Basic Tissue - Anatomy & Physiology BIOL 101 PDF

Anatomy & Physiology BIOL 101 3. Basic Tissue Dr. Ali Drigo [email protected] Session ID: adclick ...

Anatomy & Physiology BIOL 101 3. Basic Tissue Dr. Ali Drigo [email protected] Session ID: adclick  Your Objectives will show here! 1. Describe the general structure and function of epithelial tissue. a) Describe the features used to classify epithelial tissue. b) List and describe the different classes of epithelial tissue. c) Identify the different types of epithelial tissue on histological images. d) Describe the function of each type of epithelial tissue and give examples of their location. 2. Identify the five main types of cell junction complexes. a) Describe the basic structure and function of each cell junction. Biol 101. Block 1. Lecture 3. Basic Tissue b) Identify the location of the different junctional complexes. 3. Describe the structure and function of glands. a) Compare and contrast the structure and function of endocrine and exocrine glands. b) Describe the structural and functional classification of exocrine glands. Session ID: adclick  Your Objectives will show here! 4. Describe the components that make up connective tissue. a) Name and describe the most numerous cell found in connective tissue and describe its function. b) List the fibers found in connective tissue and briefly describe their function. c) Describe the classifications of connective tissue. i. Embryonic ii. Mature: I Proper II Specialized iii. List and describe the subclassifications under each, their functions and locations. d) Identify the different types of connective tissue on histological imaging. e) List the locations of the different types of connective tissue. Biol 101. Block 1. Lecture 3. Basic Tissue 5. Describe the two types of cells found in nervous tissue. a) Briefly describe the structure and function of a neuron. b) Briefly describe the function of neuroglia Session ID: adclick  Objectives 2a, 2b Cell Junctions Cell junctions are contact points between the plasma membranes of tissue cells. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 2a, 2b Cell Junctions Cell junctions are contact points between the plasma membranes of tissue cells. Tight Junctions Adhering Junctions Desmosomes Structure: web-like strands of Structure: plaque (dense layer Structure: transmembrane transmembrane proteins that of proteins) that attaches both glycoproteins that extend into the fuse together the outer to the membrane proteins and intercellular space between surfaces of adjacent the microfilaments of the adjacent cell membranes and membranes. cytoskeleton. attach cells to one another. Function: they inhibit the passage Function: help epithelial surfaces Function: Prevent epidermal cells of substances between cells resist separation during various from separating under tension and and prevent the contents of organs contractile activities, e.g., when cardiac muscle cells from pulling from leaking into the blood or Biol 101. Block 1. Lecture 3. Basic Tissue food moves through the intestines. apart during contraction. surrounding tissues. Session ID: adclick  Objectives 2a, 2b Cell Junctions Cell junctions are contact points between the plasma membranes of tissue cells. Hemidesmosomes Gap Junctions Structure: membrane proteins called Structure: resemble desmosomes connexins form tiny fluid-filled tunnels but do not link adjacent cells. called connexons that connect neighboring cells. Function: allow cells in a tissue to Function: anchor cells to the communicate with one another such as basement membrane. nerve or muscle tissue impulses to spread quickly among cells. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 2a, 2b Tissue Overview A group of cells that usually have a common embryological origin and function together to carry out specialized activities. Four (4) basic tissue types: 1. Epithelial Tissue: covers body surfaces and lines hollow organs, body cavities, and ducts; it also forms glands. 2. Connective Tissue: protects and supports the body and its organs; bind organs together, store energy reserves as fat, and help provide the body with immunity to disease-causing organisms. Biol 101. Block 1. Lecture 3. Basic Tissue 3. Muscle Tissue: is composed of cells specialized for contraction and generation of force and generate heat that warms the body. 4. Nerve Tissue: detects changes in a variety of conditions inside and outside the body and responds by generating electrical signals called nerve action potentials (nerve impulses) that activate muscular contractions and glandular secretions. Session ID: adclick  Objectives 1a Epithelial Tissue Cells arranged in continuous sheets. Lies on a basement membrane. Avascular Tissue (no blood vessels) Exhibit polarity Covers exterior body surfaces e.g., skin Lines body tubes/cavities Biol 101. Block 1. Lecture 3. Basic Tissue Forms secretory portion (parenchyma) & excretory portion (ducts of glands). Can function as receptors for special senses e.g., smell, taste, hearing and vision. Session ID: adclick  Objectives 1a Epithelial Tissue - Classification 1. Number of cell layers: 1 cell layer: Simple 2+ cell layers: Stratified 2. Shape of cells (the most apical layer): Squamous: width is greater than height Cuboidal: width equal to height equal to depth Biol 101. Block 1. Lecture 3. Basic Tissue Columnar: height is greater than width 3. Specialization of apical cell (when applicable): Cilia, Microvilli, Stereocilia, Flagella Keratinized VS Non-keratinized Session ID: adclick  Objectives 1b, 1c, 1d Simple Squamous Epithelium Description: single layer of cells with a centrally located flattened, oval nucleus. Function: Present at sites of exchange; filtration or diffusion and secretion. Location: Lines heart, blood vessels, lymphatic vessels (endothelium) Lines serous membranes of abdominal and thoracic cavities (mesothelium) Found in air sacs of lungs, inner surface of cornea (eye). Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 1b, 1c, 1d Simple Cuboidal Epithelium Description: Single layer of cube-shaped cells; with round, centrally located nucleus. Function: Secretion and absorption. Location: Covers surface of ovary. Makes up portions of some glands such as thyroid and pancreas. Lines kidney tubules and smaller ducts of many glands. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 1b, 1c, 1d Simple Columnar Epithelium Description: Single layer of column-like cells with oval nuclei near the base of cells. Apical specializations may include microvilli or cilia. Function: Secretion and absorption. Location: Lines digestive canal, gallbladder, uterine tubes, uterus and larger ducts of many glands. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 1b, 1c, 1d Stratified Squamous Non-Keratinized Epithelium Description: Two or more layers; cells in the most apical nucleated layer is squamous. Nonkeratinized: does not contain large amounts of keratin in apical layers. Function: Protection against abrasion, water loss, foreign invasion. Location: Mouth, esophagus, vagina, anus. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 1b, 1c, 1d Stratified Squamous Keratinized Epithelium Description: Two or more layers; cells in the most apical nucleated layer is squamous. Keratinized: develops tough layer of keratin in apical layers of cells. Function: Protection against abrasion, water loss, UV radiation, foreign invasion. Location: Superficial layer of skin (epidermis) Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 1b, 1c, 1d Stratified Cuboidal Epithelium Description: has two or more layers; cells in the apical layer is cube-shaped (rare). Function: Protection; limited secretion and absorption. Location: Ducts of adult sweat glands and esophageal glands, part of male urethra. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 1b, 1c, 1d Stratified Columnar Epithelium Description: Basal layer usually consists of shortened irregularly shaped cells; only apical layer has columnar cells (rare). Function: Protection and secretion. Location: Lines large excretory ducts of some glands such as esophageal glands, part of male urethra, part of the conjunctiva of the eye. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 1b, 1c, 1d Pseudostratified Epithelium Description: Appears to have several layers because the nuclei of the cells are at various levels. However, all the cells are attached to the basement membrane in single layer. May contain cilia and goblet cells. Function: Absorption, secretion and conduit. Location: Cilia and goblet cells: Most of upper respiratory tract. No cilia or goblet cells: Epididymis, parts of male urethra. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 1b, 1c, 1d Transitional Epithelium AKA Urothelium Description: Has variable appearance. Cells change shape, from squamous to cuboidal and vice versa as the organs of the urinary system stretch (distend) to a larger size and then collapse to a smaller size. Function: Allows urinary organs to stretch and maintain protective lining while holding variable amount of fluid without rupturing. Location: Urinary excretory passages: Minor and Major Calyces, Ureters, Urinary bladder, and portions of urethra. Biol 101. Block 1. Lecture 3. Basic Tissue Sectional view of urothelium in urinary Sectional view of urothelium in urinary bladder in partially relaxed state. bladder in filled state. Session ID: adclick  Objectives 3a Glands Glands are one or more cells, mostly epithelial that secrete substances directly into the blood stream or through a conduit onto surface/cavities. Can be classified based on how they secrete their products: Endocrine: Ductless Secrete into blood vessels or extracellular space via the process of exocytosis. They secrete hormones that regulate many metabolic and physiological Biol 101. Block 1. Lecture 3. Basic Tissue activities to maintain homeostasis. Exocrine: Secrete into ducts that connects to the surface of the cell or to body cavities. Can be classified in many ways: structurally and functionally. Session ID: adclick  Objectives 3b Exocrine Glands Structurally: Unicellular: single-celled glands such as goblet cells that secrete mucus. Multicellular: Composed of many cells e.g., sudoriferous (sweat), sebaceous (oil) and salivary glands. Structure of ducts (purple) Biol 101. Block 1. Lecture 3. Basic Tissue Simple: have unbranched ducts Compound: have branched ducts Shape of secretary cells (pink) Tubular: tube-like Acinar/Alveolar: flask Tubuloacinar: tube ends in a dilation Session ID: adclick  Objectives 3b Exocrine Glands Functionally: Mode of Secretion Merocrine Apocrine Holocrine Products are released Products collect apically The entire cell ruptures. in secretory vesicles. and are pinched off. Examples: Salivary Examples: Mammary Examples: Sebaceous glands, glands of the glands glands. pancreas Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objective 4 Connective Tissue Highly vascularized and innervated (except cartilage). Functions: Supports and binds tissues Defends against infections Stores nutrients Insulation Protection and transport Composition: Biol 101. Block 1. Lecture 3. Basic Tissue Extracellular Matrix: 1. Ground Substance 2. Protein Fibers. Cells: secretes the extracellular matrix and has other functions. Session ID: adclick  Objectives 4a, 4b Connective Tissue Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objective 4b Connective Tissue – Extracellular Matrix Ground Substance: Found between the cells and fibers. Can be fluid, semi-fluid, gelatin-like or calcified. Support, bind, stores water and provides a medium for transport. Contains numerous proteins and polysaccharides. Glycosaminoglycans (GAGS) Proteoglycans Biol 101. Block 1. Lecture 3. Basic Tissue Protein Fibers: Collagen: It is strong and resistant to pulling and stretch. Reticular: Forms stroma of organs; binds smooth muscle tissue cells; filters and removes worn out blood cells in spleen and microbes in lymph nodes. Elastic: Allows stretching of various organs; is strong and can recoil to original shape after being stretched. Session ID: adclick  Objective 4a Connective Tissue - Cells Fibroblasts: large, flat cells with branching processes. They are present in all the general connective tissue and are the most numerous. They secrete fibers and ground substance. Macrophages: phagocytes that move throughout the tissue and gather at the site of infection or inflammation to carry on phagocytosis. Plasma Cells: a type of white blood cell that produces antibodies/immunoglobulins. Biol 101. Block 1. Lecture 3. Basic Tissue Mast cells: involved in the inflammatory response, can also ingest and kill bacteria. Adipocytes: they store fat and found deep to the skin and around organs. Leukocytes: white blood cells that migrate from the blood to the site of infection, parasitic invasions and allergic responses. Session ID: adclick  Objective 4c Connective Tissue – Classification Embryonic Connective Tissue Mesenchyme Mucoid (mucous) Mature Connective Tissue Connective Tissue Proper Loose connective tissue Dense connective tissue Biol 101. Block 1. Lecture 3. Basic Tissue Specialized Connective Tissue Cartilage Bone Adipose Tissue Blood Session ID: adclick  Objectives 4c Connective Tissue – Classification Mesenchyme Mucoid Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c Connective Tissue – Classification Mesenchyme Mucoid Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Connective Tissue – Embryonic: Mesenchyme Description: has irregularly shaped mesenchymal cells embedded in semifluid ground substance that contains delicate reticular fibers. Function: Forms almost all other types of connective tissue. Location: Embryo: almost exclusively under skin and along developing bones. Can be found in the adult connective tissue, especially along blood vessels. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Connective Tissue - Embryonic: Mucoid Description: has widely scattered fibroblasts embedded in viscous, jellylike ground substance that contains fine collagen fibers. Function: Support Location: Umbilical cord of fetus. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c Connective Tissue – Classification Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Connective Tissue – Connective Tissue Proper Loose Connective Tissue/Areolar Tissue Description: consists of fibers arranged randomly and several kinds of cells embedded in semifluid ground substance. There are more cells than fibers. Function: Strength, elasticity and support (nutritional and structural). Location: In and around nearly every body structure: in subcutaneous tissue deep to skin, lamina propria of mucous membranes, around blood vessels, nerves and body organs. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Connective Tissue – Connective Tissue Proper Dense Regular Connective Tissue Description: mainly collagen fibers regularly arranged in bundles with fibroblasts in rows between them. There are more fibers than cells. Function: Provide strong attachment between various structures. Tissue structure withstands pulling (tension) from one direction. Location: Forms tendons (attach muscle to bones),ligaments (attach bone to bone) and aponeuroses (sheetlike tendons that attach muscle to muscle or muscle to bone). Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Connective Tissue – Connective Tissue Proper Dense Irregular Connective Tissue Description: is made up of collagen fibers; usually irregularly arranged with a few fibroblasts. There are more fibers than cells. Function: Provide tensile (pulling) strength in many directions. Location: Often occurs in sheets such as tissue beneath skin and around muscles and other organs, dermis of the skin, fibrous covers of organs such as heart (pericardium), bone (periosteum), cartilage (perichondrium) kidneys, liver, testes. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c Connective Tissue – Classification Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Specialized Connective Tissue- Adipose Tissue White Adipose Tissue Description: cells derived from fibroblasts that are specialized for storage of triglycerides (fats) as a large, centrally located droplet. Function: Reduces heat loss through skin; serves as an energy reserve; supports and protects organs. Location: subcutaneous tissue deep to skin, around heart and kidneys, yellow bone marrow. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Specialized Connective Tissue - Cartilage Description Cells: Single or grouped chondrocytes within spaces called cartilage lacunae. Extracellular Matrix: Dense, avascular network of collagen and or elastic fibers embedded ground substance. Surrounded by perichondrium (dense irregular connective tissue) that contains blood vessels and nerves. Functions: Biol 101. Block 1. Lecture 3. Basic Tissue It resists tension(stretching), compression (squeezing) and sheer (pushing in opposite directions.) Its strength is due to its collagen fibers and its resilience is due to chondroitin sulfate. Location: There are 3 different types. Session ID: adclick  Objectives 4c, 4d, 4e Cartilage – Hyaline Description: Chondrocytes are in a resilient gel-like ground substance that appears in the body as a bluish-white, shiny substance; perichondrium present. Function: Provides smooth surfaces for movement of joints, flexibility and support. Location: Fetal skeleton, end of long bones, anterior ends of ribs, tip of nose, laryngeal and tracheal rings. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Cartilage – Elastic Description: Chondrocytes are embedded in a threadlike network of elastic fibers within ECM; perichondrium present. Function: Provide strength and elasticity; maintains shape of certain structures. Location: Epiglottis, part of external ear, auditory tubes. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Cartilage – Fibrous AKA Fibrocartilage Description: Chondrocytes embedded in thick bundles of collagen fibers within ECM; lacks perichondrium. Function: Provides strength and rigidity. Supports and joining structures together. Location: Pubic symphysis (where hip bones join anteriorly), intervertebral discs, menisci (cartilage pads) of knee. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Specialized Connective Tissue - Bone Description: Calcified Extracellular Matrix that contains Osteons that contain bone lamellae: concentric rings of ECM giving it tensile and compressive strength) Bone lacunae: small spaces between bone lamellae containing bone cells called osteocytes. Bone canaliculi: networks of minute canals containing processes of osteocytes) Haversian/Osteonic canals contains blood vessels and nerves. Location: All the bones of the body. Functions: Support and protection, calcium storage and blood cell formation (hematopoiesis). Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c, 4d, 4e Specialized Connective Tissue - Blood Description: consists of blood plasma and formed elements: red blood cells (erythrocytes), white blood cells (leukocytes), platelets (thrombocytes). Location: within blood vessels and within chambers of the heart. Function: RBC: transport oxygen and some carbon dioxide. WBC: carry on phagocytosis and mediate allergic reactions and immune system responses. Platelets; essential for blood clotting. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Objectives 4c Connective Tissue – Classification Mesenchyme Mucoid Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick  Muscular Tissue Consists of elongated cells called muscle fibers or myocytes that can use ATP to generate force. Functions: Produces body movements Maintains posture Generates heat Provides protection Biol 101. Block 1. Lecture 3. Basic Tissue Types: Skeletal Cardiac Smooth Will be discussed in upcoming Muscle Session ID: adclick lectures!  Objectives 5a, 5b Nervous Tissue Description: consists of 1. Neurons (nerve cells), which consists of cell body and processes extending from cell body (one to multiple dendrites and a single axon); and 2. neuroglia, which do not generate or conduct nerve impulses but have other important supporting functions. Location: Nervous system Function: Exhibits sensitivity to various types of stimuli; converts stimuli into nerve impulses (action potentials); conducts nerve impulses to other neurons, muscle fibers or glands. Biol 101. Block 1. Lecture 3. Basic Tissue Will be discussed in upcoming Excitable Session ID: adclick Tissue lectures!  References Tortora, G. J., & Derrickson, B. H. (2022). The cellular level of organization. In Principles of anatomy and physiology(16th ed., pp. 63- 110). John Wiley & Sons. Pawlina, W., & Ross, M. H. (2020). Histology: A text and Atlas: With Correlated Cell and Molecular Biology (8th ed.). Philadelphia etc.: Wolters Kluwer. Biol 101. Block 1. Lecture 3. Basic Tissue Session ID: adclick