Epithelia

Question 1

Simple Squamous Epithelia

Locations (6 points)

Answer 1

-Lining of blood vessels “endothelium”
-Lining of body cavities - pericardium, pleura, pertoneum ‘mesothelium’
-Respiratory epithelium (pulmonary alveoli)
-Bowman’s capsule (kidney)
-Loop of Henle (kidney
)-Inner and middle ear

Question 2

Simple Squamous EpitheliaFunctions(LGBaT)

Answer 2

• Lubrication (pericardium, pleua, peritoneum/viscera)
• Gas exchange (alveoli)
• Barrier (bowmans capsule)
• Active transport via pinocytosis (meso/endothelium)

Question 3

Simple Cuboidal EpitheliaLocations (four)

Answer 3

• Thyroid follicles
• Small ducts of many exocrine glands
• Kidney tubules
• Surface of the ovary (germial epithelium

Question 4

Simple Cuboidal Epithelia - It’s glandular!Functions (four)Baah(riatric)

Answer 4

• Barrier/covering (ovary)
• Absorption & Conduit (exocrine glands)
• Absorption & Secretion (kidney tubules)
• Hormone synthesis, storage and metabolism (thyroid)

Question 5

Simple Columnar EpitheliaLocations (seven)

Answer 5

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

Question 6

Simple Columnar EpitheliaFunctions (four)LAST

Answer 6

• Lubrication (small intestine & colon)
• Absorption (small intestine, colon & gall bladder)
• Secretion (stomach lining & gastric pits, small intestine & colon)
• Transport (oviduct)

Question 7

(simple) Pseudostratified EpitheliaLocations (five)

Answer 7

• Lining of nasal cavity, trachea and bronchi- Epididymis and ductus deferens- Auditory tube and part of typanic cavity- Lacrimal sac- Large excretory ducts

Question 8

(simple) Pseudostratified EpitheliaFunctions (four)MAPS

Answer 8

• Mucus secretion (Nasal Cavity, trachea and bronchi (URT)
• Absorption (Epdidiymis)
• Particle trapping and removal (URT)
• Secretion and conduit (URT, ductus deferens)

Question 9

Stratified Squamous Non-Keratinised EpitheliaLocations (seven)

Answer 9

• Oral cavity
• Oesophagus
• Larynx
• Vagina
• Part of anal canal
• Surface of cornea
• inner surface of eyelid

Question 10

Stratified Squamous Non-Keratinised EpitheliaFunctions (two)

Answer 10

• Protections against abrasion

- Reduces water loss whilst remaining moist

Question 11

Stratified Squamous Keratinised EpitheliaLocations (two)

Answer 11

• Surface of skin

- Limited distribution in oral cavity

Question 12

Stratified Squamous Keratinised EpitheliaFunctions (four)

Answer 12

• Protection against abrasion
• Prevents water loss
• Prevents ingress of microbes
• Shields against UV light damage

Question 13

Stratified Transitional (urinary) EpitheliaLocations (four)

Answer 13

• Renal calyces
• Ureters
• Bladder
• Urethera

Question 14

Stratified Transitional (urinary) EpitheliaFunctions (two)

Answer 14

• distensibility

- protection of underlying tissue from toxic chemicals

Question 15

Basement membranePosition + Description

Answer 15

Thin, flexible, acellular layer which lies between epithelial cells and subtending connecting tissue

Question 16

Basement membraneStructure

Answer 16

• Basal lamia, laid down by epithelial cells
• Thickness increased by a variably thick layer of reticular fibrils (type 3 collagen), elaborated by subtending connective tissue

Question 17

Basement MembraneFunction (three)

Answer 17

• Strong, flexible layer to which epithelial cells adhere- Serves as cellular and molecular filter
• Degree to which malignant cells penetrate basmenent membrane highly relevant to prognosis

Question 18

Defintion of Epithelial tissue

Answer 18

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

Question 19

Describe rate of renewal in epithelial tissue

Answer 19

• High rate of renewal
• Differs depending on type and function
• Constant rate unless accelerated by damage
• In skin, time from differentiation, migratiion to exterior, keritnization and death 28 days.

Question 20

State the meaning of the term tissue

Answer 20

A collection of cells specialised to perform a particular function. Aggregation of tissues constitutes organs.

Question 21

Define histology

Answer 21

The study of the structure of tissues by means of special staining techniques combined with light and electron microscopy

Question 22

Why is histology important to doctors?

Answer 22

Many diseases, such as chron’s or cancer, doctors will not give a treatment until histopathologists have given a diagnosis.

Question 23

How big are most cells?

Answer 23

10-20 micrometers

Question 24

What is a smear and what tissues can it be used on?

Answer 24

Collect cells by spontaneous/mechanical exfoliation and smeared on slide. Cervix or the buccal cavity

Question 25

What is a curettage and what tissues can it be used on?

Answer 25

Remove tissue by scooping/scraping | Endometrial lining of uterus

Question 26

What is a needle biopsy and what tissues can it be used on?

Answer 26

Put into tissues to gather cells | Brain, breast, liver, kidney, muscle

Question 27

What is a direct incision and what tissues can it be used on?

Answer 27

Cut directly into tissues of interest and remove tissueSkin, mouth, larynx

Question 28

What is endoscopy and what tissues can it be used on?

Answer 28

Removal of tissues via intruments through an endoscopeLung, intestine, bladder

Question 29

What is transvascular and what tissues can it be used on?

Answer 29

Tissue taken from blood vessels | Heart, liver

Question 30

Give two fixatives

Answer 30

Glutaraldehyde and formaldehyde

Question 31

What do fixatives do on a cellular level?

Answer 31

Form covalent bonds between free amino groups of proteins, cross lining adjacent proteins. This arrests biological activity, preventing autolysis and putrefaction and makes cells more ammenable to staining and rendering them more stable.

Question 32

What is a shrinkage artifact and how can it be caused?

Answer 32

Abnormalities in slide, caused by tissue dehydration and re-hydration in slide preparation process.

Question 33

What does Haematoxylin stain, and what colour? Is haemotoxylin basic or acidic?

Answer 33

Acidic components of cell, such as Nucelolus (RNA), Chromatin (DNA). Stains them purple/blue. Haemotoxylin is basic.

Question 34

What does Eosin stain, and what colour? Is Eosin basic or acidic?

Answer 34

Stains basic components of cells, such as cytoplasmic proteins and extracellular fibres. Stains them pink. Eosin is acidic.

Question 35

What is PAS?

Answer 35

Period Acid-Schiff | Stains carbohydrates and glycoproteins magenta.

Question 36

What is Phase contrast microscopy, and what are its advantages?

Answer 36

Uses interference effects of two comibining light wavesEnhances the image of unstained cells

Question 37

What is dark field microscopy, and what are its advantages?

Answer 37

Exclude unscattered beam (light/electron) from the image.Good with live and unstained samples

Question 38

What is fluorescent microscopy, and what what are its advantages?

Answer 38

Target molecule of interest with fluorescent antibodies Use multiple different fluorescent stains on one specimen

Question 39

What is confocal microscopy, and what are its advantages?

Answer 39

Tissue labelled with one or more fluorescent probesEliminates "out of focus flare", Allows 3d imaging from a series of 2D imagesAllows imaging of living specimens.

Question 40

Define epithelial cells

Answer 40

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

Question 41

What is the function of microvilli occludin?

Answer 41

Bind adjacent plasma membranes tight together in the apical portions of some epithelia. This means membrane proteins cannot bypass zonula occluden, so cell is able to restrict certain proteins to its apical surface and segregate other to its lateral basal surfaces.

Question 42

Define microvili

Answer 42

Apical extensions that greatly increase the surface area for selective absoption of intestinal contenes

Question 43

Define stereocillia

Answer 43

Very long microvili extrend from surface of ductus deferens and the epididymis. May have an absorptive function.

Question 44

Define cillia

Answer 44

Extensions from cells which beat in coordinated waves. Found in the lining of trachea where they sweep mucus and dirt out of liungs. Also found in fallopian tubes, where they move the ovum from the ovary.