BL S5 - Epithelial TIssue And Exocrine Glands

Question 1

What does a mucous membrane do?

Give examples of where mucous membranes are found.

Answer 1

Lines internal tubes which open to the exterior of the body.

The respiratory, urinary and alimentary tract.

Question 2

What does a mucous membrane consist of?

Answer 2

Epithelium lining a lumen
Adjacent layers of CT called lamina propria.
Muscularis mucosae - smooth muscle - alimentary tract.

Question 3

What is a serous membrane and where are they found?

Answer 3

Thin 2 part membranes which line internal closed body cavities - enveloping viscera.

Peritoneum - enveloped abdominal organs
Pleural sacs - envelop lungs
Pericardial sacs - envelops heart

Question 4

What does a serous membrane consist of?

Answer 4

Mesothelium - secretes the lubricating fluid

Thin layer of connective tissue attached the epithelium to adjacent tissues.

Question 5

What is epithelium tissue?

Where us is found?

Answer 5

Sheets of contiguous cells, of varied embryonic origin that cover the external surface of the body and line the internal surfaces.

Skin
GI tract, respiratory, genitourinary tract. - open to exterior
Pericardium, peritoneum, pleural sacs, blood and lymphatic vessels - don’t open to exterior.

Question 6

What is the function of simple squamous epithelium?

Answer 6

Lubrication
Gas exchange - short diff distance
Physical barrier
Active transport via pinocytosis

Question 7

Where is simple squamous found?

Answer 7

Bowmans capsule
Lung alveoli
Endothelium
Mesothelium

Question 8

What happens if excessive secretion of fluid occurs from squamous cells?

Answer 8

Hydroceles around testes

Serous fluid between visceral andparietal layers of the tunica vaginalis

Question 9

Describe simple cuboidal epithelium.

Answer 9

Single layer of polygonal cells where their height is the same as their width.

Question 10

What are the functions of simple cuboidal and where are they found associated with the function?

Answer 10

Absorption / conduit - exocrine glands
Absorption and secretion - kidney tubules
Barrier - ovary
Hormone synthesis, storage and mobilisation - thyroid

Question 11

Describe simple columnar epithelium.

Answer 11

Single layer of cells with heights greater than their wights.

Question 12

What are the functions of simple columnar and where are the Found associated with these functions?

Answer 12

Absorption - small intestine, colon and gall bladder.
Secretion - stomach lining, small intestine and colon
Lubrication - small intestine and colon
Transport - oviduct.

Question 13

Describe psuedostratified epithelium.

Answer 13

All cells make contact with the basement membrane but not all reach surface - nuclei at varying levels. Often ciliated.

Question 14

What are the functions of pseudostratified epithelium and where are they found?

Answer 14

Secretion and conduit - respiratory tract, vas deferens
Mucous secretion - respiratory tract
Particle trapping and removal - respiratory tract

Question 15

Describe stratified squamous epithelium.

Answer 15

Multiple layers with the outermost being squamous cells.

Question 16

Where is non-keratinised stratified squamous epithelium found?

Answer 16

Anal canal
Cornea
Oral cavity 
Oesophagus 
Valine
Inner surface of the eye

Question 17

What is the fucntion of non-keratinised epithelium?

Answer 17

Protect against abrasion

Reduce water loss but remain moist

Question 18

What are the functions of keratinised epithelium?

Answer 18

Reduces water loss and ingress
Prevents toxin ingress
Protects against abrasion 
Acidic pH - reduces microbial colonisation
Shielding against UV damage.

Question 19

Where is keratinised epithelium mainly Found?

Answer 19

Skin epidermis

Question 20

Describe transitional epithelium.

Answer 20

Surface cells vary in shape from columnar to cuboidal depending on where the tissue is stretch or relaxed.

Question 21

Where is transitional epithelium aka urothelium found?

Answer 21

Urinary tract
Renal calyces 
Ureter
Bladder
Urethra

Question 22

What are the functions of transitional epithelium?

Answer 22

Distensibility

Protection of underlying tissue from toxic chemicals

Question 23

What percentage of the epidermis is keratinocytes?

Answer 23

90%

Question 24

What are the 4 layers of the epidermis?

Answer 24

Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum basale

Question 25

Where does keratinocytes mitosis occur?

Answer 25

Basal layer.

Question 26

What does keratin form?

Answer 26

Hair and nails

Question 27

What is normal transit time from basal layer to corneum?

Answer 27

28-40 days

Question 28

What is different about normal transit time and transit time of keratinocytes from the basal to corneum layer in diseases such as psoriasis?

What are symptoms?

Answer 28

Decreased transit time

Silvery scales and redness in affected area.

Question 29

What are some other epidermal cells?

Answer 29

Melanocytes

Langerhans cells

Question 30

What are functions of melanocytes?

Answer 30

Produce melanin - transferred to other epidermal cells via phagocytosis of the melanosomes contained in the dendritic processes of the melanocytes.

Question 31

What is the function of langerhans cells?

Answer 31

Pro APCs
Present antigens to T lymphocytes
Mediate immune reactions such as contact dermatitis

Question 32

What is a gland?

Answer 32

A gland is an epithelial cell or collection of cells specialised for secretion.

Question 33

What is an adenocarcinoma?

Answer 33

Malignant growth derived from glandular tissue or epithelial origin.

Question 34

What are some ways glands can be classified?

Answer 34

Multi or unicellular
Tubular or acinar
Exocrine or endocrine

Question 35

Give 2 examples of unicellular glands.

Answer 35

Goblet cells.

Crypts of lieuberkuhns

Question 36

What is an acinus?

Answer 36

A small sac like cavity surrounded by secretory cells.