Question

12/11/25, 9:18 am bio 121 final exam
6.
part a
from the list below, select the least likely explanation for the relatively high mobility of the arms.
the subscapular notch is a passageway for nerves.
the scapula does not articulate to the axial skeleton directly.
the clavicle articulates to the axial skeleton at only the sternal end.
the relatively open glenoid cavity of the glenohumeral joint.

7.
part a
the shallow socket of the shoulder joint restricts dislocation of the humerus and is the main contributor to the stability of the
true
false

8.
part a
the wrist joint can exhibit adduction and eversion movements.
true
false

9.
part a
movement of the ankle so that the superior aspect of the foot approaches the shin is called plantar flexion.
true
false

10.
part a
which of the following is true about smooth muscle?
smooth muscle, in contrast to skeletal muscle, cannot synthesize or secrete any connective
tissue elements.
smooth muscle cannot stretch as much as skeletal muscle.
certain smooth muscle cells can actually divide to increase their numbers.
smooth muscle has well - developed t tubules at the site of invagination.

11.
part a
although all the anatomical parts of muscle work together to give it its characteristics, which of the following proteins is
be most associated with the characteristics of extensibility?
potassium (k⁺) leak channels
thick (myosin) filaments
elastic (titin) filaments
acetylcholine receptors in the motor end plate

Explanation:

Question 6

To determine the least likely explanation for arm mobility, analyze each option:

• Subscapular notch (nerve passage) doesn’t directly relate to mobility (focuses on nerves, not joint mechanics).
• Scapula not articulating directly with axial skeleton allows more movement (reduces restrictions).
• Clavicle articulating only at sternal end (and with scapula) enables scapular/arm mobility.
• Open glenoid cavity (shallow socket) increases mobility (but reduces stability).

The subscapular notch’s role in nerve passage is unrelated to mobility mechanics, making it the least likely explanation.

The shoulder joint’s glenoid cavity (socket) is shallow, which increases mobility but decreases stability (dislocation is common in shoulders). A shallow socket does not restrict dislocation or contribute to stability. Thus, the statement is false.

The wrist joint (radiocarpal) allows abduction/adduction (side-to-side) but eversion (turning sole outward) is an ankle/foot movement (involves subtalar joint). Wrist cannot evert. Thus, the statement is false.

Answer:

The subscapular notch is a passageway for nerves.

Question 7