Introduction to Microanatomy (Histology) UM1010 2023-2024 PDF

Introduction to Histolog Dr Anthony Adefolaju Lecturer, Anatomy [email protected] UM1010 - Core Block Where opportunity creates success Macro Learni...

Introduction to Histolog Dr Anthony Adefolaju Lecturer, Anatomy [email protected] UM1010 - Core Block Where opportunity creates success Macro Learning Outcome M1.1.COR.ANA4 Outline the histology of the basic tissue types and their key features. 1. Define histology and understand its medical application Learning 2. Understand tissue processing for light objectives microscopy for this 3. Describe the basic types of tissue session Histology and its medical application  Introduction Histology - the study of the tissues of the body and - how these tissues are arranged to form organs. The Greek root “histo” can be translated as either "tissue" or "web" - tissues are usually webs of interwoven filaments and fibres, both cellular and noncellular, with lining membranes. helps to understand the normal structure and function of tissues and provides a link between gross anatomy, physiology, cell biology and biochemistry.  Biopsies Biopsies are tissue samples removed during surgery or routine medical procedures. Biopsies can diagnose or rule out: cancer ulcers hepatitis kidney disease endometriosis  Basic steps used in tissue preparation for light microscopy Commonly used fixatives are: Formaldehyde Glutaraldehyde Bouin’s fluid Picric acid  Basic steps used in tissue preparation for light microscopy Tissue sectioning  Interpretation of structures in tissue sections  Tissue Sectioning Slices 1 & 5 miss the yolk/cell nucleus Cell nucleus is smaller in sections 2 & 4  Tissue Sectioning Image A is a cross section of elbow macaroni, resembling a blood vessel, piece of gut, or other tubular organs. Image B is a longitudinal section of a sweat gland. Notice what a single slice could look like Tissue Sectioning Types of Tissue Sections Longitudinal section tissue cut along the longest direction of an organ Cross section tissue cut perpendicular to the length of an organ Oblique section tissue cut at an angle between a cross & longitudinal section  Staining Most cells and extracellular material are colourless, and to be studied microscopically sections must typically be stained (dyed). Cell components such as nucleic acids with a net negative charge (anionic) stain more readily with basic dyes and are termed basophilic; Cationic components, such as proteins with many ionized amino groups, have an affinity for acidic dyes and are termed acidophilic or eosinophillic.  Staining HAEMATOXYLIN behaves like a basic dye, staining basophilic tissue components. Acid dyes (eg, EOSIN) stain the acidophilic components of tissues such as mitochondria, secretory granules, and collagen. H&E  Staining https://www.youtube.com/watch?v=P0cZKC Staining  Microscopes - Activity Click on the link and hover your cursor on each question mark to see how big a grain of salt would be if it was magnified... https://view.genial.ly/5e9da31b1e336e0dcf6fd770/interactive-content-magnifyi ng-a-grain-of-salt Modern - Histology learning session  Basic types of tissue There are only four basic types of tissue:  Body tissues - Epithelial tissue Composed of one or more layers of closely packed cells – Lines every body surface and all body cavities (digestive, respiratory and urogenital systems, Heart and blood vessels) Avascular Regenerative Polarity - Has apical, basal, and lateral surfaces Absorption (e.g., the intestinal lining) Secretion (e.g., intestinal glands) Provide Sensation- Body tissues - Epithelial tissue Body tissues - Epithelial tissue  Apical surface modifications of Epithelia CILIA MICROVILLI STEREOCILIA Function: Motility of lumen Function: Increase “Long branched contents surface area for microvilli” Movement via Dynein motor absorption Function: Increase proteins between Microtubules e.g., small intestine surface area for e.g., trachea absorption e.g., Epididymis Glands – Derivatives of epithelium  Epithelia tissues Type of Epithelial Location Functions Tissue - Lining of blood vessels 1. Facilitates diffusion of gases, Simple Squamous (endothelium) - Alveoli of the nutrients, and waste products. Epithelium lungs - Lining of body cavities 2. Provides a smooth, protective lining. (mesothelium) - Kidney tubules - Glands - Simple Cuboidal Surface of ovaries - Thyroid Secretion and absorption Epithelium follicles - Lining of the digestive tract 1. Absorption of nutrients and secretion Simple Columnar (stomach, small intestine, large of mucus and enzymes in the Epithelium intestine) - Uterine lining digestive tract. (endometrium) 2. Protection and secretion in the uterus. 1. Provides protection against abrasion, Stratified Squamous - Skin (epidermis) - Oral cavity - pathogens, and dehydration. Epithelium Esophagus - Vagina - Anal canal 2. Keratinized version forms the skin's outer layer. 1. Secretion in sweat, mammary, and - Ducts of sweat glands - Stratified Cuboidal salivary glands. Mammary glands - Salivary Epithelium 2. Provides protection and support in glands gland ducts. 1. Protection in the pharynx and male Stratified Columnar - Pharynx - Male urethra - urethra. Epithelium Glandular ducts  Body tissues – Muscle tissues Mobility. Stability. Posture. Circulation. Respiration. Digestion.  Body tissues – Muscle tissues Characteristi Skeletal Muscle Smooth Muscle Cardiac Muscle c Control Voluntary (conscious) Involuntary (unconscious) Involuntary (unconscious) Striations Striated (striped) Non-striated Striated (striped) Nucleation Multinucleated fibers Single, central nucleus Single, central nucleus Branched and Fiber Shape Long, cylindrical Spindle-shaped interconnected Contraction Rapid and powerful Slow and sustained Rhythmic and coordinated Speed Location in Associated with the Found in various internal Exclusively in the heart Body skeletal system organs Involved in involuntary Role in Organ Responsible for Responsible for the functions like digestion and Systems voluntary movement blood vessel constriction rhythmic pumping of blood Intercalated Discs Present and allow for Not present Not present (Specialized coordinated contractions Body tissues – Nervous tissues Nervous tissues – Types of neuroglia Nervous tissues – Types of neuroglia  Nerve cells Function of Neurons Description Receive, integrate, and transmit nerve impulses for processing information from various sources. Information Enable communication within the nervous system, transmitting signals Processing between sensory organs, the CNS, muscles, and glands. Summation and processing of inputs (excitatory or inhibitory) to determine the generation of action potentials. Rapidly transmit electrical impulses (action potentials) along the neuron's axon for long-distance communication. Synaptic Release neurotransmitters at synapses to transmit signals from one Transmission neuron to the next across the synaptic cleft. Coordinating Body Responsible for sensory perception, motor control, cognitive processes, Functions and regulating physiological functions (e.g., heartbeat, digestion). Learning and Underlie learning and memory processes by forming and retrieving Memory memories through neural connections. Homeostasis Regulate bodily functions and respond to changes in the internal and Regulation external environment to maintain homeostasis. Adaptability Exhibit plasticity, allowing neurons to change and adapt in response to (Plasticity) experiences and learning  Neuroglia Type of Neuroglia Functions 1. Provide structural support to neurons. 2. Regulate the extracellular environment by maintaining ion balance. Astrocytes 3. Help form the blood-brain barrier, protecting the brain from harmful substances. 4. Participate in synapse formation and modulation. Produce myelin sheaths that insulate and increase the Oligodendrocytes speed of nerve impulse conduction in the central nervous (CNS) system (CNS). Produce myelin sheaths that insulate and increase the Schwann Cells speed of nerve impulse conduction in the peripheral (PNS) nervous system (PNS). Act as the immune cells of the CNS, defending against Microglia pathogens and removing cellular debris. Line the cavities of the brain and spinal cord (ventricles and Ependymal Cells central canal). 2. Produce cerebrospinal fluid (CSF), which provides cushioning and nutrition for the CNS. Satellite Cells Provide support and nutrition to neurons in the peripheral  Body tissues – Connective tissues Connective tissues are a diverse group of tissues in the body that serve to support, connect, or separate different types of tissues and organs.  Body tissues – Connective tissues Connective tissues are a diverse group of tissues in the body that serve to support, connect, or separate different types of tissues and organs. Classification of CT  Connective tissues - Composition  Composition Cells, and Extracellular matrix. ― fibres & ― ground substance Cellular and extracellular components of connective tissue. ground substance = glycosaminoglycans (GAGs), proteoglycans, and multi-adhesive  Cellular components of connective tissue. CT Cell Type Products/Summary of functions 1. Extracellular matrix (ECM) components, including collagen, Fibroblasts elastin, and glycosaminoglycans (GAGs). 2. Growth factors that stimulate tissue repair. 1. Phagocytosis of pathogens and debris. 2. Cytokines and chemokines for immune response and Macrophages inflammation. 3. Antigen presentation to lymphocytes. 1. Release histamine and other mediators in response to allergens or Mast Cells injury, causing inflammation and vasodilation. 2. Contain heparin, an anticoagulant. Produce antibodies (immunoglobulins) as part of the adaptive Plasma Cells immune response against pathogens. Adipocytes (Fat Store and release lipids for energy, insulation, and as an energy Cells) reserve. Regulate capillary blood flow and contribute to blood vessel Pericytes formation and stability. Form the reticular network in lymphoid tissues and secrete reticular  Cellular components of connective tissue- contd. CT Cell Type Products/Summary of functions Chondrocytes Produce and maintain the extracellular matrix of cartilage. Synthesize and mineralize bone matrix, including collagen and Osteoblasts hydroxyapatite. Osteoclasts Regulate bone remodelling and calcium homeostasis. Blood Cells Red Blood Cells 1. Transport oxygen from the lungs to body tissues and transport (Erythrocytes) carbon dioxide from body tissues to the lungs. 1. Part of the immune system for defending against infections and White Blood Cells pathogens. (Leukocytes) 2. Types include neutrophils, lymphocytes, monocytes, eosinophils, and basophils, each with specific functions in immunity. Platelets Essential for blood clotting and wound healing. Body tissues – Summary Basic Tissues 4 types  Additional Reading Young B. Wheater’s Functional Histology : a Text and Colour Atlas. Sixth edition. (O’Dowd G, Woodford P, Wheater PR, eds.). Churchill Livingston/Elsevier; 2014. https://uclan.alma.exlibrisgroup.com/leganto/public/44UOCL_IN ST/citation/5693585150003821?auth=SAML Ovalle WK. Netter’s Essential Histology : with Correlated Histopathology. Third edition. (Nahirney PC, Netter FH, eds.). Elsevier Inc; 2021:1 online resource (xi, 508 pages) : https://uclan.alma.exlibrisgroup.com/leganto/public/44UOCL_IN ST/citation/5693585160003821?auth=SAML 1. Define histology and understand its medical application. Summ 2. Understand tissue processing for light ary microscopy. 3. Describe basic tissue types.  Thank you for listening [email protected]