connective tissue

• Functions of Connective Tissue:

  • Structural framework
  • Transports nutrients, waste, and gases
  • Protection and support
  • Energy storage (fat cells)
  • Mineral storage
  • Defense and protection
  • Hematopoiesis
• Components of Connective Tissue:

  • Fibroblast: synthesizes various components of connective tissue
  • Lymphocytes: involved in immune responses
  • Mast cell:
  • Produces inflammation inhibitors such as histamine, prostaglandins, and leukotrienes
  • Alleviates pain, edema, and allergic reactions
  • Plasma cell:
  • Derived from B-lymphocytes
  • Produces antibodies
• Types of Collagen (protein fibers):

  • Type 1 collagen: provides strength and structure to various tissues
  • Type 2 collagen: found in cartilage
  • Type 3 collagen: forms a supportive network in organs like lymphoid tissue
• Locations of Connective Tissues:

  • Loose Connective Tissue:
  • Areolar tissue:
  • Provides support and elasticity
  • Found beneath epithelial tissues, lamina propria of mucous membranes, and surrounding organs
  • Adipose tissue:
  • Stores energy, provides insulation, and cushions organs
  • Found in the hypodermis, around kidneys and eyeballs, abs, and breasts
  • Reticular tissue:
  • Supports and filters blood cells in lymphoid organs
  • Found in lymphoid organs like the spleen and lymph nodes, bone marrow
• Clinical Conditions:

  • Ehlers Danlos syndrome:
  • Hyper elasticity of skin and hypermobility of joints
  • Due to abnormal collagen type 3 (reticular), causing ruptures in arteries and other organs
  • Marfan syndrome:
  • Mutation of the fibrillin gene
  • Results in arterial rupture (high blood pressure) and abnormalities in elastic tissue
• Dense Connective Tissue:

  • Elastic tissue:
  • Provides flexibility and recoil
  • Found in walls of large arteries, bronchioles, and elastic ligaments
  • Dense regular tissue:
  • Provides strength and resists tensile forces
  • Found in tendons, ligaments, and aponeurosis
  • Dense irregular tissue:
  • Provides strength and support in multiple directions
  • Found in the dermis of the skin, submucosa of intestines, capsules around organs, and fibrous sheaths
• Blood:

  • Fluid connective tissue composed of plasma, erythrocytes, leukocytes, and platelets
  • Functions in transporting oxygen, nutrients, hormones, and waste products throughout the body
• Cartilage Types, Characteristics, and Growth:

  • Supportive Connective Tissue
  • Chondroblast: synthesizes cartilage matrix
  • Chondrocytes: mature cartilage cells found within lacunae
  • Types of Cartilage:
  • Hyaline cartilage: provides support and flexibility
  • Elastic cartilage: provides flexible support
  • Fibrocartilage: resists compression
  • Cartilage Growth:
  • Appositional growth: addition of new matrix on the surface
  • Interstitial growth: growth from within the cartilage matrix
• Characteristics/Properties of Bone:

  • Vascularized
  • Canaliculi deliver nutrients and oxygen to bone cells
  • Periosteum: fibrous membrane surrounding bones
  • Osteoblasts: responsible for bone matrix formation
  • Osteocytes: mature bone cells found within lacunae
  • Osteoprogenitor cells: stem cells for bone repair
  • Osteoclasts: responsible for bone resorption
  • Matrix:
  • Hardened
  • Inorganic component: Calcium salts
  • Organic component (osteoid): Type 1 collagen and proteoglycans