Ch 4 Tissues PDF

9/12/2024 CHAPTER 4: TISSUES...

9/12/2024 CHAPTER 4: TISSUES Principal Types of Tissue Nervous tissue: Internal communication individual cells  specialized Muscle tissue: Contracts to cause movement. to perform specific functions to. maintain homeostasis. Epithelial tissue: Forms boundaries between different environments, protects, secretes, absorbs, filters tissue = a mass of cells that Lining of digestive tract organs and other hollow organs. perform a common or related Skin surface (epidermis). function Connective tissue: Supports, protects, binds other tissues together Bones Tendons Fat and other soft padding tissue Mosby items and derived items © 2007, 2003 by Mosby, Inc. © Pearson Education, Inc. 1 2 The early embryo develops three distinct germ layers, Principal Types of Tissue. ectoderm, endoderm, and mesoderm. Epithelial tissue: covers, protects, lines body cavities, secretes, excretes, absorbs, forms glands Connective tissue: supports, connects, transports 16-day-old embryo (dorsal surface view) substances throughout the body, protects Muscle and connec- tive tissue (mostly from mesoderm) Muscle tissue: produces movement Epithelium Nervous tissue Ectoderm (from ectoderm) Mesoderm Inner lining of Nervous tissue: controls, coordinates, communicates Endoderm digestive system (from endoderm) Note: most organs contain all four tissue types! These 3 germ (stem) cell types will give rise to all tissues of the body  histogenesis. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 3 4 Epithelial tissues are sheets of closely adherent cells covering a body surface, lining a body cavity, or forming glands. Distinguishing Characteristics polarity: apical & basal surfaces; apical surface may be membranous: (skin, peritoneum, pleura, vascular endothelium). specialized with microvilli & cilia -- form boundaries between environments; substances, tight junctions: enable epithelial cells to form barriers received or released, must pass through them basement membrane: basal pole rests on this barrier layer innervated but avascular: nourished by diffusion from the glandular (thyroid, liver, kidney, pancreas, sweat glands). connective tissue on which it rests -- make secretions cells regenerate (by cell division) in response to injury Mosby items and derived items © 2007, 2003 by Mosby, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 5 6 1  9/12/2024 Basement membrane = Basal lamina + reticular lamina tight junctions – Connects epithelial sheet to underlying, supportive connective tissue cilia polarity – Resists stretching and tearing apical pole – Consists of adhesive glycoproteins and collagen fibers (basal lamina) of cells on top of a network of collagen fibers (reticular lamina) avascular – Noncellular regeneration basal pole basement membrane of cells connective basement tissue membrane 7 8 Classification of Epithelia Simple squamous epithelium Single layer of flattened cells with central nuclei and sparse cytoplasm. Ask two questions: 1. How many layers? air sacs of 1 = simple epithelium lung tissue Allows passage of materials >1 = stratified epithelium by diffusion and filtration in sites where protection is. not important; secretes 2. What type of cell? lubricating substances in serosae. squamous cuboidal columnar Where? pulmonary alveoli (air sacs); lining of heart & blood vessels, & ventral body cavities (serosae) (side view) Mosby items and derived items © 2007, 2003 by Mosby, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 9 10 Simple cuboidal epithelium Simple columnar Single layer of cubelike renal tubules cells with large, central epithelium Microvilli nuclei. Simple cuboidal epithelial Simple columnar cells epithelial Function: absorption; cell Basement secrete mucus, Mucus of goblet cell membrane enzymes, & other Function: secretion & substances; ciliated absorption. type propels mucus (or Connective reproductive cells). tissue Location: lines most of the digestive tract (stomach to rectum); ciliated variety lines small bronchi, uterine tubes Location: renal tubules; glandular ducts Figure 4.3b Mosby items and derived items © 2007, 2003 by Mosby, Inc. 11 12 2  9/12/2024 simple columnar with goblet cells (ileum, colon) small bronchus cilia Mosby items and derived items © 2007, 2003 by Mosby, Inc. Slide 13 Mosby items and derived items © 2007, 2003 by Mosby, Inc. 13 14 microvilli (small intestine) columnar epithelium with villi & microvilli (small intestine) microvilli are microscopic villi are barely visible to the naked eye Mosby items and derived items © 2007, 2003 by Mosby, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 15 16 stratified squamous epithelium Pseudostratified columnar epithelium Thick membrane of >2 cell layers; basal cells are Function: mucous secretion; mitotically active & migrate propulsion of mucus by basal to apical; surface cells esophagus ciliary action. trachea cilia flatten goblet cell Single cell layer of varying height, some don’t reach basement the surface, but all reach BM; Function: protects membrane nuclei at varying levels; may underlying tissues in connective have goblet cells & cilia. areas subjected to tissue abrasion. Trachea nonkeratinized  moist linings of. Location: nonciliated in sperm ducts the esophagus, mouth, and vagina & large gland ducts; ciliated variety * lines trachea, most of upper resp tract keratinized  dry epidermis of the skin Mosby items and derived items © 2007, 2003 by Mosby, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 17 18 3  9/12/2024 epidermis  stratified squamous, keratinized stratified cuboidal epithelium Quite rare Found in some sweat and mammary glands Typically only two cell layers thick sweat gland © 2016 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 19 20 stratified columnar epithelium transitional epithelium basal cells are cuboidal or Also very limited distribution in body columnar; surface cells Small amounts found in pharynx, in male urethra, and dome shaped or flat bladder lining some glandular ducts depending on degree of Transitional stretch Usually occurs at transition areas between two other epithelium types of epithelia Only apical layer is columnar Function: stretches readily & permits distension of urinary organ by urine. Basement membrane Connective tissue Location: Lines the ureters, urinary bladder, and part of the urethra. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 21 22 Mucous Membranes (mucosae) line body cavities which open to the exterior. > mucus is secreted to protect underlying cells Body (water + proteoglycans) mucosa of nasal cavity Membranes mucosa of mouth esophagus lining mucosa of lung bronchi Mosby items and derived items © 2007, 2003 by Mosby, Inc. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 23 24 4  9/12/2024 Serous membranes (serosae) line body cavities Glandular Epithelium: specialized for secretion closed to the exterior > Serous fluid is secreted to lubricate neighboring regions (water + hyaluronic acid)  endocrine glands — discharge secretions (hormones) directly into the blood or.interstitial fluid; “ductless” glands  exocrine glands — secrete into ducts or surfaces parietal parietal pleura peritoneum may be unicellular or multicellular visceral 2 types of exocrine glands in humans visceral pleura peritoneum  merocrine parietal visceral  holocrine pericardium pericardium 25 26 Goblet cell (unicellular exocrine gland) Microvilli Secretory vesicles containing mucin Golgi apparatus Rough ER Nucleus © Pearson Education, Inc. Different structures of multicellular exocrine glands 27 28 Chief modes of secretion in human exocrine glands. Secretory cell fragments Secretory vesicles Merocrine glands secrete their In holocrine glands, the entire secretory products by exocytosis. cell ruptures most common sebaceous glands. secrete via exocytosis, are sole example leaving the cell intact e.g. sweat glands, sebaceous. pancreas, liver, glands. breast (holocrine type) 29 30 5  9/12/2024 Connective Tissue (CT) Prototype: Areolar Loose Connective Tissue found throughout the body Cell Types Extracellular Matrix ground substance arises during embryonic development from stem macrophage Fibers cell tissue called mesenchyme [derived from mesoderm]. elastic reticular many varied forms…from bone to cartilage to fibroblast collagen blood! lymphocyte mostly extracellular matrix (ECM) with relatively few cells imbedded in it. fat cell capillary mast cell CT is comprised of 3 elements  ground substance [site of the ECM (extracellular matrix) neutrophil  fibers inflammatory  cells response] Mosby items and derived items © 2007, 2003 by Mosby, Inc. 31 32 Ground Substance Ground Substance unstructured filler material between cells Proteoglycans have a protein core  composed of interstitial fluid, cell adhesion proteins. rooted in a polysaccharide with. (e.g.fibronectin/laminin), & proteoglycans. long glycosaminoglycans (GAGs). sticking out like a bottle brush. GAGs = chondroitin sulfate, heparin. & hyaluronic acid These GAGs have a variety of Fibronectins. important functions.  for one, their long negatively. charged polysaccharides attract. & trap water molecules.  the interstitial space is a gel -. like water reserve for the body. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 33 34 Fibers  3 types Collagen Fibers Fibers  3 types collagen proteins are secreted by fibroblasts & self Reticular & Elastic Fibers assemble into fibers. Reticular fibers occur not in dense bundles, but in collagen is the most abundant protein in the body (25%) delicate networks to support nerves and capillaries. collagen fibers size for size are stronger than steel fibers! Made of a special form of collagen. Elastic fibers are made of protein called elastin which as the name suggests, returns to its original length tendon after being stretched  skin, blood vessel walls, ear cartilage. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 35 36 6  9/12/2024 Connective Tissue Cells Other cell types in connective tissues – Fat cells Each major class of CT is associated with a ‘blast’ cell: Store nutrients immature form of cell that actively secretes ground – White blood cells substance and fibers Neutrophils, eosinophils, lymphocytes Tissue response to injury Fibroblast  CT proper – Mast cells Initiate local inflammatory response against foreign Osteoblast  bone microorganisms they detect; release histamine Chondroblast  cartilage – Macrophages Phagocytic cells that “eat” dead cells, microorganisms; Blood stem cells  blood function in immune system Note: ‘blast’ cells mature into ‘cyte’ cells (e.g. osteocytes) that maintain ECM health © Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 37 38 connective tissue proper: loose CT, areolar connective tissue proper: loose CT, adipose Gel-like matrix with all Description: sparse matrix; three fiber types; cells: Elastic closely packed adipocytes fibroblasts, macrophages, fibers make up 90% of the mass, & mast cells, & WBCs have nucleus pushed aside by a large fat droplet. Function: wraps & cushions Nucleus of organs; engulfs bacteria Function: provides reserve fat cell Ground (macrophages); hosts the substance food fuel; insulates against inflammatory response; heat loss; supports and Collagen Vacuole holds interstitial fluid. fibers protects organs. containing Fibroblast adipose fat droplet nuclei tissue epithelium mammary lamina glands propria Widely distributed under epithelia of body, Location: under skin in the e.g., forms lamina propria of mucous membranes; hypodermis; around kidneys & packages organs; surrounds capillaries. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items eyes; in abdomen © 2007, 2003 by Mosby, Inc. & breasts. 39 40 connective tissue proper: loose CT, reticular Description: network of reticular fibers & fibroblasts CT proper: dense connective tissues spleen – Three varieties of dense connective tissue Function: fibers form a soft internal skeleton that Dense regular supports cells (mast cells, Dense irregular lymphocytes & macrophages) WBC Elastic (lymphocyte) – Fibers are the prominent element for all three Reticular fibers Spleen Location: Lymphoid organs (lymph nodes, bone marrow, and spleen). © Pearson Education, Inc. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 41 42 7  9/12/2024 connective tissue proper: dense CT, dense regular connective tissue proper: dense CT, dense irregular Description: Primarily parallel collagen fibers; a Description: same as dense few elastic fibers; a few tendon regular CT, but collagen fibers fibroblasts; poorly are thicker and arranged vascularized irregularly. Function: Attaches muscles collagen fibers to bones or to muscles; Function: able to withstand attaches bones to bones; tension exerted in many withstands great tensile directions; provides structural stress when pulling force is strength. applied in one direction. shoulder nuclei of joint fibroblasts fibrous ligament joint capsule tendon Location: Fibrous capsules of organs Location: tendons, ligaments and of joints; dermis of the skin; Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. fascias; Copyright © 2010 Pearson Education, Inc. Mosby items and derived submucosa items © 2007, of digestive tract. 2003 by Mosby, Inc. 43 44 connective tissue proper: dense CT, elastic Description: dense regular Bone CT containing a high proportion of elastic aorta fibers. Osteoblasts produce Function: allows recoil of. crystals of tissue following stretch;. hydroxyapatite to fill maintains pulsatile flow. the spaces of the of blood through arteries; elastic fibers. collagenous matrix. aids passive recoil of lungs following inspiration. As they do so, they. become trapped by. distinctive concentric. layers of bone and. become osteocytes. Location: walls of large arteries; some vertebral ligaments; walls of the bronchial tubes. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 45 46 bone (osseous tissue) Cartilage Description: hard, overall pattern similar to bone calcified matrix containing many collagen fibers;  lacunae contain chondroblasts that turn into chondrocytes osteocytes lie in lacunae. Moderately well central chondroblasts deposit a matrix of vascularized. canal. chondroitin sulfate, a Function: supports & lacunae. mucopolysaccharide. protects; provides levers for the muscles to act on; unlike bone, cartilage is avascular stores Ca2+ & fat; marrow lamella.  O2 & nutrients diffuse in from is birth site for blood cells. peripheral capillaries poor blood supply makes for poor healing not innervated contains up to 80% H2O 3 types of cartilage  Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 47 48 8  9/12/2024 Cartilage: hyaline Cartilage: elastic Amorphous but firm Description: similar to matrix; collagen fibers hyaline cartilage, but more ear form an imperceptible network; trachea elastic fibers in matrix. Function: maintains the chondrocyte Function: supports and shape of a structure while in lacuna chondrocyte reinforces; has resilient in lacuna allowing great flexibility. cushioning properties; resists compressive stress. matrix matrix Location: embryonic skeleton; ends Location: supports the external of long bones; rib costal cartilages; costal cartilages of the nose & airways. ear (pinna); epiglottis. cartilages Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 49 50 Cartilage: fibrocartilage BLOOD Description: matrix Description: arguably intervertebral disc similar to but less firm the strangest CT because than that in hyaline it is a fluid matrix Plasma cartilage; thick collagen without ground fibers predominate. substance or fiber Neutrophil (except fibrin clot). Function: tensile strength Cells = RBCs & WBCs allows it to absorb chondrocytes compressive shock. in lacunae Liquid 55% -- cells 45%. Red blood cells collagen Lymphocyte fiber Location: intervertebral discs; Function: transport of respiratory gases, intervertebral pubic symphysis; menisci of knee nutrients, wastes, and other substances. disc Copyright © 2010 Pearson Education, Inc. joint. Mosby items and derived items © 2007, 2003 by Mosby, Inc. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 51 52 Skeletal Muscle Smooth Muscle Description: Long, Description: spindle- cylindrical, multinucleate shaped cells with central cells; obvious striations. nuclei; no striations; form sheets. striations Function: Voluntary movement Function: propels Smooth nuclei muscle substances or objects cell (foodstuffs, urine, a baby) along internal Nuclei muscle passageways; involuntary fiber (cell) control. Location: skeletal muscles are attached to bones or, in a few Location: in the walls of hollow locations, to skin or other muscles. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc.. organs and blood vessels. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 53 54 9  9/12/2024 Cardiac Muscle Description: branching, Nervous Tissue striated, single nuclei; interdigitate at specialized senses, integrates and junctions  intercalated striations. motivates discs. intercalate capable of very rapid Function: contracts to discs. impulse conduction circulate blood; involuntary control. 2 types of cells: Nucleus neurons: conduct impul. glia: connect, protect, and support Location: heart Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 55 56 Tissue Repair Scab Epidermis Tissues have a varying capacity to heal themselves; damaged tissues regenerate or repair by scar. Blood clot in Vein Regeneration—growth of new tissue incised wound Migrating white Scar—dense fibrous mass; unusually thick scar is Inflammatory blood cell chemicals a keloid Artery  epithelial & connective tissues have the greatest ability to regenerate 1 Inflammation sets the stage: severed blood vessels bleed and inflammatory chemicals are released.  muscle & nervous tissues have a very limited capacity to local blood vessels become more permeable, allowing white regenerate blood cells, fluid, clotting proteins and other plasma proteins to seep into the injured area. clotting occurs; surface dries and forms a scab. Mosby items and derived items © 2007, 2003 by Mosby, Inc. Slide 57 Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 57 58 Regenerating Regenerated epithelium epithelium Area of granulation Fibrosed tissue area ingrowth Fibroblast Macrophage 2 Organization restores the blood supply: the clot is replaced by granulation tissue, which restores the vascular supply. 3 Regeneration and fibrosis effect permanent repair: fibroblasts produce collagen fibers that bridge the gap. the fibrosed area matures and contracts; the epithelium macrophages phagocytize cell debris. thickens. surface epithelial cells multiply and migrate over the a fully regenerated epithelium with an underlying area of granulation tissue. scar tissue results. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. Copyright © 2010 Pearson Education, Inc. Mosby items and derived items © 2007, 2003 by Mosby, Inc. 59 60 10