Week 0: Intro to Histology PDF

Week 0: Intro to Histology James Inno Guanzon, RMT Topic Outline I. The Cell: Fundamentals A. Cytoplasm B. Nucleus II. Types of Tissue III. Preparation of Tissues for Study 2 Cells comprise tissues along with extracellular material can be e...

Week 0: Intro to Histology James Inno Guanzon, RMT Topic Outline I. The Cell: Fundamentals A. Cytoplasm B. Nucleus II. Types of Tissue III. Preparation of Tissues for Study 2 Cells comprise tissues along with extracellular material can be eukaryotic or prokaryotic nearly 40 trillion populate the human body 3 Cell Differentiation spermatozoa + oocyst zygote blastomeres embryonic stem cells 4 Cell Differentiation is underwent by the fetus cells express sets of genes that mediate specific cytoplasmic activities, becoming efficiently organized in tissues with specialized functions 5  Basic Tissue Types I. Epithelial II. Connective III. Muscle IV. Nervous 6 Cell is the fundamental structural and functional unit of all living organisms over 200 types are found in the body; have a common structural plan 7 Protoplasm is the living part of a cell surrounded by an external plasma membrane components include: ○ nucleus nuclear envelope chromatin ○ cytoplasm organelles inclusions 8 Important Notes Most cells have one nucleus that conforms to the cell’s shape. A few cells may be multinucleated. Internal cell structure is modified to reflect function. 9 Epithelial Tissue covers body surfaces, lines body cavities, and forms glands characterized by close cell apposition and presence of a free surface 10 Connective Tissue underlies or supports the other three tissues, both structurally and functionally characterized on the basis of its extracellular matrix 11 Muscle Tissue is made up of contractile cells responsible for movement 12 Nerve Tissue receives, transmits, and integrates information from outside and inside the body to control the activities of the body 13 Visualization of Tissues light microscopes are often used the ability to discriminate two points that are close together is the resolving power of a microscope study specimens absorb visible light; glass lenses focus and magnify specimens 14 Preparation of Tissues for Study the most common procedure in histologic research is the preparation of tissue slices or “sections” that can be examined visually with transmitted light steps include: 1. Fixation 2. Dehydration 3. Clearing 4. Infiltration 5. Embedding 6. Trimming 15 Fixation preserves tissue structure and prevent degradation by enzymes released from the cells or microorganisms pieces of organs are placed as soon as possible after removal from the body in solutions called fixatives ○ function to stabilize or cross-link compounds buffered isotonic solution of 37% formaldehyde (formalin) is a widely used fixative Glutaraldehyde is often used for electron microscopy ○ can be used with buffered with osmium tetroxide 16 Dehydration water is extracted gradually by transfers through a series of increasing ethanol solutions 17 Clearing ethanol is replaced by an organic solvent miscible with both alcohol and the embedding medium 18 Infiltration fully cleared tissue is placed in melted paraffin in an oven at 52°-60°C ○ evaporates the clearing solvent 19 Embedding infiltrated tissue is allowed to harder in a small container of paraffin at room temperature 20 Trimming hardened block with tissue and surrounding embedding medium is trimmed and placed for sectioning in a microtome ○ typically at 3-10 um for for light microscopy