What are he four main tissues classifications
Epithelial
Connective
Muscle
Nervous
Why is histology a gold standard in some diagnosis
The biopsy is cellular proof of some problems like cancer or chrons, moles
What is a biopsy and what are some common techniques
Removal of small tissue from organs or part of the body for microscopic inspection
Smear Curettage Needle Incision Endoscopic Transvascular
Why are tissues fixed and what is it?
To stop degregation of the tissues
Formaldehyde
The tissue is dehydrated, embedded in wax, sectioned, rehydrated and stained
What are the two most common stains
Haematoxylin and evasion A&E - stains basic components
Periodic schiff PAS - stains carbs and glycoproteins
What is epithelia
Sheets of contiguous cells of varied embryonic origin that cover the external surface and line internal surfaces
What are the epithelial derivatives of the three germ layers of the embryo
Ectoderm - epidermis of skin / corneal of eye
Mesoderm - urogenital / blood and lymphatic vessels / pericardial and peritoneal
Endoderm - respiratory and gi tract / liver / other glands inc thyroid thymus and salivary
What are the 6 classifications of epithelia
Simple
- Pseudo stratified
- Squamous
- cuboidal
- Columnar
Stratified/compound
- Squamous
- Cuboidal
- columnar
- transitional
What is the basement membrane
Thin flexible acellular layer which lies between epithelial cells and subtending connective tissue
- consists of basal laming
- thickness augmented by reticular fibrils
- flexible layer which epithelial cells can adhere - filter
What simple squamous epithelium lines all vascular elements
Endothelium
- gaseous exchange and let’s certain blood cells to enter
What simple stratified epithelium lines pleural sac, pericardial and peritoneum
Mesothelium
What is the location and function of dimple cuboidal
Location
- thyroid
- kidney tumbles
- small ducts of many exocrine glands
Functions
- absorption and conduit (endocrine)
- absorption and secretion (kidney tubules)
- barrier (ovaries)
- hormone synthesis storage and metabolism - thyroid
What are locations and functions of simple columnar
Locations
- stomach and gastric lining
- small intestine and colon
- gallbladder
- larger ducts of some exocrine glands
- oviducts
- uterus
Functions
- absorption
- secretion
- lubrication
- transport (oviduct)
What are the locations and functions of pseudostratified epithelium
Locations
- lining of nasal cavity, trachea and bronchi
- epididymis
- auditory tube and tympanic cavity
- lacrimal sac
- large excretory ducts
Functions
- secretion and conduit (respiratory, ductus deferens)
- absorption (epididymis)
- mucus secretion (respiratory)
- particle trapping and removal (respiratory)
What are the locations and functions of non-keratinized stratified squamous
Locations
- oral cavity
- oesophagus
- larynx
- vagina
- anal canal
- surface of cornea
- inner surface of eyelid
Functions
- protection against abrasion
- reduces water loss but remains moist
Name the locations and functions of keratinized stratified squamous epithelium
Location
- surface of skin
- limited distribution in the oral cavity
Function
- protect against abrasion
- prevents water loss
- prevents ingress of microbes
- shields again against UV
Name locations and functions of the transitional epithelium
Locations
- renal calyces
- ureters
- bladder
- urethra
Function
- distensibility
- protection of underlying tissues from toxins
What is a tissue
Collection if cells specialised to perform a specific function
