BIO 201 Chapter 4, Part 2 Lecture

8/14/2019 BIO 201 Chapter 4, Part 2 Lecture

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Chapter 4, Part 2The Tissue Level of


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Connective Tissue

Most abundant and widely distributedtissues in the body

Numerous functions Binds tissues together

Supports and strengthen tissue

Protects and insulates internal organs

Compartmentalize and transport

Energy reserves and immune responses


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Extracellular matrix ofConnective Tissue

Extracellular matrix is the materiallocated between the cells

Consist of protein fibers and groundsubstanceConnective tissue is highly vascularSupplied with nerves Exception is cartilage and tendon. Both

have little or no blood supply and nonerves


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Cells and Fibers inConnective Tissue


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Connective Tissue Cells

Fibroblasts

Secrete fibers and components of groundsubstance

Adipocytes (fat cells)

Store triglycerides (fat) Mast cells

Produce histamine White blood cells

Immune response Neutrophil and Eosinophils

Macrophages

Engulf bacteria and cellular debris byphagocytosis

Plasma cells


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Connective TissueExtracellular Matrix

Ground substance Between cells and fibers

Fluid, semifluid, gelatinous, or calcified

Functions to support and bind cells, store water, andallow exchange between blood and cells

Complex combination of proteins andpolysaccharides

Fibers Collagen fibers

Elastic fibers

Reticular fibers


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Classification ofConnective Tissues

Embryonic connective tissue Mesenchyme and mucous connective tissue

Mature connective tissue

Loose connective tissueAreolar, adipose, and reticular

Dense connective tissueDense regular, dense irregular, and elastic

Cartilage

Hyaline, fibrocartilage, and elastic cartilage Bone tissue

Liquid connective tissueBlood and lymph


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Embryonic Connective Tissue

Mesenchyme

Gives rise to all other connective tissues

Mucous (Whartons Jelly)

Found in umbilical cord of the fetus


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Loose Connective Tissue:Areolar Connective Tissue

Most widely distributed in the body

Contains several types of cells and all three fibers


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Loose Connective Tissue:Adipose Tissue

Contains adipocytes

Good for insulation and energy reserves

White (common) and brown adipose tissue


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Loose Connective Tissue:Reticular Connective Tissue

Fine interlacing reticular fibers and cells

Forms the stroma of liver, spleen, and lymph nodes


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Dense Connective Tissue

Dense connective tissue

Contains numerous, thicker, and denser fibers

Packed closely with fewer cells than loose connectivetissue

Dense regular connective tissue Bundles of collagen fibers are regularly arranged in

parallel patterns for strength


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Types of Mature ConnectiveTissue: Dense Irregular

Collagen fibers are usually irregularly arranged

Found where pulling forces are exerted in manydirections

Dermis of skin and heart


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Dense Connective Tissue:Elastic Connective Tissue

Contain branching elastic fibers

Strong and can recoil to original shape afterstretching

Lung tissue and arteries


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Types of Mature ConnectiveTissue: Cartilage

Cartilage is a dense network ofcollagen fibers and elastic fibersfirmly embedded in chondroitin

sulfate Chrondrocytes

Cartilage cells found in the spaces calledlucunae

PericondriumCovering of dense irregular connective tissuethat surrounds the cartilage

Two layers: outer fibrous layer and innercellular layer


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Hyaline cartilage

Most abundant cartilage in the body

Surrounding by perichondrium (some exceptions likearticular cartilage)

Provide flexibility and support. Reduces friction


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Fibrocartilage

Chondrocytes are scattered among bundles ofcollagen fibers within the extracellular matrix

Lack a perichondrium

Strongest type of cartilage

Found in intervertebral disc (between vertebrae)


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Elastic Cartilage

Chondrocytes are located within a threadlikenetwork of elastic fibers

Perichondrium is present

Provides strength and elasticity


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Repair and Growth ofCartila e

Cartilage grows slowlyWhen injured or inflamed, repairs is

slow due to its avascular nature.Two patterns of cartilage growth: Interstitial growth

Growth from within the tissue

Appositional growthGrowth at the outer surface of the tissue


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Bone tissue

Bones are organs composed of severaldifferent connective tissues: bone (osseous)tissue, periosteum, and endosteum.

Compact or spongy

Osteon or haversian system Spongy bone lacks osteons. They have columns

called trabeculae


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Liquid Connective Tissue

Blood tissue

Connective tissue with liquid extracellular matrix calledblood plasma

Lymph


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Membranes


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Epithelial Membranes

Mucous membranes Lines a body cavity that opens directly to

the exterior

Epithelial layer is important for thebodys defense against pathogens

Connective tissue layer is areolar

connective tissue and is called laminapropria


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Epithelial Membranes

Serous membranes or serosa Lines a body cavity that does not open

directly to the exterior. Also covers the

organs that lie within the cavity Consist of areolar connective tissue

covered by mesothelium (simplesquamous epithelium) that secrete a

serous fluid for lubrication


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Synovial Membranes

Synovial membranes Lines joints and contains connective

tissue but not epithelium


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Muscular Tissue

Consists of elongated cells calledmuscle fibers or myocytes

Cells use ATP to generate force Several functions of muscle tissue

Classified into 3 types: skeletal,cardiac, and smooth muscular tissue


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Skeletal Muscle Tissue

Attached to bones of the skeleton

Have striations

Voluntary movement or contractions by consciouscontrol

Vary in length (up to 40 cm) and are roughlyc lindrical in sha e


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Muscular Tissue

Cardiac muscle tissue Have striations

Involuntary movement or contraction is notconsciously controlled

Intercalated disc unique to cardiac muscle tissue


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Smooth Muscle Tissue

Walls of hollow internal structures

Blood vessels, airways of lungs, stomach, andintestines

Nonstriated

Usually involuntary control


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Nervous Tissue

Consists of two principle types of cells Neurons or nerve cells

Neuroglia


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Excitable Cells

Neurons and muscle fibersExhibit electrical excitability

The ability to respond to certain stimuliby producing electrical signals such asaction potentials

Actions potentials propagate along a

nerve or muscle plasma membrane tocause a response

Release of neurotransmitters

Muscle contraction

Ti R i R t i


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Tissue Repair: RestoringHomeostasis

When tissue damage is extensiveboth stroma and parenchymal cells

are active in repair Fibroblast divide rapidly New collagen fibers are manufactured

New blood capillaries supply materials

for healingAll of these process create an

actively growing connective tissue


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Aging and Tissues

Tissue heal faster in young adultsSurgery of a fetus normally leaves no

scarsYoung tissues have a better

nutritional state, blood supply, andhigher metabolic rate

Extracellular components alsochanges with ageChanges in the bodys use of glucose,

collagen, and elastic fibers contribute


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End of Chapter 4, Part 2

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BIO 201 Chapter 4, Part 2 Lecture