Tissue: The Living Fabric

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Tissue The Living Fabric

• Part II Connective Tissue

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Connective Tissue

• Most abundant and widely distributed tissue
• Main classes
• Connective tissue proper (loose and dense)
• Cartilage
• Bone
• Blood
• Functions
• Binding and support
• Protection
• Insulation
• Transport substances

Specialized
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Classification What makes a tissue connective?

• Variation in Blood supply
• Vascular connective tissue proper, blood, bone
• Tendons ligaments are poorly vascular
• Cartilage is avascular
• Do not appear on surface
• Unlike epithelial
• Extracellular matrix
• secreted by cells that provides structural and
  biochemical support
• Ground substance fills spaces, surrounds fibers,
  clear, colorless, and has the consistency of
  syrup
• water adhesion proteins polysaccharides
• Fibers
• provide support
• Collagen - no branching strength
• Elastic branched provides stretch
• Reticular fine branched network, skeleton of
  organs

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Lets talk about collagen a bit

• Gelatin can come from the collagen in cow or pig
  bones, hides and connective tissues.
• Today, the gelatin in Jell-O is most likely to
  come from pigskin.
• Collagen doesn't dissolve in water in its natural
  form, so it must be modified to make gelatin.
• Manufacturers grind the body parts and treat them
  with either a strong acid or a strong base to
  dissolve the collagen.
• Then the pre-treated material is boiled. Controls
  at every step of the process ensure purity and
  safety.
• During this process, the large collagen protein
  ends up being partially broken down the
  resulting product is a gelatin solution.
• That solution is chilled into a jelly-like
  material, cut and dried in a special chamber. At
  this point, the dried gelatin -- about 10 water
  -- is ground. If it's going to make Jell-O, it
  will be ground into a fine powder.

• Collagen
• Most abundant protein in the body (25-35)
• As you get older, your body makes less collagen,
  and individual collagen fibers become
  increasingly cross-linked with each other.
• stiff joints from less flexible tendons, or
  wrinkles due to loss of skin elasticity
• Plastic surgery?
• Put it through hydrolysis ? gelatin

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Loose Connective Tissue

• Known as the universal packing material
• Subclasses areolar, adipose, reticular
• Structure softer, fewer fibers, gel-like matrix
• Functions
• Cushion protect organs (areolar, fat)
• Store nutrients (fat)
• Internal framework of support (reticular)
• Fight infection (areolar)
• Cellular makeup fibroblasts, adipocytes (fat
  cells)
• Locations under skin, lymph nodes, hips, behind
  eyeballs

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Areolar tissue (aka loose connective)

• Functions Cushioning surrounding organs,
  connecting different tissues, and supporting
  blood vessels 
• Made up of collagenous, elastic and reticular
  fibers and ground substance

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Adipose Tissue

• Functions store energy in the form of fat,
  although it also cushions and insulates the body.
• In mammals, two types of adipose tissue exist
• white adipose tissue (WAT) dominant fat type in
  the body, less mitochondria but biggest energy
  reserve
• brown adipose tissue (BAT) iron containing
  mitochondria , burns calories for heat mainly
  found in hibernating mammals and babies
• Adipose tissue is primarily located beneath the
  skin, but is also found around internal organs.

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Reticular Tissue

• Named for the reticular fibers which are the main
  structural part of the tissue.
• Cells that make the reticular fibers are
  fibroblasts called reticular cells. 
• Function fibers form a soft internal skeleton
  that supports other tissues
• Found lymph organs, spleen, and bone marrow

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Cellulite?

• Poor circulation, build up of toxins, pressure on
  connective tissue
• Hormones to blame?
• 90 of women have it
• Why not seen in men as much?
• Women have less supportive connective tissue to
  keep fat cells in place.

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Dense Connective Tissue (proper)

• Tendons ligaments
• Subclasses dense regular, dense irregular,
  elastic
• Structure mainly collagen fibers
• Functions
• Elasticity, strength
• Resist tension
• Cells fibroblasts
• Locations tendons (muscle-bone), ligaments
  (bone-bone), lower layers of skin.

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Dense Regular vs. Dense irregular

• Woven network of fibers
• Can be stressed in many directions
• Found lower levels (dermis) of skin arranged
  in sheets
• 4/5 of all skin tissues are dense irregular

• Parallel fibers
• Tears when stressed in the incorrect direction
• Found tendons, ligaments

• Regular

• Irregular

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Elastic Connective Tissue

• Lots of elastic fibers give squiggly appearance
• Function Allows stretching of organs 
• Found lungs, around elastic arteries, and vocal
  cords

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Cartilage

• Subclasses hyaline, elastic, fibrocartilage
• Structure flexible, no nerves or blood
• Functions
• Support
• Compression
• Cells chondrocytes
• Create and maintain the cartilaginous matrix
• Locations larynx, joints, tip of nose, ear,
  intervertebral discs, rib-breastbone, knee joint.

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Hyaline cartilage

• Helps with joint movement, bone growth,
  strengthens respiratory tract
• Found in bronchi, joint surface, larynx

Elastic cartilage

• Resembles hyaline cartilage but it also has
  elastic fibers
• Provides flexibility and support
• Found in the outer ear, epiglottis, larynx

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Fibrocartilage

• Densely packed collagen fibers
• fibers that are in wavy lines
• Function Support and protection
• Found bone joints, knee, backbone

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Bone

• Osseous tissue
• Subclasses compact, spongy
• Structure hard, calcified matrix blood vessels
• Functions
• support protect
• Store calcium
• Blood cell formation (marrow)
• Cells osteoblasts, osteocytes
• Synthesize bone
• Locations bones

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Blood

• Vascular tissue
• Subclasses blood cells, plasma
• Structure fluid within blood vessels, no fibers
• Functions
• Transport vehicle (nutrients, wastes, gases,
  hormones)
• Cells white blood cells (leukocytes), red blood
  cells (erythrocytes), platelets
• Locations blood vessels

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