Introduction Flashcards

1
Q

what is histology

A

study of microscopic structure of normal tissues
understand how tissues are built to carry out their functions
knowledge of normal histology is essential in histopathological diagnosis of disease, guides treatment

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2
Q

light microscopy

A

most common way to study cells
tissues are mounted on glass slides as thin preparations, stained with appropriate dyes, illuminated by light and viewed using glass lenses

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3
Q

electron microscopy

A

uses parallel beam of electrons instead of light waves, increases resolution
the beams of electrons have shorter wavelengths so have greater magnification than light microscopes
use transmission and scanning

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4
Q

label the light microscope

A

image in the eye
ocular lens
objective lens
specimen
condenser lens
mirror
lamp

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5
Q

tissue preparation for light microscope

A

fixation- preserve a tissue using formalin (LM) or glutaraldehyde (EM)
dehydration- remove water using alcohol
clearing- remove the alcohol
embed in a suitable medium- paraffin
section into thin slices
mount onto the glass slides (easy handling)
stain with various dyes to see the structures
apply coverslip over section

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6
Q

stains for electron microscopes

A

salts of heavy metals
lead citrate or uranyl acetate
areas that bind to the metals are electron dense
areas where the metals don’t bind are electron Lucent

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7
Q

which parts of chromatin are heavy and light staining

A

heterochromatin is dense and euchromatin is light

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8
Q

what is the most commonly used stain

A

H&E
hematoxylin and eosin

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9
Q

hematoxylin

A

is a base
binds to acidic components of the cell, DNA
stains blue
these components are referred to as basophilic

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10
Q

eosin

A

is an acid
binds to cytoplasmic constituents of the cell that have a basic pH
stains pink
these components are referred to as acidophilic

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11
Q

Masson’s trichrome

A

stains nuclei dark blue
stains muscle and cytoplasm red
combination of 3 dyes and reveals the presence of collagen
third stain is normally nuclear counterstain like hematoxylin

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12
Q

Verhoeff’s van Gieson

A

elastic stain
stains black or brown

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13
Q

what do the 4 tissue types develop from

A

3 embryonic layers of tissue
ectoderm
endoderm
mesoderm

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14
Q

what are the 4 tissue types

A

epithelial
muscular
nervous
connective

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15
Q

epithelial tissue overview

A

derived from ectoderm
covers surfaces, lines body cavities and forms solid glands such as salivary glands

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16
Q

muscular tissue overview

A

derived from mesoderm
possess contractile properties

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17
Q

nervous tissue overview

A

derived from ectoderm

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18
Q

connective tissue overview

A

derived from mesoderm
cartilage, bone

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19
Q

ectoderm

A

related to skin

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20
Q

endoderm

A

associated with the gut/lungs

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21
Q

mesoderm

A

vascular
urinary

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22
Q

functions of epithelial tissue

A

protection- of underlying tissues of the body from abrasion and injury
transcellular transport- of molecules across epithelial sheets
secretion- of mucus, hormones, enzymes from various glands
absorption- of material from a lumen (epithelia which cover and line surfaces)
selective permeability- control of movement of materials between body compartments
detection of sensations

23
Q

sensory epithelium

A

neuroepithelium

24
Q

contractile epithelium

A

myoepithelial cells

25
Q

epithelium being avascular

A

adjacent supporting connective tissue through its capillary beds supplied nourishment and oxygen via diffusion through the basement membrane

26
Q

two classifications of epithelia

A

simple: single layer of cells
stratified: composed of two or more layers

27
Q

how are epithelia separated from underlying connective tissue

A

by a thin acellular layer called the basement membrane
provides support and attachment for epithelial cells and acts as a selective diffusion barrier
composed of basal lamina and reticular lamina
basal lamina is secreted by the epithelial cells and consists of the lamina lucid and lamina densa

28
Q

types of simple epithelia

A

squamous (flat)
cuboidal
columnar (with or without cilia)

29
Q

what type of epithelia is this

A

stratified cuboidal
usually confined to the lining of the larger excretory ducts of exocrine glands such as the salivary glands

30
Q

what type of epithelia is this

A

stratified squamous non keratinised
cuboidal basal layer to flattened surface layer, basal cells adherent to the underlying basement membrane include continuously dividing stem cells, offspring shed as enucleate squames

31
Q

what type of epithelia is this

A

transitional epithelium/urothelium
multilayered with cuboidal/polyhedral basal and middle layers and has a unique surface layer
domed and almost columnar when the bladder is undistended
squamous and more flattened when the bladder is distended
found in the urinary tract and bladder

32
Q

what type of epithelia is this

A

pseudo stratified columnar ciliated epithelium
has cilia on the apical surface of the cells that reach the epithelial surface
found in the lining of most of the trachea and primary bronchi, auditory tube, part of the tympanic cavity, the nasal cavity

33
Q

what’s the difference between the two epithelia

A

left is nonkeratinised and right is keratinised
both stratified squamous epithelia
both separated from the connective tissue by the basement membrane
kerinised provides added protection from frictional forces

34
Q

example and function of simple squamous

A

peritoneum
vascular endothelium

facilitates the movement of the viscera (mesothelium), active transport by pinocytosis (mesothelium and endothelium), secretion of biologically active molecules

35
Q

example and function of simple cuboidal

A

collecting tube of the kidney

covering, secretion

36
Q

example of simple cuboidal with microvilli

A

proximal convoluted tubule of the kidney

37
Q

example and function of simple columnar

A

gallbladder

protection, lubrication, absorption and secretion

38
Q

example of simple columnar with microvilli

A

small intestine

39
Q

example of simple columnar with surface cilia

A

Fallopian tube

40
Q

example of simple columnar with pseudo stratification

A

respiratory tract

protection, secretion: cilia-mediated transport of particles trapped in mucus out of the air passages

41
Q

example of simple columnar with goblet cells

A

small and large bowel

42
Q

example of simple columnar with stereo cilia

A

vas deferens

43
Q

example of stratified squamous

A

oral cavity

protection, secretion, prevents water loss

44
Q

example of keratinised stratified squamous

A

epidermis of the skin

protection, prevents water loss

45
Q

example of stratified cuboidal

A

exocrine gland ducts

protection, secretion

46
Q

example of stratified transitional

A

bladder

protection, distensibility

47
Q

junctional complexes are composed of three types, what are they?

A

zonula occludens
zonula adherent
desmosomes (macula adherens)

48
Q

zonula occludens

A

control paracellular diffusion and prevent exchange of intrinsic proteins
impermeable barrier
tight junction

49
Q

zonula adherens and desmosomes

A

junction
deep to tight junctions
links cellist form cohesive epithelium/cell to cell adherence

50
Q

gap junctions

A

present on lateral cell membrane allow intercellular signalling and exchange of ions
provide metabolic and electrical continuity via pores between cells

51
Q

hemidesmosomes

A

anchor the basal layer of cells to basal lamina

52
Q

label the cell

A

microvilli
tight junction
adherens junction
desmosome
intermediate filament
gap junction
hemidesmosome
basal lamina

53
Q

functions of epithelial tissue

A

protection- of underlying tissues of the body from abrasion and injury
transcellular transport- of molecules across epithelial sheets
secretion- of mucus, hormones, enzymes from various glands
absorption- of material from a lumen (epithelia which cover and line surfaces)
selective permeability- control of movement of materials between body compartments
detection of sensations