Structure of blood vessels MCQs With Answer

Structure of blood vessels MCQs With Answer is a focused study resource tailored for B. Pharm students to master vascular anatomy, histology, and pharmacological relevance. This introduction covers key concepts such as layers of blood vessels (tunica intima, media, adventitia), types of vessels (elastic, muscular arteries, arterioles, veins, capillaries), endothelial functions, vasa vasorum, and capillary types. Emphasis is placed on how structural features influence blood flow, compliance, permeability, and responses to vasoactive drugs like nitrates, calcium channel blockers, and ACE inhibitors. Clear, keyword-rich content supports exam preparation and clinical understanding. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the innermost layer of a blood vessel composed primarily of endothelial cells?

• Tunica media
• Tunica intima
• Tunica adventitia
• Vasa vasorum

Correct Answer: Tunica intima

Q2. Which layer of an artery contains smooth muscle responsible for vasoconstriction and vasodilation?

• Tunica intima
• Tunica media
• Tunica adventitia
• Endothelium

Correct Answer: Tunica media

Q3. Which vessels have the highest proportion of elastic fibers to allow stretch and recoil during the cardiac cycle?

• Muscular arteries
• Veins
• Elastic arteries (e.g., aorta)
• Capillaries

Correct Answer: Elastic arteries (e.g., aorta)

Q4. What is the primary function of the endothelial glycocalyx?

• Structural support of the tunica media
• Barrier to plasma proteins and mechanotransduction
• Formation of elastic lamellae
• Generating action potentials

Correct Answer: Barrier to plasma proteins and mechanotransduction

Q5. Which type of capillary has fenestrations that facilitate rapid exchange of water and solutes?

• Continuous capillary
• Fenestrated capillary
• Sinusoidal (discontinuous) capillary
• Arteriovenous shunt

Correct Answer: Fenestrated capillary

Q6. The external elastic lamina is most prominent in which type of vessel?

• Arterioles
• Large elastic arteries
• Muscular arteries
• Venules

Correct Answer: Muscular arteries

Q7. Which structural feature of veins helps prevent backflow of blood in the limbs?

• Elastic lamellae
• Endothelial fenestrations
• Venous valves
• Vasa vasorum

Correct Answer: Venous valves

Q8. Pericytes are associated with which vascular structure and what is their role?

• Arteries; generate pulse pressure
• Capillaries; stabilize endothelial cells and regulate blood flow
• Veins; form venous valves
• Lymphatics; absorb interstitial fluid

Correct Answer: Capillaries; stabilize endothelial cells and regulate blood flow

Q9. Which protein in the tunica media provides contractile function in vascular smooth muscle?

• Elastin
• Collagen type I
• Actin–myosin filaments
• Glycocalyx

Correct Answer: Actin–myosin filaments

Q10. The vasa vasorum supplies oxygen and nutrients to which part of large blood vessels?

• Tunica intima only
• Tunica media and adventitia of large vessels
• Capillary beds exclusively
• Endothelial glycocalyx

Correct Answer: Tunica media and adventitia of large vessels

Q11. Which receptor on vascular smooth muscle mediates vasoconstriction when activated by norepinephrine?

• Beta-2 adrenergic receptor
• Alpha-1 adrenergic receptor
• Muscarinic M2 receptor
• Histamine H1 receptor

Correct Answer: Alpha-1 adrenergic receptor

Q12. Endothelial production of nitric oxide (NO) primarily causes which effect on blood vessels?

• Vasoconstriction and increased permeability
• Vasodilation and inhibition of platelet aggregation
• Formation of venous valves
• Increased smooth muscle proliferation

Correct Answer: Vasodilation and inhibition of platelet aggregation

Q13. Which capillary type is typically found in the liver with large gaps allowing passage of cells and large proteins?

• Continuous capillary
• Fenestrated capillary
• Sinusoidal (discontinuous) capillary
• Metarteriole

Correct Answer: Sinusoidal (discontinuous) capillary

Q14. Which structural change increases arterial stiffness and is associated with aging and atherosclerosis?

• Increased glycocalyx thickness
• Fragmentation of elastic fibers and collagen deposition in the media
• Enhanced vasa vasorum perfusion only
• Loss of adventitial connective tissue

Correct Answer: Fragmentation of elastic fibers and collagen deposition in the media

Q15. Which technique or stain is commonly used to visualize elastic fibers in histology?

• Hematoxylin and eosin (H&E)
• Orcein or Verhoeff-Van Gieson stain
• Periodic acid–Schiff (PAS)
• Silver stain for reticulin

Correct Answer: Orcein or Verhoeff-Van Gieson stain

Q16. What structural feature distinguishes arterioles from small arteries?

• Presence of vasa vasorum
• Proportionally thicker tunica media with more elastic lamellae
• Smaller lumen with relatively more smooth muscle and fewer elastic fibers
• Endothelial fenestrations

Correct Answer: Smaller lumen with relatively more smooth muscle and fewer elastic fibers

Q17. How does the structure of capillary endothelial cells support selective permeability?

• Abundant smooth muscle in capillary walls
• Tight junctions and selective transport mechanisms like transcytosis
• Large tunica adventitia surrounding capillaries
• Presence of elastic lamellae

Correct Answer: Tight junctions and selective transport mechanisms like transcytosis

Q18. Which structural attribute primarily determines vascular compliance (capacity to expand with pressure)?

• Endothelial cell mitochondria count
• Relative amounts of elastin versus collagen in vessel wall
• Thickness of the internal elastic lamina only
• Number of pericytes on capillaries

Correct Answer: Relative amounts of elastin versus collagen in vessel wall

Q19. In which vessel type is the tunica adventitia the thickest relative to the media?

• Arterioles
• Large elastic arteries
• Veins
• Continuous capillaries

Correct Answer: Veins

Q20. Which molecule synthesized by endothelium promotes vasodilation and inhibits smooth muscle proliferation?

• Endothelin-1
• Nitric oxide (NO)
• Angiotensin II
• Thromboxane A2

Correct Answer: Nitric oxide (NO)

Q21. Which vascular layer contains connective tissue with collagen and fibroblasts and anchors vessels to surrounding tissue?

• Tunica intima
• Tunica media
• Tunica adventitia (externa)
• Basement membrane

Correct Answer: Tunica adventitia (externa)

Q22. What is the primary structural difference between muscular (distributing) arteries and elastic (conducting) arteries?

• Muscular arteries have more elastic lamellae than elastic arteries
• Elastic arteries have multiple elastic lamellae in the media; muscular arteries have more smooth muscle and less elastic tissue
• Muscular arteries lack endothelium
• Only elastic arteries contain vasa vasorum

Correct Answer: Elastic arteries have multiple elastic lamellae in the media; muscular arteries have more smooth muscle and less elastic tissue

Q23. Which structure regulates blood flow into capillary beds and is composed of smooth muscle?

• Venous valve
• Precapillary sphincter
• Vasa vasorum
• Elastic lamella

Correct Answer: Precapillary sphincter

Q24. Which feature of the endothelium plays a key role in preventing thrombosis under normal conditions?

• Expression of anticoagulant molecules like thrombomodulin and prostacyclin
• Endothelial fenestrations
• Dense collagen exposure on the luminal surface
• Endothelial synthesis of angiotensin II

Correct Answer: Expression of anticoagulant molecules like thrombomodulin and prostacyclin

Q25. How do calcium channel blockers induce vasodilation at the level of vascular smooth muscle?

• Increase intracellular calcium concentration
• Block L-type calcium channels, reducing calcium influx and smooth muscle contraction
• Activate alpha-1 receptors
• Inhibit nitric oxide synthase

Correct Answer: Block L-type calcium channels, reducing calcium influx and smooth muscle contraction

Q26. Which vessel type acts as the primary site of vascular resistance and contributes most to control of systemic blood pressure?

• Large elastic arteries
• Arterioles
• Capillaries
• Venules

Correct Answer: Arterioles

Q27. Which of the following best describes the basement membrane underlying endothelial cells?

• Thin extracellular matrix composed of collagen IV and laminin supporting endothelial cells
• Layer of smooth muscle fibers
• Aggregated elastic lamellae
• Collection of pericytes

Correct Answer: Thin extracellular matrix composed of collagen IV and laminin supporting endothelial cells

Q28. Which structural adaptation is typical of coronary arteries to meet high oxygen demand of the heart?

• Very thin tunica media with few muscle cells
• Well-developed tunica media with abundant smooth muscle and elastic tissue for autoregulation
• Absence of endothelium
• Extensive fenestrations in endothelial lining

Correct Answer: Well-developed tunica media with abundant smooth muscle and elastic tissue for autoregulation

Q29. Which vascular change is characteristic of venous hypertension and varicose veins?

• Loss of adventitia only
• Dilation of veins with valve incompetence and remodeling of the vessel wall
• Proliferation of elastic lamellae
• Transformation into muscular arteries

Correct Answer: Dilation of veins with valve incompetence and remodeling of the vessel wall

Q30. Which adhesion molecule on endothelial cells is upregulated during inflammation to recruit leukocytes?

• VEGF
• VCAM-1 and ICAM-1
• Elastin
• Thrombomodulin

Correct Answer: VCAM-1 and ICAM-1

Q31. Which type of capillary exchange involves bulk flow driven by hydrostatic and oncotic pressure differences?

• Diffusion
• Bulk filtration (Starling forces)
• Active transport via pumps
• Endocytosis of leukocytes

Correct Answer: Bulk filtration (Starling forces)

Q32. Which structural component is primarily responsible for tensile strength of the vessel wall?

• Elastic fibers (elastin)
• Collagen fibers (type I and III)
• Endothelial glycocalyx
• Pericytes

Correct Answer: Collagen fibers (type I and III)

Q33. In histology, which cell junctions are important for maintaining barrier function between endothelial cells?

• Desmosomes only
• Tight junctions (zonula occludens) and adherens junctions
• Neuromuscular junctions
• Gap junctions exclusively

Correct Answer: Tight junctions (zonula occludens) and adherens junctions

Q34. Which class of drugs improves endothelial function by enhancing nitric oxide availability and reducing vascular remodeling?

• ACE inhibitors and statins
• Thromboxane analogs
• Calcium salts
• Alpha-1 agonists

Correct Answer: ACE inhibitors and statins

Q35. What structural feature distinguishes postcapillary venules from arterioles?

• Postcapillary venules have more smooth muscle than arterioles
• Postcapillary venules have thin walls, pericytes, and are primary sites of leukocyte extravasation
• Arterioles lack endothelium
• Postcapillary venules contain elastic lamellae

Correct Answer: Postcapillary venules have thin walls, pericytes, and are primary sites of leukocyte extravasation

Q36. Which structural element on endothelial cells converts angiotensin I to angiotensin II at the vascular surface?

• Angiotensin-converting enzyme (ACE) on endothelial surface
• Endothelin-converting enzyme only in smooth muscle
• Thrombomodulin
• Nitric oxide synthase

Correct Answer: Angiotensin-converting enzyme (ACE) on endothelial surface

Q37. Which vessel has the greatest total cross-sectional area and is the slowest site of blood flow, facilitating exchange?

• Aorta
• Arterioles
• Capillaries
• Large veins

Correct Answer: Capillaries

Q38. Which histological change is typically seen in atherosclerotic plaques affecting arteries?

• Intimal thickening with lipid core, fibrous cap, and calcification
• Loss of endothelium only without intimal changes
• Exclusive adventitial inflammation with no intimal involvement
• Uniform increase in elastin only

Correct Answer: Intimal thickening with lipid core, fibrous cap, and calcification

Q39. Which vascular structure is primarily responsible for thermoregulatory shunting of blood between arterioles and venules?

• Continuous capillaries
• Arteriovenous anastomoses (shunts)
• Vasa vasorum
• Sinusoidal capillaries

Correct Answer: Arteriovenous anastomoses (shunts)

Q40. How does nitric oxide synthase in endothelium respond to shear stress and what is its consequence?

• Shear stress inhibits NOS, causing vasoconstriction
• Shear stress upregulates endothelial NOS (eNOS), increasing NO release and vasodilation
• Shear stress causes endothelial apoptosis only
• Shear stress converts endothelium into smooth muscle

Correct Answer: Shear stress upregulates endothelial NOS (eNOS), increasing NO release and vasodilation

Q41. Which structure prevents excessive distension of arteries and contributes to elastic recoil?

• Collagen in the adventitia only
• Elastic fibers in the tunica media
• Endothelial tight junctions
• Pericyte contraction

Correct Answer: Elastic fibers in the tunica media

Q42. Which factor is most important for transcytosis of macromolecules across continuous capillary endothelium?

• Fenestrations
• Caveolae-mediated vesicular transport
• Large intercellular gaps
• Elastic lamellae

Correct Answer: Caveolae-mediated vesicular transport

Q43. Which vessel component contains nerve fibers and provides autonomic regulation of vessel tone?

• Tunica intima only
• Tunica media and adventitia with sympathetic nerve fibers in adventitia
• Only capillaries have nerve innervation
• Vasa vasorum exclusively

Correct Answer: Tunica media and adventitia with sympathetic nerve fibers in adventitia

Q44. Which change in vessel wall composition would decrease compliance and increase pulse pressure?

• Increase in elastin relative to collagen
• Increase in collagen and decrease in elastin (stiffening)
• Thinning of the adventitia only
• Increased endothelial glycocalyx thickness

Correct Answer: Increase in collagen and decrease in elastin (stiffening)

Q45. Which vascular lesion involves a localized dilation of an artery due to weakening of the vessel wall?

• Varicose vein
• Aneurysm
• Thrombophlebitis
• Arteriovenous fistula

Correct Answer: Aneurysm

Q46. How do nitrates (e.g., nitroglycerin) cause vasodilation at the structural/biochemical level?

• Block adrenergic receptors
• Release NO, activate guanylate cyclase, increase cGMP and relax vascular smooth muscle
• Inhibit ACE directly in the adventitia
• Cross-link collagen fibers

Correct Answer: Release NO, activate guanylate cyclase, increase cGMP and relax vascular smooth muscle

Q47. Which structural property of capillaries in the blood–brain barrier maintains tight control of substance movement?

• Fenestrated endothelium and large intercellular clefts
• Tight junctions, continuous basement membrane, and astrocyte end-feet support
• Sinusoidal discontinuities
• High density of pericytes only

Correct Answer: Tight junctions, continuous basement membrane, and astrocyte end-feet support

Q48. Which change in the vessel wall is commonly induced by chronic hypertension?

• Medial hypertrophy with increased smooth muscle and reduced lumen diameter
• Thinning of the tunica media exclusively
• Loss of endothelial cells without remodeling
• Transformation into sinusoidal capillaries

Correct Answer: Medial hypertrophy with increased smooth muscle and reduced lumen diameter

Q49. Which structural characteristic allows veins to act as blood reservoirs (capacitance vessels)?

• Thick elastic media and low compliance
• Thin walls, large lumen, and high compliance
• Abundant fenestrated endothelium
• Multiple internal elastic lamellae

Correct Answer: Thin walls, large lumen, and high compliance

Q50. Which cellular event in endothelial cells promotes angiogenesis and new vessel formation in response to ischemia?

• Downregulation of VEGF receptors
• Upregulation of VEGF expression and endothelial cell proliferation/migration
• Complete loss of basement membrane without remodeling
• Inhibition of matrix metalloproteinases (MMPs)

Correct Answer: Upregulation of VEGF expression and endothelial cell proliferation/migration

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

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