TOB S1 - Light Microscopy and Epithelia Flashcards Preview

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Flashcards in TOB S1 - Light Microscopy and Epithelia Deck (49)
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1
Q

What is meant by the term tissue?

A

A collection of cells specialised to perform a particular function

2
Q

Why is histology valuable to diagnosing disease?

A

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

3
Q

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

A

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

Cervix or buccal cavity

4
Q

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

A

Removal of tissue via scooping or scraping

Endometrium of uterus

5
Q

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

A

Needle used to gather cells

Brain, kidney, muscle, breast, liver

6
Q

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

A

Cut into and remove tissue

Skin, larynx, mouth

7
Q

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

A

Removal via endoscope instrument

Lung, intestine, bladder

8
Q

What tissues can trans vascular biopsy be used to sample?

A

Heart, liver

9
Q

Why does biopsied tissue require fixation?

A

Preserves cellular structure by cross linking macromolecules

No autolysis or putrefaction

10
Q

Commonly used fixatives for tissue include?

A

Glutaraldehyde, formaldehyde

11
Q

Why do shrinkage artefacts arise in preserved tissues?

A

Dehydration and rehydration during fixing

12
Q

Why is histological staining useful?

A

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

13
Q

Haemotoxylin staining is taken up by _________

A

Acidic components of cells eg Nucleolus or chromatin

14
Q

What colour is conferred onto tissue that take up haemotoxylin?

A

Purple/blue

15
Q

Eosin staining is taken up by ________

A

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

16
Q

Eosin staining confers what colour?

A

Pink

17
Q

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

A

Carbohydrates, glycoproteins

Magenta

18
Q

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

A

Uses interference of two combined light waves

Enhances un-stained cell image

19
Q

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

A

Uses light not directly aimed at objective lens

Enhances contrast in un-stained samples

20
Q

What is confocal microscopy and what advantages does it have?

A

Tissue labelled with fluorescent probes

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

21
Q

Define epithelia

A

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

22
Q

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

A

Skin
Alimentary tract
Respiratory tract
Genitourinary tract

23
Q

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

A
Pericardial sac
Pleural sac
Peritoneum
Blood vessels
Lymphatic vessels
24
Q

Where can simple squamous epithelium be found?

A
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
25
Q

Functions of simple squamous epithelia include?

Relate this to location

A

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

26
Q

Where are simple cuboidal epithelia found?

A

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

27
Q

Function of simple cuboidal epithelia include?

Relate this to location

A

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

28
Q

Simple columnar epithelium are found where?

A
Stomach lining 
Small intestine and colon
Gallbladder
Large ducts of exocrine glands
Uterus
Oviducts
Ductili efferents of testis
29
Q

Functions of simple columnar epithelia include?

Relate this to location

A

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

30
Q

Pseudo stratified epithelia is found where?

A

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

31
Q

Functions of pseudo stratified epithelia include?

Relate this to location

A

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

32
Q

Stratified squamous non keratinised epithelia can be found where?

A
Oral cavity
Oesophageal
Larynx
Vagina
Part of anal canal
Surface of cornea
Inner surface of eyelid
33
Q

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

A

Protection against abrasion (all sites)

Reduces water loss while remaining moist.

34
Q

Stratified squamous keratinised epithelia can be found where?

A

Surface of skin

Limited distribution in oral cavity

35
Q

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

A
Protection from abrasion and trauma
Prevents water loss
Prevents ingress of microbes
Shields from UV damage
(All sites)
36
Q

Stratified transitional epithelia (urothelium) found where?

A

Renal calices
Ureters
Bladder
Urethra

37
Q

Functions of stratified transitional epithelia include?Relate this to location

A

Distension
Protection from toxic chemicals
(All sites)

38
Q

Where would you find a basement membrane?

A

Between epithelia and subtending tissues

39
Q

Describe a basement membrane

A

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

40
Q

Function of basement membrane?

A

Epithelium adheres to it

Cellular and molecular filter (prevents malignant ingress through it)

41
Q

Epithelial cell renewal rate can be described as?

A

Constant rate for different epithelia

42
Q

Rate of renewal for skin epithelium?

A

28 days

43
Q

Rate of renewal for small intestine epithelia?

A

4-6 days

44
Q

Epithelia renewal can be triggered by?

A

Damage or trauma

45
Q

Epithelial regeneration rate depends on?

A

Location and function

46
Q

What are microvilli and what is their function?

A

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

47
Q

What are stereo cilia and what is their function??

A

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

48
Q

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

A

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.

49
Q

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

A

Creates the zona occludens

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

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