Chapter 3

Connective Tissue

Muscle Tissue

Nervous Tissue

Connective TissueConnective Tissue

Found everywhere in the body

Includes the most abundant and widely distributed tissues

Functions

Binds body tissues together

Supports the body

Provides protection

Transportation

Connective Tissue CharacteristicsConnective Tissue Characteristics

Vascularized (except tendons, ligaments and cartilage)

Extracellular matrix

Non-living material that surrounds different types of living cells

Extracellular MatrixExtracellular Matrix Ground substance

Mostly water – absorbs water Adhesion proteins – serves as glue Polysaccharide molecules – as number of molecules

goes up, tissue goes from fluid to rock hard Fibers

Three types Collagen fibers (white) Elastic fibers (yellow) Reticular fibers (fine collagen)

Collagen FibersCollagen Fibers

Collagen Fibers as seen with a scanning electron microscope

Composed of:

Interwoven strands of the protein collagen.

Thick fibers with great tensile strength – i.e., it’s tough to pull them apart.

Tendons, ligaments and the deep layers of the skin

Elastic FibersElastic Fibers

In this slide, “A” is an elastic fiber – what do you suppose “B” is?

Composed of:

A protein called elastin, whose coiled structure allows it to stretch and snap back like a rubber band.

Account for the ability of the lungs, arteries, and skin to spring back after they are stretched.

Reticular FibersReticular Fibers

Composed of:

A thinner collagen fiber coated with glycoproteins.

These fibers can branch extensively and form networks for certain organs.

Osseous Tissue (Bone)Osseous Tissue (Bone) Composed of:

Cells called osteoblasts that secrete hard matrix of calcium salts and surround themselves in it until they become trapped in little cavities known as lacunae

Once enclosed in lacunae, cells are called osteocytes.

Hard matrix of calcium salts

Large numbers of collagen fibers

Functions:

Used to protect and support the body

CartilageCartilage1

2 3

3 types (classified based on fiber differences):

Hyaline Cartilage

Elastic Cartilage

Fibrocartilage

CartilageCartilage Avascular

Without blood supply

Healing of torn cartilage is a long process

Chondrocytes produce antiangiogenesis factor that prevents the growth of blood vessels.

Why do you suppose shark cartilage could be a possible aid in the fight against cancer?

Figure 3.18a

Hyaline CartilageHyaline Cartilage Most common cartilage

Composed of:

Abundant collagen fibers

Rubbery matrix

Locations:

Entire fetal skeleton is hyaline cartilage

Attaches ribs to the sternum.

Functions:

Precursor of bone in fetal skeleton

Structural attachment

Figure 3.18b

Elastic CartilageElastic Cartilage Locations:

External ear

Epiglottis – flap of tissue that covers the trachea

Functions:

Provides flexible support

What happens when you bend and release your ear?

FibrocartilageFibrocartilage Locations:

Intervertebral discs between vertebrae

Meniscus (shock-absorbing pads of cartilage) in the knee joint.

Functions:

Resists compression and absorbs shock in some joints

Dense Connective TissueDense Connective Tissue Composed of:

Main matrix element is collagen fibers

Cells are fibroblasts (manufacture fibers)

Locations and Functions:

Tendon – attach muscle to bone

Ligaments – attach bone to bone

Figure 3.18d

Areolar Connective TissueAreolar Connective Tissue

Most widely distributed connective tissue

Soft, pliable tissue

Can soak up excess fluid; reservoir of water

Composed of:

All 3 fiber types (loose arrangement)

Highly vascularFigure 3.18e

Areolar Connective TissueAreolar Connective Tissue Locations:

Underlying epithelia

Surrounds blood vessels, nerves, and esophagus

Functions: Binds epithelia to deeper

tissues

Allows passage of nerves and blood vessels through other tissues

Provides an arena for immune defense

Can soak up excess fluid

Adipose TissueAdipose Tissue Composed of:

Matrix in which fat globules predominate

Adipocytes contain large fat deposits

Locations: Subcutaneous fat beneath skin

Breast

Functions: Insulation and protection

Serves as a fuel storage

Reticular Connective Tissue Reticular Connective Tissue Composed of:

Delicated network of interwoven reticular fibers

Numerous white blood cells

Locations and Functions: Forms stroma (internal

supporting network) of lymphoid organs

Lymph nodes

Spleen

Bone marrow

Figure 3.18g

BloodBlood

Composed of: Blood cells surrounded

by fluid matrix

Fibers are visible during clotting only

Functions: Transport vehicle for

materials

Figure 3.18h

Muscle TissueMuscle Tissue

Function is to produce movement

Three types Skeletal muscle

Cardiac muscle

Smooth muscle

Skeletal Muscle Skeletal Muscle

Can be controlled voluntarily

Cells attach to connective tissue

Cells are striated

Cells have more than one nucleus

Figure 3.19b

Cardiac Muscle Cardiac Muscle Found only in the

heart

Function is to pump blood (involuntary)

Cells attached to other cardiac muscle cells at intercalated disks

Cells are striated

One nucleus per cell (uni-nucleate)

Figure 3.19c

Smooth Muscle Smooth Muscle

Involuntary muscle

Surrounds hollow organs

Attached to other smooth muscle cells

No visible striations

One nucleus per cell

Figure 3.19a

Nervous TissueNervous Tissue

Composed of:

Neurons and nerve support cells

Function:

Irritability

Conductivity

ResponsivenessFigure 3.20

Tissue RepairTissue Repair

1. Regeneration Replacement of destroyed tissue by the

same kind of cells

2. Fibrosis Repair by dense fibrous connective tissue

(scar tissue)

Determination of method Type of tissue damaged

Severity of the injury

Events in Tissue RepairEvents in Tissue Repair

Capillaries become very permeable Introduce clotting proteins

Wall off injured area

Formation of granulation tissue

Regeneration of surface epithelium

Regeneration of TissuesRegeneration of Tissues

Tissues that regenerate easily Epithelial tissue

Fibrous connective tissue and bone

Tissues that regenerate poorly Skeletal muscle

Tissues that are replaced largely with scar tissue Cardiac muscle

Nervous tissue within the brain and spinal cord