Fundamentals of Anatomy & Physiology

Fundamentals of Anatomy & Physiology
Eleventh Edition Chapter 4 The Tissue Level of Organization Lecture Presentation by Deborah A. Hutchinson Seattle University © 2018 Pearson Education, Inc.

Learning Outcomes 4-1 Identify the four major types of tissues in the body, and describe their roles. 4-2 Discuss the types and functions of epithelial tissue. 4-3 Describe the relationship between structure and function for each type of epithelium. 4-4 List the specific functions of connective tissue, and describe the three main categories of connective tissue. 4-5 Compare the structures and functions of the various types of connective tissue proper, and the layers of connective tissue called fasciae. 4-6 Describe the fluid connective tissues blood and lymph, and explain their relationship with interstitial fluid in maintaining homeostasis. © 2018 Pearson Education, Inc.

Learning Outcomes 4-7 Describe how cartilage and bone function as supporting connective tissues. 4-8 Explain how epithelial and connective tissues combine to form four types of tissue membranes, and specify the functions of each. 4-9 Describe the three types of muscle tissue and the special structural features of each type Discuss the basic structure and role of nervous tissue Describe how injuries affect the tissues of the body Describe how aging affects the tissues of the body. © 2018 Pearson Education, Inc.

An Introduction to Tissues
Collections of specialized cells and cell products that perform specific functions Tissues in combination form organs, such as the heart or liver Histology is the study of tissues © 2018 Pearson Education, Inc.

4-1 Four Types of Tissue Four types of tissue Epithelial Connective
Muscle Nervous © 2018 Pearson Education, Inc.

4-1 Four Types of Tissue Epithelial tissue Covers exposed surfaces
Lines internal passageways Forms glands Connective tissue Fills internal spaces Supports other tissues Transports materials Stores energy © 2018 Pearson Education, Inc.

4-1 Four Types of Tissue Muscle tissue Specialized for contraction
Skeletal muscle, heart muscle, and muscular walls of hollow organs Nervous tissue Carries electrical signals from one part of the body to another © 2018 Pearson Education, Inc.

Figure 4–1 An Orientation to the Body’s Tissues.
Secrete and regulate EXTRACELLULAR MATERIAL AND FLUIDS CELLS Combine to form TISSUES with special functions EPITHELIAL TISSUE CONNECTIVE TISSUE MUSCLE TISSUE NERVOUS TISSUE Covers exposed surfaces Fills internal spaces Contracts to produce movement Propagates electrical impulses Lines internal passageways and chambers Provides structural support Carries information Produces glandular secretions Stores energy Combine to form ORGANS with multiple functions Interact in ORGAN SYSTEMS © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Epithelial tissue includes epithelia and glands
Epithelia (singular, epithelium) Layers of cells covering internal or external surfaces Glands Structures that produce fluid secretions © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Functions of epithelial tissue
Provide physical protection Control permeability Provide sensation Produce specialized secretions © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Characteristics of epithelia
Polarity (apical and basal surfaces) Cellularity (cell junctions) Attachment (basement membrane) Avascularity (avascular) Regeneration © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Specializations of epithelial cells
Move fluids over the epithelium (protection) Move fluids through the epithelium (permeability) Produce secretions (protection and messaging) Polarity Apical surface Microvilli increase absorption or secretion Cilia on a ciliated epithelium move fluids Basolateral surface © 2018 Pearson Education, Inc.

Figure 4–2 The Polarity of Epithelial Cells.
Cilia Microvilli Apical surface Lateral surfaces Golgi apparatus Nucleus Mitochondria Basement membrane Basal surface © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Intercellular connections
Support and communication Cell adhesion molecules (CAMs) Transmembrane proteins Proteoglycans act as intercellular cement Contain glycosaminoglycans such as hyaluronan (hyaluronic acid) © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Intercellular connections Cell junctions
Form bonds with other cells or extracellular material Gap junctions Tight junctions Desmosomes © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Gap junctions Allow rapid communication
Cells held together by interlocking transmembrane proteins (connexons) Allow small molecules and ions to pass Coordinate contractions in heart muscle © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Tight junctions Between two plasma membranes
Adhesion belt attaches to terminal web Prevent passage of water and solutes Keep enzymes, acids, and wastes in the lumen of the digestive tract © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Desmosomes
CAMs and proteoglycans link opposing plasma membranes Spot desmosomes Tie cells together Allow bending and twisting Hemidesmosomes Attach cells to the basement membrane © 2018 Pearson Education, Inc.

Figure 4–3a Cell Junctions.
Tight junction Adhesion belt Terminal web Gap junctions Spot desmosome Hemidesmosome a View of an epithelial cell, showing the major types of intercellular connections. © 2018 Pearson Education, Inc.

Figure 4–3b Cell Junctions.
Embedded proteins (connexons) b Gap junctions permit the free diffusion of ions and small molecules between two cells. © 2018 Pearson Education, Inc.

Figure 4–3c Cell Junctions.
Interlocking junctional proteins Tight junction Terminal web Adhesion belt c A tight junction is formed by the fusion of the outer layers of two plasma membranes. Tight junctions prevent the diffusion of fluids and solutes between the cells. A continuous adhesion belt lies deep to the tight junction. This belt is tied to the microfilaments of the terminal web. © 2018 Pearson Education, Inc.

Figure 4–3d Cell Junctions.
Intermediate filaments Cell adhesion molecules (CAMs) Dense area Proteoglycans d A spot desmosome ties adjacent cells together. © 2018 Pearson Education, Inc.

Figure 4–3e Cell Junctions.
Basal lamina Basement membrane Reticular lamina e Hemidesmosomes attach a cell to extracellular structures, such as the protein fibers in the basement membrane. © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Attachment to the basement membrane Basal lamina
Closest to the epithelium Reticular lamina Deeper portion of basement membrane Provides strength © 2018 Pearson Education, Inc.

4-2 Epithelial Tissue Epithelial maintenance and repair
Epithelial cells are replaced by continual division of stem cells Located near basement membrane © 2018 Pearson Education, Inc.

4-3 Classification of Epithelia
Based on shape Squamous—thin and flat Cuboidal—square shaped Columnar—tall, slender rectangles Based on layers Simple epithelium—single layer of cells Stratified epithelium—several layers of cells © 2018 Pearson Education, Inc.

Table 4-1 Classifying Epithelia (Part 1 of 2)
© 2018 Pearson Education, Inc.

Table 4-1 Classifying Epithelia (Part 2 of 2)
© 2018 Pearson Education, Inc.

Squamous epithelia Simple squamous epithelia Absorption and diffusion Mesothelium Lines body cavities Endothelium Forms inner lining of heart and blood vessels Stratified squamous epithelia Protect against mechanical stresses Keratin adds strength and water resistance © 2018 Pearson Education, Inc.

Figure 4–4a Squamous Epithelia.
Simple Squamous Epithelium LOCATIONS: Mesothelia lining pleural, pericardial, and peritoneal cavities; endothelia lining heart and blood vessels; portions of kidney tubules (thin sections of nephron loops); inner lining of cornea; alveoli of lungs Cytoplasm Nucleus FUNCTIONS: Reduces friction; controls vessel permeability; performs absorption and secretion Connective tissue LM × 238 Lining of peritoneal cavity © 2018 Pearson Education, Inc.

Figure 4–4b Squamous Epithelia.
Stratified Squamous Epithelium LOCATIONS: Surface of skin; lining of mouth, throat, esophagus, rectum, anus, and vagina Squamous superficial cells FUNCTIONS: Provides physical protection against abrasion, pathogens, and chemical attack Stem cells Basement membrane Connective tissue Surface of tongue LM × 310 © 2018 Pearson Education, Inc.

Cuboidal epithelia Simple cuboidal epithelia Secretion and absorption Glands and portions of kidney tubules Stratified cuboidal epithelia Relatively rare Ducts of sweat glands and mammary glands © 2018 Pearson Education, Inc.

Figure 4–5a Cuboidal and Transitional Epithelia.
Simple Cuboidal Epithelium LOCATIONS: Glands; ducts; portions of kidney tubules; thyroid gland FUNCTIONS: Limited protection, secretion, absorption Connective tissue Nucleus Cuboidal cells Basement membrane Kidney tubule LM × 650 © 2018 Pearson Education, Inc.

Figure 4–5b Cuboidal and Transitional Epithelia.
Stratified Cuboidal Epithelium LOCATIONS: Lining of some ducts (rare) FUNCTIONS: Protection, secretion, absorption Lumen of duct Stratified cuboidal cells Basement membrane Nucleus Connective tissue Sweat gland duct LM × 500 © 2018 Pearson Education, Inc.

Figure 4–5c Cuboidal and Transitional Epithelia.
Transitional Epithelium LOCATIONS: Urinary bladder; renal pelvis; ureters FUNCTIONS: Permits repeated cycles of stretching without damage Epithelium (not stretched) Basement membrane Connective tissue and smooth muscle layers LM × 400 Empty bladder Epithelium (stretched) Basement membrane Connective tissue and smooth muscle layers Full bladder LM × 400 Urinary bladder © 2018 Pearson Education, Inc.

Columnar epithelia Simple columnar epithelia Absorption and secretion Found in stomach, small intestine, large intestine Pseudostratified columnar epithelia Typically have cilia Found in nasal cavity, trachea, bronchi Stratified columnar epithelia Relatively rare Provide protection in pharynx, anus, urethra © 2018 Pearson Education, Inc.

Figure 4–6a Columnar Epithelia.
Simple Columnar Epithelium LOCATIONS: Lining of stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys Microvilli Cytoplasm FUNCTIONS: Protection, secretion, absorption Nucleus Basement membrane Loose connective tissue LM × 350 Intestinal lining © 2018 Pearson Education, Inc.

Figure 4–6b Columnar Epithelia.
Pseudostratified Ciliated Columnar Epithelium LOCATIONS: Lining of nasal cavity, trachea, and bronchi; portions of male reproductive tract Cilia Cytoplasm FUNCTIONS: Protection, secretion, move mucus with cilia Nuclei Basement membrane Loose connective tissue Trachea LM × 350 © 2018 Pearson Education, Inc.

Figure 4–6c Columnar Epithelia.
Stratified Columnar Epithelium LOCATIONS: Small areas of the pharynx, epiglottis, anus, mammary glands, salivary gland ducts, and urethra Loose connective tissue Deeper cells FUNCTION: Protection Superficial columnar cells Lumen Lumen Cytoplasm Nuclei Basement membrane Salivary gland duct LM × 175 © 2018 Pearson Education, Inc.

Glandular epithelia Glands are collections of epithelial cells that produce secretions Endocrine glands Release hormones that enter bloodstream No ducts Exocrine glands Produce exocrine secretions Discharge secretions through ducts onto epithelial surfaces © 2018 Pearson Education, Inc.

Gland structure Unicellular glands Multicellular glands Goblet cells are unicellular exocrine glands In epithelia of intestines Secrete mucin, which mixes with water to form mucus © 2018 Pearson Education, Inc.

Multicellular exocrine glands are classified by Structure of the duct Simple (undivided) Compound (divided) Shape of secretory portion of the gland Tubular (tube shaped) Alveolar or acinar (blind pockets) Relationship between ducts and glandular areas Branched (several secretory areas sharing one duct) © 2018 Pearson Education, Inc.

Figure 4–7a A Structural Classification of Exocrine Glands.
Simple Glands Duct Gland cells SIMPLE TUBULAR SIMPLE COILED TUBULAR SIMPLE BRANCHED TUBULAR SIMPLE ALVEOLAR (ACINAR) SIMPLE BRANCHED ALVEOLAR Examples: Examples: Examples: Examples: Examples: • Intestinal glands • Merocrine sweat glands • Gastric glands • Not found in adult; a stage in development of simple branched glands • Sebaceous (oil) glands • Mucous glands of esophagus, tongue, duodenum © 2018 Pearson Education, Inc.

Figure 4–7b A Structural Classification of Exocrine Glands.
Compound Glands COMPOUND TUBULAR COMPOUND ALVEOLAR (ACINAR) COMPOUND TUBULO-ALVEOLAR Examples: Examples: Examples: • Mucous glands (in mouth) • Mammary glands • Salivary glands • Bulbo-urethral glands (in male reproductive system) • Glands of respiratory passages • Testes (seminiferous tubules) • Pancreas © 2018 Pearson Education, Inc.

Figure 4–8a Methods of Glandular Secretion.
Merocrine secretion In merocrine secretion, the product is released from secretory vesicles at the apical surface of the gland cell by exocytosis. Secretory vesicle Golgi apparatus Nucleus TEM × 3039 Salivary gland Mammary gland © 2018 Pearson Education, Inc.

Figure 4–8b Methods of Glandular Secretion.
Salivary gland b Apocrine secretion Apocrine secretion involves the loss of apical cytoplasm. Inclusions, secretory vesicles, and other cytoplasmic components are shed in the process. The gland cell then grows and repairs itself before it releases additional secretions. Mammary gland Breaks down Golgi apparatus Secretion Regrowth 1 2 3 4 © 2018 Pearson Education, Inc.

Figure 4–8c Methods of Glandular Secretion.
Salivary gland Mammary gland Hair Sebaceous gland Hair follicle c Holocrine secretion Holocrine secretion occurs as superficial gland cells burst. Continued secretion involves the replacement of these cells through the mitotic divisions of underlying stem cells. 3 Cells burst, releasing cytoplasmic contents 2 Cells form secretory products and increase in size 1 Cell division replaces lost cells Stem cell © 2018 Pearson Education, Inc.

4-4 Connective Tissue Components of connective tissues
Specialized cells Extracellular protein fibers Fluid called ground substance Matrix consists of extracellular components of connective tissue (fibers and ground substance) Majority of tissue volume Determines specialized function © 2018 Pearson Education, Inc.

4-4 Connective Tissue Functions of connective tissues
Establishing a structural framework for the body Transporting fluids and dissolved materials Protecting delicate organs Supporting, surrounding, and interconnecting other types of tissue Storing energy reserves, especially triglycerides Defending the body from invading microorganisms © 2018 Pearson Education, Inc.

4-4 Connective Tissue Categories of connective tissues
Connective tissue proper Connect and protect Fluid connective tissues Transport Supporting connective tissues Structural strength © 2018 Pearson Education, Inc.

4-5 Connective Tissue Proper
Categories of connective tissue proper Loose connective tissue More ground substance, fewer fibers Example: fat (adipose tissue) Dense connective tissue More fibers, less ground substance Example: tendons © 2018 Pearson Education, Inc.

Fibroblasts The most abundant cell type Found in all types of connective tissue proper Secrete proteins and hyaluronan (cellular cement) Fibrocytes Second most abundant cell type Maintain connective tissue fibers © 2018 Pearson Education, Inc.

Adipocytes Fat cells Each cell stores a single, large fat droplet Mesenchymal cells Stem cells that respond to injury or infection Differentiate into fibroblasts, macrophages, etc. Melanocytes Synthesize and store the brown pigment melanin © 2018 Pearson Education, Inc.

Macrophages Large phagocytic cells of the immune system Engulf pathogens and damaged cells Fixed macrophages stay in tissue Free macrophages migrate Mast cells Stimulate inflammation after injury or infection Release histamine and heparin Basophils are leukocytes that also contain histamine and heparin © 2018 Pearson Education, Inc.

Lymphocytes Migrate throughout the body May develop into plasma cells, which produce antibodies Microphages Phagocytic blood cells (neutrophils, eosinophils) Attracted to signals from macrophages and mast cells © 2018 Pearson Education, Inc.

Collagen fibers Most common fibers in connective tissue proper Long, straight, and unbranched Strong and flexible Resist force in one direction Abundant in tendons and ligaments © 2018 Pearson Education, Inc.

Reticular fibers Form a network of interwoven fibers (stroma) Strong and flexible Resist forces in many directions Stabilize functional cells (parenchyma) and structures Example: sheaths around organs © 2018 Pearson Education, Inc.

Figure 4–9 The Cells and Fibers of Connective Tissue Proper.
Reticular fibers Mast cell Melanocyte Elastic fibers Fixed macrophage Plasma cell Free macrophage Collagen fibers Blood in vessel Fibroblast Fibrocyte Mesenchymal cell Adipocytes (fat cells) Ground substance Lymphocyte © 2018 Pearson Education, Inc.

Ground substance Is clear, colorless, and viscous Fills spaces between cells and slows pathogen movement Loose connective tissues “Packing materials” Fill spaces between organs, cushion cells, and support epithelia © 2018 Pearson Education, Inc.

Embryonic connective tissues Not found in adults Mesenchyme (embryonic connective tissue) First connective tissue in embryos Mucous connective tissue Loose embryonic connective tissue © 2018 Pearson Education, Inc.

Figure 4–10a Embryonic Connective Tissues.
Blood vessel Mesenchymal cells Mesenchyme LM × 136 a This is the first connective tissue to appear in an embryo. © 2018 Pearson Education, Inc.

Figure 4–10b Embryonic Connective Tissues.
Blood vessel Mesenchymal cells Mucous connective tissue (Wharton’s jelly) LM × 136 b This sample was taken from the umbilical cord of a fetus. © 2018 Pearson Education, Inc.

Figure 4–11a Loose Connective Tissues.
Areolar Tissue LOCATIONS: Within and deep to the dermis of skin, and covered by the epithelial lining of the digestive, respiratory, and urinary tracts; between muscles; around joints, blood vessels, and nerves Fibrocytes Macrophage Collagen fibers FUNCTIONS: Cushions organs; provides support but permits independent movement; phagocytic cells provide defense against pathogens Mast cell Areolar tissue from pleura Elastic fibers LM × 380 Areolar tissue © 2018 Pearson Education, Inc.

Adipose tissue Contains many adipocytes (fat cells) Adipocytes in adults do not divide Expand to store fat Shrink as fats are released Mesenchymal cells divide and differentiate To produce more fat cells When more storage is needed May be removed (temporarily) via liposuction in cosmetic surgery © 2018 Pearson Education, Inc.

White fat Most common Stores fat and absorbs shocks Slows heat loss (insulation) Brown fat Found in babies and young children More vascularized Adipocytes have many mitochondria Breakdown of lipids releases energy and warms body © 2018 Pearson Education, Inc.

Figure 4–11b Loose Connective Tissues.
Adipose Tissue LOCATIONS: Deep to the skin, especially at sides, buttocks, and breasts; padding around eyes and kidneys FUNCTIONS: Provides padding and cushions shocks; insulates (reduces heat loss); stores energy Adipocytes (white adipose cells) LM × 300 Adipose tissue © 2018 Pearson Education, Inc.

Reticular tissue Provides support Reticular fibers form a complex, three-dimensional stroma Support functional cells of organs Found in liver, kidney, spleen, lymph nodes, and bone marrow © 2018 Pearson Education, Inc.

Figure 4–11c Loose Connective Tissues.
Reticular Tissue LOCATIONS: Liver, kidney, spleen, lymph nodes, and bone marrow FUNCTIONS: Provides supporting framework Reticular fibers Reticular tissue from liver LM × 230 Reticular tissue © 2018 Pearson Education, Inc.

Dense regular connective tissue Tightly packed, parallel collagen fibers Tendons attach muscles to bones Ligaments connect one bone to another and stabilize organs Aponeuroses are tendinous sheets that attach a broad, flat muscle to another structure © 2018 Pearson Education, Inc.

Figure 4–12a Dense Connective Tissues.
Dense Regular Connective Tissue LOCATIONS: Between skeletal muscles and skeleton (tendons and aponeuroses); between bones or stabilizing positions of internal organs (ligaments); covering skeletal muscles; deep fasciae Collagen fibers FUNCTIONS: Provides firm attachment; conducts pull of muscles; reduces friction between muscles; stabilizes positions of bones Fibroblast nuclei Tendon LM × 440 © 2018 Pearson Education, Inc.

Dense irregular connective tissue Interwoven network of collagen fibers Provides strength to dermis Forms sheath around cartilages (perichondrium) and bones (periosteum) Forms capsules around some organs (e.g., liver, kidneys, and spleen) © 2018 Pearson Education, Inc.

Figure 4–12b Dense Connective Tissues.
Dense Irregular Connective Tissue LOCATIONS: Capsules of visceral organs; periostea and perichondria; nerve and muscle sheaths; dermis FUNCTIONS: Provides strength to resist forces from many directions; helps prevent overexpansion of organs, such as the urinary bladder Collagen fiber bundles Deep dermis LM × 111 © 2018 Pearson Education, Inc.

Figure 4–12c Dense Connective Tissues.
Elastic Tissue LOCATIONS: Between vertebrae of the spinal column (ligamenta flava and ligamentum nuchae); ligaments supporting penis; ligaments supporting transitional epithelia; in blood vessel walls Elastic fibers FUNCTIONS: Stabilizes positions of vertebrae and penis; cushions shocks; permits expansion and contraction of organs Fibroblast nuclei Elastic ligament LM × 887 © 2018 Pearson Education, Inc.

Connective tissues Provide strength and stability Maintain positions of internal organs Provide routes for blood vessels, lymphatic vessels, and nerves Fasciae (singular, fascia) Connective tissue layers and wrappings that support and surround organs © 2018 Pearson Education, Inc.

Three layers of fasciae Superficial fascia Separates skin from underlying tissues Deep fascia Sheets of dense regular connective tissue Subserous fascia Lies between deep fascia and serous membranes that line body cavities © 2018 Pearson Education, Inc.

Connective Tissue Framework of Body
Figure 4–13 The Fasciae. Body wall Connective Tissue Framework of Body Body cavity Superficial Fascia • Between skin and underlying organs • Areolar tissue and adipose tissue • Also known as subcutaneous layer or hypodermis Skin Deep Fascia • Bound to capsules, tendons, and ligaments • Dense connective tissue • Forms a strong, fibrous internal framework Subserous Fascia • Between serous membranes and deep fascia • Areolar tissue Rib Serous membrane Cutaneous membrane © 2018 Pearson Education, Inc.

4-6 Blood and Lymph Fluid connective tissues include blood and lymph
Contains a watery matrix called plasma Contains cells and cell fragments, collectively known as formed elements Red blood cells (erythrocytes) White blood cells (leukocytes) Platelets © 2018 Pearson Education, Inc.

Figure 4–14 Formed Elements in the Blood (Part 1 of 3).
Red blood cells Red blood cells, or erythrocytes (e-RITH-rō-sīts), transport oxygen (and, to a lesser degree, carbon dioxide) in the blood. Red blood cells lack a nucleus. They account for about half the volume of whole blood and give blood its color. © 2018 Pearson Education, Inc.

White blood cells White blood cells, or leukocytes (LŪ-kō-sīts; leuko-, white), are nucleated cells, which defend the body from infection and disease. Neutrophil Eosinophil Basophil Monocytes are phagocytes similar to the free macrophages in other tissues. Lymphocytes are un- common in the blood but they are the dominant cell type in lymph, the second type of fluid connective tissue. Eosinophils and neutrophils are phagocytes (microphages). Basophils promote inflammation much like mast cells in other connective tissues. © 2018 Pearson Education, Inc.

Platelets Platelets are membrane- enclosed packets of cytoplasm that function in blood clotting. These cell fragments are involved in the clotting response that seals leaks in damaged or broken blood vessels. © 2018 Pearson Education, Inc.

4-7 Supporting Connective Tissues
Supporting connective tissues include cartilage and bone Cartilage Provides shock absorption and protection Matrix is a firm gel Contains polysaccharide derivatives called chondroitin sulfates Cells in the matrix are chondrocytes In chambers called lacunae © 2018 Pearson Education, Inc.

Cartilage structure Avascular Chondrocytes produce antiangiogenesis factor that discourages formation of blood vessels Perichondrium Outer, fibrous layer (for support and protection) Inner, cellular layer (for growth and maintenance) © 2018 Pearson Education, Inc.

Hyaline cartilage Most common type Tough and somewhat flexible Reduces friction between bones Found in synovial joints, rib tips, sternum, and trachea Elastic cartilage Supportive but bends easily Found in external ear and epiglottis © 2018 Pearson Education, Inc.

Figure 4–15a Types of Cartilage.
Hyaline Cartilage LOCATIONS: Between tips of ribs and bones of sternum; covering bone surfaces at synovial joints; supporting larynx (voice box), trachea, and bronchi; forming part of nasal septum Chondrocytes in lacunae FUNCTIONS: Provides stiff but somewhat flexible support; reduces friction between bony surfaces Matrix LM × 500 Hyaline cartilage © 2018 Pearson Education, Inc.

Figure 4–15b Types of Cartilage.
Elastic Cartilage LOCATIONS: Auricle of external ear; epiglottis; auditory canal; cuneiform cartilages of larynx FUNCTIONS: Provides support, but tolerates distortion without damage and returns to original shape Chondrocytes in lacunae Elastic fibers in matrix LM × 358 Elastic cartilage © 2018 Pearson Education, Inc.

Figure 4–15c Types of Cartilage.
Fibrocartilage LOCATIONS: Pads within knee joint; between pubic bones of pelvis; intervertebral discs FUNCTIONS: Resists compression; prevents bone- to-bone contact; limits movement Chondrocytes in lacunae Fibrous matrix LM × 400 Fibrocartilage © 2018 Pearson Education, Inc.

Figure 4–16a The Growth of Cartilage.
Interstitial growth Matrix New matrix Chondrocyte Lacuna Chondrocyte undergoes division within a lacuna surrounded by cartilage matrix. As daughter cells secrete additional matrix, they move apart, expanding the cartilage from within. © 2018 Pearson Education, Inc.

Figure 4–16b The Growth of Cartilage.
Appositional growth Fibrous layer Fibroblast Dividing stem cell Perichondrium New matrix Chondroblasts Immature chondrocyte Older matrix Mature chondrocyte Cells of the inner layer of the perichondrium differentiate into chondroblasts. These immature chondroblasts secrete new matrix. As the matrix enlarges, more chondroblasts are incorporated; they are replaced by stem cell divisions in the perichondrium. © 2018 Pearson Education, Inc.

Bone (osseous tissue) For weight support Calcified (made rigid by calcium salts) Resists shattering (flexible collagen fibers) Osteocytes (bone cells) lie in lacunae Arranged around central canals within matrix Small channels through matrix (canaliculi) allow for exchange of materials with blood Periosteum covers bone Fibrous (outer) and cellular (inner) layers © 2018 Pearson Education, Inc.

Canaliculi Periosteum Osteocytes in lacunae Fibrous layer Matrix
Figure 4–17 Bone. Canaliculi Periosteum Osteocytes in lacunae Fibrous layer Matrix Cellular layer Osteon Central canal Blood vessels Osteon LM × 375 © 2018 Pearson Education, Inc.

4-8 Tissue Membranes Tissue membranes Physical barriers
Line or cover body surfaces Consist of an epithelium supported by connective tissue © 2018 Pearson Education, Inc.

4-8 Tissue Membranes Four types of tissue membranes Mucous membranes
Serous membranes Cutaneous membrane Synovial membranes © 2018 Pearson Education, Inc.

4-8 Tissue Membranes Mucous membranes (mucosae)
Line passageways that have external connections In digestive, respiratory, urinary, and reproductive tracts Epithelial surfaces must be moist To reduce friction To facilitate absorption or secretion Lamina propria is areolar tissue in mucous membranes © 2018 Pearson Education, Inc.

Figure 4–18a Types of Membranes.
Mucous secretion Epithelium Lamina propria (areolar tissue) a Mucous membranes are coated with the secretions of mucous glands. These membranes line most of the digestive and respiratory tracts and portions of the urinary and reproductive tracts. © 2018 Pearson Education, Inc.

4-8 Tissue Membranes Serous membranes
Line cavities that do not open to the outside Thin but strong Parietal portion lines inner surface of cavity Visceral portion (serosa) covers the organs Serous fluid reduces friction © 2018 Pearson Education, Inc.

4-8 Tissue Membranes Serous membranes Peritoneum
Lines peritoneal cavity Covers abdominal organs Pleura Lines pleural cavities Covers lungs Pericardium Lines pericardial cavity Covers heart © 2018 Pearson Education, Inc.

Figure 4–18b Types of Membranes.
Serous fluid Mesothelium Areolar connective tissue b Serous membranes line the peritoneal, pleural, and pericardial cavities. © 2018 Pearson Education, Inc.

4-8 Tissue Membranes Cutaneous membrane Skin that covers the body
Thick, relatively waterproof, and usually dry Synovial membranes Line synovial joint cavities Movement stimulates production of synovial fluid for lubrication Lack a true epithelium © 2018 Pearson Education, Inc.

Figure 4–18c Types of Membranes.
Epithelium Areolar connective tissue Dense irregular connective tissue c The cutaneous membrane, or skin, covers the outer surface of the body. © 2018 Pearson Education, Inc.

Figure 4–18d Types of Membranes.
Articular (hyaline) cartilage Synovial ﬂuid Capsule Capillary Adipocytes Synovial membrane Areolar tissue Epithelium Bone d Synovial membranes line joint cavities and produce the synovial ﬂuid within the joint. © 2018 Pearson Education, Inc.

4-9 Muscle Tissue Muscle tissue Specialized for contraction
Three types of muscle tissue Skeletal muscle Large muscles responsible for body movement Cardiac muscle Found only in the heart Smooth muscle Found in walls of hollow, contracting organs © 2018 Pearson Education, Inc.

4-9 Muscle Tissue Skeletal muscle tissue
Consists of long, thin cells called muscle fibers Cells do not divide New fibers are produced by divisions of myosatellite cells Striated voluntary muscle © 2018 Pearson Education, Inc.

Figure 4–19a Types of Muscle Tissue.
Skeletal Muscle Tissue Cells are long, cylindrical, striated, and multinucleate. LOCATIONS: Combined with connective tissues and neural tissue in skeletal muscles Striations Nuclei FUNCTIONS: Moves or stabilizes the position of the skeleton; guards entrances and exits to the digestive, respiratory, and urinary tracts; generates heat; protects internal organs Muscle fiber LM × 180 Skeletal muscle © 2018 Pearson Education, Inc.

4-9 Muscle Tissue Cardiac muscle tissue
Cells form branching networks connected at intercalated discs Regulated by pacemaker cells Striated involuntary muscle Smooth muscle tissue Cells are small and spindle shaped Can divide and regenerate Nonstriated involuntary muscle © 2018 Pearson Education, Inc.

Figure 4–19b Types of Muscle Tissue.
Cardiac Muscle Tissue Cells are short, branched, and striated, usually with a single nucleus; cells are interconnected by intercalated discs. Nuclei Cardiac muscle cells LOCATION: Heart FUNCTIONS: Circulates blood; maintains blood pressure Intercalated discs Striations LM × 450 Cardiac muscle © 2018 Pearson Education, Inc.

Figure 4–19c Types of Muscle Tissue.
Smooth Muscle Tissue Cells are short, spindle shaped, and nonstriated, with a single, central nucleus. LOCATIONS: Found in the walls of blood vessels and in digestive, respiratory, urinary, and reproductive organs Nuclei FUNCTIONS: Moves food, urine, and reproductive tract secretions; controls diameter of respiratory passageways; regulates diameter of blood vessels Smooth muscle cells Smooth muscle LM × 235 © 2018 Pearson Education, Inc.

4-10 Nervous Tissue Nervous tissue
Specialized for conducting electrical impulses Concentrated in the brain and spinal cord Types of cells in nervous tissue Neurons Neuroglia (supporting cells) © 2018 Pearson Education, Inc.

4-10 Nervous Tissue Parts of a neuron Cell body
Contains the nucleus and nucleolus Dendrites Short branches extending from the cell body Receive incoming signals Axon (nerve fiber) Long, thin extension of the cell body Carries outgoing electrical signals to their destination © 2018 Pearson Education, Inc.

Figure 4–20 Nervous Tissue (Part 1 of 3).
Nuclei of neuroglia Cell body Axon Dendrites Nucleolus Nucleus LM × 600 © 2018 Pearson Education, Inc.

NEUROGLIA (supporting cells) • Maintain physical structure of tissues • Repair tissue framework after injury • Perform phagocytosis • Provide nutrients to neurons • Regulate the composition of the interstitial fluid surrounding neurons © 2018 Pearson Education, Inc.

Dendrites (contacted by other neurons) Contact with other cells Axon (conducts information to other cells) Microfibrils and microtubules Cell body (contains nucleus and major organelles) Nucleus Nucleolus Mitochondrion A representative neuron (sizes and shapes vary widely) © 2018 Pearson Education, Inc.

4-11 Tissue Injuries and Repair
Tissues respond to injury in two stages Inflammation (inflammatory response) Regeneration to restore normal function © 2018 Pearson Education, Inc.

Inflammatory response Can be triggered by Trauma (physical injury) Infection (the presence of pathogens) Damaged cells release prostaglandins, proteins, and potassium ions Damaged connective tissue activates mast cells © 2018 Pearson Education, Inc.

Process of inflammation Lysosomes release enzymes that destroy the injured cells and attack surrounding tissues Tissue destruction is called necrosis Begins several hours after injury Necrotic tissues and cellular debris (pus) accumulate in the wound Abscess—pus trapped in an enclosed area © 2018 Pearson Education, Inc.

The ability to regenerate varies among tissues Epithelia, connective tissues (except cartilage), and smooth muscle regenerate well Skeletal muscle, cardiac muscle, and nervous tissues regenerate poorly, if at all Damaged cardiac muscle cells are replaced by fibrous tissue through fibrosis © 2018 Pearson Education, Inc.

Figure 4–21 Inflammation and Regeneration (Part 1 of 5).
Mast Cell Activation When an injury damages connective tissue, mast cells release a variety of chemicals. This process, called mast cell activation, stimulates inflammation. Mast cell Histamine stimulates Exposure to Pathogens and Toxins Injured tissue contains an abnormal concentration of pathogens, toxins, wastes, and the chemicals from injured cells. When a tissue is injured, a general defense mechanism is activated. © 2018 Pearson Education, Inc.

Mast Cell Activation When an injury damages connective tissue, mast cells release a variety of chemicals. This process, called mast cell activation, stimulates inflammation. Mast cell Histamine Heparin Prostaglandins INFLAMMATION Inflammation produces several familiar indications of injury. These indications are the so-called cardinal signs of inflammation: redness, heat (warmth), swelling, pain, and sometimes loss of function. Inflammation may also result from the presence of pathogens, such as harmful bacteria, within the tissues. The presence of these pathogens constitutes an infection. Increased Blood Flow Increased Vessel Permeability Pain In response to the released chemicals, blood vessels dilate, increasing blood flow through the damaged tissue. Vessel dilation is accompanied by an increase in the permeability of the capillary walls. Plasma now diffuses into the injured tissue, so the area becomes swollen. The abnormal conditions within the tissue and the chemicals released by mast cells stimulate nerve endings that produce the sensation of pain. PAIN © 2018 Pearson Education, Inc.

Inflammation produces several familiar indications of injury. These indications are the so-called cardinal signs of inflammation: redness, heat (warmth), swelling, pain, and sometimes loss of function. Inflammation may also result from the presence of pathogens, such as harmful bacteria, within the tissues. The presence of these pathogens constitutes an infection. Increased Blood Flow Increased Vessel Permeability Pain In response to the released chemicals, blood vessels dilate, increasing blood flow through the damaged tissue. Vessel dilation is accompanied by an increase in the permeability of the capillary walls. Plasma now diffuses into the injured tissue, so the area becomes swollen. The abnormal conditions within the tissue and the chemicals released by mast cells stimulate nerve endings that produce the sensation of pain. PAIN Increased Local Temperature Increased Oxygen and Nutrients Increased Phagocytosis Removal of Toxins and Wastes The increased blood flow and permeability cause the tissue to become warm and red. Vessel dilation, increased blood flow, and increased vessel permeability result in enhanced delivery of oxygen and nutrients. Phagocytes in the tissue are activated, and they begin engulfing tissue debris and pathogens. Enhanced circulation carries away toxins and wastes, distributing them to the kidneys for excretion, or to the liver for inactivation. O2 Toxins and wastes © 2018 Pearson Education, Inc.

4-12 Aging, Regeneration, and Cancer
Aging and tissue structure Speed and effectiveness of tissue regeneration decrease with age, due to Slowing of repair and maintenance activities Hormonal alterations Reduced physical activity © 2018 Pearson Education, Inc.

Effects of aging Chemical and structural tissue changes Thinner epithelia Fragile connective tissues Increased bruising Brittle bones Cardiovascular disease Mental deterioration © 2018 Pearson Education, Inc.

Aging and cancer incidence Cancer rates increase with age Twenty-five percent of all people in the United States develop cancer Cancer is the second leading cause of death in the United States Most cancers are caused by chemical exposure or environmental factors Forty percent of cases are caused by cigarette smoke © 2018 Pearson Education, Inc.

Fundamentals of Anatomy & Physiology

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Fundamentals of Anatomy & Physiology

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