Histology Flashcards
What does alcian blue stain?
GAG-rich structures
Mucous goblet cells
Mast cell granules
Cartilage matrix
What does Perl’s stain do?
Stains ferric iron a Prussian blue colour.
Give two places where you would find stratified squamous non-keratinising epithelium:
- Mouth
2. Vagina
What can be used to stain basement membranes?
Periodic acid shiff (PAS).
What is contact inhibition?
When epithelial cells will grow until they are in contact with their neighbours where they will then stop.
What help to spread mechanical forces across a tissue?
Desmosomes that join the cytoskeletons of adjacent cells.
What are connective tissue cells mainly derived from?
Pluripotent undifferentiated mesenchymal cells.
Name the three main types of connective tissue:
- Fibrous
- Hard
- Fatty
What do fibroblasts secrete?
Collagen - in the form of tropocollagen subunits.
What is ground substance?
An amorphous gel-like substance which contains mainly glycosaminoglycans (GAGS) which link together to form proteoglycans. It also contains some invisible fibres such as laminin and fibronectin.
What is another name for type III collagen?
Reticulin
Where is reticulin found?
Liver, bone marrow, lymph node, spleen and Peyer’s patches.
What colour will extracellular fibres stain?
Pink, due to eosin.
What stain do we have to use for Reticulin and why?
Silver stain, because it does not show up on H + E.
What produces elastic fibres?
Fibroblasts.
What is the difference between white and brown adipocytes?
White adipocytes have one large fat globule whereas brown adipocytes have many smaller globules.
What do white adipocytes sometimes get confused with on a histological slide?
Lung cells.
- as the fat globule is usually lost during processing, leaving a large white space.
Why is brown adipose tissue important in neonates?
It is used in thermoregulation as heat is produced on its breakdown.
(Found on the backs and shoulders of children and shrinks as you age)
What are the three types of cartilage?
Hyaline, elastic and fibrocartilage.
What do chondrocytes (blasts if immature) produce?
The major extra cellular component of cartilage.
What type of cartilage is found in synovial joints and what are some of it’s features?
Hyaline Cartilage.
- Blueish grey matrix with chondrocytes entrapped within it.
- glassy appearance with no visible fibres.
- perichondrium on the outside, which is comprised of fibroblasts and extracellular collagen fibres.
What is found in the annulus fibrosus and what are it’s features?
Fibrocartilage.
- matrix rich in visible collagen fibres and bas entrapped chondrocytes.
- has a perichondrium.
What type of cartilage is in the epiglottis and what are it’s features?
Elastic cartilage.
- Blue/grey with entrapped chondrocytes.
- Elastic fibre in the matrix that stain.
What are the two types of synovial cell?
Type A - Phagocytes.
Type B - Rich in RER and secrete synovial fluid.
Make up the 4 layers of the synovium which is a high vascularised and innervated tissue.
What are the layers of an artery from the inside to the out?
Lumen -> endothelium -> basement membrane -> Intima -> internal elastic lamina -> media -> external elastic lamina -> adventitia.
When is the vessel defined as an arteriole and not an artery?
- When is has 3 or fewer layers of muscle in the media.
And/Or - It has a diameter of 100um or smaller.
What are pericytes and where are they found in the body?
They are contractile cells that are present in capillaries and venules - in the smallest vessels they form an incomplete ring. They are replaced by smooth muscle in veins.
What is missing from the walls of a vein?
Elastic lamina.
What are the characteristics of a lymph vessel?
- Thin layers of intima, media and adventitia.
- Contains valves like veins.
- Carries lymph not blood.
What are the layers of connective tissue in nerves?
- Endoneurium - binds individual axons together.
- Perineurium - surrounds groups of axons to form fascicles.
- Epineurium - binds fascicles together to form nerve fibres.
What colour does silver stain (golgi’s method) stain neuronal tissue?
Dark brown/black.
Are schwann cells present with unmyelinated axons?
Yes - they are just not wrapped round. The may be more than one unmyelinated axon per schwann cell.
Where are the cell bodies of lower motor neurons found?
The anterior part of the spinal grey matter (usually ventral horn).
Where are the cell bodies of sensory neurons found?
In the dorsal root ganglion, just before the spinal chord.
What are the four layers of the heart? (from inside to out)
Endocardium, Myocardium, Epicardium, Pericardium.
What are the three layers of the pericardium? (From outside to in)
- Fibrous pericardium.
- Parietal pericardium.
- Visceral pericardium (epicardium)
Why is the Heart regarded as an endocrine organ?
Myocytes of the atria have perinuclear neuroendocrine granules containing atrial natriuretic peptide.
Why do purkinje fibres stain white on H + E?
Because they have a glycogen rich cytoplasm.
What are the percentages of the different constituents of the blood?
Plasma (56%)
Erythrocytes (43%)
Leukocytes (1%)
What is serum?
Plasma WITHOUT clotting factors.
What is the lifespan of an erythrocyte?
Approximately 120 days.
What is the lifespan of a platelet?
8 to 9 days in circulation.
What maintains the cell shape of an erythrocyte?
The endoskeleton that is attached to a protein called spectrin.
What are the most common type of leukocyte?
Neutrophils.
How do neutrophils destroy bacteria?
By engulfing them and releasing reactive oxygen species (respiratory/oxidative burst).