Histology - Cytology Flashcards
phosopholipid bilayer (histological trilayer), Transport through the membrane may be passive or active (requires extra energy). Some organelles are membrane-bound (e.g., golgi, RER, SER, mitochondria, lysosomes, nucleus).
Plasma membrane
outside layer
e-face
inner face
p-face
“condensed” DNA, electron sense; little or no trnscription.
Heterochromatin
“uncoiled” DNA; electron lucent; active transcription
Euchromatin
rRNA synthesis, ribosome assembly; prominent feature during protein synthesis.
Nucleolus
double-membrane later; nuclear pores.
Nuclear envelope
contains organelles required to synthesize, package, and secrete proteins - exocytosis. Has a lot of RER, golgi app., and secretory vesicles.
Protein-secreting cell
Flattened, membranous sacs w/ ribosomes. ER-bound ribosomes on membrane surface synthesize proteins into cisterna (lumen). (secretory proteins, membrane proteins, and lysosomal enzymes)
Rough endoplasmic reticulum (RER)
Flattened, membranous sacs; no ribosomes. Modifies, sorts, and packages proteins from the RER into membrane-bound vesicles. Vesicles are transported to the plasma membrane (or to lysosomes).
Golgi Apparatus
Membrane-bound, carry secretory proteins. Transported to the plasma membrane, fuse with it, release products into extracellular environment.
Secretory vesicles (granules)
vesicles stored until signaled to be released at once. (paneth cells)
Regulated secretion
products secreted as they are formed (plasma cells)
Constitutive secretion
Abundant organelles required to synthesize lipid-based products. No vesciles: lipids pass easily through membranes. See a lot of smooth endoplasmic reticulum (SER), vesicular mitochondria, lipid inclusions.
Steroid-secreting cell
Membrane-enclosed tubes; no ribosomes. Convert choloestreols into streroid products (e.g., testosterone, estrogen, clucocoticoids)
Smooth endoplasmic reticulum (SER)
Contain tube-shaped cristae; modify steroids.
Vesicular mitochondria
Cholesterol storage for steroid production.
Lipid inclusions (droplets)
Rod-shaped, double-membrane. Outer: smooth. Inner: folded, from cristae. ATP sysnthesis during aerobic respiation. Provides energy for active transport. Has microvilli and basal folds.
Mitochondria
folded plasma membrane and cytoplasm adjacent ot lumen.
Microvilli
folded plasma membrane and cytoplasm adjacent to a other tissies, increases SA.
Basal folds
Engulf macromolecules, cellular debris, bacteria. Identifys targets with receptors, engulfs targes with pseudopodia. Degrades targets with lysosomes (pgaholysosomes). Stores non-degradable components within residual body.
Phagocytic cell
spherical, membrane-enclosed. Degrade ALL endocytosed material (anything brought into cell within vesicles) with hydrolytic enzymes. Also has autophagy - “self-eating”. Degraded contents are recycles; indigestible contents are stored in residual bodies and exocytosed.
Lysosomes
“cell drinking”, generalized type of endocytosis by all cells. Brings in water & small dissolved solutes. Forms vesicles; fuse with lysosomes.
Pinocytosis
highly selective endocytosis. Cargo proteins bind to cargo receptors.
Receptor-mediated endocytosis
