6b

Osteophyte and Rickets

  • Rickets is a disease in children, while osteophyte (or osteomalacia) presents similarly in adults.

  • Both conditions result from poorly mineralized bones.

    • Osteoid Production:

    • Osteoblasts are responsible for producing osteoid.

    • However, calcium salts are not adequately deposited.

    • Resulting Symptoms:

    • Soft, weak bones.

    • Pain when bearing weight.

    • In children, rickets can lead to bow legs and other deformities.

  • Common causes in children:

    • Vitamin D deficiency.

    • Dietary calcium deficiency.

    • Note: This is rare in the United States, usually occurring when a mother is solely breastfeeding and is vitamin D deficient.

Osteoporosis

  • Osteoporosis characterized by the presence of pores in bone tissue (indicated by visible porosity).

  • It is often associated with calcium deficiency.

  • Population Affected:

    • Primarily affects women; more common in women than men.

    • This is because of the drop in estrogen levels post-menopause.

    • By age 60-70, approximately 30% of women will experience this condition.

    • By age 80, this figure rises to about 70%.

    • Fracture Risk:

    • About 30% of Caucasian women are expected to experience fractures related to osteoporosis.

  • Factors contributing to osteoporosis:

    • Gender: Women are at higher risk due to estrogen loss during menopause.

    • Age: Risk increases significantly with age.

    • Body Composition: Individuals with a petite body form are at greater risk.

    • Lifestyle: Lack of exercise, poor dietary intake (especially of calcium and protein), smoking, and alcohol consumption (which leeches calcium from bones).

    • Medical Conditions:

    • Hyperthyroidism, low levels of thyroid-stimulating hormones, and diabetes mellitus.

    • Males with prostate or testicular cancer, especially those treated with anti-testosterone medications, are also at risk.

Treatment for Osteoporosis

  • Key intervention strategies for osteoporosis include:

    • Calcium and Vitamin D supplements: Essential for bone health.

    • Weight-bearing exercises: Activities such as walking and running help strengthen bones.

    • Hormone Replacement Therapy:

    • Controversial due to increased risk of heart attacks, strokes, and breast cancer associated with estrogen replacement after menopause.

    • Medications:

    • Bisphosphonates: Designed to inhibit osteoclast activity (cells that break down bone).

    • Selective Estrogen Receptor Modulators and Adenosine-based treatments: Mentioned for awareness but not on tests.

  • Preventive Measures:

    • Start prevention early. Regular calcium intake is crucial to prevent osteoclast activity from weakening bones.

    • Physical Activity Recommendations:

    • Minimum of 30 minutes of exercise per day for maintenance; longer durations for weight loss or muscle building are preferred.

Other Diseases of Bone

  • Paget's Disease:

    • Characterized by accelerated bone remodeling leading to uneven bone growth (appearing moth-eaten).

    • Occurs generally after age 40, and the specific cause is unknown, possibly linked to viral infection.

    • Treatment Options:

    • Calcitonin: Hormone regulating calcium levels in the body.

    • Bisphosphonates: Similar role in inhibiting osteoclasts as in osteoporosis treatment.

Bone Development and Ossification

  • Embryonic Skeleton Development:

    • Ossification begins at approximately 8-9 weeks of embryonic development, with most long bones ossifying by 8 weeks and completion expected by 12 weeks.

    • At birth, most long bones are ossified, with exceptions for epiphyses, which include cartilage.

  • Epiphyseal Plates:

    • These persist through childhood and adolescence, playing a crucial role in bone growth.

  • Growth and Resorption Patterns:

    • In children and adolescents, bone formation exceeds resorption.

    • Males typically have greater bone mass than females.

    • In adulthood, resorption of bone exceeds formation, leading to a gradual decrease in bone density over time.

    • Bone density is influenced by genetics and decreases with age.

    • There is a specific gene related to Vitamin D's cellular docking, affecting early mass, bone mineralization, and healing capacity.

Final Quiz Preparation

  • Students are encouraged to familiarize themselves with images and terms covered in class for an oral quiz, particularly names and locations of bones within the skeletal system.

  • Assessments:

    • Students should be prepared to identify various bones and structures from the skeleton.