Anatomy and Physiology Basics Flashcards

Which layer of the skin contains the keratinocytes that produce the protein keratin?

Answer: Epidermis

Keratinocytes are the predominant cells of the epidermis and synthesize keratin to form a protective barrier.

The sinoatrial (SA) node is located in which chamber of the heart?

Answer: Right atrium

The SA node, the heart's natural pacemaker, is located in the upper wall of the right atrium.

Which hormone is responsible for stimulating the reabsorption of sodium in the renal tubules?

Answer: Aldosterone

Aldosterone, secreted by the adrenal cortex, promotes sodium reabsorption in the distal tubule and collecting duct.

The brachial plexus originates from which spinal cord segments?

Answer: C5–T1

The brachial plexus arises from ventral rami of C5 through T1 and innervates the upper extremity.

Which digestive enzyme, secreted by the pancreas, specifically cleaves peptide bonds adjacent to aromatic amino acids?

Answer: Chymotrypsin

Chymotrypsin cleaves peptide bonds on the carboxyl side of aromatic (phenylalanine, tyrosine, tryptophan) and large hydrophobic amino acids.

The glomerular filtration rate (GFR) is primarily maintained by which mechanism when systemic blood pressure fluctuates?

Answer: Renal autoregulation

Renal autoregulation keeps GFR stable across a wide range of blood pressures through myogenic and tubuloglomerular mechanisms.

Which cranial nerve controls the majority of parasympathetic innervation to thoracic and abdominal viscera?

Answer: Cranial nerve X

The vagus nerve (CN X) provides parasympathetic innervation to the heart, lungs, and most abdominal organs as far as the splenic flexure.