Question

Anatomy Mini-Tutorial: Skeletal System Disorders

Answer 1

> too much growth hormone: gigantism (bones are too long) and acromegaly (bones are too thick) often caused by a tumor in the pituitary gland

conversely if there is too little growth hormones there is insufficient activity at the epiphyseal ends of long bones resulting in very short bones. uncommon condition.

> achondroplasia: caused when the epiphyseal cartilage ends are replaced w/ bone too early. results in abnormally short limbs. caused by deformity on chromosome 4.
- major cause of dwarfism (which is why the head/vertebra/etc. of people w/ the condition are normal but their limbs are abnormally short)

> Marfan syndrome: too much cartilage formed, causes abnormally long limbs. weakened blood

> Osteomalcia (adult rickets): softening of the bones due to poor ossification
- called "rickets" if in children. usu. caused by low vitD.

Answer 2

> Osteopoenia: inadequate ossification that is a normal part of aging. Caused by an decrease in osteoblast (remember, osteoblasts are the cells that lay down bone matrix to make more bone) while osteoclast activity remains the same
- affects the epiphyses, jaws, and vertebra which is why older people tend to be shorter, have more teeth/jaw problems, and weaker limbs

> Osteoporosis: similar to osteopoenia but is considered abnormal lack of ossification and damage to structural integrity that interferes w/ normal functioning.
- linked to menopause (lower estrogen production) which is why it's more common in women then men
- some cancers produce osteoclast activating factor which stimulates osteoclast activity which may contribute to this condition

Put these in a separate category b/c osteoporosis is more common and more easily preventable with adequate nutrition (calcium, vitD, sunlight, weight-bearing exercise). Drugs like calcitonin + estrogen supplements and biphosphonates can also help.