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
what is the significance of collagen
- strength comparable to steel
- type I (precursor to bone), II (cartilage), and IV (basement membrane)
what is the structure of collagen
- glycoproteins due to sugar that holds helix proteins together
- molecule w/ triple helix
what is the production of collagen
vitamin c transforms preprocollagen to procollagen
what are problems that can arise from collagen
- scurvy
- oral - scorbutic gingivitis, gingival swelling, periodontitis
what is the significance of reticular fibers
composed of type III, reticular, supports lymph tissues
what are reticular fibers produced by
reticular cell
what is the significance of elastic fiber
cross linked elastin and fibrillin network
what is the function of adipose
energy homeostasis and hormone production
what are key points of white adipose tissue
- unilocular
- 10% of body weight if healthy
- function is storage
- ECM is elastic fibers
what are key points of brown adipose tissue
- multilocular
- large amounts in newborns
- function is heat production
what are the 4 types of papillae
filliform, fungiform, foliate, circumvallate
describe filliform papillae
no taste buds, thick keratin layer
where are papillae? what is the cell classification
cover dorsal tongue, variations of SSE
describe fungiform papillae
taste buds
describe foliate papillae
taste buds
what is a significant point about dental pulp
some nerve fibers enter proximal portions of dentinal tubules and contact odontoblast processes
what is cartilage? give a couple of key features
CT formed by chondrocytes and highly specialized ECM
- avascular
- >95% ECM
what is in the ECM of cartilage
Large GAG to Type II collagen ratio= allows diffusion to chondrocytes
what are the 3 types of cartilage
hyaline, elastic, fibrocartilage
describe hyaline cartilage
- lacunae house chondrocytes-> chondros produce matrix
- in articular surface of synovial joints
- contains perichondrion
describe perichondrion
- dense irregular CT
- source of new cartilage cells
- articular joint surfaces do not have
describe the ECM of hyaline cartilage
- collagen type II (80%)
- proteoglycans
- multiadhesive glycoprotein
- precursor for endochondral ossification
describe elastic cartilage
- found in epiglottis
- has perichondrium
describe ECM of elastic cartilage
- type II collagen fibrils, elastic fibers, and aggrecan monomers
- proteoglycans
- multiadhesive glycoproteins
- precursor for endochondral ossification
describe fibrocartilage
- temporomandibular joints
- chondrocytes and FIBROBLASTS
describe ECM of fibrocartilage
aggrecan (chondrocyte) and versican (fibroblast)
when does growth and repair of cartilage occur
- contact w/ bone tissue while growing/ adult
- about to be replaced by bone
- part of aging process
what are the 4 types of bones
long, short, flat, and irregular
describe the long bone
proximal epiphysis/ distal epiphysis, metaphysis, diaphysis
describe the flat bone
intramembranous ossification, skull, mandible, and clavicle
what are 2 important features of bone
covered in periosteum, sharpey fibers connect periosteum to bone
describe bone ECM
- hydroxyapatite (Calcium phosphate)
- bone ground substance (growth factors BMP)
- lacunae surrounding osteocytes and canciuli connecting lacuna
describe endochondral ossification
osteoprogenitor cells -> osteoblasts -> deposit on cartilage surface
how are the primary and secondary ossification center separated
epiphyseal growth plate
what bones undergo intramembranous ossification
skull, mandible, clavicle
what are the cells of bone
osteoprogenito cells have RUNX2 (CBFA1 transcription factor) affect them -> osteoblasts -> secrete osteoid
what is an osteocyte
mature bone cells enclosed w/ lacunae of bone matrix, begin as osteoblasts before enclosed
what is the pathway of an osteoclast
osteoclast -> hematopoietic progenitor cells -> resorb bone matrix
what are the important components of bone
- immature (interwoven) bone
- compact (dense, cortical) bone
- spongy trabecular bone
- mature (lamellar) bone: osteons and haversian canal
- perforating (volkman canals)
how does bone grow
length= increase epiphyseal growth plate
width (appositional) = increase compact bone and periosteum
why is muscle and how is muscle
why: primary role of contraction, responsible for nearly all movement
how: myofilament interaction, thin- actin, thick- myosin
what are three important features of skeletal muscle
- striations
- regeneration thru satellite cells
- hypertrophy
what are the components of skeletal muscle cells
- peripherally located nuclei
- sarcoplasmic reticulum (smooth ER)
- many myofibrils, series of sarcomeres
- sarcolemme (PM)
what does the I band have? A band?
I: thin filaments and titin
A: thick and thing, central M line, Hzone (only thick)
what happens when a muscle contracts
sarcomere shortens, myofilament remains
what are important features of cardiac muscle
- striations
- no regeneration
- hypertrophy
describe cardiac muscle
- 1-2 centrally located nuclei
- intercalated discs: transverse regions (desmosomes) and gap junctions
- no satellite cells
- involuntary (purkinje fibers)
how does the nervous system help with cardiac muscle
- autonomic nerves, example heart rate
- some contraction is modified by autonomic innervation (symp. vs. parasymp)
describe smooth muscle
- no striations
- regeneration b/c mitosis
- hypertrophy and hyperplasia
what are important parts about smooth muscle
- individual small tapering cells
- still thin and thick filaments
- involuntary: ANS
where do nerve cells originate from
ectoderm
- neural tube -> CNS
- neural crest cells -> PNS
describe the sensory nerves
afferent
somatic: sensory input received consciously
visceral: not consciously (ex. internal organs)
describe motor nerves
efferent
somatic: voluntary
autonomic: involuntary
what are the parts of a neuron
dendrites, cell body, axon
what are the elements of support in nervous system
supporting cells (CNS: neuroglia, PNS: schwann and satellite)
macrophages
CT elements
- meninges surround CNS
- endo/peri/epineurium surround peripheral nerves
what are the layers of PNS CTs
- endoneurium: axon and myelin sheath
- perineurium: group of axons and perineurium = nerve fascicle
- epineurium covers multiple fascicles
what is neoplasia
new growth, uncontrolled, of cells/ tissues
what does neoplasia start off as
monoclonal” single mutated cell leads to neoplasm
what are aspects of a benign neoplasm and an example
- circumscribed
- well diff.
- locally invasive
- uniform cells
- normal/ few/ no mitotic figures
- ex: ameloblastoma (locally aggro)
what are aspects of a malignant neoplasm
- can spread in body
- poorly diff.
- metastasize
- increased nucleus: cytoplasm ratio
- pleomorphic
- bizarre mitosis
