Histology- intro, epithelia, connective blood vessels Flashcards
What does periodic acid schiff stain show?
It stains basement hexose sugars Magenta such as goblet cells cartilage matrix, glycogen, basement membranes
What does haemotoxylin stain?
Nuclei RNA it stains them blue
What does Eosin stain?
Colloidal proteins(plasma) and keratin. it stains them pink or orange/red.
What does Perl’s stain?
Ferric iron a prussian blue
What does Alacian blue stain?
GAG- rich structures mucous goblet cells mast cell granules and cartilage matrix.
Iron haematoxylin stains what?
nuclei and elastic fibres are black.
What is a smear used for?
looking at blood mainly but can be done with solid tissues
How can tissues be prepared to look at them under a microscope?
The tissue are fixed with formalin. then embedded in wax/parafin which removes lipids.
What is a thick slice?
when some tissue is ground up
What size are smaller cells roughly?
10 micrometers
What shape can cells be classified as?
rounded, polyconal, fusiform(spindle shaped), squamous, cuboidal, columnar
Are dormant cells usually bigger or smaller than metabolic cells?
dormant are usually smaller than others.
Which cells last your whole life?
the nerves and brain cells and also heart muscles
Which cells last only a few days?
the cells of the intestinal tract
What is the nucleus?
houses DNA there is euchromatin which is dark and hetero chromatin which is light
What is the nucleolus?
Where ribosomal RNA is produced darker area of the nucleus.
What is a mitochondrium?
they are powerhouses of the cells the have mDNA and are site of oxidative phosphorylation and fatty acid oxidation.
what are the functions of associated enzymes of the mitochondrion in the outer membrane, inner membrane, matrix and intermembranous space?
outer- lipid synthesis, fatty acid metabolism
inner- respiratory chain ATP production.
matrix- TCA cycle
inter membranous space- nucleotide phosphorylation.
what do the golgi aparatus do?
processes macro molecules in the endoplasmic reticulum.
What does the RER do?
it produces proteins with its ribosomes
What is the sER?
It producesl membrane lipid and processes synthesised proteins
What organelle causes a perinuclear hoff?
golgi apparatus especially in the plasma cells.
What are the surfaces of the golgi?
cis face which recieves transport vesicles from smooth ER and phosphorylates some proteins.
The trans Golgi network does proteolysis and sorts macro molecules into vesicles
the medial golgi forms complex oligosaccharides by adding sugars to lipids and peptides.
What are lysosomes?
Lysosomes are vesicles that contain hydrolases that degrade proteins. if they fuse with endosomes which produce acid to produce and endolysosome.
What is a peroxisome?
it is a smaller lysosome that breaks down long-chain fatty acids
What is the smalles fillament of the cytosceleton?
Micro filaments which are 5nm diamiter and are made of actin. G-actin polymerises into F-actin. forming a bracing mesh on the inner surface of the cell membrane
Describe microtubules
they have diameter of 25nm made of tubulin proteins. they aren’t found in RBC’s. made of alpha and beta units
What are intermediate filaments
there are many types they are usually 10nm. they are evenly spread. can stain them to identify cell types.
Where might you find Desmin?
in Myocytes
where might you find Glial fibriallary acidic protein?
in astrocitic glial cells
where might you find vimentin?
in mesodermal cells
wher might you find cytokeratins?
in epithelial cells
What is lipofuscin
membrane bound orang-brown oigment from breakdown of lipids in older cells and they are common in the heart and the liver.
how are lipids stored in the cells ?
in globules not stored in membranes. they appear as empty space in the slides
what is interstitial fluid made of?
water salts in solution peptides and proteins
Extracellular material?
fibrillar proteins Glycosaminoglycan jelly and inorganic salts as solids.
What are the features of all epithelia?
they have a layer or layers of cells, a basement membrane
what are the main functions of epithelia?
they protect the body, absorb substances and secret substances.
what are the features of a simple epithelia?
There is only one layer of cells
What is a stratified epithelia?
An epithelium which has many layers of cells.
Simple squamous is usually found where?
in blood vessels the outside of the lungs, and abdominal organs.
where are simple cuboidal cells usually found?
the kidney tubules and ducts of the gall bladder. or salivary glands
where is simple columnar epithelium found?
in the stomach intestines and uterus they can have villi or microvilli.
What is the structure of a micro villus?
many actin filaments joined by actin binding filaments. the cell membrane convers the whole thing. It is linked to an actin cortex in the membrane.
What is the structure of cilia?
There are microtubules in the centre of the cilia. There are two tubules arranged in nine pairs. the contractile proteins are tubulin and dynein.
where might you find microvilli?
in the intestinal epithelum
what is the name for a none motile cillia?
stereocillia
where are cillia found?
reproductive tract, in respiratory epithelia.
what is pericilliary fluid
layer of fluid below the mucus that allows it to flow
Where might you find stratified epithelium?
On abrasive surfaces, mouth oesophagus, vagina, oesphagus, the skin also/
What is pseudo-stratified epithelium?
Looks as though there is more than one layer but there is really only one layer.
What is urothelium?
lines the bladder, ureters and the pelvis. it looks stratified but has a surface layer of ummbrella cells and appears 3-7 layers thick but is pseudostratified.
What types of collagen make the basement membrane?
Collagen type IV and fibronectin.
What are tight junctions?
tight or occluding junctions are band like fusions between cells that are imperveous to most molecules. they prevent diffusion between cells.
What type of junctions are desmosomes used in?
anchoring junctions and adherent junctions. they spread mechanical load and connect the cytoskeletons of adjacent cells.
What are gap junctions?
they are junctions that allow communication between cells
What type of cells are connective tissues derived from?
pluripotent Mesenchymal cells.
what are the components of connective tissues?
There are cells, visible fibres like collagen and elastic or reticulin. the ground substance which doesn’t usually stain made of proteoglycans, glycosaminoglycans laminin and fibronectin.
what are the 3 main types of connective tissue?
Fibrous, Hard or fatty.
What are the types of fibrous connective tissue?
Loose or Dense
What are the types of hard connective tissue?
Cartilage or bone
What are the types of fatty tissue?
White or brown.
What are the precursors of collagen?
tropocollagen a triple helix of peptides
which cell type produces collagen precursors?
fibroblasts.
Name some common types of collage and their distribution.
type 1 - Skin, Tendons, bone ligaments, fibrous cartilage, corea, loose fibrous connective tissue.
Type 2 - hyaline and elastic cartilage, vertebral disks, vitreous of eye
Type 3 - liver, bone marrow, spleen this is reticulin
Type 4 - basement membranes
type 5 placental basement membrane skeletal muscles.
What is the histologyical appearence of collagen?
they stain pink in H&E they are variable thickness and often run in bundles. they can look like muscle but they are intracellular fibres and collagen is not.
What is loose connective tissue?
widely spaced thin collagen fibres and fibroblasts and ground substance.
what does dense connective tissue look like?
very darkly stained not very much unstained areas. can be regular or irregular.
What is reticulin?
it froms scaffold in bone marrow in bone , liver and kidney tissue need silver stain for differentiation.
Describe the nature and appearence of elastin.
It is sereted by fibroblasts and stain pink on H and E staining. they look like smooth muscle cells.
What is white adipose?
Individual fat cells with a large blob of fat inside. they look white and empty as lipid removed in. there are organelles at the edgeof the cells. can look like airways.
what is brown adipose tissue?
Present mainly in neonates. multivacuolate cells giving speckled appearance. in adults they can be found across the shoulders and down the back.
what are the constituents of caritilage?
Cells Chondroblasts and chondrocytes
Extracellular matrix GAGs hyaluronic acid, proteoglycans extracellular bibres like collagen and elastin and no blood vessels.
what does Hyaline cartilage look like and where is it found?
Found in synovial joints.
Many chodrocytes found alone in the tissue. it is blue purple colour glassy looking with no visible fibres. at the edge there is perichondrium which has fibroblasts.
Where is elastic cartilage and what does it look like?
found in ears and epiglottis. there are visible fibres in the matrix and can see chondrocytes in the tissue also has a perichondrium
What is Fibrocartilage and where can it be found?
Found in the annulus fibrosis in the spine and pubic symphysis. long fibres
What is the other layer other than cartilage in a synovial joint?
synovium. with phagoctes and cells rich in rER and it had lots of nerves an blood vessels.
What are the three main types of muscles?
Smooth muscle, Skeletal and cardiac
Where can smooth muscles be found?
srterial walls, walls of intestines and in the airways
What is the histological appearence of smooth muscle
It has no striations, there are no branches it is fusiform shapped the nucleus is in the centre of the cell usually.
What is the general structure of blood vessels?
the lumen, endothelium with a basement membrane then loos connective tissue the intima then internal elastic lamina then thick layer of connective tissue the media, then had external elastic lamina then there is the adventitia.
What is the structure of an elastic artery and where are they found?
They have endothelium with BM loose fibrous connective intima then internal elastic lamia thick media and an external elastic lamina. they are found at aorta and pulmonary arteries.
What is the structure of a muscular artery?
they have lumen endothelium with BM then intima then internal elastic lamina and media, then external elastic lamina and advetitia. media is mainly muscle and there is less elastic
What is the structure of an arteriole and how can it be distinguished from the arterioles?
it has 3 or fewer muscles layers or diameter less than 100um but it is arbitrary. they have pooly defined elastic laminae
What is the structure of a
capillary?
endothelium and basement membrane sometiems has a pericyte on the outside of the capillary. there are fenestrations sometimes like in kidneys or liver
What is the structure of veins. ?
there is a large lumen there is a basement membrane with endothelium then an intima an internal elastic lamina then a thinner media and then an adventitia.
How can venules be distinguished from veins?
they are often with arterioles.
What is the strucutre of a vein?
they have endothelium and BM then have smooth muscle as well they are thin walled and often collapse in section
What are the features of lymphatics?
They have valves, no RBC there are sometimes lymphocytes they have thin walls like veins.
What are the general structures of a peripheral nerve?
Dendrites then cell body with axon which may be myelinated and ten end bits
Which cells prouce myelin?
Schwann cells
What are the names for the 3 types of connective tissue around nerves?
Each axon (white) is surrrounded by endoneurium, which binds axons. theen around all of this there is perineurium to form a fascicle and around that is the epineurium which binds fascicles into nerve fibres.
Can myelin be seen under a microscope?
Not with Hand E but can be with special silver stains
How is myelin made?
the Schwann cell wrapps itself around the nerve several times it can do this to only one cell
Where are Schwann cells found?
They are found along all axons myelinated and unmyelinated. only one cell is associated to one myelinated neuron but with unmyelinated neurons they are associated with many neruons.
Where are you likely to find cell bodies of nerve cells?
In the spinal cord. Motor neurons in the ventral root. the sensory have then un the dorsal root. sympathetic in ganglia.
what are the nerve cells like when stained?
Dark cell bodies
Can nerve fibres regenerate?
yes in perpheral systems
What is the role of satelite cells?
Provide nutrients to the cells
What is in the adventitia of arteries?
elastiv and vollagen fibres
what is the action of NO on the muscles of the vessel walls?
Causes them to relax
Can Schwann cells be found in the brain?
No
What is nissl substance?
RER found in nerve cells.
What is the name of tissue that binds many nerve fibres together to form a peripheral nerve?
Epineurium
What is the mesaxon?
Where the roles of membrane join on myelin sheath
What type of caritalge is the nose?
Hayline
Do all smooth muscle cells contain a nucleus?
yes
How does cartilage get nutrients?
By diffusion as it is avasucular.
Are collagen fibres secreted by fibroblasts?
No the components of it are though
Is elastic tissue always in fibres?
no it can be in sheets and other forms
Where is brown fat most likely to be found?
on the back and sholders and aortic arch
What sets reticulin apart from other forms of collagen?
it can form branched fibres
