Question

1. part a

which of the following describes the suprahyoid muscles?
○ they are a group of muscles that lie superior to the hyoid bone and help form the floor of the
oral cavity.
○ they move the pharynx superiorly during swallowing.
○ they depress the larynx and hyoid bone if the mandible is fixed.
○ they are often called strap muscles.

1. part a

the supraspinatus is named for its location on the posterior aspect of the scapula above the spine. what is its action?
○ to initiate abduction of the arm, to stabilize the shoulder joint and to help prevent downward
dislocation of the humerus
○ to flex and adduct the humerus and to act as a synergist of the pectoralis major
○ to extend and medially rotate the humerus and to act as a synergist of the latissimus dorsi
○ to help hold the head of the humerus in the glenoid cavity and rotate the humerus laterally

1. part a

the concentration of ions in the chemical environment surrounding the neurons must be tightly regulated for neurons to function
which of the following cells is most responsible for this?
○ schwann cells
○ astrocytes
○ oligodendrocytes
○ satellite cells

Explanation:

Question 17 (Suprahyoid Muscles)

To determine the correct description of suprahyoid muscles:

• Option 1: Suprahyoid muscles lie superior to the hyoid bone and form the floor of the oral cavity. This matches their anatomical role.
• Option 2: Moving the pharynx superiorly during swallowing is not their primary action (infrahyoid or other muscles are more involved).
• Option 3: Depressing the larynx/hyoid with a fixed mandible is an action of infrahyoid muscles, not suprahyoid.
• Option 4: “Strap muscles” typically refer to sternohyoid, sternothyroid, etc. (infrahyoid), not suprahyoid.

The supraspinatus is part of the rotator cuff:

• Option 1: It initiates arm abduction, stabilizes the shoulder joint, and prevents downward dislocation (matches its function).
• Option 2: Flexing/adducting the humerus is not its role (pectoralis major is for adduction/flexion).
• Option 3: Extending/medially rotating the humerus is not its action (latissimus dorsi is for extension/medial rotation).
• Option 4: Holding the humeral head in the glenoid and lateral rotation is not its primary action (other rotator cuff muscles like infraspinatus handle lateral rotation).

To identify the cell regulating ion concentration around neurons:

• Schwann cells: Form myelin in the PNS (not ion regulation).
• Astrocytes: Regulate ion concentration, neurotransmitter uptake, and blood-brain barrier (matches).
• Oligodendrocytes: Form myelin in the CNS (not ion regulation).
• Satellite cells: Support PNS ganglia (not ion regulation around CNS neurons).

Answer:

A. They are a group of muscles that lie superior to the hyoid bone and help form the floor of the oral cavity

Question 18 (Supraspinatus Action)