Anatomy & Physiology Flashcards

The external carotid artery (ECA) is distinguished from the internal carotid artery (ICA) by the fact that the ECA:

Answer: Gives rise to branches in the neck

The ECA has multiple branches in the neck (e.g., superior thyroid, lingual, facial arteries), whereas the ICA has no branches in the neck until it enters the skull.

The ankle-brachial index (ABI) is calculated by dividing the ankle systolic pressure by:

Answer: The higher of the two brachial systolic pressures

ABI is calculated using the highest ankle systolic pressure (dorsalis pedis or posterior tibial) divided by the highest of the two brachial systolic pressures.

Fenestrated capillaries, which allow rapid exchange of larger molecules, are most characteristic of which organ?

Answer: Kidney glomerulus

Glomerular capillaries of the kidney are fenestrated to permit filtration of plasma components across the glomerular filtration barrier.

The peroneal (fibular) artery typically arises from which vessel?

Answer: Tibioperoneal trunk

The tibioperoneal trunk is a short common segment that branches off the popliteal artery and then bifurcates into the posterior tibial and peroneal arteries.

Which mechanism primarily drives the return of lymph through lymphatic vessels against gravitational forces?

Answer: Intrinsic smooth muscle contraction of lymphangions

Lymphangions are segments of lymphatic vessels separated by valves; their smooth muscle walls contract rhythmically to propel lymph centrally.

At rest, approximately what percentage of total blood volume is contained in the venous system?

Answer: 65%

About 64–65% of total blood volume resides in the venous system at rest, making veins the primary capacitance vessels of the circulation.

The circle of Willis provides collateral cerebral circulation by connecting the anterior and posterior circulations. Which vessel connects the two anterior cerebral arteries?

Answer: Anterior communicating artery

The anterior communicating artery bridges the left and right anterior cerebral arteries, completing the anterior portion of the circle of Willis.