Connective Tissue
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Connective tissue: Binds, supports, strengthens, transports, stores energy
Composition of ground substance: Water, proteins and polysaccharides
Types of protein fibre: Collagen, reticular and elastic
Glycosaminoglycans: Large polysaccharides that join with core proteins to form proteoglycans
Dermatan sulfate: GAG found in skin, tendons, heart valves, blood vessels
Keratan sulfate: GAG found in bone, cartilage, cornea of the eye
Chondroitan sulfate: GAG that supports and provides adhesive features of cartilage, bone, skin and blood vessels
Hyaluronic acid: A non-sulfated GAG. Viscous slippery substance that binds cells, lubricates joints and maintains the shape of the eyeball. Does not bind directly to proteins.
Hyaluronidase: An enzyme produced by WBC's, sperm and some bacteria that digests hyaluronic acid, making the ECM more liquid
Collagen: Very strong but flexible. Features such as water content can vary depending on function. Forms parallel bundles.
Reticular fibres
Fine bundles of collagen with a glycoprotein coating. Made by fibroblasts. Provides strength and support, and forms the lower part of the basment membrane. Thinner than collagen and branching, spreads through tissue and forms networks in vessels and through tissues.
Elastic fibres
Thinner than collagen, forming a fibrous network. Elastin and fibrillin together. Provides strength and support, while being highly elastic.
Composition of ECM: Ground substance and protein fibres
Function of sulfated GAGs: Trap water to make it more jellylike
Location of fibroblasts: Widely distributed and migratory
Function of fibroblasts: Secrete fibrous components of ECM
Location of adipocytes: Under the skin and around the organs
Function of adipocytes: Store triglycerides
Function of mast cells: Produce histamine to dilate blood vessels
Location of mast cells: Alongside the blood vessels
Function of macrophages: Phagocytosis
Dust cells: Macrophages found in alveoli
Kupffer cells: Macrophages in the liver
Langerhan's cells: Macrophages in the skin
Mesenchyme: Embryonic connective tissue that gives rise to all other connective tissues.
Structure of mesenchyme: Mesenchymal cells in a semi-fluid ground substance containing reticular fibres
Mucous tissue: Widely scattered fibroblasts embedded in a jelly-like ground substance.
Function of mucous tissue: Supports the umbilical cord
Perichondrium: Dense irregular connective tissue membrane covering cartilage
Loose connective tissue: Many cells and fewer fibres than in other CT types.
Areolar connective tissue: Wraps and cushions organs, provides strength, elasticity and support.
Areolar connective tissue: Collagen, reticular and elastic fibres arranged randomly around the cells.
Adipose tissue: Adipocytes with central triglyceride droplets.
Loose reticular connective tissue
Interlacing network of reticular fibres and reticular cells. Forms stroma, binds smooth muscle tissue cells, filters and removes worn-out blood cells in spleen and microbes in lymph nodes.
Location of loose reticular connective tissue
Stroma of liver, spleen, lymph nodes, red bone marrow, reticular layer of basement membrane, around blood vessels and muscles.
Dense connective tissue: More fibres and fewer cells than LCT
Irregular connective tissue: Provides tensile strength from all directions. Often in sheets. Irregularly arranged.
Elastic connective tissue: Mostly elastic fibres with fibroblasts. Allows stretching and recoiling, provides strength.
Cartilage: Collagen and elastin fibres in chondroitin sulfate
Structure of hyaline cartilage: Relatively weak, resilient gel in which fibres are present but not obvious. Flexibility and support.
Fibrocartilage: Chondrocytes scattered among thick bundles of collagen fibres within ECM. Supports and joins structures. Strongest type of cartilage.
Elastic cartilage
Chondrocytes in threadlike networks of elastic fibres within ECM. Perichondrium present. Provides strength and elasticity; maintains shape of certain structures.
Structure of compact bone: Composed of osteons. Stores calcium, phosphorous, provides protection and support.
Location of elastic cartilage
Epiglottis and external ear, auditory tubes
Structure of spongy bone
No osteons, composed of trabeculae. Stores triglycerides in YBM, forms erythrocytes in RBM.
Osteogenic cells
Mesenchymal stem cells that develop, lay down collagen, become trapped and become osteoblasts.
Osteoblasts
Bone forming cells. Lay down more collagen, starts the mineralization process.
Osteocytes
Mature bone cells derived from osteoblasts trapped in ECM. Maintains the bone tissue. Involved in exchange of nutrients and waste. Have gap junctions.
Osteoclasts
Large, multinucleated cells formed from the fusion of blood monocytes. Break down and reshape bone.
Lamellae
Concetric rings of mineral salts (hydroxyapatite) for hardness, collagen for tensile strength.
Lacunae
Small spaces between lamellae that contain osteocytes.
Canaliculi
Tiny channels that radiate from lacunae and provide routes for oxygen, nutrients and waste.
Central (Haversian) canal
Contains blood vessels and nerves
Bone healing process
Osteoclasts reabsorb dead bone -> Chondroblasts lay down hyaline cartilage callus -> Osteoblasts lay down new bone -> Osteoclasts remodel new bone
Erythrocytes
Cells that transport oxygen and carbon dioxide
Neutrophils, macrophages
Phagocytic cells
Basophils and mast cells
Cells that release substances (histamines) that increase immune response
Eosinophils
Cells that kill parasitic worms and are effective in acute immune responses.
Lymphocytes
Cells involved in immune response
Platelets
Cells involved in blood clotting
Cartilage
Type of connective tissue that does not have a nerve supply
Mucopolysaccharides - Alternative name for glycosaminoglycans
N aminoglycosamine - Example of an amino sugar
glucuronic acid - Example of a uronic sugar
N aminoglycosamine, glucuronic acid - Disaccharide in hyaluronic acid (2 monomers)
Location of chondroitin sulfate - Cartilage, bone, skin, blood vessels
Location of keratan sulfate - Bone, cartilage, cornea
Location of dermatan sulfate - Skin, tendons, blood vessels, heart valves
Location of hyaluronic acid - Between cells, in joints, in the eyeball
Exopthalmosis
Condition produced by hyperthyroidism in which the eyeballs protrude beyond their normal protective orbit because of swelling in the tissues behind them
Goitre - Swollen thyroid gland
Cortical bone is also known as Compact bone
Cancellous bone is also known as Spongy bone
Composition of ground substance: Water, proteins and polysaccharides
Types of protein fibre: Collagen, reticular and elastic
Glycosaminoglycans: Large polysaccharides that join with core proteins to form proteoglycans
Dermatan sulfate: GAG found in skin, tendons, heart valves, blood vessels
Keratan sulfate: GAG found in bone, cartilage, cornea of the eye
Chondroitan sulfate: GAG that supports and provides adhesive features of cartilage, bone, skin and blood vessels
Hyaluronic acid: A non-sulfated GAG. Viscous slippery substance that binds cells, lubricates joints and maintains the shape of the eyeball. Does not bind directly to proteins.
Hyaluronidase: An enzyme produced by WBC's, sperm and some bacteria that digests hyaluronic acid, making the ECM more liquid
Collagen: Very strong but flexible. Features such as water content can vary depending on function. Forms parallel bundles.
- Location of collagen: Bone, cartilage, tendons, ligaments
Reticular fibres
Fine bundles of collagen with a glycoprotein coating. Made by fibroblasts. Provides strength and support, and forms the lower part of the basment membrane. Thinner than collagen and branching, spreads through tissue and forms networks in vessels and through tissues.
- Location of reticular fibres: Adipose tissue, nerve fibres, smooth muscle areas, basement membrane
Elastic fibres
Thinner than collagen, forming a fibrous network. Elastin and fibrillin together. Provides strength and support, while being highly elastic.
- Location of elastic fibres: Skin, blood vessels, lungs
Composition of ECM: Ground substance and protein fibres
- Marfan Syndrome - A hereditary defect. Caused by a dominant mutation on Chromasome 15 coding for fibrillin.
- Signs of Marfan Syndrome - Individuals are tall, long limbed and often have a chest deformity. Medical vigilance is needed, especially as pertains to blood pressure. May have weakened heart valves and arterial walls.
- Direct effect of Marfan Syndrome - The body produces Transforming Growth Factor Beta which increases growth due to not binding normally with fibrillin to keep it inactive.
Function of sulfated GAGs: Trap water to make it more jellylike
Location of fibroblasts: Widely distributed and migratory
Function of fibroblasts: Secrete fibrous components of ECM
Location of adipocytes: Under the skin and around the organs
Function of adipocytes: Store triglycerides
Function of mast cells: Produce histamine to dilate blood vessels
Location of mast cells: Alongside the blood vessels
Function of macrophages: Phagocytosis
Dust cells: Macrophages found in alveoli
Kupffer cells: Macrophages in the liver
Langerhan's cells: Macrophages in the skin
Mesenchyme: Embryonic connective tissue that gives rise to all other connective tissues.
Structure of mesenchyme: Mesenchymal cells in a semi-fluid ground substance containing reticular fibres
Mucous tissue: Widely scattered fibroblasts embedded in a jelly-like ground substance.
Function of mucous tissue: Supports the umbilical cord
Perichondrium: Dense irregular connective tissue membrane covering cartilage
Loose connective tissue: Many cells and fewer fibres than in other CT types.
Areolar connective tissue: Wraps and cushions organs, provides strength, elasticity and support.
Areolar connective tissue: Collagen, reticular and elastic fibres arranged randomly around the cells.
Adipose tissue: Adipocytes with central triglyceride droplets.
- Adipose tissue- - Insulation, energy storage (WAT), temperature control (BAT).
- Location of adipose tissue - Under skin, around buttocks, flanks, abdomen, orbit of eye.
Loose reticular connective tissue
Interlacing network of reticular fibres and reticular cells. Forms stroma, binds smooth muscle tissue cells, filters and removes worn-out blood cells in spleen and microbes in lymph nodes.
Location of loose reticular connective tissue
Stroma of liver, spleen, lymph nodes, red bone marrow, reticular layer of basement membrane, around blood vessels and muscles.
Dense connective tissue: More fibres and fewer cells than LCT
- Location of dense regular connective tissue- -Tendons, ligaments, aponeuroses
- Dense regular connective tissue - Regularly arranged collagen fibres. Used for attachment, as it provides high tensile strength across the long axis.
Irregular connective tissue: Provides tensile strength from all directions. Often in sheets. Irregularly arranged.
- Location of dense irregular connective tissue- -Fasciae, reticular region of dermis, fibrous pericardium, periosteum, perichondrium, joint and membrane capsules, heart valves
Elastic connective tissue: Mostly elastic fibres with fibroblasts. Allows stretching and recoiling, provides strength.
- Location of elastic connective tissue - Lung tissue, walls of arteries, trachea, bronchial tubes, vocal chords, suspensary ligaments of penis, some ligaments between vertebrae
Cartilage: Collagen and elastin fibres in chondroitin sulfate
Structure of hyaline cartilage: Relatively weak, resilient gel in which fibres are present but not obvious. Flexibility and support.
Fibrocartilage: Chondrocytes scattered among thick bundles of collagen fibres within ECM. Supports and joins structures. Strongest type of cartilage.
- Location of fibrocartilage - Pubic symphysis, intervertebral discs, cartilage pads of knee, portions of tendons
Elastic cartilage
Chondrocytes in threadlike networks of elastic fibres within ECM. Perichondrium present. Provides strength and elasticity; maintains shape of certain structures.
Structure of compact bone: Composed of osteons. Stores calcium, phosphorous, provides protection and support.
Location of elastic cartilage
Epiglottis and external ear, auditory tubes
Structure of spongy bone
No osteons, composed of trabeculae. Stores triglycerides in YBM, forms erythrocytes in RBM.
Osteogenic cells
Mesenchymal stem cells that develop, lay down collagen, become trapped and become osteoblasts.
Osteoblasts
Bone forming cells. Lay down more collagen, starts the mineralization process.
Osteocytes
Mature bone cells derived from osteoblasts trapped in ECM. Maintains the bone tissue. Involved in exchange of nutrients and waste. Have gap junctions.
Osteoclasts
Large, multinucleated cells formed from the fusion of blood monocytes. Break down and reshape bone.
Lamellae
Concetric rings of mineral salts (hydroxyapatite) for hardness, collagen for tensile strength.
Lacunae
Small spaces between lamellae that contain osteocytes.
Canaliculi
Tiny channels that radiate from lacunae and provide routes for oxygen, nutrients and waste.
Central (Haversian) canal
Contains blood vessels and nerves
Bone healing process
Osteoclasts reabsorb dead bone -> Chondroblasts lay down hyaline cartilage callus -> Osteoblasts lay down new bone -> Osteoclasts remodel new bone
Erythrocytes
Cells that transport oxygen and carbon dioxide
Neutrophils, macrophages
Phagocytic cells
Basophils and mast cells
Cells that release substances (histamines) that increase immune response
Eosinophils
Cells that kill parasitic worms and are effective in acute immune responses.
Lymphocytes
Cells involved in immune response
Platelets
Cells involved in blood clotting
Cartilage
Type of connective tissue that does not have a nerve supply
Mucopolysaccharides - Alternative name for glycosaminoglycans
N aminoglycosamine - Example of an amino sugar
glucuronic acid - Example of a uronic sugar
N aminoglycosamine, glucuronic acid - Disaccharide in hyaluronic acid (2 monomers)
Location of chondroitin sulfate - Cartilage, bone, skin, blood vessels
Location of keratan sulfate - Bone, cartilage, cornea
Location of dermatan sulfate - Skin, tendons, blood vessels, heart valves
Location of hyaluronic acid - Between cells, in joints, in the eyeball
Exopthalmosis
Condition produced by hyperthyroidism in which the eyeballs protrude beyond their normal protective orbit because of swelling in the tissues behind them
Goitre - Swollen thyroid gland
Cortical bone is also known as Compact bone
Cancellous bone is also known as Spongy bone