Which bone is commonly known as the collarbone?

A. Cardiac muscle: Cardiac muscle is found only in the heart and contracts involuntarily to pump blood. While it shares some involuntary characteristics with smooth muscle, it is specialized for rhythmic contraction and is not present in the walls of other internal organs.

B. Smooth muscle: Smooth muscle is found in the walls of internal organs such as the stomach, intestines, and blood vessels. It functions involuntarily, controlling movements like peristalsis and vessel constriction without conscious effort, making it essential for organ function.

C. Striated muscle: Striated muscle refers to muscle with a striped appearance, including both skeletal and cardiac muscle. Striated muscle does not describe smooth muscle and is not primarily involved in involuntary movements of internal organs.

D. Skeletal muscle: Skeletal muscle is under voluntary control and is attached to bones to facilitate movement. It is not found in internal organs and does not function automatically, distinguishing it from smooth muscle.

A. Detection of chemical changes: Chemoreceptors respond to chemical stimuli, such as changes in oxygen, carbon dioxide, or pH, rather than mechanical forces.

B. Detection of mechanical stimuli such as pressure and vibration: Mechanoreceptors are specialized to sense physical deformation of tissues, including pressure, vibration, touch, and stretch, providing critical information about the environment and body position.

C. Detection of light stimuli: Photoreceptors in the eyes detect light and are not involved in sensing mechanical changes.

D. Detection of temperature changes: Thermoreceptors respond specifically to heat or cold, not to mechanical forces like pressure or vibration.