Histology L1.pdf

## Histology ### Why Histology? - To see tissue under microscope, it needs to be transparent. - The tissue should also be stained. ### Basic Stains - **H&E** (Hematoxylin and Eosin) - **Carbohydrates** - PAS (Periodic Acid Schiff) - Magenta - **Lipids** - Sudan III - Orange - Sudan B...

## Histology ### Why Histology? - To see tissue under microscope, it needs to be transparent. - The tissue should also be stained. ### Basic Stains - **H&E** (Hematoxylin and Eosin) - **Carbohydrates** - PAS (Periodic Acid Schiff) - Magenta - **Lipids** - Sudan III - Orange - Sudan Black - Black - Osmic acid - Black - **Basic** - Hematoxylin - Blue ### Microscope - **Electron microscope (EM)** - 100,000x magnification - **Light microscope (LM)** - 1,000x magnification ### Structure of the Cell - **Cytoplasm** - **Nucleus** - **Cell membrane** - **Cytosol** - **Cytoplasmic matrix** - **Organelles** - living units in cells that have an important function in the cell - **Inclusions** - non living units stored in the cell, with a specific function. ## The Cell Membrane - **The outer limiting membrane that surrounds the cell, regulating the passage of materials into and out of the cell.** - **LM** - Too thin to be seen. - May stain its carbohydrates using PAS. - **EM** - 3 parallel layers (trilaminar) - 2 dark layers - 1 light layer ### Chemical Structure of Cell Membrane - **Lipids** - **Head (outwards)** - Hydrophilic and polar - **Tail (center)** - Hydrophobic and non-polar - **Phospholipid** - **Cholesterol** - **Proteins** - Give stability and rigidity to the membrane. - **Integral/Intrinsic proteins** - large, form channels for water-soluble substances - **Peripheral/Extrinsic proteins** - smaller in size, located peripherally on the cell membrane, attached to the outer surface of the cell membrane, easily extracted. - **Carbohydrates** - **Glycolipids** - **Glycoproteins** - **Cell Coat** - **Glycocalyx** ### Functions of Cell Membrane - Keeps internal composition of the cell - **Cell coat** - Attachment to other cells - Receptors - Cell to cell recognition - Immunity - **Bulk Transport** - **Endocytosis** - **Phagocytosis** - for solid materials - **Pinocytosis** - for water or fluids - **Exocytosis**