Bone Tissue Pt2 Feb 20

Morphism and Body Proportions

• Morphism: Refers to the study of the shape and size of organisms.

• Different types and reasons behind disproportionate body development:

  • Pituitary Growth: A condition characterized by overall short stature with short arms, legs, and torso, but normal proportions.

  • Axial vs. Appendicular Proportions:

    • Axial: Refers to the central part of the body (skull, vertebral column).

    • Appendicular: Refers to limbs (arms and legs).

    • Examples involve having short appendicular components while axial remains normal or vice versa.

Bone Differences and Composition

• Brittle Bone vs. Rubbery Bone:

  • Brittle Bone: Results from lack of collagen or inadequate calcium leading to fracturing under tension.

  • Rubbery Bone: High in collagen; lacks calcium which leads to flexibility.

• Organic Material:

  • Collagen: The organic component that provides flexibility.

  • Inorganic Material:

    • Calcium and Minerals: Provide strength and rigidity.

Bone Structure and Function

• Resistance to Forces:

  • Bones need to balance resistance to compression and tension to avoid fractures.

  • Weak or overly flexible bones can lead to instability.

• Mineral Deposition:

  • Involves cells that deposit bone (osteoblasts) and cells that absorb bone (osteoclasts).

  • Osteoblasts: Build bones and require a cooperative balance with osteoclasts.

  • Osteoclasts: Resorb bone; essential for maintaining calcium levels in the blood.

Role of Calcium in the Body

• Importance of Calcium:

  • Crucial for muscle contractions, nerve signaling, and blood clotting.

  • Homeostasis maintained through hormones such as calcitriol and parathyroid hormone (PTH).

• Hypocalcemia vs. Hypercalcemia:

  • Hypocalcemia (low calcium): Leads to muscle spasms, increased muscle tension, potential for injury.

  • Hypercalcemia (high calcium): Can result in lethargy, weakness, and potential cardiac issues.

Hormonal Regulation of Calcium Levels

• Calcitriol:

  • Synthesized from vitamin D. Increases calcium absorption in the intestine.

  • Acts as a hormone and regulates calcium levels.

• PTH and Calcitonin:

  • PTH: Elevates blood calcium levels by promoting osteoclast activity and reducing calcium excretion in urine.

  • Calcitonin: Lowers blood calcium levels, inhibiting osteoclasts and promoting osteoblasts.

Bone Fractures and Healing Process

• Types of Bone Fractures:

  • Classified based on the complexity of the break:

    • Closed (Simple): Bone does not break the skin.

    • Open (Compound): Bone breaks through the skin.

    • Complete: Fracture goes through the entire bone.

    • Incomplete: Fracture does not go fully through the bone (e.g., greenstick fracture in children).

• Healing Process:

  • Stages include hematoma formation, granulation tissue, callus formation (both soft and hard), and remodeling.

  • Healing can take several weeks depending on fracture severity and individual health.

Osteoporosis and Bone Health

• Osteoporosis: Condition characterized by porous and fragile bones, common in older adults due to mineral loss.

• Risk Factors: Age, gender, diet (calcium and vitamin D deficiency), and hormonal changes, especially post-menopause.

• Prevention and Treatment:

  • Exercise, proper nutrition, hormone replacement therapies, and medications that affect calcium metabolism.

Conclusion

• Understanding the structure and function of bones is essential in fields such as medicine and genetics.

• A balanced approach to calcium and hormone regulation is key to maintaining healthy bones throughout life.