Connective Tissue Proper

Cartilage

Bone

Connective Tissue Proper:

Loose Connective Tissue

Dense Connective Tissue

Adipose Tissue

Loose Connective Tissue:

Locations:-Space between skin and internal body parts-adventitia of blood vessels-surrounds gland parenchyma (epi)-lamina propria of GI tract

Loose Connective Tissue contains:

-ground substance-fibroblasts-adipose cells-macrophages-mast cells-undifferentiated cells-collagen, elastic and reticular fibers

Dense Connective Tissue:

Dense Irregular CT

Dense Regular CT

Dense Regular Collagenous CT

Dense Regular Elastic CT

Reticular Tissue

Adipose Tissue

Dense Connective Tissue:

-same components as LCT -fewer cells, more fibers

Dense Irregular CT - fiber arrangement is irregular-dermis of skin, nerve sheaths, capsules of spleen, -Testes, kindney, lymph nodes

Dense Regular Collagenous CT

– coarsely packed collagen bundles densely packed- parrallel or sheet like orientation- little space for cells and ground substance- Thin, sheet-like fibroblasts between collagen

bundles- Tendons and ligaments

Dense regular elastic connective tissue

• Around large blood vessels

• In the vertebral column

• Has course branching elastic fibers

• Few collagen fibers

• Elastic fibers are arranged parallel to each other, forming thin sheets of fenestrated membranes

Elastic fibers

• Found in LCT and as course bundles and sheets in dense regular elastic connective tissue

• Made by fibroblasts of CT and by smooth muscle cells in blood vessels

• Fibers contain the protein elastin (lots of glycine, proline, aa’s desmosine, isodesmosine cross-link elastin molecules.

Elastic fibers

• Fibers contain the protein elastin (lots of glycine, proline, aa’s desmosine, isodesmosine cross-link elastin molecules and impart elasticity (can stretch)

• Elastin in fiber core

• Sheath of microfibrils (10 nm), a glycoprotein

Reticular Tissue

• Framework (scaffolding) for liver, adipose tissue, bone marrow, lymph nodes, spleen etc.

• Fibroblasts make type II collagen

Adipose Tissue

• White (unilocular)

- single lipid droplet, capillaries go into ct septa between fat cells.

- Receptors for insulin, growth hormone, norepinephrine, glucocorticoids

- Subcutaneous, in masses around the body

Adipose Tissue

• Brown (multilocular)

• Multiple droplets

• Many mitochondria with cytochromes, lots of bv near the adipocytes

• In human infants around the neck and interscapular region (?around eyes?)

Formation of adipocytes

• Mesenchyme, may be a specific adipocyte precursor cell

• Early Fetal: epitheloid precursors

• Late fetal: secondary fat formation from fusiform precursor cells in ct.