Connective TissueConnective Tissue

Chapter 4 (cont.)Chapter 4 (cont.)

I. General CharacteristicsI. General Characteristics

A.A. Three components:Three components:1.1. Specialized cellsSpecialized cells

2.2. Extracellular protein fibersExtracellular protein fibers

3.3. Ground substanceGround substance

* Extracellular fibers & ground substance together * Extracellular fibers & ground substance together make up the make up the matrixmatrix, which surrounds the , which surrounds the specialized cells.specialized cells.

B.B. Never exposed to the outside environmentNever exposed to the outside environment

C.C. Highly vascularHighly vascular

D.D. Provide pain, pressure, temperature & other Provide pain, pressure, temperature & other sensationssensations

E.E. Make up the framework of the bodyMake up the framework of the body

F.F. Transport fluids & dissolved materialsTransport fluids & dissolved materials

G.G. Protect organsProtect organs

H.H. Support, surround, and interconnect other Support, surround, and interconnect other tissuestissues

I.I. Defend against microorganismsDefend against microorganisms

II. Classification of C.T.II. Classification of C.T.

A.A. Connective Tissue ProperConnective Tissue Proper (C.T.P.) (C.T.P.)1.1. There are many different types, depending on There are many different types, depending on

proportion of cells, fibers, & ground substance.proportion of cells, fibers, & ground substance.

2. Cell Types2. Cell Types

a.a. FibroblastsFibroblastsi.i. Most abundant, permanent cell in CTPMost abundant, permanent cell in CTP

ii.ii. Only cell that is ALWAYS in every CTPOnly cell that is ALWAYS in every CTP

b.b. MacrophagesMacrophagesi.i. Large cells scattered in matrixLarge cells scattered in matrix

ii.ii. Engulf pathogens and damaged cellsEngulf pathogens and damaged cells

iii.iii. Play an important role in the immune systemPlay an important role in the immune system

c.c. Adipocytes-Adipocytes- adipose cells (fat cells) adipose cells (fat cells)

d.d. Mesenchymal cellsMesenchymal cellsi.i. Stem cellsStem cells

ii.ii. Respond to local injury or infectionRespond to local injury or infection

e.e. MelanocytesMelanocytesi.i. Make and store melaninMake and store melanin

ii.ii. Common in epithelium of skin, determines skin Common in epithelium of skin, determines skin colorcolor

iii.iii. Also in eyeAlso in eye

f.f. Mast cellsMast cellsi.i. Small, mobile cellsSmall, mobile cellsii.ii. Found near blood vesselsFound near blood vesselsiii.iii. Release chemicals (like histamine) to stimulate Release chemicals (like histamine) to stimulate

inflammation after injury or infectioninflammation after injury or infection

g.g. LymphocytesLymphocytesi.i. Migrate throughout the bodyMigrate throughout the bodyii.ii. May turn into plasma cells, which make May turn into plasma cells, which make

antibodiesantibodies

h.h. Microphages-Microphages- help out macrophages help out macrophages

3. Connective Tissue Fibers3. Connective Tissue Fibers(all formed by fibroblasts)(all formed by fibroblasts)

a.a. Collagen fibersCollagen fibersi.i. Long, straight, unbranchedLong, straight, unbranched

ii.ii. Most common fibers in CTPMost common fibers in CTP

iii.iii. Fibers are like strands in a ropeFibers are like strands in a rope

iv.iv. Flexible, yet VERY strongFlexible, yet VERY strong

• Tendons-Tendons- connect muscle to bone connect muscle to bone• Ligaments-Ligaments- connect bone to bone connect bone to bone• Bones will usually break before T&L will!Bones will usually break before T&L will!

b.b. Reticular FibersReticular Fibersi.i. Thinner than collagen fibersThinner than collagen fibers

ii.ii. Branched network that stabilizes positions of Branched network that stabilizes positions of blood vessels, nerves…blood vessels, nerves…

c.c. Elastic FibersElastic Fibersi.i. Contain the protein Contain the protein elastinelastin

ii.ii. Fibers are branched and wavyFibers are branched and wavy

4. Ground Substance4. Ground Substance

a.a. Fills spaces between cells, Fills spaces between cells,

surrounds fiberssurrounds fibers

b.b. Viscous, clear fluid, slowsViscous, clear fluid, slows

spread of pathogensspread of pathogens

5. Lose Connective Tissue (Areolar)5. Lose Connective Tissue (Areolar)

a.a. Packing material of the bodyPacking material of the body

b.b. Cushions & supports organs & tissuesCushions & supports organs & tissues

c.c. Contains elastic fibersContains elastic fibers

d.d. Forms a layer that separates skin from muscleForms a layer that separates skin from muscle

e.e. Common injection site of drugsCommon injection site of drugs

* * Adipose Tissue-Adipose Tissue- padding, shock padding, shock absorbing, insulatingabsorbing, insulating

* * Reticular TissueReticular Tissue

Fibroblasts - - Magenta arrowElastic fibers - - Red/Orange arrowMacrophages - - Green arrowCollagen - - Blue arrow

6. Dense 6. Dense RegularRegular Connective Tissue Connective Tissue(Dominated by collagen fibers)(Dominated by collagen fibers)

a.a. Dense Regular Connective TissueDense Regular Connective Tissuei.i. Parallel fibersParallel fibers

ii.ii. Ex. Tendons, LigamentsEx. Tendons, Ligaments

b.b. Dense Irregular Connective TissueDense Irregular Connective Tissuei.i. Interwoven meshInterwoven mesh

ii.ii. Ex. Skin, LeatherEx. Skin, Leather

B.B. Fluid Connective TissueFluid Connective Tissue- cells suspended - cells suspended in a watery matrix w/ dissolved proteins.in a watery matrix w/ dissolved proteins.

1.1. BloodBlooda.a. ErythrocytesErythrocytes--

i.i. red blood cells (RBC)red blood cells (RBC)

ii.ii. Make up ½ of the volume of bloodMake up ½ of the volume of blood

iii.iii. Carry OxygenCarry Oxygen

b.b. PlasmaPlasma- watery ground substance- watery ground substance

c.c. LeukocytesLeukocytesa.a. White blood cells (WBC)White blood cells (WBC)

b.b. Immune system componentImmune system component

d.d. PlateletsPlatelets- function in clotting- function in clotting

2.2. LymphLympha.a. Interstitial fluid that enters back into the blood streamInterstitial fluid that enters back into the blood stream

b.b. Carries messages of injury/infection to immune Carries messages of injury/infection to immune systemsystem

C.C. Supporting Connective TissuesSupporting Connective Tissues- Closely - Closely packed cellspacked cells

1.1. Chondrocytes- cartilage cellsChondrocytes- cartilage cells

2.2. Lacunae- small chambers that chondrocytes Lacunae- small chambers that chondrocytes occupyoccupy

3. Cartilage- firm gel, avascular3. Cartilage- firm gel, avascular

a.a. Hyaline CartilageHyaline Cartilagei.i. Most common typeMost common type

ii.ii. Made of closely packed collagen fibersMade of closely packed collagen fibers

iii.iii. Tough, but flexibleTough, but flexible

iv.iv. Found between ribs & sternum, nose, elbow, kneeFound between ribs & sternum, nose, elbow, knee

Hyaline CartilageHyaline Cartilage

b.b. Elastic CartilageElastic Cartilagei.i. Extremely resilient & flexibleExtremely resilient & flexible

ii.ii. Found in ears, & larynxFound in ears, & larynx

c.c. FibrocartilageFibrocartilagei.i. Made of densely interwoven collagen fibersMade of densely interwoven collagen fibers

ii.ii. Extremely tough & durableExtremely tough & durable

iii.iii. Found between vertebrae, kneeFound between vertebrae, knee

4.4. Bone- composed of calcium, other minerals Bone- composed of calcium, other minerals & collagen& collagen

a.a. Osteocytes- bone cellsOsteocytes- bone cells

b.b. CanaliculiCanaliculii.i. Branching network of cytoplasmic extensionsBranching network of cytoplasmic extensions

ii.ii. Transfer materials between blood vessels & Transfer materials between blood vessels & osteocytesosteocytes

c.c. Periosteum- sheath around bonesPeriosteum- sheath around bones

BoneBone