Topic 06 - Types of Tissues (S2 AY23-24) PDF

Topic 6 The Tissue Level of Organization This slide deck contains animations. Please disable animations if they cause issues with your device. Course Learning Outcomes CLO-3: Explain the organizational structure and function of specific organ systems. Learning Objectives 1. Learn about the vari...

Topic 6 The Tissue Level of Organization This slide deck contains animations. Please disable animations if they cause issues with your device. Course Learning Outcomes CLO-3: Explain the organizational structure and function of specific organ systems. Learning Objectives 1. Learn about the various types of tissues and their origins 2. Discuss how cells of tissue are held together 3. Compare and contrast epithelial, connective, muscular, and nervous tissue 4. Learn about the structure and function of membranes GRD101 Biology - The Tissue Level of 2 Organization What Is a Tissue? A tissue is a group of cells that usually have a common embryonic origin and function together to carry out specialized activities There are 4 basic types of tissues in the human body, and they are categorized according to their structure and function Copyright ©2021 John Wiley & Sons, Inc. 3 The Main Types of Tissues 1. Epithelial - covers body surfaces and lines hollow organs 2. Connective - protects and supports the body and its organs. 3. Muscular - cells specialized for contraction and generation of force 4. Nervous - detects changes in a variety of conditions inside and outside the body Copyright ©2021 John Wiley & Sons, Inc. 4  Cell Junctions Cells can be held together in several ways. These points of contact between cells are called cell junctions. a. Tight junction - Impermeable junction - Form continuous seals around the cell - Prevent molecules from passing b. Desmosomes junction - Anchoring junction - Bind adjacent cells together like a. b. c. the teeth of a zipper, - Prevent cells from tearing apart c. Gap junction - Communication junction - Allow small molecules to pass from one cell to the other Copyright ©2021 John Wiley & Sons, Inc. 5 5 Characteristics of Epithelial Tissue Cells are arranged in sheets and with little ECM (Extracellular Matrix) in between cells Many cell junctions are present Epithelial cells attach to a basement membrane- Apical and Basal surfaces Epithelial tissue is avascular but has a nerve supply (innervated) High rate of regeneration (Mitosis) Copyright ©2021 John Wiley & Sons, Inc. 6 6 Surfaces of Epithelial Cells and the Basement Membrane Copyright ©2021 John Wiley & Sons, Inc. 7 Classification of Epithelial Tissue Covering and lining epithelia are classified according to the following: i) shape of the cells ii) how many layers thick are they Copyright ©2021 John Wiley & Sons, Inc. 8 8 Classification of Epithelial Tissue SHAPE OF CELLS TISSUE TYPE One Layer (simple) Squamous Simple squamous Cuboidal Simple cuboidal Columnar Simple columnar (non-ciliated & ciliated) Pseudostratified Pseudostratified columnar columnar (ciliated) Several Layers (stratified) Squamous Stratified squamous Cuboidal Stratified cuboidal Columnar Stratified columnar (Varies) Transitional Copyright ©2021 John Wiley & Sons, Inc. 9 Epithelial Tissue: Surface Epithelium 1. Simple Squamous Epithelium Description A single layer of flat cells with a centrally located nucleus. Location Kidney glomeruli; air sacs of lungs; lining of heart, blood vessels, and lymphatic vessels; serosae Function Allows materials to pass by filtration (kidneys) or diffusion (lungs) and where protection is not important; Copyright ©2021 John Wiley & Sons, Inc. 10 Epithelial Tissue: Surface Epithelium 2. Simple Cuboidal Epithelium Description Single layer of cubelike cells with large, spherical central nuclei. Location Kidney tubules; ducts and secretory portions of small glands; ovary surface. Function Secretion and absorption. Copyright ©2021 John Wiley & Sons, Inc. 11 Epithelial Tissue: Surface Epithelium 3. Non-ciliated Simple Columnar Epithelium Description A single layer of non-ciliated column-like cells with oval nuclei near base of cells; contains 1) columnar epithelial cells with microvilli at apical surface and 2) goblet cells. Location Lines GI tract, ducts of many glands and gallbladder. Function Absorption; secretion of mucus, enzymes, and other substances Copyright ©2021 John Wiley & Sons, Inc. 12 Epithelial Tissue: Surface Epithelium 4. Ciliated Simple Columnar Epithelium Description Single layer of ciliated column-like cells with oval nuclei near base of cells. Goblet cells usually interspersed. Location lines small bronchi, uterine tubes, and some regions of the uterus. Function In respiratory system, 1) cilia beat in unison (together) to move mucus and foreign particles toward throat to be coughed up or swallowed. 2) Cilia also move oocytes from ovaries through fallopian tubes into uterus. Copyright ©2021 John Wiley & Sons, Inc. 13 Epithelial Tissue: Surface Epithelium 5. Ciliated Pseudostratified Columnar Epithelium Description Appears to have several layers because the nuclei are a various levels Contains cells that extend to surface and secrete mucus (goblet cells) and have cilia. Location Lines airways of most upper respiratory tract. Function Secretes mucus that traps foreign particles, and cilia sweep away mucus for elimination from body. Copyright ©2021 John Wiley & Sons, Inc. 14 Epithelial Tissue: Surface Epithelium 6. Non-ciliated Pseudostratified Columnar Epithelium Description Appears to have several layers because the nuclei are a various levels. Even though the cells are attached to the basement membrane in a single layer, some cells do not extend to the apical surface- (pseudo = false). Contains cells with NO cilia and lacks goblet cells. Location Lines epididymis, larger ducts of many glands and parts of male urethra. Function Absorption and secretion. Copyright ©2021 John Wiley & Sons, Inc. 15 Epithelial Tissue: Surface Epithelium 7. Stratified Squamous Epithelium Description Contains two or more layers of cells. Cells in the apical layer and several layers deep to it are squamous; cells in deeper layers are cuboidal and columnar. As basal cells divide, daughter cells arising from cell divisions push upward toward the apical layer. There are two types: 1. keratinized stratified squamous epithelium (containing keratin) and 2. nonkeratinized stratified squamous epithelium (does not contain large amounts of keratin). Location Keratinized variety forms superficial layer of skin; Nonkeratinized variety lines wet surfaces (lining of mouth, esophagus, part of epiglottis, party of pharynx and vagina) and covers tongue. Function Protection against abrasion, water low, UV radiation, and foreign invasion. First line of defense against microbes. Copyright ©2021 John Wiley & Sons, Inc. 16 Epithelial Tissue: Surface Epithelium Stratified Squamous Epithelium, continued. Copyright ©2021 John Wiley & Sons, Inc. 17 Epithelial Tissue: Surface Epithelium 8. Stratified Cuboidal Epithelium Description Has two or more layers of cells; cells in apical layer are cube- shaped; fairly rate type. Location Ducts of adult sweat glands and esophageal glands, part of male urethra. Function Protection; limited secretion and absorption. Copyright ©2021 John Wiley & Sons, Inc. 18 Epithelial Tissue: Surface Epithelium 9. Stratified Columnar Epithelium Description Basal layers consist of shortened, irregularly shaped cells; only apical layer has columnar cells; uncommon. Location Lines part of urethra; large excretory ducts of some glands, such as esophageal glands; small areas in anal mucous membrane; part of conjunctiva of eye. Function Protection and secretion. Copyright ©2021 John Wiley & Sons, Inc. 19 Epithelial Tissue: Surface Epithelium 10. Transitional Epithelium (Urothelium) Description In relaxed or unstretched state, looks like stratified cuboidal epithelium. As tissue is stretched, cells become flatter, giving the appearance of stratified squamous epithelium. Multiple layers with high elasticity Location Lines urinary bladder, ureters, and portions of urethra. Function Stretches readily, permits stored urine to distend urinary organ. Copyright ©2021 John Wiley & Sons, Inc. 20 Glandular Epithelium A gland is a single cell, or a mass of epithelial cells adapted for secretion. The secretions of endocrine glands enter the interstitial fluid and diffuse into the bloodstream The secretions of exocrine glands enter ducts that empty onto the surface of a covering/lining epithelium, such as the skin surface or the lumen of the stomach Interactions Animation: Epithelial Tissues Copyright ©2021 John Wiley & Sons, Inc. 21 Glandular Epithelium (1 of 2) A. Endocrine Glands Description Endocrine gland secretions (hormones) enter interstitial fluid and then diffuse into bloodstream without flowing through a duct. Endocrine glands will be described in detail in Chapter 18. Location Examples include: pituitary gland at base of brain, pineal gland in brain, thyroid and parathyroid glands near larynx (voice box), adrenal glands superior to kidneys, pancreas near stomach, ovaries in pelvic cavity, testes in scrotum, thymus in thoracic cavity. Function Hormones regulate many metabolic and physiological activities to maintain homeostasis. Copyright ©2021 John Wiley & Sons, Inc. 22 Glandular Epithelium (2 of 2) B. Exocrine Glands Description Exocrine gland secretory products are released into ducts that empty onto surface of a covering and lining epithelium, such as skin surface or lumen of lumen of hollow organ. Location Sweat, oil, and earwax glands of skin; digestive glands such as salivary glands (secrete into mouth cavity) and pancreas (secretes into small intestine). Function Produce substances such as sweat to help lower body temperature, oil, earwax, saliva, or digestive enzymes. Copyright ©2021 John Wiley & Sons, Inc. 23 Characteristics of Connective Tissue Consists of two basic elements: 1. Cells 2. Extracellular matrix (ECM): composed of fibers and ground substance Connective tissue cells do not have any free surfaces Connective tissue is highly vascularized and has a nerve supply o Exceptions: tendons and cartilage Copyright ©2021 John Wiley & Sons, Inc. 24 Connective Tissue Connective tissue is the most abundant and widely distributed of the primary tissues, but its amount in particular organs varies. For example, skin consists primarily of connective tissue, while the brain contains very little. Interactions Animation: Connective Tissues Copyright ©2021 John Wiley & Sons, Inc. 25 The Component of Connective Tissue Copyright ©2021 John Wiley & Sons, Inc. 26 Connective Tissue Extracellular Matrix Extracellular matrix is located in the spaces between connective tissue cells. - composed of fibers and ground substance (Water + Organic Molecules) - Ground substances provide a medium for the exchange of materials between the blood and cells Copyright ©2021 John Wiley & Sons, Inc. 27 Connective Tissue Extracellular Matrix Fibers in the extracellular matrix provide strength and support to a tissue: Collagen fibers - most abundant and provide strength, support, and a bit of rigidity to tissues. Elastic fibers - allow tissues to stretch and then return to their original shape Reticular fibers - create a soft internal skeleton that supports other cell types in lymphoid organs and other specific locations Copyright ©2021 John Wiley & Sons, Inc. 28 Comparison: Epithelial vs. Connective Tissue Epithelial tissue Connective tissue Cell Density Very high Relatively low Cell Junction High Not attached to each other Polarization Yes No. goes in all direction Vascularity none Vascular (except collagen) ECM Little/no ECM lots of extracellular matrix Copyright ©2021 John Wiley & Sons, Inc. 29 Classification of Connective Tissue Types of connective tissue Connective tissue Specialized Connective proper tissue Cartilage Bone Blood Hyaline Cartilage Fibrous Cartilage Elastic Cartilage Copyright ©2021 John Wiley & Sons, Inc. 30 Mature Connective Tissue: Supporting Connective Tissue - Cartilage A. Hyaline Cartilage Description Contains resilient gel as ground substance and appears as a bluish-white, glassy appearance. Location Most abundant cartilage in body; at ends of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, bronchial tubes, embryonic and fetal skeleton. Function It provides smooth surfaces for movement at joints, flexibility, and support. However, it is the weakest type of cartilage and can be fractured. Copyright ©2021 John Wiley & Sons, Inc. 31 Mature Connective Tissue: Supporting Connective Tissue - Cartilage B. Fibrous Cartilage (Fibrocartilage) Description Has chondrocytes among clearly visible thick bundles of collagen fibers within extracellular matrix; lacks perichondrium. Location Public symphysis, intervertebral discs, menisci of knee, portions of tendons that insert into cartilage. Function Support and joining structures together. Strength and rigidity make it the strongest type of cartilage. Copyright ©2021 John Wiley & Sons, Inc. 32 Mature Connective Tissue: Supporting Connective Tissue - Cartilage C. Elastic Cartilage Description Has chondrocytes in a threadlike network of elastic fibers within extracellular matrix; perichondrium present. Location Lid on top of larynx (epiglottis), part of external ear (auricle), auditory (Eustachian) tubes. Function Provides strength and elasticity; maintains shape of certain structures. Copyright ©2021 John Wiley & Sons, Inc. 33 Mature Connective Tissue: Supporting Connective Tissue - Bone Description Compact bone tissue consists of osteons (haversian systems) that contain bone lamellae, bone lacunae, osteocytes, bone canaliculi, and central (haversian) canals. Spongy bone tissue consists of thin columns called trabeculae; spaces between trabeculae are filled with red bone marrow. Location Both compact and spongy bone tissue make up the various parts of bones of the body. Function Support, protection, storage; houses blood-forming tissue; serves as levers that act with muscle tissue to enable movement. Copyright ©2021 John Wiley & Sons, Inc. 34 Mature Connective Tissue: Supporting 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, within chambers of heart. Function Red blood cells: transport oxygen and some carbon dioxide; White blood cells: carry on phagocytosis and mediate allergic reactions and immune system responses; Platelets: essential for clotting. Copyright ©2021 John Wiley & Sons, Inc. 35 Membranes Membranes are flat sheets of pliable tissue that cover or line a part of the body. 2 types of membranes: 1. Epithelial membranes o Mucous membranes o Serous membranes o Cutaneous membranes 2. Synovial membranes Copyright ©2021 John Wiley & Sons, Inc. 36 36 Membranes Copyright ©2021 John Wiley & Sons, Inc. 37 Membranes Copyright ©2021 John Wiley & Sons, Inc. 38 General Characteristics of Muscular Tissue - Muscular tissue consists of fibers that provide motion, maintain posture, and produce heat. - are considered excitable cells because they exhibit electrical excitability: 3 types of muscle tissues: 1. Skeletal muscle 2. Cardiac muscle 3. Smooth muscle Copyright ©2021 John Wiley & Sons, Inc. 39 Muscular Tissue 1. Skeletal Muscle Tissue Description Consists of long, cylindrical, striated fibers. Vary greatly in length. Multinucleated cell with nuclei at the periphery. It is voluntary because it can be made to contract or relax by conscious control. Location Usually attached to bones by tendons. Function Motion, posture, heat production, protection. Copyright ©2021 John Wiley & Sons, Inc. 40 Muscular Tissue 2. Cardiac Muscle Tissue Description Consists of branched, striated fibers with usually only one centrally located nucleus. Attach end to end by intercalated discs, which contain desmosomes and gap junctions. Involuntary control. Location Heart wall. Function Pumps blood to all parts of body. Copyright ©2021 John Wiley & Sons, Inc. 41 Muscular Tissue 3. Smooth Muscle Tissue Description Consists of nonstriated fibers (lacking striations, hence the term smooth. Spindle-shaped cell thickest in the middle, and containing a single, centrally located nucleus. Usually involuntary Location Walls of hollow internal structures such as blood vessels, airways to lungs, stomach, intestines, gallbladder, urinary bladder, and uterus, Iris of eyes Function Motion (constriction of blood vessels and airways, propulsion of foods through gastrointestinal tract, contraction of urinary bladder and gallbladder). Copyright ©2021 John Wiley & Sons, Inc. 42 Nervous Tissue Two kinds of cells: Neurons Neuroglia ( supporting cells- glial cells) Most neurons have a cell body, dendrites, and axons o Neurons can carry sensory or motor information, and they can perform integrative functions (excitable cells) Neuroglia protects and supports neurons. Copyright ©2021 John Wiley & Sons, Inc. 43 General Characteristics of Nervous Tissue Description Consists of: (1) neurons (nerve cells), which consist of cell body and processes extending from cell body (one to multiple dendrites and a single axon); and (2) neuroglia, which does not generate or conduct nerve impulses but has 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. Copyright ©2021 John Wiley & Sons, Inc. 44 Aging Younger bodies generally experience: – A better nutritional state – A better blood supply to tissues – A faster metabolic rate Aging slows the process of tissue repair Aging also results in stiffening and loss of elasticity in tissues Copyright ©2021 John Wiley & Sons, Inc. 45 Homeostatic Imbalances Disorders of epithelial tissues tend to be specific to individual organs, such as ulcers in the stomach Disorders of connective tissues tend to be autoimmune in nature, such as lupus Disorders of muscular and nervous tissues will be discussed in later chapters Copyright ©2021 John Wiley & Sons, Inc. 46