Specialized Connective Tissue

• specialized connective tissue include a number of different tissues with specialized cells and unique ground substance
• 1. Adipose Tissue
  2. Cartilage
  3. Bones
  4. Blood
• connective tissue in which fat storing cells or adipocytes predominates
• adipose tissue normally represents 15-20% of the bodyweight in men and more than 20 in women
• adipocytes are very large cells derived from mesenchyme and specialized for energy storage in lipid droplets with triglyceride
• adipocytes of white fat are typically very large cells ranges in diameter from 50 to 150 micrometer
• cell in white adipose tissue contain primarily one large lipid droplet, causing the nucleus and remaining cytoplasm to be pushed against the plasmalemma
• 20% in well nourished men

  up to 25% In women

  more than 50% in obese
• white adipose tissue is distributed throughout the body particularly In deep layers of the skin
• White adipose tissue is specialized for relatively long term energy storage
• Brown adipose tissue has more mitochondria per cell than any other type of human tissue
• brown adipose tissue comprises up to 5% of the newborns body weight but smaller amounts in adults
• brown adipose tissue contain primarily small lipid droplet in cytoplasm containing many mitochondria and a central nucleus
• brown adipose tissue is specialized for generation of heat that plays a part in body
• BAT is characterized by expression of a unique coupling protein, UCP 1 [THGERMOGENIN]

  • in association with several other modulating factors, serves to uncouple mitochondrial metabolism from production of ATP to produce heat
• cartilage is a tough and resilient type of connective tissue that structurally support certain soft tissues
• cartilage provide cushioned, low friction surfaces in joints
• all types of cartilage lack vascular supplies and chondrocyte receive nutrients by diffusion from capillaries
• cartilage ECM includes CAP: Collagen, Aggrecan and Proteoglycan
• Cells of cartilage Is chondrocyte

  • synthesize and maintain all ECM components and are located in lacunae
• Pericondrium is a sheat of dense connective tissue that surround cartilage in most places, forming an interface between the cartilage and the tissues supported by the cartilage
• hyaline cartilage is the most common among three types. Is homogenous and semi transparent in fresh state
• hyaline cartilage is rich in type II collagen, has glassy appearance.
• perichondrium is usually present, but not at the hyaline cartilage of articular surfaces
• elastic cartilage provides support for the external ear as well as the walls of the external auditory canals
• elastic cartilage resembles hyaline in its chondrocyte and major ECM components but it's matrix includes abundant elastic fibers
• fibro cartilage contains varying combinations of hyaline cartilage in small amounts of dense connective tissue
• fibro cartilage provides very tough, strong support at tendon insertions
• all forms of cartilage forms from embryonic mesenchyme
• chondrogenesis is the process of cartilage formation
• cartlaginous structures grow by mitosis of existing chondroblast in lacunae or formation of new chondroblast
• repair or replacement of injured cartilage is very slow and ineffective, due in part to the tissues avascularity and low metabolic rate
• bone provides:

  • solid support for the body
  • protection for vital organs
  • site for hematopoiesis
  • serves as repository for calcium
  • system for mechanical locomotion
• osteoblast synthesize osteoid and mediate it's mineralization. Found lined up along bone surfaces
• osteocytes represents largely inactive osteoblast trapped within formed bone.
• osteoclast are phagocytic cells which are capable of eroding bone.
• bone matrix is the intercellular substance of the bone that forms most of the mass. It consists of organic and inorganic material
• Inorganic Material

  • 50% of the dry weight of bone matrix
• Organic Material

  • 90% type I collagen but also includes mostly small proteoglycans and multiadhesive glycoproteins such as osteonectin and osteocalcin
• Periosteum is a layer of dense connective tissue on the outer or external surface of bone