Physiology II w/Lab Q&A | Portage Learning
1. The three layers of blood vessel walls, from innermost to outermost, are:
A) Tunica media, tunica intima, tunica externa
B) Tunica intima, tunica media, tunica externa
C) Tunica externa, tunica media, tunica intima
D) Tunica media, tunica externa, tunica intima
Correct Answer: B) Tunica intima, tunica media, tunica externa
Rationale: The innermost layer is the endothelium‑lined tunica intima; the
middle, smooth muscle‑rich tunica media controls vasomotion; the outermost
connective tissue tunica externa anchors the vessel. This order is consistent
throughout the vascular system.
2. The tunica media is primarily composed of:
A) Simple squamous epithelium
B) Smooth muscle and elastic fibers
C) Dense irregular connective tissue
D) Areolar connective tissue
Correct Answer: B) Smooth muscle and elastic fibers
Rationale: The tunica media's smooth muscle allows vasoconstriction and
vasodilation, regulating blood flow and pressure. Elastic fibers provide recoil.
,The other layers are endothelium (intima) or supportive connective tissue
(externa).
3. Which blood vessels have valves to prevent backflow?
A) Arteries
B) Arterioles
C) Capillaries
D) Veins
Correct Answer: D) Veins
Rationale: Venous valves, formed from folds of tunica intima, ensure
unidirectional flow toward the heart, especially in limbs. Arteries rely on
pressure; capillaries lack valves.
4. The vasa vasorum are small vessels that supply blood to:
A) The endocardium
B) The tunica intima
C) The walls of large blood vessels
D) Capillary beds
Correct Answer: C) The walls of large blood vessels
Rationale: Large arteries and veins have their own nutrient supply via vasa
vasorum within the tunica externa. The innermost layers receive nutrients from
the lumen.
, 5. Which layer of the heart wall is responsible for contraction?
A) Epicardium
B) Myocardium
C) Endocardium
D) Pericardium
Correct Answer: B) Myocardium
Rationale: The myocardium is the thick, contractile middle layer of cardiac
muscle. The epicardium is the outer serous layer, the endocardium lines
chambers, and the pericardium is the protective sac.
6. The pericardial cavity contains which organ?
A) Lungs
B) Heart
C) Thymus
D) Trachea
Correct Answer: B) Heart
Rationale: The heart is located within the pericardial cavity, surrounded by the
pericardial sac. Lungs are in pleural cavities, thymus in the mediastinum,
trachea in the neck/thorax.
7. The right atrium receives deoxygenated blood from the: