Tissue Level PDF

L6: Tissue Level Menu LO1-4 Section A: Micro...

L6: Tissue Level Menu LO1-4 Section A: Microscopic anatomy, location, & functional roles of Epithelial tissue LO5-9 Section B: Microscopic anatomy, location, & functional roles of Connective tissue LO10-11 Section C: Membranes & Glands ©Beatriz Castro References:Professor Dave Explains-YouTube Channel, Pearson, Inc., OpenStax © Rice University under a CC-BY 4.0 LO1: List the four major tissue types. Tissue - a group or mass of similar cells working together to perform common functions. https://www.rxlist.com/histology/definition.htm  Epithelium = epithelial tissue LO2: Discuss general characteristics of epithelial tissue 2 Main types: Most epithelial cells are separated from the 1. Glandular epithelium- make up glands connective tissue by a sheet of extracellular material Cells are specialized to secrete substances called the BASEMENT MEMBRANE 2. Covering & Lining epithelium- Covers all apical surface body surfaces both inside and out. can be lined with Cells tightly microvilli or cilia packed together basal surface Usually has no vascular tissue (avascular) - no blood supply Innervated (supplied with nerves) Epithelial cells exhibit polarity (opposite sides Cells reproduce rapidly, results in rapid healing exhibit different features & functions) (and scarring)  LO3: Classify the different types of epithelial tissues based on distinguishing structural characteristics. Categorized based on : FIRST WORD SECOND WORD (1) Number of layers in the tissue: (2) Specific shape of each cell: Simple- single layer of cells Stratified- several layers of cells (square) (rectangle) One type of tissue can be arranged in different forms, each form has a different function. LO4: Describe the locations and functions of each type of epithelial tissue in the human body. Correlate function with structure for each tissue type. Endothelium (lining blood vessels) Lining of Air sacs in lungs kidney tubules round to oval nuclei *May contain mucus-secreting unicellular glands Disc-shaped (goblet cells) central nuclei digestive tract *Can have microvilli to increase surface area diffusion and filtration Named based on the shape of the cells in the (rare, in some glands) (rare) uppermost layer, even though the deeper layers might have different cell shapes. It can be further classified as: a modified stratified squamous epithelium (a) keratinized The surface cells are dead and packed with keratin protein (b) Nonkeratinized type line mouth, esophagus Ureters Bladder Cells are alive and lack keratin Urethra It lines hollow urinary system organs.  Pseudostratified Columnar Epithelium It is a simple columnar epithelium that appears stratified. -just a single layer of cells of differing heights, some not reaching the free surface, nuclei at different levels Can have cilia (hair-like projections) & mucus-secreting cells It lines most of the upper respiratory passages. Function: Mucus Secretion & propulsion of mucus by ciliary action  LO5: Describe the structure of the basement membrane Thin, acellular structure, specialized part of the extracellular matrix (ECM) Located between any form of epithelium and its underlying connective tissue Epithelium 2 layers: Lamina lucida BASAL LAMINA Lamina densa RETICULAR LAMINA lamina reticularis Connective tissue  Connective tissue LO6: Describe the structural elements of the connective tissue EXTRACELLULAR MATRIX (ECM) Limited # 3 Types of Fibers: Long & thin, form networks Strongest fibers matrix-secreting cell (-blast) Elastic (Elastin) fibers Collagen fibers Fills the space b/w cells & fibers Mature cell (-cyte) Gel-like, amorphous material 10% Large organic molecules + 90% Water (Interstitial fluid) Glycosaminoglycans (GAGs): unbranched polysaccharides. Examples include hyaluronic acid, chondroitin sulfate, and heparin sulfate. Proteoglycans: formed by GAGs linked to a core protein. Reticular fibers Glycoproteins Similar to collagen Also contains other molecules like adhesion proteins fibers but form (fibronectin) that help connect cells and other ECM components. networks for support "Connective tissue" is a term used to describe various body tissues that connect, support, and bind other tissues together. https://biologydictionary.net/connective-tissue/ https://courses.lumenlearning.com/  Connective tissue Proper Specialized loose dense bone blood cartilage consists of blood cells in a fluid areolar adipose reticular matrix (plasma) regular irregular elastic LO7: Distinguish between the types of loose and dense connective tissue proper. Dense Regular Dense Irregular Elastic fibers arranged in different Dense regular with a high planes; resists tension exerted proportion of elastic fibers – allows packed into parallel bundles from many directions tissue to recoil after stretching tendons, fibrous capsules of joints; walls of large arteries ligaments, dermis of skin fascia https://ditki.com/  Loose Areolar Form the lamina propria---part of the mucous membranes (moist linings), which line tubes, such as the respiratory tract, the gastrointestinal tract, and the urogenital tract. Mucosa Adipose Reticular Adipose tissue itself “bubble-like” appearance, little matrix supports blood cells within lymphoid organs  Protective cushion, insulation to preserve (lymph nodes, bone marrow, and spleen) body heat, Stores energy https://ditki.com/  LO8: Describe the composition of skeletal cartilage Cartilage is a type of “DENSE CONNECTIVE TISSUE” Cartilage cells are called chondrocytes It exhibits chondrocytes housed in lacunae within the extracellular matrix Lacunae (singular: lacuna) are small spaces found within the matrix of bone and cartilage. It consists of collagenous fibers embedded in a firm matrix of lacks nerve fibers, is avascular chondroitin sulfates– produced by chondroblasts ---when mature (chondrocytes) lie in lacunae  LO9: Identify the types of cartilage tissues found in the skeletal system. Elastic elastic fibers predominate→provides flexible support of the external ear Fibrocartilage Tough, shock absorbing Location: Between vertebrae parallel Hyaline Collagen fibers form an imperceptible network. Most abundant Provide support Location: Forms costal cartilages of the ribs, nose, trachea, and larynx covers ends of joints,- serves as padding https://www.premedhq.com/cartilage  LO10: Describe the structure, function, and location of mucous, serous, cutaneous & synovial membranes. Body membranes are essentially thin sheets of tissues that cover, line, and protect various parts of our body. They consist of an epithelium bound to an underlying connective tissue layer. Synovial membrane Cutaneous membrane (skin) Line the inner surfaces of synovial joints and bursae Lubrication: ↓ friction b/w bones during joint movement Helps cushion the impact on bones during activities like jumping or running. Secreted by Fibroblast-like synoviocytes within the Covers the body surface synovial mb It is the thickest membrane and the only dry membrane ©Pearson, Inc.  Mucous membranes (mucosa)  Respiratory tract  Digestive tract  Urinary tract Line body cavities that are open to the exterior  Reproductive tract Lined with epithelial tissue, which contains specialized goblet cells that produce mucus. Sits on top of a layer of connective tissue called the lamina propria. Mucous coat cilia Epithelium Goblet cells Protection: Mucus traps dust, dirt, and pathogens, Mucosa preventing them Basement mb from entering the Lamina propria body. Collagen Lubrication: Mucus fibers keeps these Fibroblasts surfaces moist and Elastic fibers slippery, reducing Muscularis friction. mucosae  Serous membranes (Serosa) Line body cavities that are closed to the exterior Consist of a single layer of flat epithelial cells called mesothelium, which sits on a layer of connective tissue. It secretes a lubricating fluid called serous fluid--a watery fluid, resembling (blood-)serum. This also explains the name 'serous membrane’. Main function: reduce friction between organs. Named using the terms "visceral" and "parietal“+ describing the body cavity where they are located. 3 Major serous membranes: pericardium, pleural, and peritoneum. line the body cavities line the outer part of the organs within the body cavity Serosa of the abdominopelvic cavity are called either parietal peritoneum or visceral peritoneum https://bio.libretexts.org/Courses/West_Hills_College_-_Lemoore/Human_Anatomy_Laboratory_Manual_%28Hartline%29/01%3A_Introduction_to_Anatomy_and_Anatomical_Terms/1.09%3A_Serosa_%28Serous_Membranes%29  LO11: Classify exocrine glands based on structure and function. A gland is one or more cells specialized to secrete a product. On the basis of site of product release, glands are classified as exocrine or endocrine. Exocrine glands release their products through ducts onto an epithelial surface They are classified structurally as multicellular or unicellular: Multicellular exocrine glands classified according to duct structure as simple or compound, and according to the structure of their secretory parts as tubular, alveolar, or tubuloalveolar. Unicellular glands, typified by goblet cells and mucous cells, are mucus- secreting single- celled glands. ©McGrawHill, Inc.  Multicellular exocrine glands are classified functionally as merocrine or holocrine. Holocrine glands Merocrine glands Secrete their products by The entire secretory cell exocytosis ruptures, releasing secretions and dead cell fragments the cell remains intact e.g. sebaceous glands ©McGrawHill, Inc. Image: Shutterstock  L7: Integumentary System SUPPORT AND MOVEMENT Menu LO1-8 Section A: Anatomy and functional role of Skin & Subcutaneous tissue LO9-10 Section B: Anatomy and functional role of Associated Exocrine Glands LO11-13 Section C: Anatomy and functional role of Hair Follicles and Nails ©Beatriz Castro References:Professor Dave Explains-YouTube Channel, Pearson, Inc., OpenStax ©. STATPEARLS  mechanical protection for the skin, increases sensory function, and aids in regulating body temperature. The nail is an unfolding of skin that occurs at the terminal end of each digit They assists in grasping small objects and functions as a protective covering to the end of the digit physical barrier that prevents direct entry of pathogens & physical injury  LO1: Identify the tissue types making up the skin The skin (=integument) consists of two layers: the epidermis and dermis, resting on subcutaneous tissue, the hypodermis. eno entere blood vessel keratinized sheet of stratified squamous epithelium Most epidermal cells are keratinocytes. 00 https://www.youtube.com/watch?v=p4hnFf_jmvU&ab_channel=ProfessorDaveExplains  LO2: Identify the layers of the epidermis; differentiate between thick and thin skin Depending on the differentiation stage of the keratinocytes, the epidermis is subdivided into different sublayers or strata: (horny layer) * absent in thin skin * Hairy areas found on palms, fingertips, sole Non hairy areas-- LACK OF HAIR FOLLICULES and SEBACOUS GLANDS (Image credits: (A) “Epidermal Strata Thick Skin vs. Thin Skin" illustration by Jennifer Lange is licensed under CC BY-NC-SA 4.0, modification of original by Scientific Animations;  LO3: Indicate the cell types found within each layer of the epidermis (Corneocytes) form a tough barrier Thin, translucent layer of dying keratinocytes (↑ keratin) Keratin protects epithelial cells from mechanical and non- mechanical stresses that cause cell rupture and death. As they mature and move away from the basal layer, they produce keratin 90% tissue-resident macrophages a - rapidCelt de A single layer of mitotically active, cuboidal keratinocytes + stem cells Melanin pigment-producing cells mechanoreceptors sensory receptor that detect mechanical pressure.