Chapter 7
Skeletal System
Part A
1. List four groups of bones based upon their shapes, and name an example from each group.
a. Long bones—Humerus and Femur
b. Short bones—Tarsals and Carpals
c. Flat bones—Scapula, Cranial Bones
d. Irregular bones—Vertebral column, Ear bones
2. Sketch a typical long bone, and label its epiphyses, diaphysis, medullary cavity, periosteum, and articular cartilages.
On diagram that we drew and labeled.
3. Distinguish between spongy and compact bone.
Spongy bone is lighter than compact bone due to the spaces that appear between multiple bony plates. Compact bone on the other hand is made up of tissues compressed together therefore solidifying the tissues making the bone less susceptible to bend. Explain how central canals and perforating canals are related.
Central canals are surrounded by loose connective tissue and contain few blood vessels and a nerve that provide nourishment to the bone cells in the osteonic canals whereas Perforating canals house larger blood vessels and nerves and provide communication to the surface of the bone and medullary cavity from the osteonic canals.
4. Explain how the development of intramembranous bone differs from that of endochondral bone.
Intramembranous bones are flat bones that develop from layers of connective tissue. The osteoblasts then deposit tissue around them and eventually form osteocytes in the lacunae. These cells then give rise to the periosteum. Endochondral bones develop a hyaline cartilage that eventually develops into bone due to ossification and the appearance of the periosteum. Distinguish between osteoblasts and osteocytes.
5. Distinguish between osteocytes and osteoblasts
Osteocytes are bone cells that are located in the middle of the matrix while osteoblasts create bone cells such as the osteocytes.

6. Explain the function of an epiphyseal plate.
The epiphyseal plate is located near the epiphyses of the bone that contain cells responsible for growth as the plate thickens due to cell production.

7. Explain how a bone grown in thickness.
The bone grows thicker due to the deposit of connective tissues outside the periosteum.

8. Define osteoclast.
An osteoclast is a bone cell developed from an osteoblast that absorbs bone tissue during the growth and healing processes.
9. Explain how osteoclasts and osteoblasts regulate bone mass.
Osteoclasts digest the organic components of the lysosomal enzymes and break down the inorganic material within the calcified matrix. The osteoblasts then appear to replace and deposit bone tissue.
10. Describe the effects of vitamin deficiencies on bone development.
A lack of vitamins that provide the bone with calcium could result in weakening of the bones and other deficiencies such as osteomalacia. The lack of other vitamins responsible for the absorption of nutrients could affect the growth rate of an individual.
11. Explain the causes of pituitary dwarfism and gigantism.
Pituitary dwarfism is a result of an inadequate amount of the pituitary growth hormone. Pituitary gigantism, in turn, is a result of an overabundant supply of the pituitary growth hormone prior to ossification.
12. Describe the effects of thyroid and sex hormones on bone development.
Thyroid hormones are responsible for replacing cartilage located within the long bone tissue which can thereby effect bone growth as a result of early ossification. Sex hormones have a huge effect on bone tissue responsible for providing females with specific attributes that males do not possess and vice versa. A deficiency in this hormone could affect the physical stature of a being.
13. Explain the effects of exercise on bone structure.
Exercise is beneficial to the bones and their tissues providing solidity and strength. A lack of exercise could then result in weak, brittle bones as the muscles and tissues working hand in hand with the bone are no longer being activated as often.
14. Provide several examples to illustrate how bones support and