Which of following is a function of the skeletal system?
A) body support
B) calcium homeostasis
C) protection of internal organs
D) blood cell production
Small, oddly shaped bones that fill gaps between bones of the skull are called ________ bones.
The ________ interactions allow bone to be strong, somewhat flexible, and highly resistant to shattering.
How would removing hydroxyapatite from bone matrix affect the physical properties of a bone?
The bone would be more flexible.
The type of bone that is adapted to withstand stresses that arrive from many directions is ________ bone.
Which of the following is a characteristic of bone?
The bone matrix is very dense and contains deposits of calcium salts.
Which statement is true regarding calcium in bone matrix?
Calcium is found in crystals called hydroxyapatite.
Which of the following is formed by intramembranous ossification?
the roof of the skull and the clavicle
The following are important steps in the process of endochondral ossification.
1. Enlarged chondrocytes die.
2. Osteoblasts replace calcified cartilage with spongy bone.
3. Chondrocytes enlarge and the surrounding matrix begins to calcify.
4. Blood vessels invade the perichondrium.
5. Perichondrial cells become osteoblasts and produce a thin shell of bone.
The correct order for these events is
Which of the following statements about Marfan's syndrome is false?
results in short, stubby fingers
Bone growth in length occurs by mitosis of
cartilage cells in the epiphyseal side of the metaphysis.
Suppose that epiphyseal lines appear in a 10-year-old's long bones. Which of the following statements is therefore true?
The epiphyseal plates have ossified and further growth in length is not possible.
When cartilage is produced at the epiphyseal side of the metaphysis at the same rate as bone is deposited on the opposite side, bones
The following are major steps in the process of intramembranous ossification:
1. Clusters of osteoblasts form osteoid that becomes mineralized.
2. Osteoblasts differentiate within mesenchymal connective tissue.
3. Spicules of bone radiate out from the ossification centers.
4. Mesenchymal cells aggregate.
When stress is applied to a bone,
the minerals in the bone produce a weak electrical field that attracts osteoblasts.
Parathyroid hormone functions in all of the following ways, except that it
inhibits calcitonin secretion.
Hundreds of years ago explorers often died of scurvy. How can this bone-related disease be prevented?
supplement the diet with fresh fruit rich in Vitamin C
How is vitamin D (vitamin D3) related to calcium homeostasis in bone?
Vitamin D is involved in calcium absorption by the digestive tract so calcium is available for ossification and remodeling.
The disease osteomalacia causes calcium loss from the skeleton, which would result in bones that are
weaker and more flexible.
After a fracture of the diaphysis has healed, the thickened region that results is called the
While on a school skiing trip in Colorado, Heidi falls and breaks her tibia and fibula in a Pott fracture. What would you expect as a prominent part of her clinical assessment several hours after the fall?
Put the following steps of bone repair in correct sequence:
1. Cartilage in the external callus is replaced by bone.
2. A hematoma occurs.
3. An internal callus forms at the site of injury.
4. Osteoclasts remodel the bone at the site of repair.
Osteoclast-activating factor does all of the following, except that it
is released in large amounts early in life.
Why does osteoporosis affect more women than men?
Women have a decrease in sex hormones after menopause whereas men continue to produce male sex hormones throughout adulthood.
If a tumor secretes high levels of osteoclast-activating factor, which of the following would you expect to occur as a result of this condition?
increases in blood levels of calcium
decreased bone density
increased osteoclast activity
Mary is 50 years old and has entered menopause. During a checkup, a bone scan reveals the beginnings of osteoporosis. Her physician suggests hormone therapy. What hormone might she prescribe for her patient?