Theme 1 : Histology Flashcards
Germ line cells
reproductive cells (ovocytes/eggs, spermatozoa)
How are tissues received in the laboratory?
in fixative (mostly formalin = 10% formaldehyde in H2O)
What does Fixation do?
Prevents autolysis (self-digestion)
ensures preservation (e.g. protein preservation)
hardens the tissue for cutting
How do we process tissues into a wax block?
Saturation in alcohol removes water
Saturation in xylene removes alcohol
Saturation in paraffin removes xylene
What is Immunohistochemistry?
A way to detect proteins on/in cells or tissues
An antibody is labelled with a brown marker dye / indicator
That means: Brown slide = protein present
Blue background stain only = protein absent
What are the types of Epithelium cells?
Squamous
Glandular (columnar)
Urothelium of urinary tract
Endothelium of vessels
mesothelium/serosa
What are the 6 types of tissues?
Epithelium
Connective tissue
Muscle
Neural tissue
Germ line cells
Blood
What are Epithelium cells?
The cells covering a surface (internal or external)
The underlying basement membrane
Solid organs are often mostly composed of epithelial tissues e.g. liver, kidneys, glands, … + stroma
Squamous epithelium properties
protective
glandular epithelium properties
productive (glandular secretions)
Urothelium epithelium properties
waterproof and stretchable
mesothelium epithelium properties
lines large body cavities (pleura, serosa)
endothelium epithelium properties
lines blood vessels and lymphatic channels
What are the examples that show epithelium cells interface between biological compartments?
high cell turnover
regulation of molecular exchanges
sensory functions, immune functions
Epithelium cells originate from…
ectoderm, mesoderm, endoderm
Ingrowths of epithelium specialize to form…
glands and ducts
Describe the cells in the cervix
squamous and glandular / columnar epithelium next to each other
glandular / columnar epithelium produces mucin
What are the options of shape or morphology when classifying epithelia?
Squamous
Cuboidal/columnar
Simple
Stratified
Ciliated
Keratinising
What are the options of function when classifying epithelia?
Glandular (secretions)
Neuroendocrine
What are the options of location when classifying epithelia?
Urothelium
Endothelium
Mesothelium
What is Simple epithelia? Can you give examples (5)
One layer and basement layer
endothelium
mesothelium
kidney tubules
alveoli
respiratory tract
Give the subclassification and sites of squamous epithelium cells
simple - endothelium, loop of henle
stratified - oesophagus
stratified, keratinising - skin (epidermis)
Give the subclassification and sites of cuboidal epithelium cells
Simple - surface of ovary
Stratified - larger ducts of exocrine glands
Give the subclassification and sites of columnar epithelium cells
Simple - gallbladder
Pseudostratified, ciliated - Fallopian tubes
> 1 layer+bm means
stratified means that the higher layers have NO connection to the basement membrane
Describe Epithelium structure (4)
Cells are polarized basal (to the bm) / apical (to the surface)
Basement membrane (collagen)
Cells are adherent to each other
Cytokeratin intermediate filaments within the cytoplasm
In the epithelium structure, what does the property of the cells being adherent to each other do?
tight junctions to seal borders
desmosomes for strength
gap junctions to allow transfer of molecules
Cytokeratin intermediate filaments within the cytoplasm…
to provide internal scaffold
What are cytokeratins?
intermediate filaments of epithelia
CK5/6
squamous epithelium e.g. oesophagus
CK14
squamous epithelium e.g. skin
CK7 (2)
glandular epithelium e.g. breast
urothelium
CK20 (2)
glandular epithelium e.g. colon
urothelium umbrella cells
What are the subclassifications of glandular epithelium? Can you give an example for each one?
Simple - Colon
Compound - breast
What are the subclassifications of glandular epithelium (solid organs) ? Can you give an example for each one?
Exocrine - pancreas (acinar tissue)
Endocrine - pancreas (islets of langerhans)
What are endocrine glands?
Glands with no ducts
Secretion into the blood
How are glands formed from?
Specialized cuboidal/columnar epithelial cells with a secretory ability/function.
What are glands never?
Squamous
Which glands have ducts?
Exocrine glands
Describe the layers in blood vessels (from inside the lumen to outside)
Intima
IEL - internal elastic lamina
Media
EEL - extrenal elastic lamina
Adventitia
What does the initma consists of
Simple layer of endothelium and loose connective tissue
What is the IEL and EEL made of?
elastin
What does the media layer consist of?
circumferential smooth muscle
What does the adventitia layer consist of?
Collagen and little arteries, veins and nerves to supply the vessel wall tissues - these are called vasa vasorum
What are the types of arteries?
Elastic arteries (large caliber)
Muscular arteries (medium caliber)
Arterioles (small caliber)
Where are elastic arteries found?
Aorta, large pulmonary arteries
Where are muscular arteries found?
Main distributing branches e.g. cerebral and coronary muscles
Describe the composition of veins
No elastica layers
Thin walled
Valves
