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- Occurs throughout the body, represents most abundant tissue type by weight.
- Cells are far apart.
- Abundance of intercellular matrix between cells
- Cells are able to reproduce and usually have a good blood supply.
Major Cell Types
- Fibroblast: most common type of cell, quite large, usually star shaped.
function is to produce fibres.
- Macrophages: Almost as numerous as fibroblasts. Cells can move about and
engulf and destroy foreign cells. Important defence against infectious agents.
- Mast: Widely distributed. Function not completely understood, but release
substances important for the defence against foreign cells and particles.
Connective tissue fibre types
- Collagen: Quite thick, made of the protein collagen. Major structural
protein of the body, flexible but only slightly elastic. Great tensile strength.
- Elastic: Made up of protein bundles (microfibrils) embedded in a protein
called elastin. Less strength than collagen but very elastic. Easily stretched,
but will resume original length and shape.
- Reticular: Very thin fibres made of collagen. Form delicate supporting
Functions of Connective Tissue
- Bind structures together
- Support and protection
- Store fat
- produce blood cells
Loose aerolar Connective
- Nuclei visible -belong mainly to fibroblasts.
- Thick fibres visible are collagen.
- Thin fibres visible are elastic.
- All the above embedded in a gel like ground substance (not stained here)
- Binds organs together
- Holds tissue fluids, provides a reservoir of water and salts
- Universal packaging material between other tissues
Between muscles, forms subcutaneous tissues of skin, wraps small blood vessels
and nerves, surrounds glands, forms laminar propria of mucous membranes.
- Nuclei visible -belong to fibroblast cells
- Dense, closely packed thick collagen fibres
Binds organs together.
Ligaments, tendons, skin.
- abundance of elastic fibres, note the wavy appearance
- few nuclei
Gives elastic quality.
Between adjacent vertibrae, walls of airways.
Large fat filled cells (nuclei not visible here, but usually squished to
outside of cell). Compared to other connective tissues it is very cellular.
- Storage of fat
- Provides reserve food supplies
Under the skin (subcutaneous tissue), around kidneys, bone marrow (yellow),
behind the eyeballs, breasts.
- Cells called chondrocytes found in spaces called lacunae
- Background matrix contains no visible fibres (collagen fibres are actually present,
but not visible)
- Provides pliable support
- Provides framework
Ends of bones, parts of nose, walls of trachea, connects ribs to sternum, forms
part of larynx, forms part of bronchial tree, epiphyseal plates.
- Fewer chondrocytes
- Abundance of collagen fibres
- Support that can withstand heavy pressures
Pubis symphysis of pelvic girdle, intervertebral disks, knee.
- Abundance of elastic fibres (looks messy)
- Support with great ability to bend
- Provides framework
Makes up framework for parts of the ear, larynx and epiglottis.
- Reticular Fibres present
- Cell nuclei visible belonging to reticular cells (a type of fibroblast)
Walls of liver and spleen
- Abundance of cells. Most cells are biconcave discs lacking nuclei (erythrocytes).
Also visible is one white blood cell, this is the most common type of leucocyte
called a neutrophil (note the lobed nucleus).
- Clear background matrix is the plasma, lacks any visible fibres.
- Transport of gases
- Fights infection
- Blood clotting
Inside blood vessels
Note: This is compact bone.
- Large cylindrical structures (Osteons or haversian systems)
- Smaller concentric layers (lamellae)
- In centre of haversian systems are canals (haversian canals). These
appear as solid black circles.
- Small cells (osteocytes).
- Provide framework
- Site of attachment of tendons
- Storage site of calcium
- Red marrow is site of blood cell production
Location (Compact bone)
This bone is found in the shafts of long bones.