1 Levels of Organization Fundamentals of Anatomy & Physiology Unit Frederic H. Martini PowerPoint® Lecture Slides prepared by Professor Albia Dugger, Miami–Dade College, Miami, FL Professor Robert R. Speed, Ph.D., Wallace Community College, Dothan, AL Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings

Chapter 4: The Tissue Level of Organization

What are the four tissues of the body?

Epithelial Tissue Covers exposed surfaces Lines internal passageways Forms glands

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

Neural Tissue Carries electrical signals from 1 part of the body to another

KEY CONCEPT Tissues are collections of cells and cell products that perform specific, limited functions 4 tissue types form all the structures of the human body: epithelial, connective, muscle, and neural

Epithelial Tissues Epithelia: Glands: layers of cells covering internal or external surfaces Glands: structures that produce secretions

What are the special structures and functions of epithelial tissues?

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

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

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 and basolateral surfaces Figure 4–1

Increasing Surface Area Microvilli increase absorption or secretion Cilia (ciliated epithelium) move fluids

Effective Barriers Physical integrity is maintained by: intercellular connections attachment to basal lamina maintenance and repair

Intercellular Connections Support and communication PLAY Intercellular Connections Figure 4–2a

Large Connections CAMs (cell adhesion molecules): transmembrane proteins Intercellular cement: Proteoglycans

Cell Junctions Form bonds with other cells or extracellular material: tight junctions gap junctions desmosomes

Tight Junctions Between 2 cell membranes Figure 4–2b

Tight Junctions Adhesion belt attaches to terminal web Prevents passage of water and solutes Isolates wastes in the lumen

Gap Junctions Allow rapid communications Figure 4–2c

Gap Junctions Held together by channel proteins (junctional proteins, connexons) Allow ions to pass Coordinated contractions in heart muscle

Desmosomes CAMs, dense areas, and intercellular cement Figure 4–2d

Desmososmes Button desmosomes Ties cells together Allow bending and twisting

Attachment to Basal Lamina Hemidesmosomes Figure 4–2e

Repairing and Replacing Epithelia Epithelia are replaced by division of germinative cells (stem cells) Near basal lamina

Classes of Epithelia Based on shape and layers Table 4–1

Layers Simple epithelium: Stratified epithelium: single layer of cells several layers of cells

Cell Shape Squamous epithelia: Cuboidal epithelia: Columnar epithelia: flat shaped Cuboidal epithelia: square shaped Columnar epithelia: tall shaped

Squamous Epithelia Simple squamous epithelium: Mesothelium: absorption and diffusion Mesothelium: lines body cavities Endothelium: lines heart and blood vessels

Simple Squamous Epithelium Figure 4–3a

Stratified Squamous Epithelium Figure 4–3b

Stratified Squamous Epithelium Protects against attacks Keratin proteins add strength and water resistance

Cuboidal Epithelia Simple cuboidal epithelium: secretion and absorption Stratified cuboidal epithelia: sweat and mammary ducts

Simple Cuboidal Epithelium Kidney tubules Figure 4–4a

Stratified Cuboidal Epithelium Sweat gland ducts Figure 4–4b

Transitional Epithelium Urinary bladder Figure 4–4c

Columnar Epithelia Simple columnar epithelium: absorption and secretion Pseudostratified columnar epithelium: cilia movement Stratified columnar epithelium: protection

Simple Columnar Epithelium Intestinal lining Figure 4–5a

Pseudostratified Columnar Epithelium Trachea Figure 4–5b

Stratified Columnar Epithelium Salivary gland duct Figure 4–5c

Glandular Epithelia Endocrine and exocrine glands PLAY Mechanisms of Glandular Secretion Figure 4–6

Endocrine Glands Release hormones: into interstitial fluid no ducts

Exocrine Glands Produce secretions: onto epithelial surfaces through ducts

Modes of Secretion Merocrine secretion Figure 4–6a

Modes of Secretion Apocrine secretion Figure 4–6b

Modes of Secretion Holocrine secretion Figure 4–6c

Merocrine Secretions Are produced in Golgi apparatus Are released by vesicles (exocytosis) e.g., sweat glands

Apocrine Secretions Are produced in Golgi apparatus Are released by shedding cytoplasm e.g., mammary gland

Holocrine Secretions Are released by cells bursting, killing gland cells Gland cells replaced by stem cells e.g., sebaceous gland

Types of Secretions Serous glands: Mucous glands: watery secretions Mucous glands: secrete mucins Mixed exocrine glands: both serous and mucous

Gland Structure Exocrine glands can be classified as: unicellular glands multicellular glands

Unicellular Glands Goblet cells are the only unicellular exocrine glands: scattered among epithelia e.g., in intestinal lining

Structure of Multicellular Exocrine Glands Structural classes of exocrine glands Figure 4–7 (1 of 2)

Structure of Multicellular Exocrine Glands Figure 4–7 (2 of 2)

What are the structures and functions of different types of connective tissues?

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

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

The Matrix The extracellular components of connective tissues (fibers and ground substance): majority of cell volume determines specialized function

Classification of Connective Tissues Connective tissue proper: connect and protect Fluid connective tissues: transport Supportive connective tissues: structural strength

Connective Tissue Proper Figure 4–8

Connective Tissue Proper Components of connective tissue proper

Categories of Connective Tissue Proper Loose connective tissue: more ground substance, less fibers e.g., fat (adipose tissue) Dense connective tissue: more fibers, less ground substance e.g., tendons

8 Cell Types of Connective Tissue Proper Fibroblasts Macrophages Adipocytes Mesenchymal cells Melanocytes Mast cells Lymphocytes Microphages

Fibroblasts The most abundant cell type: found in all connective tissue proper secrete proteins and hyaluronan (cellular cement)

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

Mesenchymal Cells Stem cells that respond to injury or infection: differentiate into fibroblasts, macrophages, etc.

Melanocytes Synthesize and store the brown pigment melanin

Mast Cells Stimulate inflammation after injury or infection: release histamine and heparin Basophils are mast cells carried by blood

Lymphocytes Specialized immune cells in lymphatic system: e.g., plasma cells which produce antibodies

Microphages Phagocytic blood cells: respond to signals from macrophages and mast cells e.g., neutrophils and eosinophils

Fibers in Connective Tissue Proper Collagen fibers: most common fibers in CTP long, straight, and unbranched strong and flexible resists force in 1 direction e.g., tendons and ligaments

Fibers in Connective Tissue Proper Reticular fibers: network of interwoven fibers (stroma) strong and flexible resists force in many directions stabilizes functional cells (parenchyma) and structures e.g., sheaths around organs

Fibers in Connective Tissue Proper Elastic fibers: contain elastin branched and wavy return to original length after stretching e.g., elastic ligaments of vertebrae

Ground Substance In connective tissue proper and ground substance: is clear, colorless, and viscous fills spaces between cells and slows pathogens

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

Loose Connective Tissues The packing materials of the body 3 types in adults: areolar adipose reticular

Areolar Tissue Least specialized Open framework Viscous ground substance Elastic fibers Holds blood vessels and capillary beds: e.g., under skin (subcutaneous layer)

Adipose Tissue Contains many adipocytes (fat cells) Figure 4–10a

Types of Adipose Tissue White fat: most common stores fat absorbs shocks slows heat loss (insulation)

Types of Adipose Tissue Brown fat: more vascularized adipocytes have many mitochondria breaks down fat produces heat

Adipose 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

Reticular Tissue Provides support Figure 4–10b

Reticular Tissue Complex, 3-dimensional network Supportive fibers (stroma): support functional cells (parenchyma) Reticular organs: spleen, liver, lymph nodes, and bone marrow

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

Dense Regular Connective Tissue Attachment and stabilization Figure 4–11a

Dense Regular Connective Tissues Tightly packed, parallel collagen fibers: tendons attach muscles to bones ligaments connect bone to bone and stabilize organs aponeuroses attach in sheets on large, flat muscles

Dense Irregular Connective Tissue Strength in many directions Figure 4–11b

Dense Irregular Connective Tissues Interwoven networks of collagen fibers: layered in skin around cartilages (perichondrium) around bones (periosteum) form capsules around some organs (e.g., liver, kidneys)

Elastic Tissue Made of elastic fibers: e.g., elastic ligaments of spinal vertebrae Figure 4–11c

Fluid Connective Tissues blood and lymph watery matrix of dissolved proteins carry specific cell types (formed elements)

Formed Elements of Blood Figure 4–12

Formed Elements of Blood Red blood cells (erythrocytes) White blood cells (leukocytes) Platelets

Fluid Elements of Blood Extracellular: plasma interstitial fluid lymph

Lymph Extracellular fluid: collected from interstitial space monitored by immune system transported by lymphatic system returned to venous system

Fluid Tissue Transport Systems Cardiovascular system (blood): arteries capillaries veins 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

Cartilage Matrix Proteoglycans derived from chondroitin sulfates Ground substance proteins Cells (chondrocytes) surrounded by lacunae (chambers)

Cartilage Structure No blood vessels: Perichondrium: chondrocytes produce antiangiogenesis factor Perichondrium: outer, fibrous layer (for strength) inner, cellular layer (for growth and maintenance)

Cartilage Growth (1 of 2) Interstitial growth Figure 4–13a

Cartilage Growth (2 of 2) Appositional growth Figure 4–13b

Types of Cartilage Hyaline cartilage: Elastic cartilage: translucent matrix no prominent fibers Elastic cartilage: tightly packed elastic fibers Fibrocartilage: very dense collagen fibers

Hyaline Cartilage Reduces friction in joints Figure 4–14a

Hyaline Cartilage Hyaline cartilage: stiff, flexible support reduces friction between bones found in synovial joints, rib tips, sternum, and trachea

Elastic Cartilage Flexible support Figure 4–14b

Elastic Cartilage Elastic cartilage: supportive but bends easily found in external ear and epiglottis

Fibrocartilage Resists compression Figure 4–14c

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

Bone Also called osseous tissue: strong (calcified: calcium salt deposits) resists shattering (flexible collagen fibers)

Structures of Bone Figure 4–15

Bone Cells Osteocytes: arranged around central canals within matrix small channels through matrix (canaliculi) access blood supply

Bone Surface Periosteum: covers bone surfaces fibrous layer cellular layer

Comparing Cartilage and Bone Table 4–2

connective tissues combine to form 4 types of membranes? How do epithelial and connective tissues combine to form 4 types of membranes?

Membranes Membranes: Consist of: are physical barriers that line or cover portions of the body Consist of: an epithelium supported by connective tissues

4 Types of Membranes Mucous Serous Cutaneous Synovial Figure 4–16

Mucous Membrane Mucous membranes (mucosae): line passageways that have external connections also in digestive, respiratory, urinary, and reproductive tracts

Structure of Mucous Membrane Figure 4–16a

Mucous Tissues Epithelial surfaces must be moist: Lamina propria: to reduce friction to facilitate absorption and excretion Lamina propria: is areolar tissue

Serous Membranes Line cavities not open to the outside Are thin but strong Have fluid transudate to reduce friction

Structure of Serous Membrane Figure 4–16b

Double Membranes Serous membranes: have a parietal portion covering the cavity and a visceral portion (serosa) covering the organs

Cavities and Serous Membranes Pleural membrane: lines pleural cavities covers lungs Peritoneum: lines peritoneal cavity covers abdominal organs Pericardium: lines pericardial cavity covers heart

Cutaneous Membrane Cutaneous membrane: is skin, surface of the body thick, waterproof, and dry

Structure of Cutaneous Membrane Figure 4–16c

Synovial Membranes Line articulating (moving) joint cavities Produce synovial fluid (lubricant) Protect the ends of bones Lack a true epithelium

Structure of Synovial Membranes Figure 4–16d

How do connective tissues form the framework of the body?

Framework of the Body Connective tissues: provide strength and stability maintain positions of internal organs provides routes for blood vessels, lymphatic vessels, and nerves

Fasciae Also called fascia: the body’s framework of connective tissue layers and wrappings that support or surround organs

3 Types of Fasciae Superficial fascia Figure 4–17

3 Types of Fasciae Deep fascia Figure 4–17

3 Types of Fasciae Subserous fascia Figure 4–17

What are the structures and functions of the three types of muscle tissue?

Muscle Tissue Is specialized for contraction Produces all body movement

3 Types of Muscle Tissue Skeletal muscle: Cardiac muscle: large body muscles responsible for movement Cardiac muscle: found only in the heart

3 Types of Muscle Tissue Smooth muscle: found in walls of hollow, contracting organs (blood vessels; urinary bladder; respiratory, digestive and reproductive tracts)

Classification of Muscle Cells Striated (muscle cells with a banded appearance): or nonstriated (not banded) Muscle cells can have a single nucleus: or be multinucleate Muscle cells can be controlled voluntarily (consciously): or involuntarily (automatically)

Skeletal Muscle Striated, voluntary, and ultinucleated Figure 4–18a

Skeletal Muscle Cells Skeletal muscle cells: are long and thin are usually called muscle fibers do not divide new fibers are produced by stem cells (satellite cells)

Cardiac Muscle Tissue Striated, involuntary, and single nucleus Figure 4–18b

Cardiac Muscle Cells Cardiac muscle cells: are called cardiocytes form branching networks connected at intercalated disks are regulated by pacemaker cells

Smooth Muscle Tissue Nonstriated, involuntary, and single nucleus Figure 4–18c

Smooth Muscle Cells Smooth muscle cells: are small and tapered can divide and regenerate

What is the basic structure and role of neural tissue?

Neural Tissue Also called nervous or nerve tissue: specialized for conducting electrical impulses rapidly senses internal or external environment process information and controls responses

Central Nervous System Neural tissue is concentrated in the central nervous system: brain spinal cord

2 Kinds of Neural Cells Neurons: Neuroglia: nerve cells perform electrical communication Neuroglia: support cells repair and supply nutrients to neurons

Cell Parts of a Neuron Cell body: Dendrites: contains the nucleus and nucleolus Dendrites: short branches extending from the cell body receive incoming signals

Cell Parts of a Neuron Axon (nerve fiber): long, thin extension of the cell body carries outgoing electrical signals to their destination

The Neuron Figure 4–19

Neuroglia Figure 4–19

How do injuries affect tissues of the body?

Tissue Injuries and Repair Tissues respond to injuries to maintain homeostasis Cells restore homeostasis with 2 processes: inflammation regeneration

Inflammation Inflammation: Signs of inflammatory response include: the tissue’s first response to injury Signs of inflammatory response include: swelling redness heat pain

Inflammatory Response Can be triggered by: trauma (physical injury) infection (the presence of harmful pathogens)

The Process of Inflammation Damaged cells release chemical signals into the surrounding interstitial fluid: prostaglandins proteins potassium ions

The Process of Inflammation As cells break down: lysosomes release enzymes that destroy the injured cell and attack surrounding tissues tissue destruction is called necrosis

The Process of Inflammation Necrotic tissues and cellular debris (pus) accumulate in the wound: abscess: pus trapped in an enclosed area

The Process of Inflammation Injury stimulates mast cells to release: histamine heparin prostaglandins Which dilate surrounding blood vessels

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

The Process of Inflammation Plasma diffuses into the area: causing swelling and pain Phagocytic white blood cells: clean up the area

Regeneration When the injury or infection is cleaned up: healing (regeneration) begins

The Process of Regeneration Fibroblasts move into necrotic area: lay down collagen fibers to bind the area together (scar tissue)

The Process of Regeneration New cells migrate into area: or are produced by mesenchymal stem cells

The Process of Regeneration Not all tissues can regenerate: epithelia and connective tissues regenerate well cardiac cells and neurons do not regenerate

Summary: Inflammation and Regeneration Figure 4–20

Aging and Tissue Structure Speed and efficiency of tissue repair decreases with age, due to: slower rate of energy consumption (metabolism) hormonal alterations reduced physical activity

Effects of Aging Chemical and structural tissue changes: thinning epithelia and connective tissues increased bruising and bone brittleness joint pain and broken bones cardiovascular disease mental deterioration

Aging and Cancer Cancer rates increase with age: 1 in 4 people in the U.S. develop cancer cancer is the #2 cause of death in the U.S. environmental chemicals and cigarette smoke cause cancer

SUMMARY (1 of 14) Organization of specialized cells into tissues: epithelial tissue connective tissue muscular tissue nervous tissue

SUMMARY (2 of 14) Division of epithelial tissues into epithelia and glands: epithelia as avascular barriers for protection glands as secretory structures

SUMMARY (3 of 14) Specializations of epithelial cells for sensation or motion: microvilli cilia

SUMMARY (4 of 14) Attachments of epithelia to other cells and underlying tissues: polarity (apical surface and basal lamina) cell adhesion molecules (CAMs) cell junctions (tight junctions, gap junctions and desmosomes)

SUMMARY (5 of 14) Maintenance of epithelia: germinative cells stem cells

SUMMARY (6 of 14) Classification of epithelial cells: by number of cell layers (simple or stratified) by shape of cells (squamous, columnar or cuboidal)

SUMMARY (7 of 14) Classification of epithelial glands: by method of secretion (exocrine or endocrine) by type of secretions (merocrine, apocrine, holocrine) by organization (unicellular or multicellular) by structure (related to branches and ducts)

SUMMARY (8 of 14) The functions of connective tissues: structure transport protection support connections energy storage

SUMMARY (9 of 14) The structure of connective tissues: matrix ground substance protein fibers

SUMMARY (10 of 14) The classification of connective tissues: connective tissue proper (cell types, fiber types, and embryonic connective tissues) fluid connective tissues (blood and lymph, fluid transport systems) supporting connective tissues (cartilage and bone)

SUMMARY (11 of 14) The 4 types of membranes that cover and protect organs: mucous membranes (lamina propria) serous membranes (transudate) cutaneous membrane (skin) synovial membrane (encapsulating joints)

SUMMARY (12 of 14) The fasciae (superficial, deep and subserous) The 3 types of muscle tissues (skeletal, cardiac, and smooth) The classification of muscle tissues by striation, nucleation, and voluntary control

SUMMARY (13 of 14) The 2 types of cells in neural tissue: neurons and neuroglia The parts of a neuron (nerve cell): cell body, dendrites, and axon (nerve fiber)

SUMMARY (14 of 14) Tissue injuries and repair systems (inflammation and regeneration) The relationship between aging, tissue structure, and cancer