BSC Path/ Histo Flashcards
what are the primary uses for light microscopy? phase contrast?
light: patient diagnostics
phase- contrast: unstained, live
how is tissue prepared? what are the significant solutions?
placed in fixative
- most common formalin
- michel solution for direct immunofluorescence
what is the next step after tissue prep? what is an important part of this step
embedding and cutting, piece/ entire tissue is embedded in paraffin wax blocks
what is the next step after embedding and cutting? how does this relate to diagnosis?
hematoxylin and eosin staining, first step of diagnosis
describe the 3 dyes discussed
- hematoxylin- basic dye, attracts positive charges due to (-) phosphate groups
- eosin- acidic dye, attracts negative charges due to positive lysine and anginine
- periodic- acid schiff- used to identify fungal stains and mucous cells b/c chitin and cellulose
what are the disorders in net cell production
excess- hyperplasia, cancer, autoimmune disorders
depletion- atrophy, degenerative diseases, AIDS, ischemic injury
what are some important features of the nucleus
membrane bound
nuclear envelope
chromatin
nucleolus
describe an example of a DNA checkpoint
- if normal cell acquires DNA damage P53 accumulates, and mutation of TP53 leads to tumor suppressor activity
what are the 2 types of cell death
necrosis: accidental, unfavorable environments (hypothermia, hypoxia)
apoptosis: programmed cell death
what are the 2 types of apoptosis
intrinsic vs extrinsic
- intrinsic: inside cell, tumor suppression, p53 for DNA damage
- extrinsic: outside cell, TNF- membrane receptors trigger signaling cascade
what are the 4 basic tissue types and give a fast fact for each
1) epithelium: rests on basal lamina
2) CT: loose, dense, and specialized
3) muscle tissue: lots of actin and myosin
4) nerve tissue: CNS- neuroglial, PNS- schwann and satellite
what is a feature of all types of epithelium
avascular
what are the 4 types of epithelium we discussed? which are special?
1) simple epithelium: better for exchange, absorption, secretion
2) stratified epithelium: better for barrier and conduit formation
3) pseudostratified epithelium (actually simple), special
4) transitional epithelium/ urothelium, special
what are the 3 distinct morphologic domains
apical, lateral, basal
what are the components of the apical domain and give a fast fact for each
1) microvilli: enhance absorptive capacity
2) cilia: movement of fluid & particles along epithelial surfaces
3) stereocilia: mechanosensory function
what does the lateral domain do? what are the 5 categories?
cell-to-cell adhesion
1) tight junction
2) adherens junction
3) desmosomes
4) hemidesmosomes
5) gap junction
describe the important parts of the basal domain
- basal lamina, where epithelial cells produce collagen
- basement membrane= basal lamina + reticular lamina
what is the target of pathogens and autoimmunity
junctional complexes
what are examples of autoimmune diseases that attack junctional complexes
1) pemphigus vulgaris: antibodies attack desmosomes
2) mucus membrane pemphigoid: attack hemidesmosomes
what are 3 examples of organs w/ mainly secretory epithelium
thyroid gland, sebaceous, and salivary
what is the difference between simple vs. compound exocrine ducts
simple ducts don’t branch, compound, ducts branch
what is the pathway of exocrine secretion
secretory epithelial cells release products -> blood vessel -> systemic circulation -> destination site/ organ
what are the three types of exocrine glands? give an example of each and how they look w/ microscopy
mucous, serous (parotid), mucoserous (submandibular)
- hard to see myoepithelial cells
what are the 3 types of exocrine secretions? give an example for each
merocrine: exocytosis in secretory vesicles, sweat
holocrine: entire cell is secretory product, sebaceous
apocrine: apical end is broken w/ secretory products, mammary
what is an example of endocrine secretion
basal cell layer of SSE
what are the layers of epithelium from free surface to CT
- stratum corneum: keratin layer
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
what is the classification of epithelium for the oral cavity
stratified squamous epithelium
what is an epithelial disease
epithelial dysplasia: premalignant condition, mild, moderate and severe classification, microscopic diagnosis
what are the 2 types of keratinization? what disease is associated with each?
1) non- keratinized: apthous ulcers (canker sores)
2) keratinized (recurrent intraoral herpes)
what are the 2 types of keratinized cells
orthokeratin- no nuclei in eptl cell
parakeratin- nuclei in eptl cell
what is metaplasia? an example of a metaplasia?
one cell type is converted to a different cell type
- Barret esophagus, more prone to malignancy, not malignant or pre-malignant
what are the 2 types of epithelium malignancies and give an example of each
1) carcinoma (lining), oral squamous cell carcinoma, most common oral cavity cancer
2) adeno- carcinoma (gland), polymorphous adenocarcinoma, salivary gland eptm
what are the boundaries of connective tissue
basal lamina and external lamina
what is in ECM
protein fibers (mainly collagen) and ground substance
what does ground substance contain
proteoglycans (GAGs- most abundant, hydrophilic), multi-adhesive glycoproteins
what are the types of CT
embryonic, connective tissue proper, and specialized
what are the key features of embryonic CT
- mucous and mesenchyme
- mesenchyme: from mesoderm (except ectomesenchyme), gives rise to almost all CT in body
mucous: umbilical cord is Whartons’ jelly, appear like fibroblasts, potential therapeutic application
what are key features loose CT
- sparse collagen fibers, abundant ground substance
what are key features of dense regular CT
- tendons, ligaments, and aponeuroses
- tendons connect muscle to bone, ligaments are bone to bone
what are the 3 types of fibers
collagen, reticular, and elastic