Chapter 6 Tissues. Principal Types of Tissue Four types of tissues: I. Epithelial tissue II....

Chapter 6Chapter 6TissuesTissues

Principal Types of Tissue Principal Types of Tissue

Four types of tissues:Four types of tissues:

I. Epithelial tissueI. Epithelial tissue

II. Connective tissueII. Connective tissue

III. Muscle tissueIII. Muscle tissue

IV. Nervous tissueIV. Nervous tissue

Extracellular Matrix (ECM)Extracellular Matrix (ECM)

FunctionsFunctions Helps bind tissues together structurallyHelps bind tissues together structurally Allows local communication among ECM Allows local communication among ECM

and various cellsand various cells——through connection through connection via integrins in plasma membranesvia integrins in plasma membranes

Extracellular Matrix (ECM)Extracellular Matrix (ECM) Components Components

WaterWater ProteinsProteins

Structural proteinsStructural proteins CollagenCollagen——strong, flexible protein fiberstrong, flexible protein fiber ElastinElastin——elastic fiberselastic fibers

Includes glycoproteinsIncludes glycoproteins——proteins with a proteins with a few carbohydrate attachmentsfew carbohydrate attachments

Glycoprotein attachments also allow local Glycoprotein attachments also allow local communication within a tissuecommunication within a tissue

I. Epithelial TissueI. Epithelial Tissue

FunctionsFunctions ProtectionProtection Sensory functionsSensory functions SecretionSecretion AbsorptionAbsorption ExcretionExcretion

I. Epithelial TissueI. Epithelial Tissue

Types and locationsTypes and locations Epithelium is divided into two types:Epithelium is divided into two types:

Membranous epitheliumMembranous epithelium——covers the body covers the body and some of its parts; lines the serous and some of its parts; lines the serous cavities, blood and lymphatic vessels, and cavities, blood and lymphatic vessels, and respiratory, digestive, and genitourinary respiratory, digestive, and genitourinary tractstracts

Glandular epitheliumGlandular epithelium——secretory units of secretory units of endocrine and exocrine glandsendocrine and exocrine glands

I. Epithelial TissueI. Epithelial Tissue

ClassificationClassification of epithelial tissue of epithelial tissue Classification based on cell shape Classification based on cell shape

SquamousSquamous CuboidalCuboidal ColumnarColumnar Pseudostratified columnarPseudostratified columnar

I. Simple epitheliumI. Simple epithelium

1.1. Simple squamous epithelium Simple squamous epithelium One-cell layer of flat cellsOne-cell layer of flat cellsPermeable to many substancesPermeable to many substancesExamples: endotheliumExamples: endothelium——lines blood vessels; lines blood vessels; mesotheliummesothelium——pleurapleura

I. Simple epitheliumI. Simple epithelium

2. 2. Simple cuboidal epitheliumSimple cuboidal epithelium One-cell layer of cuboidal cellsOne-cell layer of cuboidal cellsFound in many glands and ductsFound in many glands and ducts

I. Simple epitheliumI. Simple epithelium

3. 3. Simple columnar epithelium Simple columnar epithelium Single layer of tall, column-shaped cellsSingle layer of tall, column-shaped cellsCells often modified for specialized functionsCells often modified for specialized functions——e.g., e.g., goblet cells (secretion), cilia (movement), microvilli goblet cells (secretion), cilia (movement), microvilli (absorption)(absorption)Often lines hollow visceral structuresOften lines hollow visceral structures

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I. Simple epitheliumI. Simple epithelium

4. 4. Pseudostratified columnar epithelium Pseudostratified columnar epithelium Columnar cells of differing heightsColumnar cells of differing heightsAll cells rest on basement membrane but may not All cells rest on basement membrane but may not reach the free surface abovereach the free surface aboveCell nuclei at odd and irregular levelsCell nuclei at odd and irregular levelsFound lining air passages and segments of male Found lining air passages and segments of male reproductive systemreproductive systemMotile cilia and mucus are important modificationsMotile cilia and mucus are important modifications

I. Stratified epitheliumI. Stratified epithelium

5. 5.

A. A. Stratified squamous (keratinized) Stratified squamous (keratinized) epitheliumepitheliumMultiple layers of flat, squamous cells Multiple layers of flat, squamous cells Cells filled with keratinCells filled with keratinCovers outer skin on body surfaceCovers outer skin on body surface

I. Stratified epitheliumI. Stratified epithelium

5. 5.

B. B. Stratified squamous (nonkeratinized) Stratified squamous (nonkeratinized) epithelium epithelium Lines vagina, mouth, and esophagusLines vagina, mouth, and esophagusFree surface is moistFree surface is moistPrimary function is protectionPrimary function is protection

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I. Stratified epitheliumI. Stratified epithelium

6. 6. Stratified cuboidal epitheliumStratified cuboidal epitheliumTwo or more rows of cells are typicalTwo or more rows of cells are typicalBasement membrane is indistinctBasement membrane is indistinctLocated in sweat gland ducts and pharynxLocated in sweat gland ducts and pharynx

I. Stratified epitheliumI. Stratified epithelium

7. 7. Stratified columnar epitheliumStratified columnar epitheliumMultiple layers of columnar cellsMultiple layers of columnar cellsOnly most superficial cells are typical in shapeOnly most superficial cells are typical in shapeRareRareLocated in segments of male urethra and near Located in segments of male urethra and near anusanus

I. Stratified epitheliumI. Stratified epithelium

8. 8. Stratified transitional epitheliumStratified transitional epithelium Located in lining of hollow viscera subjected to Located in lining of hollow viscera subjected to stress stress (e.g., urinary bladder)(e.g., urinary bladder)Often 10 or more layers thickOften 10 or more layers thickProtects organ walls from tearingProtects organ walls from tearing

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Can you identify these?Can you identify these?

A B

C DE

F G

II. Connective TissueII. Connective Tissue

Functions, characteristics, and typesFunctions, characteristics, and types General functionGeneral function——connects, supports, connects, supports,

transports, and protectstransports, and protects General characteristicsGeneral characteristics——extracellular matrix (ECM) extracellular matrix (ECM)

predominates in most connective tissues and predominates in most connective tissues and determines its physical characteristics; consists of determines its physical characteristics; consists of fluid, gel, or solid matrix, with or without fluid, gel, or solid matrix, with or without extracellular fibers (collagenous, reticular, and extracellular fibers (collagenous, reticular, and elastic) and proteoglycans or other compounds that elastic) and proteoglycans or other compounds that thicken and hold together the tissue thicken and hold together the tissue

II. Connective TissueII. Connective Tissue Four main types:Four main types:

1.Fibrous1.FibrousA. Loose, ordinary A. Loose, ordinary (areolar)(areolar)

B. AdiposeB. Adipose

C. ReticularC. Reticular

D. DenseD. Dense IrregularIrregular Regular Regular

(collagenous and elastic)(collagenous and elastic)

2. Bone2. BoneA. Compact boneA. Compact boneB. Cancellous B. Cancellous bonebone

3. Cartilage3. CartilageA. HyalineA. HyalineB. FibrocartilageB. FibrocartilageC. ElasticC. Elastic

4. Blood4. Blood

1. Fibrous connective tissue1. Fibrous connective tissueA. A. Loose, ordinary (areolar) connective Loose, ordinary (areolar) connective tissue tissue

One of the most widely distributed of all One of the most widely distributed of all tissuestissues

Intercellular substance is prominent and Intercellular substance is prominent and consists of collagenous and elastic fibers consists of collagenous and elastic fibers loosely interwoven and embedded in soft, loosely interwoven and embedded in soft, viscous ground substanceviscous ground substance

FunctionFunction——stretchy, flexible connectionstretchy, flexible connection

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1. Fibrous connective tissue1. Fibrous connective tissue

B. B. Adipose tissueAdipose tissue Similar to loose connective tissue but Similar to loose connective tissue but

contains mainly fat cellscontains mainly fat cells FunctionsFunctions——protection, insulation, protection, insulation,

support, and food reservesupport, and food reserve

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1. Fibrous connective tissue1. Fibrous connective tissue

C. C. Reticular tissue Reticular tissue Forms framework of spleen, lymph nodes, and Forms framework of spleen, lymph nodes, and

bone marrowbone marrow Consists of network of branching reticular Consists of network of branching reticular

fibers with reticular fibers with reticular cells overlying themcells overlying them

FunctionsFunctions——defense against microorganisms defense against microorganisms and other injurious substances; reticular and other injurious substances; reticular meshwork filters out injurious particles, and meshwork filters out injurious particles, and reticular cells phagocytose themreticular cells phagocytose them

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1. Fibrous connective tissue1. Fibrous connective tissue D. D. Dense fibrous tissueDense fibrous tissue

Matrix consists mainly of fibers packed Matrix consists mainly of fibers packed densely and relatively few fibroblast cellsdensely and relatively few fibroblast cells

IrregularIrregular——fibers intertwine irregularly to form a thick mat (Figure 5-20)fibers intertwine irregularly to form a thick mat (Figure 5-20) RegularRegular——bundles of fibers are arranged in regular, parallel rowsbundles of fibers are arranged in regular, parallel rows

CollagenousCollagenous——mostly collagenous fibers in ECM (Figure 5-21 and 5-mostly collagenous fibers in ECM (Figure 5-21 and 5-22)22)

ElasticElastic——mostly elastic fibers in ECM (Figure 5-23)mostly elastic fibers in ECM (Figure 5-23)

LocationsLocations——composes structures that need composes structures that need great tensile strength, such as tendons and great tensile strength, such as tendons and ligaments; also dermis and outer capsule of ligaments; also dermis and outer capsule of kidney and spleenkidney and spleen

FunctionFunction——furnishes flexible connections that furnishes flexible connections that are strong or stretchyare strong or stretchy

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2. 2. Bone tissueBone tissue

Highly specialized connective tissue type Highly specialized connective tissue type CellsCells——osteocytesosteocytes——embedded in a calcified matrixembedded in a calcified matrix Inorganic component of matrix accounts for 65% Inorganic component of matrix accounts for 65%

of total bone tissueof total bone tissue

Functions:Functions: SupportSupport ProtectionProtection Point of attachment for musclesPoint of attachment for muscles Reservoir for mineralsReservoir for minerals Supports blood-forming tissueSupports blood-forming tissue

A. A. Compact boneCompact bone Osteon (Haversian system)Osteon (Haversian system)

Structural unity of boneStructural unity of bone Spaces for osteocytes called lacunaeSpaces for osteocytes called lacunae Matrix present in concentric rings called lamellaeMatrix present in concentric rings called lamellae Canaliculi are canals that join lacunae with the central Haversian Canaliculi are canals that join lacunae with the central Haversian

canalcanal Cell typesCell types::

OsteocyteOsteocyte——mature, inactive bone cellmature, inactive bone cell OsteoblastOsteoblast——active, bone-forming cellactive, bone-forming cell OsteoclastOsteoclast——bone-destroying cellbone-destroying cell

Formation (ossification) Formation (ossification) In membranesIn membranes——e.g., flat bones of skulle.g., flat bones of skull From cartilage (endochondral)From cartilage (endochondral)——e.g., long bones, such as the e.g., long bones, such as the

humerushumerus

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B. B. Cancellous boneCancellous bone

TrabeculaeTrabeculae——thin beams of bonethin beams of bone Supports red bone marrow Supports red bone marrow

Myeloid tissueMyeloid tissue——a type of reticular tissuea type of reticular tissue Produces blood cellsProduces blood cells

Called spongy bone because of its Called spongy bone because of its spongelike appearancespongelike appearance

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3. 3. CartilageCartilage

Chondrocyte is only cell type presentChondrocyte is only cell type present Lacunae house cells, as in boneLacunae house cells, as in bone AvascularAvascular——therefore, nutrition of cells therefore, nutrition of cells

depends on diffusion of nutrients depends on diffusion of nutrients through matrixthrough matrix

Heals slowly after injury because of slow Heals slowly after injury because of slow nutrient transfer to the cellsnutrient transfer to the cells

Perichondrium is membrane that Perichondrium is membrane that surrounds cartilagesurrounds cartilage

3. Types of Cartilage3. Types of Cartilage

A. Hyaline A. Hyaline Appearance is shiny and translucentAppearance is shiny and translucent Most prevalent type of cartilageMost prevalent type of cartilage Located on the ends of articulating bonesLocated on the ends of articulating bones

B. Fibrocartilage B. Fibrocartilage Strongest and most durable type of cartilageStrongest and most durable type of cartilage Matrix is semirigid and filled with strong, white fibersMatrix is semirigid and filled with strong, white fibers Found in intervertebral disks and pubic symphysisFound in intervertebral disks and pubic symphysis Serves as shock-absorbing material between bones at the knee Serves as shock-absorbing material between bones at the knee

(menisci)(menisci)

C. ElasticC. Elastic Contains many fine, elastic fibersContains many fine, elastic fibers Provides strength and flexibilityProvides strength and flexibility Located in external ear and larynxLocated in external ear and larynx

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4. Blood4. Blood

A liquid tissue A liquid tissue Contains neither ground substance nor fibersContains neither ground substance nor fibers Composition of whole bloodComposition of whole blood

Liquid fraction (plasma) is the matrixLiquid fraction (plasma) is the matrix——55% of total 55% of total blood volumeblood volume

Formed elements contribute 45% of total blood Formed elements contribute 45% of total blood volumevolume

Red blood cells, erythrocytesRed blood cells, erythrocytes White blood cells, leukocytesWhite blood cells, leukocytes Platelets, thrombocytesPlatelets, thrombocytes

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4. Blood (cont.)4. Blood (cont.)

FunctionsFunctions TransportationTransportation Regulation of body temperatureRegulation of body temperature Regulation of body pHRegulation of body pH White blood cells destroy bacteriaWhite blood cells destroy bacteria

Circulating blood tissue is formed in the red Circulating blood tissue is formed in the red bone marrow by a process called bone marrow by a process called hematopoiesis; the blood-forming tissue is hematopoiesis; the blood-forming tissue is sometimes called hematopoietic tissuesometimes called hematopoietic tissue

III. Muscle TissueIII. Muscle Tissue Types (Table 5-7)Types (Table 5-7)

1. 1. SkeletalSkeletal, or striated voluntary (Figure 5-, or striated voluntary (Figure 5-32)32)

2. 2. SmoothSmooth, or nonstriated involuntary, or , or nonstriated involuntary, or visceral visceral (Figures 5-33 and 5-34)(Figures 5-33 and 5-34)

3.3.CardiacCardiac, or striated involuntary (Figure 5-, or striated involuntary (Figure 5-35)35)

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III. Muscle TissueIII. Muscle Tissue

Microscopic characteristicsMicroscopic characteristics

1. 1. Skeletal muscleSkeletal muscle——threadlike cells with threadlike cells with many cross striations and many nuclei per cellmany cross striations and many nuclei per cell

2. 2. Smooth muscleSmooth muscle——elongated, narrow cells, elongated, narrow cells, no cross striations, one nucleus per cellno cross striations, one nucleus per cell

3. 3. Cardiac muscleCardiac muscle——branching cells with branching cells with intercalated disks (formed by abutment of intercalated disks (formed by abutment of plasma membranes plasma membranes of two cells)of two cells)

IV. Nervous TissueIV. Nervous Tissue FunctionsFunctions——rapid regulation and integration rapid regulation and integration

of body activitiesof body activities Specialized characteristicsSpecialized characteristics

ExcitabilityExcitability ConductivityConductivity

OrgansOrgans BrainBrain Spinal cordSpinal cord NervesNerves

IV. Nervous TissueIV. Nervous Tissue Cell typesCell types

NeuronNeuron——conducting unit of system conducting unit of system Cell body, or Cell body, or somasoma ProcessesProcesses

AxonAxon (single process) (single process)——transmits nerve impulse transmits nerve impulse away from the cell bodyaway from the cell body

DendritesDendrites (one or more) (one or more)——transmit nerve impulse transmit nerve impulse toward the cell body and axontoward the cell body and axon

NeurogliaNeuroglia——special connecting, special connecting, supporting, coordinating cells that supporting, coordinating cells that surround the neuronssurround the neurons

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IV. Tissue RepairIV. Tissue Repair Tissues have a varying capacity to repair Tissues have a varying capacity to repair

themselves; damaged tissue regenerates themselves; damaged tissue regenerates

or is replaced by scar tissueor is replaced by scar tissue RegenerationRegeneration——growth of new tissue growth of new tissue ScarScar——dense fibrous mass; unusually dense fibrous mass; unusually

thick scar is a keloid thick scar is a keloid Epithelial and connective tissues have Epithelial and connective tissues have

the greatest ability to regeneratethe greatest ability to regenerate Muscle and nervous tissues have a Muscle and nervous tissues have a

limited capacity to regeneratelimited capacity to regenerate

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Body MembranesBody Membranes Thin tissue layers that cover Thin tissue layers that cover

surfaces, line cavities, and divide surfaces, line cavities, and divide spaces or organs (Figure 6-39, Table spaces or organs (Figure 6-39, Table 6-8)6-8)

Epithelial membranes are most Epithelial membranes are most common type (Figure 6-40)common type (Figure 6-40)

Cutaneous membrane (skin)Cutaneous membrane (skin) Primary organ of integumentary Primary organ of integumentary

systemsystem One of the most important organsOne of the most important organs Composes approximately 16% of body Composes approximately 16% of body

weightweight64

Body MembranesBody Membranes Epithelial membranes (cont)Epithelial membranes (cont)

Serous membrane (serosa)Serous membrane (serosa) Parietal membranes—line closed Parietal membranes—line closed

body cavitiesbody cavities Visceral membranes—cover visceral Visceral membranes—cover visceral

organsorgans Pleura—surrounds a lung and lines Pleura—surrounds a lung and lines

the thoracic cavitythe thoracic cavity Peritoneum—covers the abdominal Peritoneum—covers the abdominal

viscera and lines the abdominal viscera and lines the abdominal cavitycavity

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Body MembranesBody Membranes Epithelial membranes (cont)Epithelial membranes (cont)

Mucous membrane (mucosa)Mucous membrane (mucosa) Lines and protects organs that open to Lines and protects organs that open to

the exterior of the bodythe exterior of the body Found lining ducts and passageways of Found lining ducts and passageways of

the respiratory, digestive, and other the respiratory, digestive, and other tractstracts

Lamina propria—fibrous connective Lamina propria—fibrous connective tissue underlying mucous epitheliumtissue underlying mucous epithelium

Mucus is made up mostly of water and Mucus is made up mostly of water and mucins—proteoglycans that form a mucins—proteoglycans that form a double-layer of protection against double-layer of protection against environmental microbes (Figure 6-41)environmental microbes (Figure 6-41)

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The Big Picture: Tissues, The Big Picture: Tissues, Membranes, and the Whole Membranes, and the Whole

BodyBody Tissues and membranes maintain Tissues and membranes maintain

homeostasishomeostasis Epithelial tissuesEpithelial tissues

Form membranes that contain and protect Form membranes that contain and protect the internal fluid environmentthe internal fluid environment

Absorb nutrientsAbsorb nutrients Secrete products that regulate functions Secrete products that regulate functions

involved in homeostasisinvolved in homeostasis Connective tissuesConnective tissues

• Hold organs and systems togetherHold organs and systems together• Form structures that support the body and Form structures that support the body and

permit movementpermit movement68

The Big Picture: Tissues, The Big Picture: Tissues, Membranes, and the Whole Membranes, and the Whole

BodyBody Tissues and membranes maintain Tissues and membranes maintain

homeostasishomeostasis Epithelial tissuesEpithelial tissues

Form membranes that contain and protect Form membranes that contain and protect the internal fluid environmentthe internal fluid environment

Absorb nutrientsAbsorb nutrients Secrete products that regulate functions Secrete products that regulate functions

involved in homeostasisinvolved in homeostasis Connective tissuesConnective tissues

• Hold organs and systems togetherHold organs and systems together• Form structures that support the body and Form structures that support the body and

permit movementpermit movement69

The Big Picture: Tissues, The Big Picture: Tissues, Membranes, and the Whole Membranes, and the Whole

BodyBody Tissues and membranes maintain Tissues and membranes maintain

homeostasis (cont)homeostasis (cont) Muscle tissuesMuscle tissues

Work with connective tissues to Work with connective tissues to permit movementpermit movement

Nervous tissuesNervous tissues• Work with glandular epithelial tissues Work with glandular epithelial tissues

to regulate body functionto regulate body function

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