Anatomy & Physiology Fundamentals Flashcards

Which type of epithelial tissue lines the alveoli of the lungs to facilitate gas exchange?

Answer: Simple squamous epithelium

Simple squamous epithelium forms the thin walls of alveoli, minimizing diffusion distance for O2 and CO2 exchange.

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

Answer: Right atrium

The SA node is embedded in the posterior wall of the right atrium near the entrance of the superior vena cava.

Which hormone is primarily responsible for regulating serum calcium levels by promoting bone resorption?

Answer: Parathyroid hormone (PTH)

PTH stimulates osteoclast activity and renal calcium reabsorption to raise blood calcium when levels fall.

What is the functional unit of the kidney responsible for filtration and urine formation?

Answer: Nephron

The nephron is the structural and functional unit of the kidney, encompassing the glomerulus, tubules, and collecting duct.

Which leukocyte type is the predominant cell in acute bacterial infections and constitutes 50–70% of circulating white blood cells?

Answer: Neutrophils

Neutrophils are the most abundant granulocytes and serve as the primary responders to bacterial infections via phagocytosis.

The portal triad in liver histology consists of a portal venule, a bile ductule, and which third structure?

Answer: Hepatic artery branch

Each portal triad contains a branch of the portal vein, a branch of the hepatic artery, and a bile ductule.

In the renal tubule, which segment is the primary site of active sodium reabsorption driven by Na+/K+-ATPase?

Answer: Proximal convoluted tubule

The proximal convoluted tubule reabsorbs approximately 65% of filtered sodium via Na+/K+-ATPase on the basolateral membrane.