Human Histology (Laboratory) PDF

HUMAN HISTOLOGY (LABORATORY) Week 1: Introduction, History, Microscope Anton Van Leeuwenhoek (16th Century) Using his handheld Histology microscope, he...

HUMAN HISTOLOGY (LABORATORY) Week 1: Introduction, History, Microscope Anton Van Leeuwenhoek (16th Century) Using his handheld Histology microscope, he was the first Study of normal body tissues and how these person to observe and tissues are arranged to form organs. describe living cells. A division of Anatomy. Leeuwenhhoek used his Prelude to Pathology. handcrafted microscopes to make groundbreaking observations of various 4 Types of Tissue microscopic organisms, including bacteria, 1. Epithelial Tissue protozoa, and any other tiny creatures. 2. Connective Tissue 3. Muscular Tissue Robert Hooke (17th Century) 4. Nervous Tissue An English microscopist and physicist observed a slice of cork under a microscope. Definition of Terms He discovered many small compartments-like Pathology honeycomb structures which he described as Study of abnormal tissues or tissues with altered cells. structure and function. His discovery served as the foundation of cell theory. Tissues Latin term cellule. Group of cells with similar structure and intercellular materials interrelated to perform a Robert Brown specific function. Introduced nucleus (17th century). Observed in epidermal cells of orchids. Cytology Noticed small dense centers in plant cells but Study of cells and structures. function is yet unknown. Cells Marie Francois Bichat (1802) Basic unit of life that composed all living things. French pathologist. Termed tissues as textures. Organology Tissues Study of a group of tissues arranged in the - Different groups of cells. pattern of a particular organ. Matthias Schleiden Mitosis Proposed cell theory for plants. Division of a cell into two daughter cells that are genetically identical to the parent cell. Theodor Schwann (1838-39) Described animals are made of cells. Meiosis Discovered cells that form sheath surrounding Division of germ cells. nerves. Results in four (4) daughter cells which are not identical to the parent cell. Friedrich Gustav Jacob Henle (1841) Only one copy of each paternal and maternal Published first human histology. chromosome can be found in the daughter cells. Max Schultze (1861) - after almost 200 years Brief History First to describe cells as mass of nucleated Marcelo Malphigi (Italian anatomist) protoplasm. First describe true units forming animal tissues using simple lenses. Rudolf Virchow (1863) The true Father of Histology. Fundamental Law of Biology or Law of Virchow. Described the human body as a “cell state”. NIX 1 HUMAN HISTOLOGY (LABORATORY) All diseases involved changes in normal cells. Parts of a Compound Microscope 19th Century Microtome, fixing, embedding and staining techniques. Preparation of Tissues for Study Fixation Preserves tissue structure by stopping self-digestion and decomposition. Also stabilizes proteins (maintaining tissue architecture) and prevents microbial growth. 10% neutral buffered formalin; glutaraldehyde. Dehydration The Composition of the Human Body Removes water from the tissue as embedding 1. Cells media are immiscible with water (tissue is 2. Intracellular Substances passed through graded series of alcohols: 70%, Formed - Collagen and elastin 95%, 100% to gradually replace water with Amorphous ground substances - Protein, alcohol). polysaccharides, protein-sugar complexes Clearing 3. Body Fluid Replaces alcohol with a clearing agent to make - Blood and lymphatic fluid. the tissue transparent and compatible with the embedding medium, making the tissue translucent allowing for better infiltration of the embedding medium. E.g. Xylene and Toluene Infiltration Ensures that the embedding medium penetrates the tissue completely. Embedding Provides a solid medium to support the tissue for sectioning (cleared tissue is infiltrated with molten paraffin). Trimming/Sectioning Produces thin slices of tissue for microscopic examination. Staining Enhances contrast by coloring specific tissue components, making them distinguishable under the microscope. NIX 2 HUMAN HISTOLOGY (LABORATORY) Week 2: Cellular Elements Trichrome/Masson Triple Stain This is a commonly used Cell connective tissue stain in Basic and fundamental unit of life, it possesses a both histology and highly organized structure that enables it to carry pathology. out its vital functions. Stains mucus as well as collagenous and reticular Types of Cells fibers blue or green. Prokaryotic Cells Lack a defined nucleus. Periodic Acid Schiff Stain (PAS) Prokaryotic Technique for - Dispersed genetic material in the demonstrating cytoplasm. glycoproteins, mucins and some proteoglycans. Eukaryotic Cells It involves the generation of Have a defined nucleus. dialdehydes from hexoses. Plant - Cellulose cell wall; chloroplasts and Elastic Fiber Stains vacuoles. Such as Aldehyde Fuchsin, Animal Weigert’s, or Verhoeff Stain - Rigid cell wall; may have flagella. stains elastic fiber deep Protist purple. - They can have a cell wall, without differentiated tissues. Silver Stain Fungal Oxidation-reduction - Chitin cell wall; they are heterotrophs. technique that visualizes extracellular matrix components like reticular fibers or basement membranes. This technique produces dark brown or black stains by treating the sample with a strong oxidizing agent. Structure and Basic Functions These components work together to maintain cellular homeostasis and perform essential life activities. Staining Stains are used to highlight the specimen at the Cell Membrane microscopic level to study it at higher The cell membrane magnification for histopathological studies and surrounds the cell and is diagnostic purposes. composed of a phospholipid bilayer, which Types of Staining is made up of a hydrophilic Hematoxylin & Eosin Stain (H&E) head and hydrophobic tail, Most commonly used making up a semipermeable barrier between the nuclear stain in histology. interior and exterior. Hematoxylin is a basic dye, Its primary role lies in regulating the passage of while Eosin is an acidic dye. substances, including nutrients and waste materials. NIX 3 HUMAN HISTOLOGY (LABORATORY) Within it, specialized proteins play a crucial role It plays a fundamental role in the transport, in facilitating molecular transport and cellular processing, and distribution of protein and lipids communication. within the cell. Cell Nucleus Rough Endoplasmic Reticulum (RER) An organelle that houses It is studded with ribosomes and is involved in DNA, located in the center of the synthesis and modification of proteins. eukaryotic cells. Its primary function is to Smooth Endoplasmic Reticulum (SER) store and safeguard genetic Specializes in lipid synthesis, carbohydrate information, controlling gene metabolism, and detoxification. expression and DNA This structure lacks ribosomes. replication. It also contains the nucleolus, which is involved Golgi Apparatus in ribosome synthesis. Key in the processing and packaging of proteins and lipids produced in the endoplasmic reticulum. Euchromatin It synthesizes carbohydrates and lipoproteins Condensed state and is essential for maintaining the cell's internal Electron-dense on E/M and basophilic clumps on balance and facilitating communication with the L/M outside. Inactive Composed of a series of flattened sacs called cisternae, it acts as the “shipping center” of the Heterochromatin cell, sorting and packaging proteins into vesicles Less coiled for transport and distribution. Less visible on histologic sections Active transcription Central Dogma of Molecular Biology Building and repairing cellular structures, Cytoplasm regulating biological processes, and expressing Gel-like matrix that fills the inside of a cell. specific characteristics of each organism. It is composed of water, salts, proteins, and various organic molecules. Replication Plays a crucial role in biochemical reaction. One strand of the parent DNA and the other is Provides structural support to the cell. newly synthesized, this process is called semiconservative DNA replication. Ribosome Ribosomes are essential organelles for cellular Transcription functioning and survival. Process by which the information is transferred They synthesize proteins using the genetic from one strand of the DNA to RNA by the information from messenger RNA (mRNA), which enzyme RNA Polymerase. is crucial for cellular structure, function, and regulation. Translation Ribosomes are located in the cytoplasm and the Process by which the RNA codes for specific rough endoplasmic reticulum. proteins. It is an active process which requires energy. Endoplasmic Reticulum A network of interconnected membranes that extends from the nuclear membrane to the cell membrane. NIX 4 HUMAN HISTOLOGY (LABORATORY) Energy Supply filaments) and provides support and enables To carry out vital functions and necessary movements in eukaryotic cells. metabolic processes essential for the proper Its specific functions encompass stability, functioning of the cell and/or organism. intracellular transport, and contraction. Furthermore, it regulates cellular shape and plays Mitochondria a role in division, migration, and communication. Present in eukaryotic animal and plant cells. Flagella and Cilia Their primary function is Specialized structures for movement. energy generation through Flagella are elongated and enable locomotion in cellular respiration (ATP liquid environments, whereas cilia are shorter production). and create coordinated flow on the cell surface. The double membrane of mitochondria allows for Composed of microtubules in a “9+2” pattern, the organization of various stages of the they are essential for sperm motility. respiratory chain, making it crucial for cellular function and survival. Storage and Transportation They manage nutrients, eliminate waste, and Cellular Digestion regulate metabolic processes. It involves breaking down molecules and unwanted materials, enabling the recycling of Vacuoles nutrients and cellular maintenance. Membrane-bound organelles found in plant cells and some animal cells. Lysosomes They store nutrients, water, ions, and waste They contain digestive materials, regulating turgor pressure and osmotic enzymes that break down balance. molecules and unwanted Vacuoles can also be involved in the digestion of cellular materials. substances and serve as a defense mechanism They facilitate cellular against predators by controlling toxins. digestion, by disposing of waste, recycling nutrients, Vesicles and Endosomes and defending against pathogenic invasions. Membranous vesicles that transport specific materials between organelles and the cell Peroxisomes membrane. They contain enzymes that Vesicles degrade hydrogen peroxide - They transport materials from the and toxic compounds, endoplasmic reticulum and the Golgi thereby protecting the cell apparatus to other destinations. from oxidative damage. Endosomes Additionally, they play a role - They capture and distribute materials for in the synthesis and degradation, recycling, or their degradation of lipids and bile acids, regulating incorporation into metabolic pathways. lipid metabolism and overall homeostasis. Cellular Division Support and Movement It involves breaking down molecules and Maintaining cellular shape, enabling cellular unwanted materials, enabling the recycling of movement and division, are essential for its nutrients and cellular maintenance. functioning and survival. Mitosis Cytoskeleton Represented by M-phase of the complete cell It is composed of protein filaments cycle. (microtubules, microfilaments, and intermediate Considered as the active cellular division stage. NIX 5 HUMAN HISTOLOGY (LABORATORY) Divided into 4 general phases: PMAT ○ Prophase ○ Metaphase ○ Prometaphase ○ Telophase Goal: Cytokinesis - Regeneration of somatic cells. Meiosis Also known as reduction division since daughter cells only contain half the chromosomes of parent cells. Meiosis I - Focuses on homologous pair separation. Meiosis II - Focuses on separation of sister chromatids. Goal: Production of gametes for sexual reproduction. Binary Fission Type of asexual reproduction seen in prokaryotes. 1. Chromosome uncoiling + replication 2. Increase in cytoplasmic content + two strands migrate to opposite poles 3. Cell elongation + septum formation 4. New cell wall is formed + cell splits at center Outcome: Two identical cells with identical chromosomes. NIX 6