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Connective TissueConnective TissueGeneral FeaturesGeneral FeaturesTwo basic elements: Two basic elements: CELLSCELLS and an and an extracellularextracellular MATRIX MATRIXThe The MATRIXMATRIX is made with a is made with a ground ground substancesubstance and and fibersfibersNot very cellular compared to the other types of Not very cellular compared to the other types of tissuetissueDoes not occur on body surfacesDoes not occur on body surfacesHas a nerve supply, except cartilageHas a nerve supply, except cartilageUsually highly vascular except cartilage Usually highly vascular except cartilage (avascular) tendons and ligaments(avascular) tendons and ligamentsVarious tissue types confer a variety of Various tissue types confer a variety of functionsfunctions
Types of Connective Tissue CellsTypes of Connective Tissue Cells
Fibroblasts- Fibroblasts- produce and produce and secrete fibrous proteins and secrete fibrous proteins and ground substanceground substance
Macrophages- Macrophages- phagocytic phagocytic cells that engulf and digest foreign cells that engulf and digest foreign particlesparticles
Plasma Cells- Plasma Cells- produce produce antibodiesantibodies
Mast Cells-Mast Cells- produce histamine, produce histamine, which dialates blood vessels, and which dialates blood vessels, and heparin, an anticoagulantheparin, an anticoagulant
Adipocytes-Adipocytes- store fat store fat Erythrocytes- Erythrocytes- red blood red blood
cells, transport oxygencells, transport oxygen
Leukocytes- Leukocytes- white blood white blood cells, several different types, cells, several different types, function in immunityfunction in immunity
Thrombocytes- Thrombocytes- blood blood platelets, aid in blood clot platelets, aid in blood clot formationformation
Chondroblasts- Chondroblasts- produce produce and secrete fibers and ground and secrete fibers and ground substance in cartilagesubstance in cartilage
ChondrocytesChondrocytes- maintains - maintains the matrix of cartilagethe matrix of cartilage
Osteoblasts- Osteoblasts- produce and produce and secrete fibers and ground secrete fibers and ground substance in bonesubstance in bone
OsteocytesOsteocytes- maintains the - maintains the extracellular matrix of boneextracellular matrix of bone
Connective Tissue Extracellular Connective Tissue Extracellular MatrixMatrix
Ground substance can beGround substance can be FluidFluid SemifluidSemifluid GelatinousGelatinous HardHard
Three Types of FibersThree Types of Fibers Collagen – strong, thick yet flexibleCollagen – strong, thick yet flexible Elastic – smaller in diameter than collagen, branch to Elastic – smaller in diameter than collagen, branch to
form a network within the tissue, very elasticform a network within the tissue, very elastic Reticular – also made with collagen, but much thinner Reticular – also made with collagen, but much thinner
than collagen fibers, provide support and strength and than collagen fibers, provide support and strength and form the basement membrane form the basement membrane
Two Major TypesTwo Major Typesof Connective Tissueof Connective Tissue
Embryonic – found in the embryo and Embryonic – found in the embryo and fetusfetus
Mature – present in newborns to adultsMature – present in newborns to adults
Types of Mature Connective TissueTypes of Mature Connective Tissue Loose Connective TissueLoose Connective Tissue
areolarareolar reticularreticular adiposeadipose
Dense Connective TissueDense Connective Tissue regularregular irregularirregular elasticelastic
CartilageCartilage hyalinehyaline elasticelastic fibrocartilagefibrocartilage
BoneBone BloodBlood LymphLymph
Loose Connective TissueLoose Connective Tissue
In Loose Connective Tissue, the fibers in the In Loose Connective Tissue, the fibers in the extracellular matrix are loosely arranged. Lots of extracellular matrix are loosely arranged. Lots of ground substance. The ground substance in ground substance. The ground substance in semifluid (viscous). Cells are scattered semifluid (viscous). Cells are scattered throughout the tissue. Not very cellular. Some throughout the tissue. Not very cellular. Some cells reside permanently in the matrix; cells cells reside permanently in the matrix; cells involved in immunity enter the matrix from blood involved in immunity enter the matrix from blood and are transient.and are transient.
Loose Connective Tissue includes:Loose Connective Tissue includes: Areolar Connective TissueAreolar Connective Tissue Adipose TissueAdipose Tissue Reticular Connective TissueReticular Connective Tissue
Areolar Connective TissueAreolar Connective TissueAll three fibers (collagen, elastin and reticular) and All three fibers (collagen, elastin and reticular) and
several kinds of cells, including fibroblasts, several kinds of cells, including fibroblasts, adipocytes and cells of the immune system, are adipocytes and cells of the immune system, are embedded in a semifluid ground substanceembedded in a semifluid ground substance
Areolar is the most abundant type of connective Areolar is the most abundant type of connective tissuetissue
Found in the subcutaneous layer deep to skin, Found in the subcutaneous layer deep to skin, superficial part of dermis, mucus membranes, superficial part of dermis, mucus membranes, around blood vessels, nerves and body organsaround blood vessels, nerves and body organs
Function: supports glandular epithelium and Function: supports glandular epithelium and mesothelial layers of mesentery, supports mesothelial layers of mesentery, supports immune cellsimmune cells
Areolar Connective Tissue
Reticular Connective TissueReticular Connective Tissue
The dominant fiber is recticular fiber. The dominant fiber is recticular fiber. Reticulocytes are fibroblasts that produce Reticulocytes are fibroblasts that produce more reticular fiber than collagen. The more reticular fiber than collagen. The ground substance is semifluid.ground substance is semifluid.
Found in lymph nodes and other Found in lymph nodes and other nonmuscular organsnonmuscular organs
Provides a support structure for Provides a support structure for macrophages and other cells involved in macrophages and other cells involved in immunity.immunity.
Reticular Connective Tissue
Adipose TissueAdipose Tissue
Contains fibers, fibroblasts and adipocytes Contains fibers, fibroblasts and adipocytes embedded in a semifluid ground embedded in a semifluid ground substance. Has a great number of substance. Has a great number of adipocytes and very little matrix. adipocytes and very little matrix. Adipocytes can appear “empty” on slides.Adipocytes can appear “empty” on slides.
Surrounds organs, abundant in the greater Surrounds organs, abundant in the greater omentumomentum
Function: provides storage for energy-rich Function: provides storage for energy-rich lipids, cushioning and insulation for organslipids, cushioning and insulation for organs
Adipose Tissue
Dense Connective TissueDense Connective Tissue
The extracellular matrix consists of tightly The extracellular matrix consists of tightly packed fibers that form bundles. Very little packed fibers that form bundles. Very little semi-fluid (viscous) ground substance. semi-fluid (viscous) ground substance. Fibroblasts are squeezed between the Fibroblasts are squeezed between the fiber bundlesfiber bundles
Three types of Dense CTThree types of Dense CT Dense Regular CTDense Regular CT Dense Irregular CTDense Irregular CT Dense Elastic CTDense Elastic CT
Dense Regular Connective TissueDense Regular Connective Tissue
The extracellular matrix consists of tightly The extracellular matrix consists of tightly packed packed parallelparallel bundles of collagen fibers bundles of collagen fibers with very little ground substance. with very little ground substance. Fibroblasts are squeezed between the Fibroblasts are squeezed between the collagen bundlescollagen bundles
Makes up tendons and ligamentsMakes up tendons and ligaments
Function: provides resistance to pulling Function: provides resistance to pulling forces while providing flexibilityforces while providing flexibility
Dense Regular Connective Tissue Tendon
Dense Irregular Connective TissueDense Irregular Connective Tissue
The matrix has little ground substance and The matrix has little ground substance and few fibroblasts. The matrix is packed with few fibroblasts. The matrix is packed with bundles of collagen fibers which are bundles of collagen fibers which are irregularly arranged (i.e. not in parallel to irregularly arranged (i.e. not in parallel to each other). each other).
Found in the dermis of the skinFound in the dermis of the skin
Function: Provides strength and support of Function: Provides strength and support of organsorgans
Dense Irregular Connective Tissue
Dense Elastic Connective TissueDense Elastic Connective Tissue
Extracellular matrix is packed with elastic Extracellular matrix is packed with elastic fibers, which mostly run parallel to each fibers, which mostly run parallel to each other, few fibroblasts and consists of very other, few fibroblasts and consists of very little ground substance.little ground substance.
Found in the aortaFound in the aorta
Function: allows tissue to be stretched and Function: allows tissue to be stretched and then regain its original size and shapethen regain its original size and shape
Elastic Connective Tissue in the Aorta
CartilageCartilageThe extracellular matrix consists of collagen The extracellular matrix consists of collagen
and elastic fibers embedded into a and elastic fibers embedded into a gelatinous ground substance.gelatinous ground substance.
Chondroblasts secrete fibers and ground Chondroblasts secrete fibers and ground substance and become isolated in spaces substance and become isolated in spaces called called lacunaelacunae (little lakes or pools) and (little lakes or pools) and then transform into chodrocytes.then transform into chodrocytes.
Cartilage is avascular and receives nutrients Cartilage is avascular and receives nutrients through diffusion from adjacent vascular through diffusion from adjacent vascular tissuetissue
Does not have a nerve supplyDoes not have a nerve supply
Hyaline CartilageHyaline Cartilage
Contains collagen fibers which are thin and not Contains collagen fibers which are thin and not visible with a compound light microscope, where visible with a compound light microscope, where the matrix appears smooth and homogenous. the matrix appears smooth and homogenous. Hyaline cartilage appears glassy to the eye. Hyaline cartilage appears glassy to the eye. Chondrocytes are found in lacunae. The most Chondrocytes are found in lacunae. The most abundant type of cartilage in the body.abundant type of cartilage in the body.
Found at the end of bones (articular), attaching Found at the end of bones (articular), attaching ribs to the sternum (costal), in the nose (nasal) ribs to the sternum (costal), in the nose (nasal) and in the trachea and bronchi.and in the trachea and bronchi.
Function: provides support, reduces friction from Function: provides support, reduces friction from moving bones, provides flexibility that allows moving bones, provides flexibility that allows movement without fracturemovement without fracture
Hyaline Cartilage
Elastic CartilageElastic Cartilage
The matrix is packed mostly with elastic The matrix is packed mostly with elastic fibers. Chondrocytes are located in fibers. Chondrocytes are located in lacunae. Ground substance is gelatinous.lacunae. Ground substance is gelatinous.
Found in the external ear and epiglottis of Found in the external ear and epiglottis of the larynxthe larynx
Function: provides flexible supportFunction: provides flexible support
Elastic Cartilage
FibrocartilageFibrocartilage
Extracellular matrix is packed with thick Extracellular matrix is packed with thick collagen fibers. Has fewer lacunae and collagen fibers. Has fewer lacunae and chrondrocytes than the other types of chrondrocytes than the other types of cartilage. cartilage.
Found in intervertebral discs and the Found in intervertebral discs and the menisci of the kneesmenisci of the knees
Function: provides cushioning and reduces Function: provides cushioning and reduces frictionfriction
Compact BoneCompact Bone
The extracellular matrix consists of collagen fibers The extracellular matrix consists of collagen fibers and a hard ground substance in which inorganic and a hard ground substance in which inorganic salts, mostly calcium and phosphorus salts, are salts, mostly calcium and phosphorus salts, are deposited. Osteocytes are located in deposited. Osteocytes are located in lacunaelacunae, , much like the spaces in cartilage. Because the much like the spaces in cartilage. Because the ground tissue is hard in bone and diffusion and ground tissue is hard in bone and diffusion and osmosis is nearly impossible, little canals, or osmosis is nearly impossible, little canals, or canaliculicanaliculi serve as passages ways for nutrients serve as passages ways for nutrients and wastes as they connect the lacunae to and wastes as they connect the lacunae to larger canals that contain blood vessels.larger canals that contain blood vessels.
The matrix is organized and develops in layers called The matrix is organized and develops in layers called lamellaelamellae. The lamellae form concentric rings that make . The lamellae form concentric rings that make up a structure called an up a structure called an osteonosteon. A single bone may have . A single bone may have several hundreds and even thousands of osteons. In the several hundreds and even thousands of osteons. In the center of each osteon is a large central canal, center of each osteon is a large central canal, sometimes referred to as a Haversian Canal, which sometimes referred to as a Haversian Canal, which contains blood vessels and nervescontains blood vessels and nerves
Found in the skeleton of all vertebrates.Found in the skeleton of all vertebrates.
Function: protects and provides support for body organs, Function: protects and provides support for body organs, provides levers to make movement possible, support for provides levers to make movement possible, support for the body.the body.
Ground Compact Bone
BloodBlood
The ground substance is a straw-colored fluid The ground substance is a straw-colored fluid called called plasmaplasma. Suspended in the plasma are . Suspended in the plasma are erythrocyteserythrocytes, or red blood cells, , or red blood cells, leucocytesleucocytes, or , or white blood cells, and white blood cells, and thrombocytesthrombocytes, or platelets. , or platelets. Fibers are only present during clotting. Fibers are only present during clotting.
Found in blood vessels throughout the body.Found in blood vessels throughout the body.
Function: transports nutrients and vital molecules, Function: transports nutrients and vital molecules, wastes and molecular signals (hormones, etc.) wastes and molecular signals (hormones, etc.) throughout the body.throughout the body.
Human Blood
