Bone Health and nutrition
Which vitamin is essential for calcium absorption and bone strength?
Vitamin D
Which hormone in males helps maintain bone density?
Testosterone
How does excessive alcohol intake affect bone health?
It reduces calcium absorption and inhibits osteoblasts, weakening bone.
What is Osteogenesis Imperfecta commonly called?
Brittle Bone Disease
What is rigor mortis and why does it occur after death?
Post-death stiffening from ATP depletion; myosin heads can’t detach from actin.
What condition results from severe vitamin D deficiency?
Rickets in children and osteomalacia in adults
Why are postmenopausal women at greater risk for osteoporosis?
Estrogen levels drop, leading to faster bone breakdown (↑ osteoclast activity).
Name one long-term medication that can reduce bone strength.
Corticosteroids (e.g., prednisone).
Which protein is defective in Osteogenesis Imperfecta?
Type I collagen
What does the term “myopathy” mean?
Any disease or disorder of muscle tissue.
How does low calcium intake during adolescence affect peak bone mass?
It reduces peak bone density, increasing future osteoporosis risk.
How does low testosterone contribute to bone weakness in men?
It lowers osteoblast activity and decreases bone formation.
Explain how corticosteroids weaken bones over time.
They inhibit osteoblasts and increase calcium loss from kidneys.
How does Osteogenesis Imperfecta differ from osteoporosis?
OI = genetic collagen defect; osteoporosis = age/hormone/lifestyle bone loss.
Which genetic disorder causes progressive muscle weakness mainly in boys?
Duchenne Muscular Dystrophy
Explain how vitamin D and calcium work together to maintain bone mineralization.
Vitamin D increases intestinal calcium absorption; calcium supplies the mineral for bone formation.
Compare how estrogen and testosterone influence osteoblast and osteoclast activity
Both promote osteoblasts and suppress osteoclasts; loss of either increases bone resorption.
How do smoking and alcohol together amplify osteoporosis risk?
They both reduce hormone levels (estrogen/testosterone) and impair calcium use.
Why can minor trauma cause fractures in OI patients?
Weak collagen matrix makes bones fragile and unable to absorb stress.
How does Myasthenia Gravis interfere with muscle contraction?
Autoantibodies block acetylcholine receptors at neuromuscular junctions.
A vegan patient presents with low bone density. Identify two dietary factors and one lifestyle factor that may contribute.
Low intake of calcium and vitamin D (food), plus limited sun exposure.
A 60-year-old woman and man both have low bone density. Explain the hormonal differences causing this.
Woman: estrogen deficiency after menopause → rapid loss. Man: gradual testosterone decline → slower loss.
A patient on long-term prednisone has bone pain. Describe the physiological process leading to fragility.
Chronic steroid use suppresses bone formation, increases bone resorption, and causes net bone loss.
Describe how a gene mutation leads to abnormal collagen and weak bones.
COL1A1/COL1A2 mutation → faulty collagen → poor mineralization → low bone strength.
Compare Duchenne Muscular Dystrophy, Myasthenia Gravis, and Spinal Muscular Atrophy
DMD = dystrophin defect (muscle fiber damage); MG = autoimmune ACh receptor loss; SMA = motor-neuron degeneration → muscle wasting.