© 2013 Pearson Education, Inc. Chapter Opener 4. © 2013 Pearson Education, Inc. Figure 4.1 Overview of four basic tissue types: epithelial, connective,

© 2013 Pearson Education, Inc.

Chapter Opener 4


Figure 4.1 Overview of four basic tissue types: epithelial, connective, muscle, and nervous tissues.

• Brain• Spinal cord• Nerves

Nervous tissue: Internal communication

• Muscles attached to bones (skeletal)• Muscles of heart (cardiac)• Muscles of walls of hollow organs (smooth)

Muscle tissue: Contracts to cause movement

Epithelial tissue: Forms boundaries between different environments, protects, secretes, absorbs, filters• Lining of digestive tract organs and other hollow

organs• Skin surface (epidermis)

• Bones• Tendons• Fat and other soft padding tissue

Connective tissue: Supports, protects, binds other tissues together


Figure 4.2 Classification of epithelia.

Basal surface

Apical surfaceSimple

Apical surface

Basal surfaceStratified

Squamous

Cuboidal

ColumnarClassification based on cell shape.

Classification based on number of cell layers.


Figure 4.2a Classification of epithelia.

Basal surfaceStratified

Classification based on number of cell layers.

Basal surfaceSimple

Apical surface

Apical surface


Figure 4.2b Classification of epithelia.

Cuboidal

Squamous

ColumnarClassification based on cell shape.


Figure 4.3a Epithelial tissues.

Air sacs of lung tissue

Nuclei of squamous epithelial cells

Function: Allows materials to pass by diffusion and filtration in sites where protection is not important; secretes lubricating substances in serosae.

Location: Kidney glomeruli; air sacs of lungs; lining of heart, blood vessels, and lymphatic vessels; lining of ventral body cavity (serosae).

Description: Single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm; the simplest of the epithelia.

Photomicrograph: Simple squamous epithelium forming part of the alveolar (air sac) walls (140x).

Simple squamous epithelium


Figure 4.3b Epithelial tissues.

Nucleus

Function: Secretion and absorption.

Location: Kidney tubules; ducts and secretory portions of small glands; ovary surface.

Description: Single layer ofcubelike cells with large, spherical central nuclei.

Photomicrograph: Simple cuboidal epithelium in kidney tubules (430x).

Simple cuboidal epithelium

Basement membrane

Connective tissue

Simple cuboidal epithelial cells


Figure 4.3c Epithelial tissues.

Function: Absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliary action.Location: Nonciliated type lines most of the digestive tract (stomach to rectum), gallbladder, and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus.

Description: Single layer of tall cells with round to oval nuclei; some cells bear cilia; layer may contain mucus-secreting unicellular glands (goblet cells).

Simple columnar epithelium

Basement membrane

Photomicrograph: Simple columnarepithelium of the small intestine mucosa (660x).

Mucus of goblet cell

Simple columnar epithelial cell

Microvilli


Figure 4.3d Epithelial tissues.

Pseudostratified columnar epithelium

Function: Secrete substances, particularly mucus; propulsion of mucus by ciliary action.

Description: Single layer of cells of differing heights, some not reaching the free surface; nuclei seen at different levels; may contain mucus-secreting cells and bear cilia.

Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (800x).

Cilia

Basement membrane

Pseudo-stratified epithelial layer

Location: Nonciliated type in male’s sperm-carrying ducts and ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract.

Trachea


Figure 4.3e Epithelial tissues.

Stratified squamous epithelium

Function: Protects underlying tissues in areas subjected to abrasion.

Description: Thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers.

Basement membrane

Location: Nonkeratinized type forms the moist linings of the esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin, a dry membrane.

Nuclei

Connective tissue

Stratified squamous epithelium

Photomicrograph: Stratified squamous epithelium lining the esophagus (285x).


Figure 4.3f Epithelial tissues.

Transitional epithelium

Function: Stretches readily, permits stored urine to distend urinary organ.

Description: Resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamouslike, depending on degree of organ stretch.

Location: Lines the ureters, bladder, and part of the urethra.

Transitional epithelium

Photomicrograph: Transitional epithelium lining the bladder, relaxed state (360x); note the bulbous, or rounded, appearance of the cells at the surface; these cells flatten and elongate when the bladder fills with urine.

Basement membraneConnective tissue


Figure 4.4 Goblet cell (unicellular exocrine gland).

Microvilli

Golgi apparatus

Rough ER

Nucleus

Secretory vesicles containing mucin


Figure 4.4a Goblet cell (unicellular exocrine gland).

Microvilli

Golgiapparatus

Rough ER

Nucleus



Figure 4.4b Goblet cell (unicellular exocrine gland).

Microvilli

Golgi apparatus

Rough ER

Nucleus



Figure 4.5 Types of multicellular exocrine glands.

Simple duct structure(duct does not branch)

Compound duct structure(duct branches)

Tubular secretory structure

Alveolar secretory structure

Surface epithelium Duct Secretory epithelium

Simple tubular ExampleIntestinal glands

Simple branched tubular

ExampleStomach (gastric)glands

Compound tubularExampleDuodenal glands of small intestine

Simple

alveolarExampleNo important example in humans

Simple branched alveolar

ExampleSebaceous (oil) glands

Compound tubuloalveolar

ExampleSalivary glands

Compound alveolar

ExampleMammary glands


Figure 4.5 Types of multicellular exocrine glands. (1 of 2)

Simple duct structure(duct does not branch)




Simple tubular

ExampleIntestinal glands

Simple branched tubular

ExampleStomach (gastric)glands

Simple

alveolarExampleNo important example in humans

Simple branched alveolar

ExampleSebaceous (oil) glands


Figure 4.5 Types of multicellular exocrine glands. (2 of 2)

Compound duct structure(duct branches)




Compound tubuloalveolar

ExampleSalivary glands

Compound alveolar

ExampleMammary glands

Compound tubular

ExampleDuodenal glands of small intestine


Figure 4.6 Chief modes of secretion in human exocrine glands.

Merocrine glands secrete their products by exocytosis.

Secretory vesicles

Secretorycell fragments

In holocrine glands, the entire secretory cell ruptures, releasing secretions and dead cell fragments.


Figure 4.6a Chief modes of secretion in human exocrine glands.

Merocrine glands secrete their products by exocytosis.

Secretory vesicles


Figure 4.6b Chief modes of secretion in human exocrine glands.

In holocrine glands, the entire secretory cell ruptures, releasing secretions and dead cell fragments.

Secretorycell fragments


Figure 4.7 Areolar connective tissue: A prototype (model) connective tissue.

Extracellular matrixGround substanceFibers• Collagen fiber• Elastic fiber• Reticular fiber

Capillary

Neutrophil

Mast cell

Fat cell

Lymphocyte

Fibroblast

Macrophage

Cell types


Table 4.1 Comparison of Classes of Connective Tissues (1 of 2)


Table 4.1 Comparison of Classes of Connective Tissues (2 of 2)


Figure 4.8a Connective tissues.

Connective tissue proper: loose connective tissue, areolarDescription: Gel-like matrix

with all three fiber types; cells: fibroblasts, macrophages, mast cells, and some white blood cells.

Function: Wraps and cushions organs; its macrophages phagocytize bacteria; plays important role in inflammation; holds and conveys tissue fluid.

Location: Widely distributed under epithelia of body, e.g., forms lamina propria of mucous membranes; packages organs; surrounds capillaries.

Epithelium

Lamina propria

Photomicrograph: Areolar connectivetissue, a soft packaging tissue of the body (340x).

Elastic fibers

Ground substance

Fibroblast nuclei

Collagen fibers


Figure 4.8b Connective tissues.

Connective tissue proper: loose connective tissue, adipose

Description: Matrix as in areolar, but very sparse; closely packed adipocytes, or fat cells, have nucleus pushed to the side by large fat droplet.

Photomicrograph: Adipose tissue fromthe subcutaneous layer under the skin (350x).

Nucleus of adipose(fat) cell

Function: Provides reserve food fuel; insulates against heat loss; supports and protects organs.

Location: Under skin in subcutaneous tissue; around kidneys and eyeballs; within abdomen; in breasts. Fat droplet

Adipose tissue

Mammary glands


Figure 4.8c Connective tissues.

Connective tissue proper: loose connective tissue, reticularDescription: Network of

reticular fibers in a typical loose ground substance; reticular cells lie on the network.

Photomicrograph: Dark-staining network of reticular connective tissue fibers forming the internal skeleton of the spleen (350x).

White blood cell(lymphocyte)Location: Lymphoid organs

(lymph nodes, bone marrow, and spleen).

Spleen

Reticular fibers

Function: Fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and macrophages.


Figure 4.8d Connective tissues.

Connective tissue proper: dense connective tissue, dense regular

Description: Primarily parallelcollagen fibers; a few elastic fibers;major cell type is the fibroblast.

Function: Attaches muscles tobones or to muscles; attachesbones to bones; withstands greattensile stress when pulling force isapplied in one direction.

Location: Tendons, mostligaments, aponeuroses.

Shoulderjoint

Ligament

Tendon

Collagenfibers

Nuclei offibroblasts

Photomicrograph: Dense regular connectivetissue from a tendon (430x).


Figure 4.8e Connective tissues.

Connective tissue proper: dense connective tissue, dense irregular

Description: Primarily irregularlyarranged collagen fibers; someelastic fibers; fibroblast is themajor cell type.

Function: Withstands tensionexerted in many directions;provides structural strength.

Location: Fibrous capsules oforgans and of joints; dermis of theskin; submucosa of digestive tract.

Shoulderjoint

Fibrousjointcapsule

Photomicrograph: Dense irregular connectivetissue from the fibrous capsule of a joint (430x).

Collagenfibers

Nuclei offibroblasts


Figure 4.8f Connective tissues.

Connective tissue proper: dense connective tissue, elastic

Description: Dense regularconnective tissue containing ahigh proportion of elastic fibers.

Function: Allows tissue to recoilafter stretching; maintains pulsatileflow of blood through arteries; aidspassive recoil of lungs followinginspiration.

Location: Walls of large arteries;within certain ligaments associatedwith the vertebral column; withinthe walls of the bronchial tubes.

Photomicrograph: Elastic connective tissuein the wall of the aorta (250x).

Aorta

Heart

Elasticfibers


Figure 4.8g Connective tissues.

Cartilage: hyaline

Description: Amorphous but firmmatrix; collagen fibers form animperceptible network;chondroblasts produce the matrixand when mature (chondrocytes)lie in lacunae.

Function: Supports and reinforces;serves as resilient cushion; resistscompressive stress.

Location: Forms most of theembryonic skeleton; covers theends of long bones in joint cavities;forms costal cartilages of the ribs;cartilages of the nose, trachea, andlarynx.

Costalcartilages Photomicrograph: Hyaline cartilage from

a costal cartilage of a rib (470x).

Matrix

Chondrocytein lacuna


Figure 4.8h Connective tissues.

Cartilage: elastic

Description: Similar to hyalinecartilage, but more elastic fibersin matrix.

Function: Maintains the shape ofa structure while allowing greatflexibility.

Location: Supports the externalear (pinna); epiglottis.

Photomicrograph: Elastic cartilage fromthe human ear pinna; forms the flexibleskeleton of the ear (800x).

Chondrocytein lacuna

Matrix


Figure 4.8i Connective tissues.

Cartilage: fibrocartilage

Description: Matrix similar to butless firm than that in hyalinecartilage; thick collagen fiberspredominate.

Function: Tensile strength allowsit to absorb compressive shock.

Location: Intervertebral discs;pubic symphysis; discs of kneejoint.

Photomicrograph: Fibrocartilage of anintervertebral disc (125x). Special stainingproduced the blue color seen.

Collagenfiber

Chondrocytesin lacunae

Intervertebraldiscs


Figure 4.8j Connective tissues.

Others: bone (osseous tissue)

Description: Hard, calcifiedmatrix containing many collagenfibers; osteocytes lie in lacunae.Very well vascularized.

Function: Supports and protects(by enclosing); provides levers forthe muscles to act on; storescalcium and other minerals andfat; marrow inside bones is thesite for blood cell formation(hematopoiesis).

Location: Bones

Photomicrograph: Cross-sectional viewof bone (125x).

Lamella

Centralcanal

Lacunae


Figure 4.8k Connective tissues.

Connective tissue: blood

Description: Red and white bloodcells in a fluid matrix (plasma).

Function: Transport respiratorygases, nutrients, wastes, and othersubstances.

Location: Contained within bloodvessels.

Photomicrograph: Smear of human blood(1670x); shows two white blood cellssurrounded by red blood cells.

Plasma

White bloodcells:• Lymphocyte• Neutrophil

Red bloodcells(erythrocytes)


Figure 4.9a Muscle tissues.

Skeletal muscle

Description: Long, cylindrical,multinucleate cells; obviousstriations.

Function: Voluntary movement;locomotion; manipulation of theenvironment; facial expression;voluntary control.

Location: In skeletal musclesattached to bones or occasionallyto skin.

Photomicrograph: Skeletal muscle(approx. 440x). Notice the obvious bandingpattern and the fact that these large cells aremultinucleate.

Striations

Nuclei

Part of musclefiber (cell)


Figure 4.9b Muscle tissues.

Cardiac muscle

Description: Branching, striated,generally uninucleate cells thatinterdigitate at specializedjunctions (intercalated discs).

Function: As it contracts, itpropels blood into the circulation;involuntary control.

Location: The walls of the heart.

Photomicrograph: Cardiac muscle (900x);notice the striations, branching of cells, andthe intercalated discs.

Striations

Nucleus

Intercalateddiscs


Figure 4.9c Muscle tissues.

Smooth muscle

Description: Spindle-shapedcells with central nuclei; nostriations; cells arranged closelyto form sheets.

Function: Propels substances orobjects (foodstuffs, urine, a baby)along internal passageways;involuntary control.

Location: Mostly in the walls ofhollow organs.

Photomicrograph: Sheet of smoothmuscle (720x).

Smoothmusclecell

Nuclei


Figure 4.10 Nervous tissue.

Nervous tissue

Description: Neurons arebranching cells; cell processesthat may be quite long extend fromthe nucleus-containing cell body;also contributing to nervous tissueare nonexcitable supporting cells.

Function: Neurons transmitelectrical signals from sensoryreceptors and to effectors (musclesand glands) which control theiractivity; supporting cells supportand protect neurons.

Location: Brain, spinalcord, and nerves.

Photomicrograph: Neurons (350x).

Neuronprocesses

Nuclei ofsupportingcells

Cell bodyof a neuron

Neuron processes Cell body

Axon Dendrites


Figure 4.11 Classes of membranes.

Cutaneous membraneThe cutaneous membrane(the skin) covers the body surface.

Cutaneousmembrane (skin)

Mucous membranes

Mucous membranes line bodycavities that are open to theexterior.

Mucosa ofnasal cavity

Mucosa ofmouthEsophagusliningMucosa oflung bronchi

Visceralperitoneum

Parietalperitoneum

Parietalpericardium

Visceralpericardium

Visceralpleura

Parietalpleura

Serous membranes line bodycavities that are closed to theexterior.

Serous membranes


Figure 4.11a Classes of membranes.

Cutaneous membraneThe cutaneous membrane(the skin) covers the body surface.

Cutaneousmembrane (skin)


Figure 4.11b Classes of membranes.

Mucous membranes

Mucous membranes line bodycavities that are open to theexterior.

Mucosa ofnasal cavity

Mucosa ofmouthEsophagusliningMucosa oflung bronchi


Figure 4.11c Classes of membranes.

Visceralperitoneum

Parietalperitoneum

Parietalpericardium

Visceralpericardium

Visceralpleura

Parietalpleura

Serous membranes line body cavities that are closed to the exterior.

Serous membranes


Figure 4.12 Tissue repair of a nonextensive skin wound: regeneration and fibrosis.

ScabBlood clot in incised wound

Epidermis

Vein

Regenerating epithelium

Inflammatorychemicals

Migratingwhiteblood cell

Artery

Fibroblast

Macro-phage

Budding capillary

Regenerated epithelium

Fibrosed area

Regeneration and fibrosis effect permanent repair:• The fibrosed area matures and contracts; the epithelium thickens.• A fully regenerated epithelium with an underlying area of scar tissue results.

Organization restores the blood supply:• The clot is replaced by granulation tissue, which restores the vascular supply.• Fibroblasts produce collagen fibers that bridge the gap.• Macrophages phagocytize dead and dying cells and other debris.• Surface epithelial cells multiply and migrate over the granulation tissue.

2Inflammation sets the stage:• Severed blood vessels bleed. • Inflammatory chemicals are released.• Local blood vessels become more permeable, allowing white blood cells, fluid, clotting proteins, and other plasma proteins to seep into the injured area.• Clotting occurs; surface dries and forms a scab.

31

Area of granulation tissue in growth


Figure 4.12 Tissue repair of a nonextensive skin wound: regeneration and fibrosis. (1 of 3)

Scab

Blood clot inincised wound

Epidermis

Vein

Inflammatorychemicals

Migrating whiteblood cell

ArteryInflammation sets the stage:• Severed blood vessels bleed. • Inflammatory chemicals are released.• Local blood vessels become more permeable, allowing white blood cells, fluid, clotting proteins, and other plasma proteins to seep into the injured area.• Clotting occurs; surface dries and forms a scab.

1



Regenerating epithelium

Area of granulationtissue ingrowth

Macrophage

Budding capillary

Fibroblast

Organization restores the blood supply:• The clot is replaced by granulation tissue, which restores the vascular supply.• Fibroblasts produce collagen fibers that bridge the gap.• Macrophages phagocytize dead and dying cells and other debris.• Surface epithelial cells multiply and migrate over the granulation tissue.

2



Regeneratedepithelium

Fibrosed area

Regeneration and fibrosis effect permanent repair:• The fibrosed area matures and contracts; the epithelium thickens.• A fully regenerated epithelium with an underlying area of scar tissue results.

3


Figure 4.13 Embryonic germ layers and the primary tissue types they produce.

16-day-old embryo(dorsal surface view)

Epithelium(from all threegerm layers)Ectoderm

MesodermEndoderm

Inner lining ofdigestive system(from endoderm)

Nervous tissue(from ectoderm)

Muscle and connec-tive tissue (mostlyfrom mesoderm)


Closer Look 4.1

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© 2013 Pearson Education, Inc. Chapter Opener 4. © 2013 Pearson Education, Inc. Figure 4.1 Overview of four basic tissue types: epithelial, connective,