6. Bones & Skeletal Tissue

During fetal intramembranous ossification, bone develops from __________.

Intramembranous ossification __________.

Long bone growth at the epiphyseal plate is similar to __________.

In adolescence, the 'growth spurt' that is observed is mainly attributed to an increase in __________.

Most bones below the base of the skull form by endochondral ossification.

Before eight weeks, the skeleton of the human embryo is composed of __________.

Rickets can be caused by __________.

A condition that produces a reduction in bone mass sufficient to compromise normal function is __________.

Mary is 50 years old. During a checkup, a bone scan reveals that portions of her skeleton show signs of osteoporosis. After reviewing the test results, her physician suggests hormone therapy. What hormone is prescribed for Mary?

If a breastfeeding mother becomes vitamin D deficient, what disease is most likely to develop in the nursing infant?

Bone remodeling in adults is regulated and directed mainly by a. growth hormone b. thyroid hormones c. sex hormones d. mechanical stress e. PTH.

The disorder in which bones are porous and thin but bone composition is normal is a. osteomalacia b. osteoporosis c. Paget's disease.

Describe in proper sequence the events of endochondral ossification in a long bone.

As we grow, our long bones increase in diameter, but the thickness of the compact bone of the shaft remains relatively constant. Explain this phenomenon.

Describe the process of new bone formation in an adult bone. Use the terms osteoid seam and calcification front in your discussion.

a. Why are fractures most common in elderly individuals? b. Why are greenstick fractures most common in children?

Why do you think wheelchair-bound people with paralyzed lower limbs have thin, weak bones of the leg and thigh?

Mrs. Abbruzzo brought her 4-year-old daughter to the doctor, complaining that she didn't 'look right.' The child's forehead was enlarged, her rib cage was knobby, and her lower limbs were bent and deformed. X rays revealed very thick epiphyseal plates. Mrs. Abbruzzo was advised to increase dietary amounts of vitamin D and milk and to get the girl outside to play in the sun. Considering the child's signs and symptoms, what disease do you think she has? Explain the doctor's instructions.

What would a long bone look like at the end of adolescence if bone remodeling did not occur?

Noah Beckenstein went to weight-lifting camp in the summer between seventh and eighth grade. He noticed that the camp trainer put tremendous pressure on him and his friends to improve their strength. After an especially vigorous workout, Noah's arm felt extremely sore and weak around the elbow. He went to the camp doctor, who took X rays and then told him that the injury was serious, for the 'end of his upper arm bone was starting to twist off.' What had happened? Could the same thing happen to Noah's 23-year-old sister, Karen, who was also starting a program of weight lifting? Why or why not?

Osteocytes residing in lacunae of osteons of healthy compact bone are located quite a distance from the blood vessels in the central canals, yet they are well nourished. How can this be explained?

Multiple Choice More than one choice may apply. osteocyte.

Multiple Choice More than one choice may apply. Which of the following would you expect to be prominent in osteoclasts? a. Golgi apparatus b. Lysosomes c. Microfilaments d. Exocytosis

Exposure to optimum amounts of sunlight is necessary for proper bone maintenance and growth in children. (a) What does sunlight do to promote bone maintenance and growth?

Exposure to optimum amounts of sunlight is necessary for proper bone maintenance and growth in children. (b) If a child lives in an area where exposure to sunlight is rare because of pollution or overcast skies, what can be done to minimize impaired maintenance and growth of bone?

The presence of an epiphyseal line indicates (a) epiphyseal growth has ended, (b) epiphyseal growth is just beginning, (c) growth of bone diameter is just beginning, (d) the bone is fractured at the location, (e) no particular event.

The hormones that coordinate the storage, absorption, and excretion of calcium ions are (a) growth hormone and thyroxine, (b) calcitonin and parathyroid hormone, (c) calcitriol and cholecalciferol, (d) estrogens and androgens.

What is the primary difference between endochondral ossification and intramembranous ossification?

a. What nutritional factors are essential for normal bone growth and maintenance?

b. What hormonal factors are necessary for normal bone growth and maintenance?

Which three organs or tissues interact to assist in the regulation of calcium ion concentration in body fluids?

What are the major effects of parathyroid hormone?

The process of bone growth at the epiphyseal cartilage is similar to (a) intramembranous ossification, (b) endochondral ossification, (c) the process of osteopenia, (d) the process of healing a fracture, (e) the process of calcification.

The vitamins essential for normal adult bone maintenance and repair are (a) A and E, (b) C and D3, (c) B and E, (d) B complex and K.

Compare and contrast controls of bone remodeling exerted by hormones and by mechanical and gravitational forces, including the purpose of each control system and changes in bone architecture that might occur.

Formation of the bony callus in fracture repair is followed by a. hematoma formation b. fibrocartilaginous callus formation c. bone remodeling d. formation of granulation tissue.

While playing on her swing set, 10-year-old Sally falls and breaks her right leg. At the emergency room, the doctor tells her parents that the proximal end of the tibia where the epiphysis meets the diaphysis is fractured. The fracture is properly set and eventually heals. During a routine physical when she is 18, Sally learns that her right leg is 2 cm shorter than her left, probably because of her accident. What might account for this difference?

Deborah, a 75-year-old woman, stumbled slightly while walking, then felt a terrible pain in her left hip. At the hospital, X-ray images revealed that the hip was broken. Also, the compact bone and spongy bone throughout her spine were very thin. What was her probable condition?

The primary reason that osteoporosis accelerates after menopause in women is (a) reduced levels of circulating estrogens, (b) reduced levels of vitamin C, (c) diminished osteoclast activity, (d) increased osteoblast activity.

The nonpathologic loss of bone that occurs with aging is called (a) osteomyelitis, (b) osteoporosis, (c) osteopenia, (d) osteitis, (e) osteomalacia.

Why do extended periods of inactivity cause degenerative changes in the skeleton?

Which of the following conditions would you possibly observe in a child who is suffering from rickets? (a) abnormally short limbs, (b) abnormally long limbs, (c) oversized facial bones, (d) bowed legs, (e) weak, brittle bones

Frank does not enter puberty until he is 16. What effect would you predict this will have on his stature? (a) Frank will probably be taller than if he had started puberty earlier. (b) Frank will probably be shorter than if he had started puberty earlier. (c) Frank will probably be a dwarf. (d) Frank will have bones that are heavier than normal. (e) The late onset of puberty will have no effect on Frank's stature.