of fluid or mucus in one direction over the epithelial surface.

Question 43

What are the common locations of cilia?

Answer 43

Respiratory epithelium, eg the surface of the pseudostratified columnar epithelium of the trachea Fallopian tube

Question 44

What are goblet cells?

Answer 44

epithelial cells that produce and secrete large amounts of mucus ■ Commonly

Question 45

What’s a common location for goblet cells?

Answer 45

the simple columnar epithelium that lines the intestines the pseudostratified epithelium that lines the respiratory tract

Question 46

Epithelial membrane = ?

Answer 46

Epithelium + underlying CT

Question 47

Mention the major types of epithelial membrane

Answer 47

1) Serous membranes 2) Mucous membranes . 3) Cutaneous membrane

Question 48

Where can serous membranes be found?

Answer 48

They line body cavities that do not open to the outside and also cover the organs within these cavities.

Question 49

The epithelium of serous membrane is called a …………..

Answer 49

“mesothelium”.

Question 50

……………….. epithelial membrane covers the surface of the body.

Answer 50

Cutaneous

Question 51

……………… epithelial membrane line the cavities and organs that open to the outside of the body.

Answer 51

Mucous

Question 52

……………. within the mucous membranes secrete the mucus

Answer 52

Goblet cells

Question 53

Epithelial cells that are specialised to produce and secrete substances into ducts or into body fluids are referred to as?

Answer 53

Glandular epithelium

Question 54

……………. are ductless glands

Answer 54

Endocrine glands

Question 55

………………. are sometimes classified as mucous secreting unicellular exocrine glands instead of being considered as intrinsic component of epithelial membranes

Answer 55

Goblet cells

Question 56

What are the components of exocrine glands?

Answer 56

Secrtory units Ducts Connective tissue that support the aforementioned components.

Question 57

What is a secretory unit?

Answer 57

A secretory unit is a group of secretory epithelial cells that release their secretion into a lumen, whereas a duct is an epitheIial lined tube that conveys the secretions from a secretory unit to an epithelial lined surface

Question 58

Outline the four ways through which exocrine glands can be classified.

Answer 58

Classification based on structure -simple gland -compound glan Based on the secretory product of the exocrine gland -Serous -Mucous -Seromucous/mixed According to overall shape of their secretory unit -tubular gland -alveolar glands -tubuloalveolar glands Classification based on mechanism of secretion -merocrine: fluid is released by exocytosis -apocrine: small portion of cell is pinched off -holocrine: cells fill with product and rupture

Question 59

Examples of merocrine gland include

Answer 59

salivary and pancreatic glands

Question 60

Classify mammary, and sebaceous glands on the basis of secretion mechanism

Answer 60

The mammary gland is an Apocrine gland The sebaceous gland is a holocrine gland

Question 61

Classify sweat and pancreatic glands on the basis of their structure.

Answer 61

The sweat gland is a simple gland The pancreatic gland is a compound gland

Question 62

Instead of releasing their secretion into ducts, endocrine glands discharge their secretions into ………..

Answer 62

The bloodstream

Question 63

Secretory cells of endocrine glands are grouped around ………………

Answer 63

wide fenestrated capillaries

Question 64

Why are the secretions of endocrine glands known as hormones?

Answer 64

because they elicit functional changes in target cells that they reach by way of the bloodstream