intro to microcopic anatomy/histology Flashcards
Define epithelium
type of tissue that lines surfaces and forms glands
Define squamous epithelial cells
epithelial cells that cannot produce secretions but keratin
Define cuboidal/columnar epithelial cells
epithelial cells that can produce secretions
Define urothelium
the epithelium of the urinary tract
Define endothelium
the epithelium of blood vessels and lymphatic channels
Define the mesothelium
the epithelium lining large body cavities and the surface of large organs
Define basement membrane
collagen layer to anchor epithelial cells to
Define glands
specialised epithelial structures to make secretions, hormones, acid
Define cytokeratins
intermediate filaments of epithelia
What are tissues received and kept in?
- fixatives
- mostly formalin (10% formaldehyde in H2O)
What is fixation useful for?
- prevents autolysis
- ensures preservation
- hardens the tissue for cutting
How do you make the specimen into a wax block?
- more fixation
- alcohol to remove water
- xylene to remove alcohol
- paraffin to remove xylene
What machine is used to cut sections of the wax block?
a microtone
What is used to stain the sections of wax ?
haematoxylin and eosin stain
Describe the haemotoxylin stain colour and what it represents
- purple
- nucleus
Describe the eosin stain colour and what it represents
- red/pink
- cytoplasm
-organelles - cell membrane
What is immunohistochemistry used for?
- as a way to detect proteins on/in cells or tissues
How does immunohistochemistry work? What is the result?
- antibody labelled with brown indicator
- brown slide = protein present
- blue background stain = no protein
What are the 6 main types of tissues?
- epithelium
- connective tissue
- muscle
- neural tissue
- germ line cells
- blood
What are the 5 types of epithelium cells
- squamous
- glandular epithelium
- urothelium
- mesothelium
- endothelium
Give 4 characteristics of epithelia?
- high cell turnover
- regulate molecular exchange
- sensory functions
- immune functions
Describe epithelium structure
- tight junctions to seal borders
- desmosomes for strength
- gap junctions to allow transfer of molecules
What does squamous epithelium look like under a microscope?
like the scales of fish
What are endocrine glands?
- glands that don’t have a duct
- secretions go directly into the blood
Give examples of endocrine glands
- thyroid
- adrenals
- pituitary
What are exocrine glands?
- glands that have a duct
Give examples of exocrine glands
- salivary glands
- sweat glands
How many different types of cytokeratins are there?
around 20
What are the layers of layers of blood vessels from inside to outside?
- intima
- internal elastic lamina (IEL)
- media
- external elastic lamina (EEL)
- adventitia
Describe the intima layer of blood vessels
simple layer of endothelium and loose connective tissue
What are the IEL and EEL made of?
elastin
Describe the media layer of blood vessels?
circumferential smooth muscle
Describe the adventitia layer of blood vessels
collagen and little arteries/veins/nerves to supply the vessel wall tissues
What are the 3 types of arteries?
- elastic arteries
- muscular arteries
- arterioles
How can you recognise the cervix from looking at epithelia?
squamous and columnar epithelium next to each other
How can you categorise epithelia by shape?
- cuboidal/columnar
- simple
- squamous
- stratified
- ciliated
- keratinising
How can you categorise epithelia by function?
- glandular (secretions)
- neuroendocrine
How can you categorise epithelia by location?
- urothelium
- endothelium
- mesothelium
Describe simple epithelia
one layer + basement membrane
Where can you find simple epithelia
- endothelium
- mesothelium
- kidney tubules
- alveoli
- respiratory tract
Describe stratified epithelia
more than one layer + basement membrane
What does the ‘stratified’ in stratified epithelia mean?
the higher layers have no connection to the basement membrane
Give some examples of stratified epithelia?
- skin
- mouth
- anus
- oesophagus
What are glands formed from?
specialised cuboidal/columnar epithelial cells with secretory ability
What are cytokeratins?
intermediate filaments of epithelia (proteins)
