Epithelia

Question 1

What is the definition of epithelia?

Answer 1

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

Question 2

Which exterior surface is lined with epithelia?

Answer 2

Skin

Question 3

Which interior surfaces that open to the exterior are lined with epithelia?

Answer 3

• GI Tract
• Respiratory tract
• Genitourinary tract

Question 4

Which interior surfaces that do not open to the exterior are lined with epithelia?

Answer 4

• Pericardial sac
• Pleural sac
• Peritoneum
• Blood vessels
• Lymphatic vessels

Question 5

What is the function of simple squamous epithelia?

Answer 5

• Lubrication
• Gas exchange
• Barrier
• Active transport via pinocytosis

Question 6

Where is simple squamous epithelia found?

Answer 6

• Endothelium
• lining of body cavities (pleura, pericardium, peritoneum; all lined with mesothelium)
• Alveoli
• Bowman’s capsule
• Loop of Henle (kidney)
• Inner and middle ear

Question 7

What is the function of simple columnar epithelia?

Answer 7

• Absorption
• Secretion
• Lubrication
• Transport

Can have cilia

Question 8

Where is simple columnar epithelia found?

Answer 8

• Stomach lining and gastric pits
• Small intestine and colon
• Gall bladder
• Large ducts of some exocrine glands
• Uterus
• Oviducts
• Ductuli efferents of testis

Question 9

Where is pseudostratified epithelia found?

Answer 9

• Lining of nasal cavity, trachea and bronchi
• Epididymis
• Lacrimal sac
• Large excretory ducts
• Auditory tube

Question 10

What are the functions of pseudostratified epithelia?

Answer 10

• Secretion and conduit
• Absorption
• Mucus secretion
• Particle trapping and removal

Question 11

What are the functions of simple cuboidal epithelia and where is it found?

Answer 11

• Absorption and conduit (exocrine glands)
• Absorption and secretion (kidney tubules)
• Barrier (Ovary)
• Hormone synthesis and storage (thyroid follicles)

Question 12

Where is stratified keratinised squamous epithelia found?

Answer 12

• Surface of skin

- limited distribution in oral cavity

Question 13

What is the function of stratified keratinised squamous epithelia?

Answer 13

• Protection against abrasion and trauma
• Prevention of water loss
• Protects against ingress of microbes

Question 14

What is the function of stratified squamous non-keratinised epithelia?

Answer 14

• protection against abrasion

- reducing water loss whilst remaining moist

Question 15

Where is stratified squamous non-keratinised epithelia found?

Answer 15

• oral cavity
• oesaphagus
• larynx
• vagina
• part of anal canal
• surface of cornea
• inner eyelid

Question 16

Where is stratified transitional epithelia found?

Answer 16

• Uterus
• Urethra
• Bladder
• Renal calyces

Question 17

What is the function of transitional epithelia?

Answer 17

• Distensibility

- Protection from toxic chemicals

Question 18

What are stereocili and where are they found?

Answer 18

• Very long cilia found in ductus deferens and epididymis

- absorptive

Question 19

What is basement membrane?

Answer 19

-Thin, flexible, acellular layer (basal lamina), between epithelia and subtending connective tissue that epithelial cells adhere to

Question 20

How is the is the thickness of the basal lamina determined?

Answer 20

Determined by thickness of reticular fibrils (Type 3 collagen)

Question 21

How are renewal rates of epithelia determined?

Answer 21

Depends on function and location, constant renewal rate. Some epithelial cells aren’t renewed but proliferation triggered by damage or loss of cells