Histology micros. more

• Orcein (deep blue).
• Verhoeffs Van Gieson (brown-black).
• Resorcin-fuchsin (blue-black).

• Extracellular matrix. Synovial fluid. Vitreous humor.
• Lubricant and shock absorber.

• Cartilage and bone. Heart valves.
• Major component of cartilage and skin.

• Cartilage and bone. Cornea.
• Functions in corneal transparency.

• Skin, blood vessels, heart valves.
• Cofactor in a variety of cell behaviors.

• Basement membranes.
• Facilitates interactions with fibroblast growth factor (FGF).

• Mast cell and basophil granules.
• Anticoagulant.

Dermatin sulfate.

Hyaluronic acid.

Chondroitin sulfate.

Collagen (mainly type IV), proteoglycans, and multiadhesive glycoproteins (laminin, fibronectin).

Laminin polymerization and formation of type IV collagen network.

Type I collagen

Collagen type III.

• Light colored chromatin.
• Gene rich, often being actively transcribed.
• "Beads on a string" structure, 8 histones with DNA wound around them.
• Amount of euchromatin corresponds with cell productivity.

• Highly condensed, dark colored, INACTIVE chromatin.
• Few genes.
• 3 locations: marginal chromatin, nucleolar-associated, karyosome.

• X chromosome in females that exists only as tightly packed, inactive heterochromatin.
• Easier to see in smears of cells.
• 

Synthesis of components of ribosomes (rRNA)

• Synthesis of FAs and phospholipids.
• Detoxification of some drugs.
• Steroid synthesis.
• Membrane formation and recycling.
• Calcium sequestration for muscle contraction.

• post-translational protein sorting and packaging.
• Prominant in secretory cells: plasma cells, osteoblasts, epididymal cells.
• Does not stain with H&E or Wright's (pale, usually perinuclear clearing, like in plasma cells)

• Golgi vesicle secretion.
• Proteins are secreted as soon as they are produced, regardless of environmental factors. Continuously secreted.

• Fusion of vesicle's membrane with cell's membrane.
• Delivery of integral membrane proteins to cell surface.
• Secretion of proteins.

ingestion of large particles (phagosome)

Nonspecific ingestion of fluids and small proteins (endosome).

entry of specific molecules (endosome)

• They are formed as vesicles originating from the golgi or rER. Proton (H+) pumps maintain a low lumen pH in them.
• They are membrane bound vesicles that hold hydrolytic enzymes.

• Membrane bound organelle formed directly from ER.
• Contain oxidizing enzymes (catalase, peroxidase, etc) important for protecting cell from H2O2.
• Prominent in hepatocytes and renal tubular cells.

For identification of undifferentiated malignant tumors.

Melanin and lipofuscin.

• Intracellular inclusion.
• Brown pigment.
• Protects skin from solar damage.
• Provides color to hair and iris.
• 

• Intracellular inclusion.
• "wear and tear" pigment.
• From oxidative breakdown of mitochondria.
• 

• Hemosiderin. Yellow-brown chunky pigment.
• Usually found in macrophages, breakdown of hemoglobin after phagocytosis of RBC.
• Commonly found in spleen and bone marrow.
• Seen in tissues following hemorrhage.
• Prussian blue stain can be used to stain the iron.

PAS and Carmin stains. Not stained by H&E.

Necrosis. This is a sign of severe inflammation.