Prac 1 IMMS - Intro Flashcards
Whats the fluid inside thyroid tissue called
Colloid
Why are there white holes in the images of thyroid cells
The lining epithelial cells are absorbing the colloid
What do thyroid cells look like
- Circles in 2D. Spheres in 3D
2. Lined by single layer if cuboidal/ columnar epithelial cells
Type 1 of preparing tissue (5steps)
- Preserved by fixing it in formalin, which is aqueous sol of FORMALDEHYDE
- Prevents tissue from rotting
- Embedded in parafin - involves extraction of H20 and other substances
- V thin slices (4um) made
- Mounted on microscope slides and stained
Preparing tissue by producing smear is used for?
Solids & fluids e.g. blood — seeing whole cells not slices
How to examine hard tissue e.g. bone
EITHER
Demineralise it to produce thin sections
OR
If want to see mineralised structure, grind it down to produce thick slice
Most commonly used dye combination
H&E - Haematoxylin and eosin
What colour does Haematoxylin stain Nuclei and RNA and why?
Blue bc acidic
What colour does eosin stain cytoplasm and extracelullar fibres
pink
What doesn’t stain with H&E and therefore appears as white spaces
Watery extracellular jelly
What are the 2 things white spaces could be when stained with H&E
GLYCOSAMINOGLYCAN matrix
OR
Artefact - where tissues have failed apart slightly during processing
What does PAS stain? and colour
SUGARS MAGENTA eg goblet cells in small Intestine
and glycosaminoglycans in intestinal brush border
What does VAN GIESON stain and colour
Elastic ( which is difficult to detect with H&E) = wavy brownish bands
ALCIAN BLUE stains what and colour
Mucins - Blue
Why are some cells small?
Need to move around body to complete function e.g. Lymphocytes( 10um- v little cytoplasm n cell mem)
example of large cell
Motor neurone (cell body = 70-100um) but axon can be up to 1m
Meaning of Fusiform and example
Spindle shaped/ eliptical eg smooth muscle cells
Meaning of squamous and example
‘Thin plates” eg squamous epithelium which goes from polygonal cells to squamous as they mature
Shape of erythrocytes
Biconcave discs
Shape of Thyroid cells
cuboidal
Shape of gallbladder cells
Columnar
Why are dormant cells smaller than metabolically active cells?
Do not need to maintain elaborate cellular mechanical machinery in order to exist - only need small no. of mitochondria and ER
Nucleoli function?
DNA —> RNA in transcription
What type of cell is more likely to have nucleoli
Metabolically active
Lifespan of cells in lining of gut
days
Lifespan of erythrocytes
120 days
Lifespan of cells skin
months
Lifespan of connective tissue cells
months
Lifespan of cells in bone
years
Lifespan of cells in tendons
years
Lifespan of cells in skeletal muscle
nearly whole life ( limited regeneration )
Lifespan of cells in brain and nerves
life
Lifespan of cells in cardiac muscle
life
Lifespan of germ cells
life
Dark chromatin
heterochromatin
Lighter chromatin
euchchromatin
size of nucleolus
1-3um
What happens in outer mem of mitochondria
- lipid synthesis
- fatty acid metabolism
What happens in inner membrane of mitochondria
- site of respiratory chain
- & atp prod
What happens in matrix of mitochondria
Krebs cycle
What happens in intermembrane space of mitochondria
Nucleotide phosphorylation
ADP —–> ATP
RER function
site of protein synthesis
SER function
- site of membrane lipid synthesis
- processes synthesised proteins
Golgi apparatus function
- Processes macromolecules synthesised in ER
In what cell is the golgi apparatus visible by light microscopy
Plasma Cell - seen as PERINUCLEAR HOFF (paler area)
Characteristics of plasma cells?
- ECCENTRIC NUCLEUS ( located towards edge of cell)
- CLOCKFACE NUCLEUS ( prominent pattern of euchromatin and heterochromatin)
What is a plasma cell?
Activated B-lymphocyte which produces antibodies
cisFace of golgi apparatus
- Nuclear facing
- Receives transport vesicles from SER
- Phosphorylates some proteins
Medial Golgi
- central part
- forms complex OLIGOSACCHARIDES by adding sugars to lipids and peptides
Trans Golgi network
- proteolysis
- Sorts macromolecules into vesicles which bud from the surface
2 types of cell surface derived vesicles
- PINOCYTOTIC
- PHAGOCYTOTIC
5 Types of vesicle
- cell surface derived
- ER derived
- Golgi derived
- lysosomes
- peroxisomes
peroxisome purpose
mem bound organelles containing enzymes which oxidise long chain fatty acids `
Why lysosome dangerous?
Bc site of protein degradation
How is cell protected from lysosome degradation
Separation between enzymes which lower pH and enzymes which degrade proteins at low pH
= HYDROLASE vesicles fuse with ENDOSOMES == ENDOLYSOSOMES (which can do both)
Endosomes - bare H+ -ATPase on them- pumps H+ in vesicle = lowers pH
Hydrolase- contains enzymes which degrade at low pH
Cytoskeleton function
- made of many filaments
- supports cell shape
Smallest microfilament?
Actin
what is actin and what does it do
- Globular G-actin polymerises into filamentous F-actin
- forms bracing mesh ( CELL CONTEX) on the inner surface of cell membrane
What forms meshwork of microtubules when cells divide and why
TUBULIN - used to act as a scaffold for chromosomes during mitosis and meiosis
- made of alpha and beta tubulin which arrange in groups of 13 to form hollow tubes
Only cell tubulin isn’t found in and why
erythrocytes bc they don’t divide
how many types of intermediate filaments are there
6 types of protein
what do intermediate filaments do and how do they work
they’re anchored to transmembrane proteins and spread tensile forces through tissues
BUT
Specific functions of diff types not known
How do intermediate filaments have diagnostic utilities
bc with immunohistochemistry can stain diff cells for diff types of intermediate filaments ( IM) - and diff types of IM are found in diff cell types
where cytokeratins found
epithelial cells
where desmin found
Myocytes
where glial fibrillary acidic protein found
astrocytic glial cells
where neurofilament proteins found
neurones
where nuclear laminin found
nuclei of all cells
Where vimentin found
mesodermal cells
Why is lipofuscin found
result of peroxidation of lipids in older cells (wear and tear pigment)
where is lipofuscin found most commonly
hearts and livers of elderly
What does lipofuscin look like
men-bound orange brown pigment
where do lipids accumulate
non- membrane bound vacuoles
why do lipids appear as white spaces in cells
bc dissolve in processing
lipids normally found where
adipocytes (fat cells)
lipids abnormally found where
hepadocytes (Liver cells )
what is the only microscopy is glycogen seen in
electron
- however are diseases where glycogen accumulates in cytoplasm of cells and become visible with light microscopy
Why does glycogen appear as white spaces
- doesn’t stain
- washes out during tissue processing
Whats in interstitial fluid
- water
- salts in solution
- peptides & proteins
- extracellular solid material like fibrillar proteins eg tendons and glycosaminoglycan jelly
some tissues have inorganic salts as solids in them e.g….
calcium in bone
types of epithelia tissue
- protection
- absorbtion
- secretion
types of muscle tissue
- Skeletal
- smooth
- cardiac
types of supporting tissues
- cartilage
- bone
- tendons
- blood
types of nerves
- brain
- peripheral
- visceral
types of germ cells
- ova
- sperm
