MCAT Biology : Musculoskeletal System and Muscle Tissue

Study concepts, example questions & explanations for MCAT Biology

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Example Questions

Example Question #32 : Bone

Which of the follwoing is not an important function of bone?  

Possible Answers:

Regulation of ion concentration

Muscular contraction

Organ and nerve protection

Regulation of pH through hydration

Correct answer:

Regulation of pH through hydration

Explanation:

The skeleton plays a role in musclular contraction in that it serves as an anchor and provides leverage against which muscles can exert force. It also serves as protection and support for soft tissues. Bones also maintain certain ion concentrations. The correct answer choice is the regulation of pH through hydration, which is not a function of the skeletal system.

Example Question #33 : Bone

Bone hardness is primarily due to which of the following?

Possible Answers:

Hydroxyapatite (composed of glycosaminoglycans and collagen) and bicarbonate

Hydroxyapatite (composed of calcium and bicarbonate) and collagen

Hydroxyapatite (composed of calcium and phosphorus) and collagen

Glycosaminoglycans and collagen

Correct answer:

Hydroxyapatite (composed of calcium and phosphorus) and collagen

Explanation:

There are organic (collagen) and inorganic (hydroxyapatite) components of the bone that contribute to its characteristic hardness. The key here is knowing the composition of hydroxypatite, which is primarily constructed of calcium and phosphorus.

Example Question #34 : Bone

Which of the following would cause a bone to lose flexibility?  

Possible Answers:

Removal of proteins

Removal of hydroxyapatite

Removal of bone minerals

Removal of organic and inorganic bone components

Correct answer:

Removal of proteins

Explanation:

Collagen is a protein that allows the bone to be somewhat flexible, so "removal of proteins" is the only correct answer. Other answer choices involve inorganic bone material, which add to hardness of the skeleton, but not to its flexibility.

Example Question #33 : Bone

Haversian systems are found in which of the following?

Possible Answers:

Compact bone

Red bone marrow

Spongy bone

Yellow bone marrow

Correct answer:

Compact bone

Explanation:

Compact and spongy bone have similar chemical and structural compositions and are both hard and resistant to compression; however, due to the fact that compact bone is denser, nutrients are delievered through canals called Haversian systems in compact bone; spongy bone is less dense and lacks these specialized canals.

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