Histo lec transes

• Histology is the science that deals with the study of normal tissues
• Cells


  The basic unit of life that composed all the living things
• Tissues


  A group of cells that have similar structure and intercellular materials interrelated to perform a specific function
• Cytology


  The study of cells
• Mitosis


  The division of a cell into two daughter cells that are genetically identical to the parent cell
• Meiosis


  The division of germ cells. It results in four daughter cells which are not identical to the parent cell- only one copy of each paternal and maternal chromosomes can be found in the daughter cells
• Anton Von Leeuwenhoek was the first person to observe and describe living cells using his handheld microscope


  16th century
• Robert Hooke observed a slice of cork under a microscope and discovered many small compartments-like honeycomb structures which he described as cells


  17th century
• Marcelo Malpighi was the true father of Histology
• Anton Van Leeuwenhoek developed compound lenses and was the first to describe the nucleus while examining red blood cells of salmon
• Nucleus


  Small dense centers in plant cells observed by Robert Brown, but its function was yet unknown
• Marie Francois Bichat termed tissues as textures and described tissues as different groups of cells
• Matthias Schleiden proposed the cell theory for plants
• Theodor Schwann described that animals are made of cells and discovered cells that form the sheath surrounding nerves
• Friedrich Gustav Jacob Henle published the first human histology
• Max Schultze was the first to describe cells as a mass of nucleated protoplasm
• Rudolf Virchow described the human body as a "cell state" and that all diseases involved changes in normal cells
• In the 19th century, techniques such as microtome, fixing, embedding and staining were developed
• Gross Anatomy


  The study of the structure of the body as a whole
• Microscopic Anatomy


  Includes cytology (study of cells and structures), histology (study of groups of similar cells for performance of specific functions), and organology (study of group of tissues arranged in pattern of a particular organ)
• Elements that compose the human body

  • Cells
  • Intercellular substances
  • Body fluids (blood and lymphs)
• Cell


  The structural, functional, hereditary and developmental unit of all living organisms
• Types of cells


  • Animal cells
  • Plant cells
• Animal cell structure


  • Cell membrane
  • Nucleus
  • Cytoplasm
• Cell membrane/Plasmalemma


  Regulates entrance and exit of nutritive and excretory substances, acts as a selective barrier
• Protoplasm


  All that are inside the cell membrane e.g. organelles, inclusion bodies and nucleus
• Cytoplasm


  All contents outside the nucleus, contains organelles and inclusion bodies, functions as a matrix embedding organelles and inclusion bodies
• Physiologic properties of protoplasm

  • Irritability
  • Contractility
  • Conductivity
  • Respiration
  • Absorption/Endocytosis
  • Exocytosis
  • Growth and reproduction
• Chemical composition of cytoplasm: 75% water, 1% salt, 3% lipids, 1% carbohydrates in the form of glycogen, 20% CHON, cations (Na, K, Ca, Mg), anions (phosphates, bicarbonates, Cl)
• Cytoplasmic organelles


  • Mitochondria
  • Lysosome
  • Centrosome
  • Golgi apparatus/Dictyosome
  • Endoplasmic reticulum
  • Ribosome
  • Fibrils
  • Microtubules
  • Microbodies/peroxisome
• Cytoplasmic inclusion bodies


  • Vacuoles/Vesicles
  • Lipid/Fat droplet
  • Glycogen granules
  • Pigment granules
  • Secretory/Zymogen granules
  • Mucigen droplets
• Nucleus


  • Stains blue, hepatic cells are binucleated, skeletal cells and osteoclasts are multinucleated, unifies, controls and integrates cell function, controls biochemical reactions and reproduction of the cell, repository of the complete set of heredity
• Nuclear structures


  • Nuclear membrane
  • Nucleoplasm/Karyoplasm
  • Nuclear chromatin/Chromatin granules
  • Nucleolus
• Eukaryotic cell cycle periods

  • G1: Initial Gap
  • S Stage: Synthetic Stage
  • G2: Second Gap
  • Mitosis
• Cell division


  Involves both cytokinesis (division of cytoplasm) and karyokinesis (division of nucleus)
• Types of cell division

  • Mitosis
  • Meiosis
• Stages of mitosis


  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Interphase


  Cell in resting state, in preparation for cell division, chromosomes duplicate from 23 pairs to 46 pairs, time for repair and re-synthesis of CHON
• Prophase


  Chromosomes become shorter and thicker, each chromosome separates longitudinally in half (chromatid) and each half attaches in a centromere, the pair of centrioles duplicates and begins to go towards the opposite poles, start of the formation of spindle fibers between separating centrioles, nuclear envelope and nucleolus start to disappear
• Metaphase


  Chromosomes aligned along the equatorial plate, chromosomes start to pass between the spindle fibers