AP-Ch04 by EVE ROAKE

Chapter

4 The Tissue Level of Organization PowerPoint® Lecture Slides prepared by Jason LaPres Lone Star College - North Harris

Four Types of Tissues   Tissues are collections of cells and cell products that perform specific, limited functions   Types of tissue   Epithelial tissue   Covers exposed surfaces   Lines internal passageways   Forms glands Copyright © 2010 Pearson Education, Inc.

Four Types of Tissues   Types of Tissue (cont d)   Connective tissue   Fills internal spaces   Supports other tissues   Transports materials   Stores energy

  Muscle tissue   Specialized for contraction   Skeletal muscle, heart muscle, and walls of hollow organs

Epithelial Tissues   Epithelia   Layers of cells covering internal or external surfaces

  Glands   Structures that produce secretions

Epithelial Tissues   Characteristics of Epithelia   Cellularity (cell junctions)   Polarity (apical and basal surfaces)   Attachment (basal lamina)   Avascularity   Regeneration

Epithelial Tissues

Epithelial Tissues   Functions of Epithelial Tissue   Provide physical protection   Control permeability   Provide sensation   Produce specialized secretions (glandular epithelium)

Epithelial Tissues   Specializations of Epithelial Cells   Move fluids over the epithelium (protection)   Move fluids through the epithelium (permeability)   Produce secretions (protection and messengers)

  Free Surface and Attached Surface   Polarity   Apical surfaces: –  microvilli increase absorption or secretion –  cilia (ciliated epithelium) move fluid

Epithelial Tissues   Maintaining the Integrity of Epithelia   Intercellular connections   Attachment to basal lamina   Epithelial maintenance and repair

Epithelial Tissues   Intercellular Connections   Support and communication   CAMs (cell adhesion molecules): –  transmembrane proteins

  Intercellular cement: –  proteoglycans

  Hyaluronan (hyaluronic acid): –  glycosaminoglycans

Epithelial Tissues   Intercellular Connections   Cell junctions   Form bonds with other cells or extracellular material: –  occluding (tight) junctions –  gap junctions –  macula adherens (desmosomes)

Epithelial Tissues   Cell Junctions   Occluding (Tight) junctions—between two plasma membranes   Adhesion belt attaches to terminal web   Prevents passage of water and solutes   Isolates wastes in the lumen

  Gap junctions—allow rapid communication   Held together by channel proteins (junctional proteins, connexons)   Allow ions to pass   Coordinate contractions in heart muscle Copyright © 2010 Pearson Education, Inc.

Epithelial Tissues   Cell Junctions   Macula adherens (Desmosomes)  CAMs, dense areas, and intercellular cement  Spot desmosomes – tie cells together – allow bending and twisting

Epithelial Tissues   Attachment to the Basal Lamina   Clear layer (Lamina lucida)   Thin layer   Secreted by epithelia   Barrier to proteins

  Dense layer (Lamina densa)   Thick fibers   Produced by connective tissue   Strength and filtration

Epithelial Tissues

Epithelial Tissues   Epithelial Maintenance and Repair   Epithelia are replaced by division of germinative cells (stem cells)   Near basal lamina

Classification of Epithelia   Singular epithelium; plural epithelia   Classes of Epithelia   Based on shape   Squamous epithelia: thin and flat   Cuboidal epithelia: square shaped   Columnar epithelia: tall, slender rectangles

  Based on layers   Simple epithelium: single layer of cells   Stratified epithelium: several layers of cells

Classification of Epithelia

Classification of Epithelia   Squamous Epithelia   Simple squamous epithelium   Absorption and diffusion

  Mesothelium   Lines body cavities

  Endothelium   Lines heart and blood vessels

Classification of Epithelia

Classification of Epithelia   Squamous Epithelia   Stratified squamous epithelium   Protects against attacks   Keratin protein adds strength and water resistance

Classification of Epithelia

Classification of Epithelia   Cuboidal Epithelia   Simple cuboidal epithelium   Secretion and absorption

  Stratified cuboidal epithelia   Sweat ducts and mammary ducts

Classification of Epithelia

Figure 4–4 Cuboidal Epithelia.

Classification of Epithelia

Figure 4–4 Cuboidal Epithelia.

Classification of Epithelia   Transitional Epithelium   Tolerates repeated cycles of stretching and recoiling and returns to its previous shape without damage   Appearance changes as stretching occurs   Situated in regions of the urinary system (e.g. urinary bladder)

Classification of Epithelia

Figure 4–4 Cuboidal Epithelia.

Classification of Epithelia   Columnar Epithelia   Simple columnar epithelium   Absorption and secretion

  Pseudostratified columnar epithelium   Cilia movement

  Stratified columnar epithelium   Protection

Classification of Epithelia

Classification of Epithelia   Glandular Epithelia   Endocrine glands   Release hormones: –  into interstitial fluid –  no ducts

Classification of Epithelia   Modes of Secretion in Glandular Epithelia   Merocrine secretion   Is produced in Golgi apparatus   Is released by vesicles (exocytosis)   For example, sweat glands

  Apocrine secretion   Is produced in Golgi apparatus   Is released by shedding cytoplasm   For example, mammary gland

Classification of Epithelia

Classification of Epithelia   Glandular Epithelia   Types of secretions   Serous glands: –  watery secretions

  Mucous glands: –  secrete mucins

  Mixed exocrine glands: –  both serous and mucous

Classification of Epithelia   Glandular Epithelia   Gland structure  Unicellular glands – Mucous (goblet) cells are the only unicellular exocrine glands: » scattered among epithelia » for example, in intestinal lining

Classification of Epithelia   Glandular Epithelia   Gland structure   Multicellular glands: –  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)

Classification of Epithelia

Connective Tissues   Connect epithelium to the rest of the body (basal lamina)   Provide structure (bone)   Store energy (fat)   Transport materials (blood)   Have no contact with environment Copyright © 2010 Pearson Education, Inc.

Connective Tissues   Characteristics of Connective Tissues   Specialized cells   Solid extracellular protein fibers   Fluid extracellular ground substance

  The extracellular components of connective tissues (fibers and ground substance) make up the matrix   Majority of tissue volume   Determines specialized function Copyright © 2010 Pearson Education, Inc.

Connective Tissues   Classification of Connective Tissues   Connective tissue proper   Connect and protect

  Fluid connective tissues   Transport

  Supportive connective tissues   Structural strength

Connective Tissues   Categories of Connective Tissue Proper   Loose connective tissue   More ground substance, less fibers   For example, fat (adipose tissue)

  Dense connective tissue   More fibers, less ground substance   For example, tendons

Connective Tissues Nine Cell Types of Connective Tissue Proper   Fibroblasts   Fibrocytes   Macrophages   Adipocytes   Mesenchymal cells

  Melanocytes   Mast cells   Lymphocytes   Microphages

Connective Tissues   Connective Tissue Proper Cells   Fibroblasts   The most abundant cell type: –  found in all connective tissue proper –  secrete proteins and hyaluronan (cellular cement)

  Fibrocytes   The second most abundant cell type: –  found in all connective tissue proper –  maintain the fibers of connective tissue proper

Connective Tissues   Connective Tissue Proper Cells   Macrophages   Large, amoeba-like cells of the immune system: –  eat pathogens and damaged cells –  fixed macrophages stay in tissue –  free macrophages migrate

  Adipocytes   Fat cells: –  each cell stores a single, large fat droplet

Connective Tissues   Connective Tissue Proper Cells   Melanocytes   Synthesize and store the brown pigment melanin

  Mast Cells   Stimulate inflammation after injury or infection: –  release histamine and heparin

Connective Tissues   Connective Tissue Proper Cells   Lymphocytes   Specialized immune cells in lymphoid (lymphatic) system: –  For example, lymphocytes may develop into plasma cells (plasmocytes) that produce antibodies

Connective Tissues   Connective Tissue Fibers   Collagen fibers   Most common fibers in connective tissue proper   Long, straight, and unbranched   Strong and flexible   Resist force in one direction   For example, tendons and ligaments

Connective Tissues   Connective Tissue Fibers   Reticular fibers   Network of interwoven fibers (stroma)   Strong and flexible   Resist force in many directions   Stabilize functional cells (parenchyma) and structures   For example, sheaths around organs Copyright © 2010 Pearson Education, Inc.

Connective Tissues   Connective Tissue Fibers   Elastic fibers   Contain elastin   Branched and wavy   Return to original length after stretching   For example, elastic ligaments of vertebrae

Connective Tissues   Ground Substance   Is clear, colorless, and viscous   Fills spaces between cells and slows pathogen movement

Connective Tissues

Connective Tissues   Embryonic Connective Tissues   Are not found in adults   Mesenchyme (embryonic stem cells)   The first connective tissue in embryos

  Mucous connective tissue   Loose embryonic connective tissue

Connective Tissues

Connective Tissues   Loose Connective Tissues   The packing materials of the body   Three types in adults   Areolar   Adipose   Reticular

Connective Tissues   Areolar Tissue   Least specialized   Open framework   Viscous ground substance   Elastic fibers   Holds blood vessels and capillary beds   For example, under skin (subcutaneous layer)

Connective Tissues   Adipose Tissue   Contains many adipocytes (fat cells)   Types of adipose tissue   White fat: –  –  –  –

most common stores fat absorbs shocks slows heat loss (insulation)

  Brown fat: –  more vascularized –  adipocytes have many mitochondria –  when stimulated by nervous system, fat break down accelerates, releasing energy –  absorbs energy from surrounding tissues

Connective Tissues   Adipose Tissue   Adipose cells  Adipocytes in adults do not divide: – expand to store fat – shrink as fats are released

Connective Tissues   Reticular Tissue   Provides support   Complex, three-dimensional network   Supportive fibers (stroma)   Support functional cells (parenchyma)

  Reticular organs   Spleen, liver, lymph nodes, and bone marrow

Connective Tissues

Connective Tissues   Dense Connective Tissues   Connective tissues proper, tightly packed with high numbers of collagen or elastic fibers   Dense regular connective tissue   Dense irregular connective tissue   Elastic tissue

Connective Tissues   Dense Regular Connective Tissue   Tightly packed, parallel collagen fibers   Tendons attach muscles to bones   Ligaments connect bone to bone and stabilize organs   Aponeuroses attach in sheets to large, flat muscles

Connective Tissues

Connective Tissues   Dense Irregular Connective Tissue   Interwoven networks of collagen fibers   Layered in skin   Around cartilages (perichondrium)   Around bones (periosteum)   Form capsules around some organs (e.g., liver, kidneys) Copyright © 2010 Pearson Education, Inc.

Connective Tissues

Connective Tissues   Elastic Tissue   Made of elastic fibers   For example, elastic ligaments of spinal vertebrae

Connective Tissues

Connective Tissues   Fluid Connective Tissues   Blood and lymph   Watery matrix of dissolved proteins   Carry specific cell types (formed elements)   Formed elements of blood –  red blood cells (erythrocytes) –  white blood cells (leukocytes) –  platelets Copyright © 2010 Pearson Education, Inc.

Connective Tissues   Fluid Elements of Fluid Connective Tissues   Extracellular   Plasma   Interstitial fluid   Lymph

Connective Tissues

Connective Tissues   Lymph   Extracellular fluid   Collected from interstitial space   Monitored by immune system   Transported by lymphoid (lymphatic) system   Returned to venous system

Connective Tissues   Fluid Tissue Transport Systems   Cardiovascular system (blood)   Arteries   Capillaries   Veins

  Lymphoid (lymphatic) system (lymph)   Lymphatic vessels

Supportive Connective Tissues   Support soft tissues and body weight   Cartilage   Gel-type ground substance   For shock absorption and protection

  Bone   Calcified (made rigid by calcium salts, minerals)   For weight support

Supportive Connective Tissues   Cartilage Matrix   Proteoglycans derived from chondroitin sulfates   Ground substance proteins

  Chondrocytes (cartilage cells) surrounded by lacunae (chambers)

Supportive Connective Tissues   Cartilage Structure   No blood vessels:   Chondrocytes produce antiangiogenesis factor   Perichondrium:   Outer, fibrous layer (for strength)   Inner, cellular layer (for growth and maintenance)

Supportive Connective Tissues

Supportive Connective Tissues   Types of Cartilage   Hyaline cartilage   Stiff, flexible support   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

  Fibrous cartilage (fibrocartilage)       

Limits movement Prevents bone-to-bone contact Pads knee joints Found between pubic bones and intervertebral discs

Supportive Connective Tissues

Supportive Connective Tissues   Bone or osseous tissue   Strong (calcified: calcium salt deposits)   Resists shattering (flexible collagen fibers)

  Bone cells or osteocytes   Arranged around central canals within matrix   Small channels through matrix (canaliculi) access blood supply

Supportive Connective Tissues

Membranes   Membranes   Are physical barriers   That line or cover portions of the body   Consist of   An epithelium   Supported by connective tissues

Membranes   Four Types of Membranes   Mucous membranes   Serous membranes   Cutaneous membrane   Synovial membranes

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 and excretion

Membranes   Serous Membranes   Line cavities not open to the outside   Are thin but strong   Have fluid transudate to reduce friction   Have a parietal portion covering the cavity   Have a visceral portion (serosa) covering the organs Copyright © 2010 Pearson Education, Inc.

Membranes   Three Serous Membranes   Pleura:   Lines pleural cavities   Covers lungs

  Peritoneum:   Lines peritoneal cavity   Covers abdominal organs

Membranes

Membranes   Cutaneous membrane   Is skin, surface of the body   Thick, waterproof, and dry

Membranes

Internal Framework of the Body   Connective tissues   Provide strength and stability   Maintain positions of internal organs   Provide routes for blood vessels, lymphatic vessels, and nerves

Internal Framework of the Body   Three Types of Fasciae   Superficial fascia   Deep fascia   Subserous fascia

Internal Framework of the Body

Muscle Tissue   Specialized for contraction   Produces all body movement   Three types of muscle tissue   Skeletal muscle   Large body muscles responsible for movement

  Cardiac muscle   Found only in the heart

Muscle Tissue   Classification of Muscle Cells   Striated (muscle cells with a banded appearance)   Nonstriated (not banded; smooth)   Muscle cells can have a single nucleus   Muscle cells can be multinucleate   Muscle cells can be controlled voluntarily (consciously)   Muscle cells can be controlled involuntarily (automatically) Copyright © 2010 Pearson Education, Inc.

Muscle Tissue   Skeletal Muscle Cells   Are long and thin   Are usually called muscle fibers   Do not divide   New fibers are produced by stem cells (myosatellite cells) Copyright © 2010 Pearson Education, Inc.

Muscle Tissue

Muscle Tissue   Cardiac muscle cells   Are called cardiocytes   Form branching networks connected at intercalated discs   Are regulated by pacemaker cells

Muscle Tissue

Neural Tissue   Also called nervous or nerve tissue   Specialized for conducting electrical impulses   Rapidly senses internal or external environment   Processes information and controls responses

Neural Tissue   Neural tissue is concentrated in the central nervous system   Brain   Spinal cord

Neural Tissue   Two Kinds of Neural Cells   Neurons   Nerve cells   Perform electrical communication

Neural Tissue   Cell Parts of a Neuron   Cell body   Contains the nucleus and nucleolus

  Dendrites   Short branches extending from the cell body   Receive incoming signals

Neural Tissue

Tissue Injuries and Repair   Tissues respond to injuries to maintain homeostasis   Cells restore homeostasis with two processes   Inflammation   Regeneration

Tissue Injuries and Repair   Inflammation = inflammatory response   The tissue s first response to injury

  Signs and symptoms of the inflammatory response include   Swelling   Redness   Heat   Pain

Tissue Injuries and Repair   Inflammatory Response   Can be triggered by   Trauma (physical injury)   Infection (the presence of harmful pathogens)

Tissue Injuries and Repair   The Process of Inflammation   Damaged cells release chemical signals into the surrounding interstitial fluid   Prostaglandins   Proteins   Potassium ions

Tissue Injuries and Repair   The Process of Inflammation   Necrotic tissues and cellular debris (pus) accumulate in the wound   Abscess: –  pus trapped in an enclosed area

Tissue Injuries and Repair   The Process of Inflammation   Dilation of blood vessels   Increases blood circulation in the area   Causes warmth and redness   Brings more nutrients and oxygen to the area   Removes wastes

  Plasma diffuses into the area   Causing swelling and pain

Tissue Injuries and Repair

Tissue Injuries and Repair   Regeneration   When the injury or infection is cleaned up   Healing (regeneration) begins

Tissue Injuries and Repair   The Process of Regeneration   Fibrocytes move into necrotic area   Lay down collagen fibers   To bind the area together (scar tissue)

  New cells migrate into area   Or are produced by mesenchymal stem cells