Anatomy & Physiology Flashcards

Which nerve is responsible for the motor innervation of the diaphragm?

Answer: Phrenic nerve (C3, C4, C5)

The phrenic nerve, arising from cervical roots C3, C4, and C5, provides the primary motor innervation to the diaphragm, the principal muscle of inspiration.

The left recurrent laryngeal nerve loops around which structure?

Answer: Aortic arch

The left recurrent laryngeal nerve loops under the aortic arch before ascending to the larynx; this long course explains why left-sided lesions (e.g., aortic aneurysm, lung tumors) commonly cause hoarseness.

Which valve separates the left atrium from the left ventricle?

Answer: Mitral (bicuspid) valve

The mitral (bicuspid) valve, consisting of two leaflets, separates the left atrium from the left ventricle and prevents backflow during ventricular systole.

The blood supply to the SA node is most commonly from which artery?

Answer: Right coronary artery

The SA node receives its blood supply from the SA nodal artery, which arises from the right coronary artery in approximately 60% of individuals.

Which portion of the nephron is primarily responsible for glucose reabsorption?

Answer: Proximal convoluted tubule

Virtually all filtered glucose is reabsorbed in the proximal convoluted tubule via sodium-glucose cotransporters (SGLT2), up to the renal threshold of approximately 180 mg/dL.

The normal adult resting heart rate range is:

Answer: 60–100 bpm

A normal resting heart rate in adults is defined as 60–100 beats per minute; rates below 60 are bradycardia and above 100 are tachycardia.