Chapter 6 Review Answers
1. Compare and contrast the two ways that bones form. (Pg. 145)
Intramembranous
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Forms many flat skull bones, parts of the mandible, and clavicles.
Develops from layers of connective tissues
Osteoblasts within the membranous layers form bone tissue (compact over spongy).
Mature bone cells are called osteocytes.
Primitive connective tissue gives rise to the periosteum.
Endochondral
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All bones except some bones of the skull and clavicles.
Bones are modeled in hyaline cartilage.
Begins forming late in 2nd month of human development until early adulthood.
Primary ossification center appears in the diaphysis whereas secondary ossification centers appear in the epiphysis.
– Epiphyseal plate between the two.
2. How do osteoclasts and osteoblasts work together to remodel bone tissue?(Pg. 143, 144, 146)
Osteoclasts dissolve the bony matrix and the osteoblasts form new bony matrix. They work together to keep the bones healthy and
strong.
3. What does bone require to grow normally? (Pg. 147)
Bones require consistent minerals including vitamin D, A and C. The role of vitamin D is being able to absorb/metabolize calcium.
Vitamin A & vitamin C help bone to grow and be strong.
4. How do bones support and protect? List some examples. (Pg. 141)
Bones support the body by creating structural support and attachments for other tissues. EX. Tibia is an attachment site for the
Achilles tendon. Bones protect soft and delicate organs. EX. Skull protects the brain.
5. What mechanical devices do we compare moving body parts to? (Pg. 141)
Bones act as levers to change the magnitude and direction of the forces generated by skeletal muscle.
6. What is the difference between red and yellow marrow? Where is each found? What happens in the
marrow? (Pg. 141/MOSTLY NOTES)
Red Bone Marrow
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Red color
Consists mainly of hematopoietic tissue-Blood making
Found in flat bones (pelvis, sternum, cranium, ribs, scapula), vertebrae and spongy epiphyses of long bones.
Produces red blood cells, white blood cells and platelets
Yellow Bone Marrow
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Yellow color
Yellow marrow is found in the medullary cavity(diaphysis of long bones)
Mainly fat cells
During aging red marrow is replaced by yellow
In cases of severe blood loss the body can convert the yellow marrow back to red
7. List the substances normally stored in bone tissue. (Pg. 141)
Calcium salts (Ca3(PO4)2 are stored to help make sure an adequate amount of calcium and phosphate ions are in the body fluids for
use. Also the bones store lipids for energy reserves (yellow marrow).
8. Why is bone lost faster, with aging, than bone replacement?(Pg. 150)
Osteoblast activity begins to decline, while osteoclast activity continues at previous levels or increases. This causes bones to become
thinner and weaker.
9. What is the difference between closed and open fractures? What steps are necessary for fractures to heal?
(Pg. 148-149)
Closed fracture are completely internal and don’t involve a break in the skin.
Open fractures project through the skin and can lead to a higher risk of infection because of the exposure to the inside.
1. Hematoma forms closing off the injured blood vessels in fractured bone.
2. Periosteum/endosteum cells divide forming an internal and external callus. In callus cells differentiate into chondrocytes and
produce hyaline cartilage.
3. Osteoblast replace cartilage with spongy bone
4. Compact bone will replace fragments of dead bone and calluses remaining.
10. How is the male and female pelvis different?(Pg. 169)
Female pelvis generally smoother, lighter in weight and has less prominent markings. Also women will have a larger pelvic opening &
pubic angle to bear children.
11. What main tissue does osseous tissue belong to? (Pg. 141)
Supporting connective tissue
Skeletal functions. Know all 5!