Self Assessment Q - Exam 1 Flashcards
- Give three examples of large molecules that are routinely lost during fixation with aqueous solutions.
• Gags, proteoglycans, glycogen
- Which tissue components are highlighted by using the PAS stain?
• Carbohydrates: glycocalyx
- How can antibodies be used to visualize specific protein components (cytoplasmic, nuclear and extracellular) in routinely processed tissue?
• Bind specifically to antigen receptor via fluorescence (immunohistology) or radioactive isotopes – best is indirect (use 2nd antibody to amplify fluoro/radioisotope of 1st)
- How does the preparation of tissue for TEM differ from that for conventional light microscopy?
• Gluteraldehyde: osmium tetroxide (heavy metal) to increase electron density and visual -> epoxy resin to plastic block -> cut with diamond knives to under thinner than 1 micrometer
What technique allows histopathologists to detect specific sequences of RNA or DNA in a cell?
• In situ hybridization
- Other than fluorescent markers, what other substances can be chemically attached to antibodies in order to detect specific tissue components with the light microscope?
• radioisotopes
- What is the advantage to using monoclonal antibodies rather than polyclonal antibodies?
- Selected to be highly specific and bind strongly to protein to be detected
- Less non-specific binding to other proteins
- Which organelles are only visible by electron microscopy?
• All aside from nucleus
- Describe the structure and function of the lipid raft.
- Protein complex with higher concentrations of cholesterol and sat fatty acids
- Reduces lipid fluidity
- Single t-duc
- List the functions of the plasma membrane.
• Physical barrier, selective permeability, electrochemical gradients, communication
- What are some of the functions of the glycocalyx?
• Contain digestive enzymes, microvilli on brush border of intestines
- Describe the structural and functional differences between smooth and rough endoplasmic reticulum.
- RER: had ribosomes – protein synthesis
* SER: no ribosomes: steroid synth (adrenal cortex), drug detox (liver), muscle contraction (skel m)
- Describe the morphology and function of the Golgi apparatus. In which cells is this organelle a prominent feature on light microscopy?
- Golgi: modify, sort, and package proteins
* lysosomes!
- What are the general structure and functions of peroxisomes?
• Oxidative reasons generating h2o2, long “sausages” in oval capsules
- What is the general structure and function of a lysosome?
- Spherical, formed from golgi
* Contain digestive enzymes
- What are the structural and functional differences between cilia and microvilli?
- Cilia: 9 + 2 (axoneme) arrangement of doubles (microtub) – mvmt of particles
- Microvilli: made of actin (microfilament) – absorption – brush border, terminal web
- Name the phase of mitosis in which the contractile ring is formed. What is the composition of the contractile ring?
• Begins in telophase, made of actin and myosin filaments
- Describe the mitotic spindle and its composition during the cell cycle.
• Made of microtubules
- Describe the structural organization of Centrioles.
• Circular: 9 triplets
- List the functions of actin in the cell.
• Motility, contraction (via myosin interactions), microfilament
- Describe the morphology of lipofuscin cytoplasmic inclusions.
- Pale brown granule
- Plenty in stable non-dividing cells
- Residual bodies after lysosomal digestion
- Distinguish permanent cells from labile and stable cells in terms of the cell cycle.
- Labile: continuously dividing – bone marrow, epithelium, gi lining
- Stable: only divide in injury – liver, kidney
- Permanent: never divide: cardiac, neural
- Distinguish the two processes of cell death; apoptosis and necrosis.
- Apoptosis: programed cell death – rapid – controlled by bcl-2 on mito memb – triggered by tumor suppression proteins
- Necrosis: cell death
- What features are used to classify epithelial tissues?
• Size and morphology are dictated by function
- What are the 8 classifications of epithelia?
- Simple squamous: endothelium, lining of cavities (pleura, pericardium, perineum)
- Simple cuiboidal: ovary, thyroid, urinary – cover, secr
- Simple columnar: intestines, gallballder
- Pseudostratified: with cilia brush border, glycocalyx – bronchi, trachea, nasal
- Urothelium/transitional: bladder, ureters, renal calyx
- Stratified squamous (kera): skin – protection, prev water loss
- Stratified squamous (non-kera): protection, prev water loss, secr – melva – mouth, esophagus, larynx, vagina, anal canal
- Stratified cuiboidal: sweat glands, (developing ovarian follicle)
- Stratified columnar: conjunctiva - protection
- What are the three specific forms of simple squamous epithelium? Name their specific anatomic locations.
- Simple squamous: endothelium, lining of cavities (pleura, pericardium, perineum)
- Stratified squamous (kera): skin – protection, prev water loss
- Stratified squamous (non-kera): protection, prev water loss, secr – melva
- What are microvilli? Describe its ultrastructural composition. What cellular function is associated with microvilli?
• Made of microfilaments (actin) – absorption in intestines – increase SA
- What are cilia? Describe its ultrastructural composition. What cellular function is associated with cilia?
• Made of microtubules: mvmt (trachea, bronchus, nasal sinus)
- What is the terminal web? Describe its ultrastructural features.
• Actin filaments on apical surface of most epithelium
- Why is the term stereocillia inappropriate?
- Not actually made of microtubules and actually resemble microvilli: but branched, immobile, longer
- Best seen in absorptive
- What are erzin, villin and fimbrin?
• Actin-binding proteins in microvilli
- What is the role of laminin?
• Makes up basal lamina (1 of 3) – attached to integrins
- What are basal bodies?
- Structure similar to centrioles (9 triplets)
* Continuous with axonemes at apical cytoplasm of cell
- Which component of the junctional complex serves to create a barrier between cells and restricts the free passage of substances between adjacent epithelial cells?
• Zonula occulens: apical surface – connect cells with adjacent cells - actin
- What is the principal function of the zonula adherens?
• Connect cytoskeletal components of adjacent cells – actin – forms part of “terminal web” – cytoskeletal feature at apical pole in many epithelial cells
- Where is the basement membrane located? Which stain is used to reveal the basement membrane?
• Beneath epithelial cells, stained with immunochemistry (lots of glycoprotein in laminin) or PAS
- In what ways are exocrine glands distinguished from endocrine glands?
• Exocrine:
o Ducts! Deliver secr materal to epithelium it is connected with
• Endocrine:
o Ductless – hormones into blood stream for distribution
- What is an acinus
• Secretory portion of exocrine gland (Also called alveoli)
- What are the characteristics of connective tissue?
• Lots of ECM with protein fibers (collagen, elastin) and ground substance (gags, proteoglycans, multi-adhesive glycoproteins)
- What is produced by fibroblast?
• fibers and ground substance
- What is meant by the regenerative capacity of connective tissue?
- Spaces left after injuries are filled by connective tissue
- Scar tissue = dense irregular
- Depends on activity and growth of fibroblasts
- What is the prevalent cell type of dense connective tissue?
• Fibroblasts: 49%
- Which stains reveal reticular and elastic fibers?
• Metal impreg – silver stanin
- In which tissues and organs can elastic fibers found in abundance?
• Mesentery, dermis, aorta
- In which locations are elastic fibers abundant?
• Bv, especially arteries – fenestrated sheets called elastic lamellae
- What is the fate of ground substance during routine processing?
• disappears
- How are proteoglycans (PGs) and glycosaminoglycans (GAGs) related?
• Part of ground substance: proteoglycans make up core protein that attached sulfated gags
- Why do PGs and GAGs stain with basic dyes?
• Basic dye: blue: basophilic (acidic/anionic) – dna, rna, gags (long polymer of repeating disacc units – hexosamine, uronic acid)
- Which connective tissue cells are derived from the bone marrow?
• Macrophage, mast cells, plasma cells
- How does Hyaluronan differ from other GAGs?
• Synth directly into ECM by hyaluronan synthase, located in memb
- With what structures is Hyaluronan associated?
• Umbilical cord, synovial fluid, cartilage, vitreous humor
- What is the chief function of Hyaluronan?
• Molecular diffusion, lubrication organs and joints
- Why is it difficult to see the cytoplasm of fibroblasts in routine H&E material
• Removed during processing
- From which type of cell does the tissue macrophage originate?
• Monocytes (bone marrow precursor cells)
o Monocytes and macrophages are same cell at different stages of maturation
- What nuclear feature of the macrophage is diagnostic for its identification?
• Prominent nucleus, nucleolus, numerous secondary lysosomes – phagocytic!
- What are the names for macrophages at various tissue sites.
- Kupffer – liver
- Microglial – CNS
- Langerhans – skin
- Osteoclasts - bone
- What are epithelioid cells?
• Activated macrophages
- What is the role of macrophages in iron metabolism?
• Recycle Fe for production of Hb in new RBCs
- How does one recognize mast cells in routine H&E material?
• Oval – strong basophilic granules
- What is secreted by mast cells, and under what circumstances are they released?
- Heparin – anticoag
* Histamine – promotes vasc permeability, smooth M contraction
- Within which type of connective tissue are mast cells most commonly found?
• Digestive and respiratory tract – sentinels against invasion
- What is meant by metachromasia?
• High content of acidic radials in sulfated GAGs of mast cells can change color of some basic dyes from blue to purple/red
- What are the precursor cells to plasma cells?
• Lymphoctye-derived, antibody producing cells
- What characteristics of the cytoplasm and the nucleus are diagnostic for plasma cells?
• “clock face” – basophilic cytoplasm with clumps of heterochromatin around nuc79.
- What is meant by wound healing?
- Done by myofibroblasts: characteristics of fibroblasts and smooth M (function more like smooth M)
- Rapidly closing wounds – high levels of actin and myosin
- What are myofibroblasts and what role do they play in wound healing?
- characteristics of fibroblasts and smooth M (function more like smooth M)
- Rapidly closing wounds – high levels of actin and myosin
- What are some of the local factors that interfere with wound healing?
• Activity and growth of fibroblasts
- Where is mucous connective tissue found
• Wharton’s jelly: fetal umbilical cord
- In which areas of the body is each type of fat typically found?
• White: in many organs, form about 20% body wt in adults
o Partly regulated by sex horm controlled adipose desposition in breast and thighs
• Brown: kidneys, adrenal glands, aorta, mediastinum (was 2-5% newborn wt located in back, neck, shoulders)
- What hormone is secreted by unilocular adipocytes and what is the action of the hormone?
• Leptin: “satiety factor” – regulate appetite
- Why do adipocytes appear empty following routine H&E processing?
• Removed by organic solvent processing usually.