Anatomy & Physiology Flashcards

The renal arteries arise from the abdominal aorta at approximately which vertebral level?

Answer: L2

The renal arteries originate from the lateral aspects of the aorta at approximately the L1–L2 vertebral level, just below the superior mesenteric artery.

Systemic vascular resistance (SVR) is primarily determined by:

Answer: Arteriolar diameter and blood viscosity

SVR is governed mainly by arteriolar tone (radius has a fourth-power effect via Poiseuille's law) and blood viscosity, making the arterioles the primary resistance vessels.

The thoracic duct drains lymph from all of the following EXCEPT:

Answer: Right upper extremity

The right upper extremity (and right head/neck/thorax) drains via the right lymphatic duct; all other body regions drain into the thoracic duct.

Which segment of the aorta passes through the diaphragm at the aortic hiatus?

Answer: Descending thoracic aorta

The descending thoracic aorta passes through the aortic hiatus of the diaphragm at the T12 level to become the abdominal aorta.

During normal respiration, the augmentation of venous return to the right heart is caused by:

Answer: Decreased intrathoracic pressure on inspiration

Inspiration lowers intrathoracic pressure, expanding the right atrium and great veins, which decreases central venous pressure and augments venous return.

The geniculate arterial network around the knee provides collateral circulation when which artery is obstructed?

Answer: Popliteal artery

The genicular branches of the popliteal artery form anastomoses around the knee joint, providing collateral flow when the popliteal artery itself is occluded.

Which layer of the venous wall is most responsible for venous tone and capacitance changes?

Answer: Tunica media

Although thinner than in arteries, the smooth muscle in the tunica media of veins responds to sympathetic stimulation to alter venous tone and the volume of blood stored.