38.E: The Musculoskeletal System (Exercises)
38.1: Types of Skeletal Systems
Review Questions
The forearm consists of the:
- radius and ulna
- radius and humerus
- ulna and humerus
- humerus and carpus
- Answer
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A
The pectoral girdle consists of the:
- clavicle and sternum
- sternum and scapula
- clavicle and scapula
- clavicle and coccyx
- Answer
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C
All of the following are groups of vertebrae except ________, which is a curvature.
- thoracic
- cervical
- lumbar
- pelvic
- Answer
-
D
Which of these is a facial bone?
- frontal
- occipital
- lacrimal
- temporal
- Answer
-
C
Free Response
What are the major differences between the male pelvis and female pelvis that permit childbirth in females?
- Answer
-
The female pelvis is tilted forward and is wider, lighter, and shallower than the male pelvis. It is also has a pubic angle that is broader than the male pelvis.
What are the major differences between the pelvic girdle and the pectoral girdle that allow the pelvic girdle to bear the weight of the body?
- Answer
-
The pelvic girdle is securely attached to the body by strong ligaments, unlike the pectoral girdle, which is sparingly attached to the ribcage. The sockets of the pelvic girdle are deep, allowing the femur to be more stable than the pectoral girdle, which has shallow sockets for the scapula. Most tetrapods have 75 percent of their weight on the front legs because the head and neck are so heavy; the advantage of the shoulder joint is more degrees of freedom in movement.
38.2: Bone
Review Questions
The Haversian canal:
- is arranged as rods or plates
- contains the bone’s blood vessels and nerve fibers
- is responsible for the lengthwise growth of long bones
- synthesizes and secretes matrix
- Answer
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B
The epiphyseal plate:
- is arranged as rods or plates
- contains the bone’s blood vessels and nerve fibers
- is responsible for the lengthwise growth of long bones
- synthesizes and secretes bone matrix
- Answer
-
C
The cells responsible for bone resorption are ________.
- osteoclasts
- osteoblasts
- fibroblasts
- osteocytes
- Answer
-
A
Compact bone is composed of ________.
- trabeculae
- compacted collagen
- osteons
- calcium phosphate only
- Answer
-
C
Free Response
What are the major differences between spongy bone and compact bone?
- Answer
-
Compact bone tissue forms the hard external layer of all bones and consists of osteons. Compact bone tissue is prominent in areas of bone at which stresses are applied in only a few directions. Spongy bone tissue forms the inner layer of all bones and consists of trabeculae. Spongy bone is prominent in areas of bones that are not heavily stressed or at which stresses arrive from many directions.
What are the roles of osteoblasts, osteocytes, and osteoclasts?
- Answer
-
Osteocytes function in the exchange of nutrients and wastes with the blood. They also maintain normal bone structure by recycling the mineral salts in the bony matrix. Osteoclasts remove bone tissue by releasing lysosomal enzymes and acids that dissolve the bony matrix. Osteoblasts are bone cells that are responsible for bone formation.
38.3: Joints and Skeletal Movement
Review Questions
Synchondroses and symphyses are:
- synovial joints
- cartilaginous joints
- fibrous joints
- condyloid joints
- Answer
-
B
The movement of bone away from the midline of the body is called ________.
- circumduction
- extension
- adduction
- abduction
- Answer
-
D
Which of the following is not a characteristic of the synovial fluid?
- lubrication
- shock absorption
- regulation of water balance in the joint
- protection of articular cartilage
- Answer
-
C
The elbow is an example of which type of joint?
- hinge
- pivot
- saddle
- gliding
- Answer
-
A
Free Response
What movements occur at the hip joint and knees as you bend down to touch your toes?
- Answer
-
The hip joint is flexed and the knees are extended.
What movement(s) occur(s) at the scapulae when you shrug your shoulders?
- Answer
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Elevation is the movement of a bone upward, such as when the shoulders are shrugged, lifting the scapulae. Depression is the downward movement of a bone, such as after the shoulders are shrugged and the scapulae return to their normal position from an elevated position.
38.4: Muscle Contraction and Locomotion
Review Questions
In relaxed muscle, the myosin-binding site on actin is blocked by ________.
- titin
- troponin
- myoglobin
- tropomyosin
- Answer
-
D
The cell membrane of a muscle fiber is called a ________.
- myofibril
- sarcolemma
- sarcoplasm
- myofilament
- Answer
-
B
The muscle relaxes if no new nerve signal arrives. However the neurotransmitter from the previous stimulation is still present in the synapse. The activity of ________ helps to remove this neurotransmitter.
- myosin
- action potential
- tropomyosin
- acetylcholinesterase
- Answer
-
D
The ability of a muscle to generate tension immediately after stimulation is dependent on:
- myosin interaction with the M line
- overlap of myosin and actin
- actin attachments to the Z line
- none of the above
- Answer
-
D
Free Response
How would muscle contractions be affected if ATP was completely depleted in a muscle fiber?
- Answer
-
Because ATP is required for myosin to release from actin, muscles would remain rigidly contracted until more ATP was available for the myosin cross-bridge release. This is why dead vertebrates undergo rigor mortis.
What factors contribute to the amount of tension produced in an individual muscle fiber?
- Answer
-
The cross-sectional area, the length of the muscle fiber at rest, and the frequency of neural stimulation.
What effect will low blood calcium have on neurons? What effect will low blood calcium have on skeletal muscles?
- Answer
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Neurons will not be able to release neurotransmitter without calcium. Skeletal muscles have calcium stored and don’t need any from the outside.