Question

prostaglandins are ______ substances that regulate neighboring cells.
○ glycoprotein
○ paracrine
○ endocrine
○ eccrine
question 18
2 pts
moving an arm so that it traces a cone is called ______.
○ rotation
○ circumduction
○ protraction
○ pronation

Explanation:

• Prostaglandins are paracrine substances. Paracrine signaling involves cells releasing signaling molecules that act on nearby cells. Prostaglandins are lipid - derived compounds that act on neighboring cells to regulate various physiological processes such as inflammation, smooth muscle contraction, etc. Glycoproteins are proteins with attached carbohydrate groups and are not the main classification for prostaglandins in terms of their signaling mechanism. Endocrine substances are secreted into the bloodstream to act on distant cells, and eccrine refers to a type of sweat gland (not relevant here).
• Moving an arm so that it traces a cone is called circumduction. Rotation is the turning of a bone around its own long axis. Protraction is the anterior movement of a body part. Pronation is the rotation of the forearm so that the palm faces backward (in the anatomical position). Circumduction is a complex movement that combines flexion, extension, abduction, and adduction in a circular motion (tracing a cone - like path).

Answer:

• For the first question: B. paracrine
• For the second question: B. circumduction