Open Chapter 4 2024 Tissue Level of Organization PDF

4 Tissue Level of Organization Lecture Presentation by Chasity O’Malley, Palm Beach State College...

4 Tissue Level of Organization Lecture Presentation by Chasity O’Malley, Palm Beach State College with Notes by Lori Garrett, Parkland College © 2018 Pearson Education, Inc.  Section 1: Epithelial Tissue Learning Outcomes 4.1 Identify the four types of tissues in the body, and describe their roles. 4.3 Describe epithelial tissues, including cell shape, layers, and functions. 4.4 Discuss the types and functions of intercellular connections between epithelial cells. 4.5 Describe the structure and function of squamous epithelium. © 2018 Pearson Education, Inc.  Section 1: Epithelial Tissue Learning Outcomes (continued) 4.6 Describe the structure, function, and locations of cuboidal and transitional epithelia. 4.7 Describe the structure, function, and locations of columnar epithelia. 4.8 Compare the three different methods of exocrine secretion by glandular epithelia. 4.9 Explain how multicellular exocrine glands are classified by their structure. © 2018 Pearson Education, Inc.  Module 4.1: Four types of tissue make up the body Body organization review Atoms → Molecules → Cells → Tissues Chemical level can only be seen using special imaging techniques Cellular level details seen best with electron microscope © 2018 Pearson Education, Inc.  Module 4.1: Types of tissue Body organization review (continued) Trillions of cells in the body Only about 200 different types of cells Cells working together form tissues Study of tissues called histology Four basic types of tissues 1. Epithelial 2. Connective 3. Muscle 4. Neural © 2018 Pearson Education, Inc.  Levels of organization up to the tissue level © 2018 Pearson Education, Inc.  Module 4.3: Epithelial tissue covers surfaces, lines cavities, and forms secretory glands Divisions of epithelial tissue 1. Epithelia Avascular layers Cover exposed surfaces Line internal cavities and passageways Often contain secretory or gland cells scattered among other cell types © 2018 Pearson Education, Inc.  Module 4.3: Epithelial tissues Divisions of epithelial tissue (continued) 1. Glands Derived from epithelia Predominantly secretory cells Two types 1. Exocrine glands o Secrete onto external surfaces or into ducts 2. Endocrine glands o Secrete hormones into interstitial fluid o Hormones then distributed by bloodstream © 2018 Pearson Education, Inc.  Epithelial tissues © 2018 Pearson Education, Inc.  Module 4.3: Epithelial tissues Functions of epithelial tissue Provide physical protection Protect surfaces from abrasion, dehydration, or destruction by chemical or biological agents Control permeability Most epithelia are capable of selective absorption or secretion Epithelial barrier can be modified in response to stimuli (Example: calluses) © 2018 Pearson Education, Inc.  Module 4.3: Epithelial tissues Functions of epithelial tissue (continued) Provide sensation Specialized epithelial cells detect changes in environment (for example, touch receptors) Neuroepithelium – Sensory epithelium found in special sense organs Produce specialized secretions Glandular epithelial cells produce secretions © 2018 Pearson Education, Inc.  Module 4.3: Epithelial tissues Features of epithelial tissue (continued) Surfaces Apical surface – Faces exterior of body or internal space Base – Attached to underlying tissues – Basolateral surface o Includes base and sides (lateral surfaces) attached to neighboring cells © 2018 Pearson Education, Inc.  Module 4.3: Epithelial tissues Features of epithelial tissue (continued) Apical surface features If lining a tube, apical surface is exposed to space inside the tube, called lumen Microvilli found on this surface in digestive, urinary, and reproductive tracts Cilia found on this surface in parts of the respiratory and reproductive tracts Epithelial cells also contain membranous organelles comparable to other cell types © 2018 Pearson Education, Inc.  Module 4.3: Epithelial tissues Epithelial cells have 3 basic shapes (viewed perpendicular to exposed surface) 1. Squamous Thin and flat 2. Cuboidal Cube-shaped Like little boxes 3. Columnar Taller than they are wide Slender rectangles © 2018 Pearson Education, Inc.  Module 4.3: Epithelial tissues Epithelial cell layers Single layer Simple epithelium Several layers of cells Stratified epithelium Found in areas that need protection from abrasion or chemical stress – Examples: surface of skin, lining of the mouth © 2018 Pearson Education, Inc.  Module 4.4: Epithelial cells are extensively interconnected, both structurally and functionally Epithelial attachments Extensive attachments between adjacent cells and adjacent tissues To function as a barrier, must have intact, complete lining Must be able to replace damaged or lost cells Epithelia lack blood vessels (avascular) – Requires attachment to underlying connective tissue for nourishment from blood vessels there © 2018 Pearson Education, Inc.  Module 4.4: Intercellular connections Types of intercellular connections 1. Hemidesmosomes Attach deepest epithelial cells to basement membrane © 2018 Pearson Education, Inc.  Module 4.4: Intercellular connections Types of intercellular connections (continued) 1. Tight (occluding) junctions Interlocking membrane proteins bind adjacent plasma membranes together Prevent passage of water and solutes between cells Isolate basolateral surfaces and deeper tissues from contents in lumen Found in intestinal tract © 2018 Pearson Education, Inc.  Module 4.4: Intercellular connections Types of intercellular connections (continued) 1. Adhesion belts Continuous band of membrane proteins Strengthens apical region of cells – Reinforces tight junctions Dense proteins attached to microfilaments of the terminal web (part of cytoskeleton) Belts encircle cells and bind to adjacent cells © 2018 Pearson Education, Inc.  Module 4.4: Intercellular connections Types of intercellular connections (continued) 1. Gap junctions Held together by interlocking transmembrane proteins (connexons) Assist chemical communication to help coordinate functions such as secretion or beating cilia Also found in cardiac muscle and smooth muscle tissue to coordinate contraction © 2018 Pearson Education, Inc.  Module 4.4: Intercellular connections Types of intercellular connections (continued) 1. Desmosomes Provide firm attachments by interlocking adjacent cells’ cytoskeletons Opposing plasma membranes locked together by cell adhesion molecules (CAMs) – Thin layer of proteoglycans may also bond o Contain polysaccharide, notably hyaluronic acid Very strong; resist stretching and twisting Found in superficial layers of skin © 2018 Pearson Education, Inc.  Module 4.5: The cells in a squamous epithelium are flat and irregularly shaped Squamous epithelium (squama, plate or scale) Thin, flat, irregularly shaped cells (like jigsaw puzzle pieces) Viewed from above, cells look like fried eggs In sectional view, disc-shaped nucleus found in thickest part of cell May be single layer (simple) or multiple layers (stratified) © 2018 Pearson Education, Inc.  Module 4.5: Squamous epithelium Simple squamous epithelium Most delicate epithelium (one layer thick) Functions include absorption, diffusion, reduction of friction Found in protected regions such as peritoneum, capillary walls, inside eye, lung alveoli © 2018 Pearson Education, Inc.  Module 4.5: Squamous epithelium Simple squamous epithelium (continued) Certain locations have special names Mesothelium lining ventral body cavities Endothelium lining heart and blood vessels © 2018 Pearson Education, Inc.  Module 4.5: Squamous epithelium Stratified squamous epithelium Located where severe mechanical or chemical stresses exist Many layers of cells Superficial layer flattened Forms surface of skin and lines mouth, throat, esophagus, rectum, anus, vagina © 2018 Pearson Education, Inc.  Module 4.5: Squamous epithelium Stratified squamous epithelium (continued) Two types 1. Keratinized – Superficial layers packed with keratin – Tough and water resistant – Resists both mechanical stress and dehydration – Found on surface of skin and in hair and nails 2. Nonkeratinized – Resists abrasion but can dry out – Found lining oral cavity, pharynx, esophagus, anus, vagina © 2018 Pearson Education, Inc.  Keratinized skin layers © 2018 Pearson Education, Inc.  Module 4.6: Cuboidal and transitional epithelia line several passageways and chambers connected to the exterior Cuboidal epithelium Cells resemble hexagonal boxes In sectional view, cells appear square Spherical nucleus near center of each cell © 2018 Pearson Education, Inc.  Module 4.6: Cuboidal and transitional epithelium Two types of epithelium 1. Simple cuboidal epithelium Functions in secretion and absorption Lines exocrine glands and ducts Lines parts of kidney tubules and thyroid gland © 2018 Pearson Education, Inc.  Module 4.6: Cuboidal and transitional epithelium Two types of epithelium (continued) 1. Stratified cuboidal epithelium Rare tissue Found in ducts of sweat glands and mammary glands © 2018 Pearson Education, Inc.  Module 4.6: Cuboidal and transitional epithelium Transitional epithelium Unusual stratified epithelium that can stretch and recoil without damage Transitional name because changes appearance Found only in urinary system (urinary bladder, ureters, urine-collecting chambers of kidneys) Changes in appearance Relaxed (e.g., empty bladder)—superficial cells cuboidal Stretched (e.g., full bladder)—superficial cells flattened © 2018 Pearson Education, Inc.  Transitional epithelium © 2018 Pearson Education, Inc.  Module 4.7: Columnar epithelia absorb substances and protect the body from digestive chemicals Columnar epithelium In sectional view, cells appear rectangular Cells taller and more slender than cuboidal Elongated nuclei in band close to basement membrane Types 1. Simple columnar epithelium 2. Pseudostratified columnar epithelium 3. Stratified columnar epithelium © 2018 Pearson Education, Inc.  Module 4.7: Columnar epithelium Simple columnar epithelium Found where absorption or secretion takes place Line stomach, intestine, gallbladder, uterine tubes, kidney ducts May have microvilli (for absorption) or cilia (for movement) on apical surface © 2018 Pearson Education, Inc.  Module 4.7: Columnar epithelium Pseudostratified columnar epithelium Cells of varying shapes and functions Distance between nuclei varies, giving appearance of layering or being stratified Each cell contacts basement membrane Cells usually have cilia Lines nasal cavities, trachea, larger airways in lungs, portions of male reproductive tract © 2018 Pearson Education, Inc.  Module 4.7: Columnar epithelium Stratified columnar epithelium Rare tissue type Two or more layers of cells Superficial layer of columnar cells Found lining large ducts such as those of salivary glands or pancreas © 2018 Pearson Education, Inc.  Module 4.8: Glandular epithelia are specialized for secretion Glands Collections of epithelial cells (or derived structures) that produce secretions Can be scattered cells or complex organs Categorized into two types 1. Endocrine glands – Release secretions into interstitial fluid 2. Exocrine glands – Release secretions into ducts onto epithelial surface © 2018 Pearson Education, Inc.  Module 4.8: Glandular epithelium Three types of exocrine gland secretion 1. Merocrine (meros, part) secretion Product released from secretory vesicles by exocytosis Most common mode of secretion Example: salivary gland secretion © 2018 Pearson Education, Inc.  Module 4.8: Glandular epithelium Three types of exocrine gland secretion (continued) 1. Apocrine (apo, off) secretion Apical cytoplasm packed with secretory vesicles Cell releases cytoplasm as well as secretory product Example: mammary gland secretion (involves combination of merocrine and apocrine secretions) © 2018 Pearson Education, Inc.  Module 4.8: Glandular epithelium Three types of exocrine gland secretion (continued) 1. Holocrine (holos, entire) secretion Destroys gland cell Entire cell bursts, releasing secretions and killing cell Destroyed cells replaced by stem cell division Example: sebaceous glands © 2018 Pearson Education, Inc.  Module 4.9: Exocrine glands can be classified by structure Multicellular exocrine gland classification Based on duct structure Simple (single duct that does not divide) Compound (duct divides one or more times) © 2018 Pearson Education, Inc.  Section 2: Connective Tissue Learning Outcomes (continued) 4.14 Describe the structure and function of bone. 4.15 Describe the arrangements of epithelial and connective tissues in the four types of tissue membranes, and describe the structures and locations of the three types of fasciae. © 2018 Pearson Education, Inc.  Module 4.10: A matrix surrounds connective tissue cells Connective tissue overview Varies widely in appearance and function Found throughout the body, but never exposed to surface Ranges from highly vascular to avascular Many contain sensory receptors that detect pain, pressure, temperature, and other stimuli © 2018 Pearson Education, Inc.  Module 4.10: Connective tissue Three basic components shared by connective tissues 1. Specialized cells 2. Extracellular protein fibers 3. Fluid called ground substance Matrix – Extracellular fibers and ground substance – Surrounds the cells – Accounts for majority of connective tissue volume – Fewer cells and more extracellular material compared to epithelial tissue © 2018 Pearson Education, Inc.  Module 4.10: Connective tissue Three subdivisions of connective tissue 1. Connective tissue proper Contains many types of cells Extracellular fibers in syrupy ground substance – Loose (fibers create loose, open framework) – Dense (fibers densely packed) © 2018 Pearson Education, Inc.  Module 4.10: Connective tissue Three subdivisions of connective tissue (continued) 1. Fluid connective tissue Distinctive group of cells Watery matrix – Blood (within cardiovascular system) – Lymph (within lymphatic system) © 2018 Pearson Education, Inc.  Module 4.10: Connective tissue Three subdivisions of connective tissue (continued) 1. Supporting connective tissue Less diverse cell population More densely packed matrix – Cartilage (solid, rubbery matrix) – Bone (solid, crystalline matrix) © 2018 Pearson Education, Inc.  Module 4.11: Loose connective tissues support other tissue types Connective tissue proper components Extracellular protein fibers Reticular fibers (strong and form branching network) Collagen fibers (thick, very strong) Elastic fibers (slender, very stretchy) Ground substance Clear and colorless Viscous (syrupy) due to presence of proteoglycans and glycoproteins © 2018 Pearson Education, Inc.  Module 4.11: Loose connective tissue Connective tissue proper components (continued) Two classes of cells 1. Fixed (stationary; involved with maintenance, repair, energy storage) – Melanocytes (synthesize melanin pigment) – Fixed macrophage (engulfs cell debris and pathogens) – Mast cells (stimulate inflammation and mobilize defenses) © 2018 Pearson Education, Inc.  Module 4.11: Loose connective tissue Connective tissue proper components (continued) Two classes of cells 1. Fixed – Fibroblasts (synthesize extracellular fibers) – Adipocytes (store lipid reserves) – Fibrocytes (differentiate from fibroblasts and maintain extracellular fibers) Lack of vitamin C in the diet interferes with the ability of fibroblasts to produce collagen. © 2018 Pearson Education, Inc.  Module 4.11: Loose connective tissue Connective tissue proper components (continued) Two classes of cells 1. Wandering (move throughout tissue; function in defense and repair) – Plasma cells (immune cells producing antibodies) – Free macrophages (engulf debris and pathogens) – Mesenchymal cells (stem cells that aid tissue repair) – Neutrophils and eosinophils (phagocytic blood cells) – Lymphocytes (immune system cells) © 2018 Pearson Education, Inc.  Connective tissue components © 2018 Pearson Education, Inc.  Module 4.11: Loose connective tissue Three types of loose connective tissue 1. Areolar tissue Most common connective tissue proper Packing material of the body Has all connective tissue proper cell types © 2018 Pearson Education, Inc.  Module 4.11: Loose connective tissue Three types of loose connective tissue (continued) 1. Adipose tissue Found deep to skin in various areas of body Forms layer of padding around eyes and kidneys Cells (adipocytes) account for most of tissue volume © 2018 Pearson Education, Inc.  Module 4.11: Loose connective tissue Three types of loose connective tissue (continued) 1. Reticular tissue Found in liver, kidney, spleen, lymph nodes, and bone marrow Provides support and resists distortion Many reticular fibers forming network (stroma) © 2018 Pearson Education, Inc.  Module 4.12: Dense connective tissues are dominated by extracellular fibers … Three types of dense connective tissues Most volume occupied by extracellular fibers 1. Dense regular connective tissue – Found in cords (tendons, ligaments) or sheets – Collagen arranged in parallel bundles © 2018 Pearson Education, Inc.  Module 4.12: Dense connective tissue Three types of dense connective tissue (continued) 1. Dense irregular connective tissue Fibers arranged in meshwork (no consistent pattern) to resist tension in many directions Found covering visceral organs; in superficial layers of bones, cartilages, and peripheral nerves; in dermis of skin © 2018 Pearson Education, Inc.  Module 4.12: Dense connective tissue Three types of dense connective tissue (continued) 1. Elastic tissue More elastic fibers than collagen Is springy and resilient Found between vertebrae, in walls of large blood vessels, erectile tissues of penis © 2018 Pearson Education, Inc.  Module 4.12: … whereas fluid connective tissues have an aqueous matrix Fluid connective tissue Fluid matrix with many suspended proteins Usually contains no insoluble fibers Two types of liquid connective tissue 1. Blood 2. Lymph © 2018 Pearson Education, Inc.  Module 4.12: Fluid connective tissue Fluid connective tissue (continued) Blood components Watery matrix called plasma Formed elements suspended in plasma – Red blood cells (transport oxygen) – White blood cells (bodily defense) o Monocytes (large phagocytes) o Lymphocytes (uncommon in blood) o Eosinophils/neutrophils (small phagocytes) o Basophils (promote inflammation) – Platelets (involved in clotting response) © 2018 Pearson Education, Inc.  Blood as fluid connective tissue © 2018 Pearson Education, Inc.  Module 4.12: Fluid connective tissue Fluid connective tissue (continued) Lymph Watery matrix called lymph located in lymphatic vessels Collected from interstitial fluid Majority of cells are lymphocytes Returned to blood at large veins near heart Functions to maintain solute levels, blood volume, and alert immune system of infection © 2018 Pearson Education, Inc.  Module 4.12: Fluid connective tissue Fluid connective tissue (continued) Extracellular fluid circulation Contractions of the heart move blood through blood vessels – Arteries (away from heart) – Capillaries (smallest vessels; sites of exchange) – Veins (toward heart) Water and solutes exchanged between plasma and interstitial fluid Lymphatic vessels collect excess interstitial fluid Lymphatic vessels return lymph to large veins near heart © 2018 Pearson Education, Inc.  Lymph as fluid connective tissue © 2018 Pearson Education, Inc.  Module 4.13: Cartilage provides a flexible support for body structures Cartilage overview Matrix is a firm gel containing chondroitin sulfates (chondros, cartilage), polysaccharide derivatives Form complexes with proteins forming proteoglycans Only one type of cell (chondrocyte) Found in small chambers called lacunae (lacus, lake) Avascular © 2018 Pearson Education, Inc.  Module 4.13: Cartilage Three types of cartilage 1. Hyaline cartilage Found between ribs and sternum, covering bones in mobile joints, part of nasal septum, supporting respiratory passageways Provides stiff but flexible support Reduces friction © 2018 Pearson Education, Inc.  Module 4.13: Cartilage Three types of cartilage (continued) 1. Elastic cartilage Distorts without damage and returns to original shape Found in external ear and smaller internal structures © 2018 Pearson Education, Inc.  Module 4.13: Cartilage Three types of cartilage (continued) 1. Fibrocartilage Found in knee joint, between pubic bones, and in intervertebral discs Durable and tough Resists compression, prevents bone-to-bone contact, and limits relative movement © 2018 Pearson Education, Inc.  Module 4.13: Cartilage Cartilage properties Set apart from surrounding tissues by perichondrium (peri-, around) Two layers of perichondrium 1. Outer layer of dense irregular connective tissue o Mechanical support, protection, attachment 2. Inner cellular layer o Where cartilage growth and maintenance occur Blood vessels in perichondrium provide oxygen and nutrients to chondrocytes © 2018 Pearson Education, Inc.  Module 4.13: Cartilage Two types of cartilage growth 1. Appositional growth (at cartilage surface) Chondroblasts (immature chondrocytes) divide in cellular layer of perichondrium Chondroblasts secrete new matrix Once surrounded by matrix, chondroblasts mature into chondrocytes © 2018 Pearson Education, Inc.  Module 4.13: Cartilage Two types of cartilage growth (continued) 1. Interstitial growth (within cartilage) Chondrocytes divide within a lacuna Daughter cells secrete additional matrix and move apart Both types of cartilage growth occur during development Normally no growth and repair in adults With slight damage or with hormonal stimulation, some appositional growth possible © 2018 Pearson Education, Inc.  Module 4.14: Bone provides a strong framework for the body Osseous (os, bone) tissue (bone tissue) Connective tissue with solid, crystalline matrix Small volume of ground substance 2/3 of matrix is calcium salts (provide strength) – Mostly calcium phosphate – Some calcium carbonate Many collagen fibers (provide flexibility) Strong, somewhat flexible, resistant to shattering © 2018 Pearson Education, Inc.  Module 4.14: Bone Typical long bone structure Hollow with two types of bone 1. Compact bone – Outer layer of bone 2. Spongy bone – Lines internal cavity – Finer network © 2018 Pearson Education, Inc.  Typical long bone structure © 2018 Pearson Education, Inc. © 2018 Pearson Education, Inc.  Module 4.14: Bone Compact bone structure Matrix organized in concentric layers Organized into functional units (osteons) – Central canal contains blood vessels in center Cells (osteocytes) located between layers Canaliculi (little canals) connect osteocytes Superficial layer of solid, calcified bone prevents interstitial growth © 2018 Pearson Education, Inc.  Module 4.14: Bone Compact bone structure (continued) Surrounded by periosteum Two layers 1. Outer fibrous layer allows attachment of ligaments 2. Inner cellular layer allows appositional growth and repair © 2018 Pearson Education, Inc.  Module 4.15: Tissues membranes are physical barriers, and fasciae support and surround organs Overview of membranes Line or cover body surfaces Typically consist of epithelium supported by connective tissue Four types in the body 1. Mucous membranes 2. Serous membranes 3. Cutaneous membrane 4. Synovial membranes © 2018 Pearson Education, Inc.  Module 4.15: Membranes and fasciae Four types of membranes 1. Mucous membranes Line passageways open to the exterior of the body – Digestive, respiratory, reproductive, urinary tracts Must be kept moist to facilitate movement, absorption, or secretion Lubricated by mucus or bodily fluids Supported by areolar connective tissue © 2018 Pearson Education, Inc.  Module 4.15: Membranes and fasciae Four types of membranes (continued) 1. Serous membranes (serosae) Composed of mesothelium supported by areolar connective tissue Delicate and never connected to exterior Watery serous fluid coats surface Three subdivisions of ventral body cavity – Pleura (pleural cavity and lungs) – Pericardium (pericardial cavity and heart) – Peritoneum (peritoneal cavity and visceral organs) © 2018 Pearson Education, Inc.  Module 4.15: Membranes and fasciae Four types of membranes (continued) 1. Cutaneous membrane Covers surface of body (skin) Composed of: – Stratified squamous epithelium – Layer of areolar tissue – Underlying dense irregular connective tissue Relatively thick, waterproof, and usually dry © 2018 Pearson Education, Inc.  Module 4.15: Membranes and fasciae Four types of membranes (continued) 1. Synovial membrane Lines freely movable joint cavities Lubricates joint cavity with synovial fluid Provides oxygen and nutrients to cartilage cells Not true epithelium – Develops within connective tissue – Lacks basement membrane – Contains gaps between cells (up to 1 mm) – Synovial fluid and capillaries continuously exchange fluid and solutes © 2018 Pearson Education, Inc.  Module 4.15: Membranes and fasciae Fasciae: Support and surround organs Three types of layers 1. Superficial fascia – Under skin – Consists of areolar and adipose tissue 2. Deep fascia – Continuous with capsules, ligaments, and other connective tissue structures – Consists of dense irregular connective tissue – Forms strong, fibrous internal framework 3. Subserous fascia – Between serous membranes and deep fascia – Consists entirely of areolar tissue © 2018 Pearson Education, Inc.  Connective tissue framework of the body © 2018 Pearson Education, Inc.  Section 3: Muscle Tissue and Nervous Tissue Learning Outcomes 4.16 Describe the relative proportions of muscle tissue and nervous tissue in the body. 4.17 Specify the functions of muscle tissue and nervous tissue. 4.18 Clinical Module: Describe the roles of inflammation and regeneration in response to tissue injury. © 2018 Pearson Education, Inc.  Module 4.16: Muscle tissue outweighs nervous tissue by 25:1 Tissue types by weight Muscle tissue is 50 percent total body weight The most of any major tissue type Nervous tissue is 2 percent total body weight The least of any major tissue type Connective tissue (45 percent) and epithelial tissue (3 percent) provide interwoven framework for body © 2018 Pearson Education, Inc.  Percentages (by weight) of the four tissue types in the body © 2018 Pearson Education, Inc.  Module 4.16: Muscle tissue and nervous tissue Types of muscle tissue Skeletal muscle tissue Moves the body Cardiac muscle tissue Moves blood within the heart and through blood vessels Smooth muscle tissue Moves fluids and solids along digestive tract Regulates diameter of small arteries, among other functions © 2018 Pearson Education, Inc.  Module 4.17: Muscle tissue is specialized for contraction … Muscle tissue Specialized for contraction to cause movement Movement of the body Movement of blood around the cardiovascular system Movement of materials along the digestive tract Three types of muscles 1. Skeletal muscle tissue 2. Cardiac muscle tissue 3. Smooth muscle tissue © 2018 Pearson Education, Inc.  Module 4.17: Functions of muscle tissue Three types of muscle tissue 1. Skeletal muscle tissue Found in skeletal muscle Elongated, cylindrical, banded (striated) cells with multiple nuclei (multinucleate) Functions – Move and stabilizes skeleton – Guard entrances and exits to digestive, respiratory, urinary tracts – Generate heat – Protect internal organs © 2018 Pearson Education, Inc.  Skeletal muscle tissue © 2018 Pearson Education, Inc.  Module 4.17: Functions of muscle tissue Three types of muscle tissue (continued) 1. Cardiac muscle tissue Found only in heart Cells (“cardiocytes”) are short, branched, and usually have a single nucleus – Interconnected with special junctions (intercalated discs) that help synchronize cardiocyte contractions Functions to move blood and maintain blood pressure © 2018 Pearson Education, Inc.  Module 4.17: Functions of muscle tissue Three types of muscle tissue (continued) 1. Smooth muscle tissue Found throughout body (skin, blood vessel walls, many organs of various systems) Cells are short, spindle-shaped, nonstriated, have a single nucleus Functions – Move food, urine, and reproductive secretions – Control diameter of respiratory passageways and blood vessels © 2018 Pearson Education, Inc.  Module 4.17: … and nervous tissue is specialized for communication Nervous tissue Specialized for conduction of electrical impulses 98 percent found in brain and spinal cord Two basic types of cells 1. Neurons (neuros, nerve) 2. Neuroglia or glial cells (glia, glue) – Various supporting cells © 2018 Pearson Education, Inc.  Module 4.17: Functions of nervous tissue Neurons Transfer information around body and perform information processing Vary in size and shape Longest cells in body are neurons (up to 1 meter) © 2018 Pearson Education, Inc.  Module 4.17: Functions of nervous tissue Neuron structure Dendrites (dendron, tree) Receive information Axon Conducts information to other cells Also called nerve fibers Cell body Contains large nucleus and other organelles Cell control center and site of information processing Most lack centrioles and cannot divide © 2018 Pearson Education, Inc.  Neuron structure © 2018 Pearson Education, Inc.  Module 4.17: Functions of nervous tissue Neuroglia Several different structural types with associated functions © 2018 Pearson Education, Inc.  Module 4.18: CLINICAL MODULE: The response to tissue injury involves inflammation and regeneration Tissues respond in a coordinated way to restore homeostasis Two restoration processes Inflammation Regeneration © 2018 Pearson Education, Inc.  Module 4.18: CLINICAL MODULE: Responses to tissue injury Injury occurs Body is exposed to pathogens and toxins and chemicals from injured cells Body activates defense mechanisms including: Mast cell activation – Mast cells release histamine and other chemicals – Stimulates inflammation © 2018 Pearson Education, Inc.  Module 4.18: CLINICAL MODULE: Responses to tissue injury Inflammation Produces indications of injury 1. Swelling 2. Redness 3. Warmth 4. Pain May result from injury or from infection (presence of pathogens within the tissue) Occurs in connective tissue, so may occur anywhere in the body (as all organs contain connective tissue) © 2018 Pearson Education, Inc.  Module 4.18: CLINICAL MODULE: Responses to tissue injury Inflammation (continued) Dilates (enlarges) blood vessels Increases blood vessel permeability Increased blood flow to the area causes: Swelling in the area Increased local temperature Increased delivery of oxygen and nutrients Increased removal of toxins and wastes Stimulates increased phagocytosis in tissues Sensation of pain from abnormal conditions and chemicals released by mast cells © 2018 Pearson Education, Inc.  Inflammation © 2018 Pearson Education, Inc.  Module 4.18: CLINICAL MODULE: Responses to tissue injury Cleanup process (removing toxins and wastes) usually eliminates inflammatory stimuli in hours to days Regeneration Occurs after damaged tissue has stabilized Fibroblasts produce collagen fibers to stabilize injury site Produces dense, collagenous framework called scar tissue Scar tissue usually remodeled and normal tissue conditions restored © 2018 Pearson Education, Inc.  Module 4.18: CLINICAL MODULE: Responses to tissue injury Each tissue has a different ability to regenerate Epithelial, connective (except cartilage), and smooth muscle regenerate well Other muscle types and neural tissue regenerate poorly, if at all In tissues that regenerate poorly, scar tissue replaces tissues that do not regenerate Fibrosis is the permanent replacement of normal tissue by scar tissue © 2018 Pearson Education, Inc.  Module 4.18: CLINICAL MODULE: Responses to tissue injury © 2018 Pearson Education, Inc.