TOB S1 - Light Microscopy and Epithelia

Question 1

What is meant by the term tissue?

Answer 1

A collection of cells specialised to perform a particular function

Question 2

Why is histology valuable to diagnosing disease?

Answer 2

The study of tissues can reveal and be final proof of a range of diseases
Eg cancer

Question 3

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

Answer 3

Collection of cells via spontaneous/mechanical exfoliation, then smeared on slide

Cervix or buccal cavity

Question 4

What is Curettage and what tissues can it be used to sample?

Answer 4

Removal of tissue via scooping or scraping

Endometrium of uterus

Question 5

What is Needle biopsy and what is it used to sample?

Answer 5

Needle used to gather cells

Brain, kidney, muscle, breast, liver

Question 6

What is direct incision biopsy and what tissues is it used to sample?

Answer 6

Cut into and remove tissue

Skin, larynx, mouth

Question 7

What is Endoscopic biopsy and what tissues can it be used to sample?

Answer 7

Removal via endoscope instrument

Lung, intestine, bladder

Question 8

What tissues can trans vascular biopsy be used to sample?

Answer 8

Heart, liver

Question 9

Why does biopsied tissue require fixation?

Answer 9

Preserves cellular structure by cross linking macromolecules

No autolysis or putrefaction

Question 10

Commonly used fixatives for tissue include?

Answer 10

Glutaraldehyde, formaldehyde

Question 11

Why do shrinkage artefacts arise in preserved tissues?

Answer 11

Dehydration and rehydration during fixing

Question 12

Why is histological staining useful?

Answer 12

Different types of tissue can be stained different colours/shades to allow differentiation between them

Question 13

Haemotoxylin staining is taken up by _________

Answer 13

Acidic components of cells eg Nucleolus or chromatin

Question 14

What colour is conferred onto tissue that take up haemotoxylin?

Answer 14

Purple/blue

Question 15

Eosin staining is taken up by ________

Answer 15

More basic components of cells eg most cytoplasmic proteins and extra cellular fibres

Question 16

Eosin staining confers what colour?

Answer 16

Pink

Question 17

Periodic acid schiff (PAS) stains what cellular components what colour?

Answer 17

Carbohydrates, glycoproteins

Magenta

Question 18

What is Phase contrast microscopy and what advantages does it have?

Answer 18

Uses interference of two combined light waves

Enhances un-stained cell image

Question 19

What is dark field microscopy and what advantages does it have?

Answer 19

Uses light not directly aimed at objective lens

Enhances contrast in un-stained samples

Question 20

What is confocal microscopy and what advantages does it have?

Answer 20

Tissue labelled with fluorescent probes

Can be used to generate a 3D image from a series of 2D images

Question 21

Define epithelia

Answer 21

Sheet of contiguous cells of varying embryonic origins that cover external and internal surface of the body

Question 22

What external or internal opening to external space does epithelia cover?

Answer 22

Skin
Alimentary tract
Respiratory tract
Genitourinary tract

Question 23

What interior spaces that don’t open to exterior are covered by epithelium?

Answer 23

Pericardial sac
Pleural sac
Peritoneum
Blood vessels
Lymphatic vessels

Question 24

Where can simple squamous epithelium be found?

Answer 24

Lining the blood vessels (endothelium)
Lining of body cavities (mesothelium)
Alveoli
Inner and middle ear
Bowman's capsule and Loop of Henle in the kidney

Question 25

Functions of simple squamous epithelia include? | Relate this to location

Answer 25

Lubrication (visceral linings) Gas exchange (alveoli) Barrier (Bowman's capsule) Active transport via pinocytosis (meso/endothelium)

Question 26

Where are simple cuboidal epithelia found?

Answer 26

Thyroid follicles Ducts of exocrine glands Kidney tubules Surface of ovary (germinal epithelium)

Question 27

Function of simple cuboidal epithelia include? | Relate this to location

Answer 27

Absorption and conduit (exocrine glands) Absorption and secretion (kidney tubules) Barrier (ovary) Hormone synthesis, storage and mobilisation

Question 28

Simple columnar epithelium are found where?

Answer 28

``` Stomach lining Small intestine and colon Gallbladder Large ducts of exocrine glands Uterus Oviducts Ductili efferents of testis ```

Question 29

Functions of simple columnar epithelia include? | Relate this to location

Answer 29

Absorption (intestines and gallbladder) Secretion (stomach lining, gastric pits, intestines) Lubrication (small intestine and colon) Transport (oviducts)

Question 30

Pseudo stratified epithelia is found where?

Answer 30

Lining of nasal cavity, bronchi and trachea Epididymis and ductus deferens Auditory cavity and part of tympanic cavity Lacrimal sacs Large excretory ducts

Question 31

Functions of pseudo stratified epithelia include? | Relate this to location

Answer 31

Secretion and conduit (upper resp tract and ductus deferens) Absorption (epididymis) Mucus secretion (URT) Particle trapping and removal (URT)

Question 32

Stratified squamous non keratinised epithelia can be found where?

Answer 32

``` Oral cavity Oesophageal Larynx Vagina Part of anal canal Surface of cornea Inner surface of eyelid ```

Question 33

Functions of stratified squamous non keratinised epithelia include? Relate this to location

Answer 33

Protection against abrasion (all sites) | Reduces water loss while remaining moist.

Question 34

Stratified squamous keratinised epithelia can be found where?

Answer 34

Surface of skin | Limited distribution in oral cavity

Question 35

Functions of stratified squamous keratinised epithelia include? Relate this to location

Answer 35

``` Protection from abrasion and trauma Prevents water loss Prevents ingress of microbes Shields from UV damage (All sites) ```

Question 36

Stratified transitional epithelia (urothelium) found where?

Answer 36

Renal calices Ureters Bladder Urethra

Question 37

Functions of stratified transitional epithelia include?Relate this to location

Answer 37

Distension Protection from toxic chemicals (All sites)

Question 38

Where would you find a basement membrane?

Answer 38

Between epithelia and subtending tissues

Question 39

Describe a basement membrane

Answer 39

Consists of basal lamina Thickness variable with introduction of type III collagen Thin, flexible and acellular

Question 40

Function of basement membrane?

Answer 40

Epithelium adheres to it | Cellular and molecular filter (prevents malignant ingress through it)

Question 41

Epithelial cell renewal rate can be described as?

Answer 41

Constant rate for different epithelia

Question 42

Rate of renewal for skin epithelium?

Answer 42

28 days

Question 43

Rate of renewal for small intestine epithelia?

Answer 43

4-6 days

Question 44

Epithelia renewal can be triggered by?

Answer 44

Damage or trauma

Question 45

Epithelial regeneration rate depends on?

Answer 45

Location and function

Question 46

What are microvilli and what is their function?

Answer 46

Apical extensions to increase surface area of intestinal epithelium Increase surface area for selective absorption

Question 47

What are stereo cilia and what is their function??

Answer 47

Very long microvilli found in Ductus deferens and epididymis May have absorptive function

Question 48

What are cilia and where are they found? What do they do?

Answer 48

Apical cell extensions on respiratory epithelia and in oviducts Beat in waves Sweep mucus and dirt out of respiratory tract Move the ovum down the oviduct Feature the 9+2 micro tubule configuration.

Question 49

What is the purpose of microvilli occludin in simple columnar epithelia?

Answer 49

Creates the zona occludens | Binds the cells together tightly in apical portion of cells, restricts proteins to either basal or apical surfaces