6. Bones & Skeletal Tissue

Which substances are stored in bones?

Where would you be most likely to find an irregular bone?

Which of the following statements is true?

Which bones form via intramembranous ossification?

a. Irregular bones

b. Certain flat bones

c. Long bones

d. Short bones

e. More than one of the above

Of the following statements, identify those that are properties of intramembranous ossification, endochondral ossification, or both.

a. The bone is formed via a hyaline cartilage model.

b. Bone tissue forms from ossification centers.

c. Bone forms from within a mesenchyme membrane.

d. The early spongy bone is formed, after which the early compact bone develops.

e. The original primary bone is replaced with secondary bone.

f. A bone collar forms, followed by the early spongy bone.

Explain the effect that the following hormones have on growth of bone tissue:

a. Growth hormone

Explain the effect that the following hormones have on growth of bone tissue:

b. Testosterone

Explain the effect that the following hormones have on growth of bone tissue:

c. Estrogen

Fill in the blanks. Bone deposition is carried out by_____, which secrete the____ of the ECM by exocytosis. They facilitate the formation of the______of the ECM by secreting_____filled with calcium ions, enzymes, and ATP. Bone resorption is carried out by______ , which secrete_____and_____from their ruffled border.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

b. Bone deposition is triggered by tension placed on the bone.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

c. The greater the load the bone must carry, the more bone that is resorbed by osteoclasts.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

d. Calcitonin is released in response to an elevated calcium ion concentration in the blood.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

e. Parathyroid hormone increases the blood calcium ion concentration by increasing the activity of osteoblasts.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

f. Vitamin D is required for calcium ion absorption from the intestines and retention in the kidneys.

Which of the following influences bone remodeling?

a. Vitamins such as vitamins D, C, and K

b. Intake of calcium ions

c. Hormones such as estrogen and testosterone

d. All of the above

Correctly order the following steps of fracture repair, placing a 1 by the first step, a 2 by the second step, and so on.          

____Osteoblasts in the periosteum lay down a bone callus of primary bone.          

____Damaged blood vessels bleed and fill the gap between the bone fragments with a hematoma.          

____The bone callus is remodeled and replaced with secondary bone.          

____Fibroblasts, chondroblasts, and blood vessels enter the clot, and the soft callus begins to bridge the gap between bone fragments.

Explain why a person who is wheelchair-bound or bed-bound often has very low bone mass, especially in his or her legs.

How could diseases of the kidney, skin, and/or intestines cause diseases of the bone?

How could a disease that affects primarily cartilage impact bone growth and bone formation?

Explain why young men who take anabolic steroids (which mimic the actions of testosterone) often display stunted growth and have an overall shorter stature.

Lucy Dupre is a 2-year-old girl living in northern Canada. You notice that her growth seems abnormally slow and she has exhibited signs of weakened bones, including fractures. Her parents admit they have not supplemented her diet with vitamin D, as they feel that any supplementation is 'unnatural' and 'not organic.' Explain why Lucy is having problems with her bones and bone growth.

Fouz Akkad is a 6-year-old girl who has been diagnosed with a rare genetic defect in which her lysosomes are unable to maintain an acidic pH. What are lysosomes? Why do lysosomes require an acidic pH? How will this affect the ability of certain bone cells to function? What consequences will this disease have on Fouz's bones?

Mark the following statements about bone tissue as true or false. If a statement is false, correct it to make a true statement.

f. Osteocytes are mature and less active osteoblasts that have become surrounded by bone ECM.

Explain how abnormal bone structure could affect muscle function.