69. Bones as a mineralized connective tissue. Chemical composition of the bones. Osteoblasts, osteocytes and osteoclasts – role in the formation and remodeling of bones. Biochemistry of the ossification and bone resorption. Regulation of the bone metabolism. Metabolic and genetic disorders that affect the bones. Biochemistry of cartilage. Calcium homeostasis and factors that affect calcium homeostasis.

Biochemical Processes in Epithelial and Connective Tissue

Epithelial Tissue:

• Function: Covers body surfaces, lines cavities, and forms glands. Functions include protection, absorption, secretion, and sensation.
• Cell Junctions: Tight junctions, adherens junctions, desmosomes, and gap junctions ensure cohesion and communication between cells.
• Basement Membrane: A specialized extracellular matrix (ECM) providing structural support and filtering functions. Composed mainly of collagen IV, laminins, nidogens, and perlecan.

Biochemical Processes in Epithelial and Connective Tissue

Connective Tissue:

• Function: Supports, binds, and protects other tissues and organs. Includes a variety of tissues such as bone, cartilage, adipose tissue, and blood.
• Extracellular Matrix (ECM): The ECM is a complex network of proteins and carbohydrates that provides structural and biochemical support to cells.

Biochemical Processes in Epithelial and Connective Tissue

Elastins

• Structure: Elastin is a key protein in connective tissue, providing elasticity. Composed of tropoelastin monomers that are cross-linked to form an elastic fiber network.
• Function: Allows tissues to resume their shape after stretching or contracting. Found in large amounts in tissues that require elasticity, such as lungs, arteries, and skin.
• Synthesis: Tropoelastin is secreted by cells and then assembled into fibers in the ECM, where it is cross-linked by lysyl oxidase.