Exam 1 Review (MC) Flashcards
The cleaving of non helical terminal ends of pro-collagen, converting it into tropocollagen occurs where?
Immediately after secretion
Name the molecular complex that primarily serves to prevent paracellular transport
Zonula occludens
The basal lamina is associated with which type of collagen?
type IV
Desmocollins and desmogleins belong to which group of CAMs?
Cadherins
What are catenins?
they serve as a major interface between cadherins that hold adjacent cells together and their actin cytoskeletons
What are molecular complexes that anchor cells together and reinforce the physical integrity of tissues and cells?
zonula adherens
What are connexons?
Components of a gap junction that consist of 6 Connexins that form a hollow, hexagonal structure
Facilitate movement of molecules (usually ions in order to allow cells to “communicate”)
Often arranged in “clustered patches”
explain the difference between hemidesmosomes and desmosomes
hemidesmosomes: link the basal domains of cells to the ECM via the intracellular tonofilaments
desmosomes: link basolateral domains of cells to ECM and other adjacent cells
Which family of CAM’s is associated with carbohydrate binding?
Selectins
What is another name for selectins? why?
lectins, bc they bind to carbohydrates
define extraversion
the movement of leukocytes from the blood to the tissues
selectins are involved in this
What best differentiates simple vs. compound glands?
ductal branching
Who recognized, without using a microscope, 21 kinds of “membranes” that could now be considered tissues?
Marie Francois Xavier Bichat
What were some of Virchow’s major contributions to histology and pathology?
He coined the phrase “omnis cellulae e cellulae” which is alluded to in the cell theory
also used histology to help explain pathological processes
Who are the 2 people credited for discovering that all living things were made of cells?
Schwann and Schleiden
Schwann = zoologist Schleiden = botanist
What type of epithelium is associated with the striated ducts of compound glands?
Cuboidal transitioning to columnar
Describe the molecular structure of the cell membrane
diphospholipid bilayer with intermembranous proteins associated with it
Aqueous materials can pass through the plasma membrane via ________
channels and transporters
What stains are included in the most common staining technique for light microscopy?
H&E
Hematoxylin and Eosin
Explain what the H&E stains stick to
Hematoxylin: stain nuclear material and some cytoplasmic components, such as RER, dark blue to light blue or purple
Eosin: is an acid dye, so it stains cytoplasmic components and much of the extracellular material a yellowish to pinkish color
Hematoxylin is a basic dye (true or false)
False
it acts like a basic dye due to the mordant that is used to help it bind to tissues
What are the 2 types of stains that depend on the Schiff reaction?
PAS and the Fuelgen reaction
What does PAS stain?
glycogen/carbs
What does Fuelgen stain?
nucleic acids/DNA
What is a schiff reaction?
it depends on the formation of aldehyde groups following exposure to HCl or periodic acid.
What is a metachromatic stain? give examples of different metachromatic stains
a stain whose color changes after it has reacted with something in the specimen
ex. toluene blue turning red after reacting with mast cells
How can the resolution of a microscope be increased?
changing the wavelength of the light source (electrons instead of light does this)
increasing the refractive index of the medium you’re looking through (oil)
What are the different granule contents that can be found in mast cells? what do they do?
Histamine: inflammatory response (packaged/stored by proteoglycans)
ECF-A (eosinophil chemotactic factor): attracts eosinophils and neutrophils
SRS-A (slow reacting substance of anaphylaxis): similar to histamine but has a more sustained effect
Heparin: poor anticoagulant that is thought to help clear plasma lipids
what is a plasma cell? what is an easy way to identify them in in photomicrograph?
a cell that produces antibodies
look for the tell tale “clockface” distribution of heterochromatin that is spherical and typically offset.
Define proteoglycan and it’s structure
they are the secreted products of resident cells ex. fibroblasts, chondroblasts, etc
structure: extracellular protein complexes of glycosaminoglycans
what is a proteoglycan aggregate?
composed of GAGS attached to a core protein
the core protein is attached to a hyalurana molecule via linker proteins
Why do collagen fibers have a 64 nm gap between one another?
in order to separate the head and the tail of adjacent tropocollagen molecules
How is type 1 collagen synthesized? (6 steps)
- type 1 collagen is synthesized as a prepropeptide
- the pre-sequence is cleaved after it is translocated to the ER lumen of the fibroblast to create a procollagen
- procollagen is secreted into the extracellular matrix
- peptidases cleave the non-helical ends ,that prevent polymerization, to form tropocollagen
- tropocollagen monomers spontaneously assemble into collagen fibers
- collagen fibers 64 nm apart are deemed collagen
How are elastic fibers synthesized?
elastin is synthesized as a prepropeptide that is secreted as a propeptide
extracellular enzymes, also secreted by the fibroblast, make the propeptide into tropoelastin
tropoelastin monomers are assembled into amorphous fibers or sheets with the aid of fibrillins
What is the epithelial layer associated with interlobular ducts of compound glands?
pseudostratified columnar
What is the epithelial layer associated with intercalated ducts of compound glands?
cuboidal transitioning to columnar
same epithelial type is associated with striated ducts of compound glands
what is the equation used to calculate diopters?
1 meter / the focal length of the lens (in meters)
Compare parenchyma vs stroma in compound glands
Parenchyma: high cellularity
Stroma: connective tissue
Laminin has binding sites for what 4 molecules?
Type IV collagen
proteoglycan
integerin
nitogen
