Blood Supply Questions
1. Which of the blood vessels below supplies most of the lateral surface of the cerebral hemispheres with blood?
- A. anterior cerebral arteries
- B. posterior cerebral arteries
- C. anterior choroidal arteries
- D. middle cerebral arteries
Show Answer
Correct answer: D
The middle cerebral arteries supply most of the lateral surface of the cerebral hemispheres, including parts of the frontal, temporal, and parietal lobes. They're especially important for areas involved in language, motor, and sensory functions.
2. Which structural feature of endothelial cells in brain capillaries most directly prevents substances from moving from the bloodstream into the brain at the blood–brain barrier?
- A. large pores in endothelial cells
- B. tight junctions between endothelial cells
- C. aquaporin channels in endothelial cell membranes
- D. voltage-gated ion channels on endothelial cells
Show Answer
Correct answer: B
It is thought that the central components of the structure of the blood-brain barrier are the tight junctions of endothelial cells, the cells that make up the interior surface of blood vessels. The endothelial cells that make up the blood-brain barrier are fused tightly together to form tight junctions that restrict diffusion across the blood vessel lining.
3. A patient experiences a stroke affecting the posterior cerebral artery. Which of the following functions is most likely to be affected?
- A. vision
- B. fine motor control of the hand
- C. language production
- D. balance and coordination
Show Answer
Correct answer: A
The posterior cerebral artery supplies the occipital lobe, which is the primary center for visual processing. A stroke in this territory commonly causes visual deficits.
4. These arteries supply most of the medial surface of the frontal and parietal lobes:
- A. middle cerebral arteries
- B. posterior cerebral arteries
- C. anterior choroidal arteries
- D. anterior cerebral arteries
Show Answer
Correct answer: D
The anterior cerebral arteries supply most of the medial surface of the frontal and parietal lobes.
5. In a thrombotic stroke (i.e., a stroke caused by a thrombus), a blood clot:
- A. forms in a distant site and then travels to the brain
- B. forms in a cerebral vein and blocks venous blood outflow from the brain
- C. forms locally in an artery in the brain or an artery that supplies the brain
- D. forms only in the blood supply to the peripheral nervous system
Show Answer
Correct answer: C
When a blood clot forms in same area where the blockage occurs, it is known as a thrombus. When a blood clot forms at a distant site and then travels to another part of the body or the brain to block a blood vessel, it is known as an embolus. A thrombotic stroke involves a blood clot that forms in the brain or in an artery that directly supplies the brain.
6. A patient reports that after a stroke, they cannot see anything in the right visual field of either eye. An MRI shows an infarct in the occipital lobe. Which artery was most likely occluded?
- A. middle cerebral artery
- B. anterior cerebral artery
- C. anterior communicating artery
- D. posterior cerebral artery
Show Answer
Correct answer: D
The posterior cerebral artery supplies the occipital lobe, including the primary visual cortex.
7. Which of the following arteries is part of the circle of Willis?
- A. posterior inferior cerebellar artery
- B. anterior cerebral artery
- C. anterior choroidal artery
- D. middle cerebral artery
Show Answer
Correct answer: B
The anterior cerebral, internal carotid, and posterior cerebral arteries on both sides of the brain are interconnected by the anterior and posterior communicating arteries, forming a ring-like structure known as the circle of Willis. This interconnection can allow blood flow to continue if a major vessel is blocked on one side of the brain.
8. Which artery connects the left and right anterior cerebral arteries?
- A. basilar artery
- B. middle cerebral artery
- C. posterior inferior cerebellar artery
- D. anterior communicating artery
Show Answer
Correct answer: D
The anterior cerebral arteries supply the medial frontal and parietal lobes, and they are connected by the anterior communicating artery.
9. The carotid arteries supply the brain with around 70-80% of its blood. Which arteries supply the remaining 20-30%?
- A. posterior cerebral arteries
- B. anterior choroidal arteries
- C. vertebral arteries
- D. spinal arteries
Show Answer
Correct answer: C
While the internal carotid arteries carry about 70-80% of the blood to the brain, the vertebral arteries carry the remaining 20-30%. The carotid system provides the majority of blood flow to the cerebral hemispheres, while the vertebral system primarily supplies the brainstem, cerebellum, and posterior parts of the cerebral hemispheres.
10. What is the most common cause of spontaneous subarachnoid hemorrhage?
- A. ischemic stroke
- B. rupture of a brain aneurysm
- C. meningitis
- D. seizure
Show Answer
Correct answer: B
The most common cause of spontaneous (non-traumatic) subarachnoid hemorrhage is the rupture of a brain aneurysm.
11. A 70-year-old man develops right-sided weakness and difficulty speaking. Imaging shows a blood clot blocking his middle cerebral artery, causing death of brain tissue in the frontal lobe. Which type of stroke has occurred?
- A. hemorrhagic stroke
- B. ischemic stroke
- C. transient ischemic attack (TIA)
Show Answer
Correct answer: B
Ischemia is a term that refers to a reduction in blood supply to a bodily tissue, and ischemic strokes occur when blood flow to a part of the brain is blocked or restricted. This is most commonly due to a blood clot blocking a blood vessel.
12. Which of the following best describes the defining difference between a transient ischemic attack (TIA), also known as a "mini-stroke," and a stroke?
- A. a TIA causes mild symptoms, while a stroke causes more severe symptoms
- B. a TIA does not cause lasting damage to the brain, while a stroke does
- C. a TIA only affects small blood vessels, while a stroke affects larger vessels
- D. a TIA occurs in individuals under the age of 45 only
Show Answer
Correct answer: B
The defining difference between a TIA and an actual stroke is that TIAs do not result in a brain infarct, or death of brain tissue, while a true stroke does.
13. A patient presents with a sudden, severe “worst headache of their life.” Imaging confirms rupture of a saccular (berry) aneurysm in the Circle of Willis. Which type of brain hemorrhage most commonly results from this event?
- A. epidural hemorrhage
- B. subdural hemorrhage
- C. subarachnoid hemorrhage
- D. intraparenchymal hemorrhage
Show Answer
Correct answer: C
Subarachnoid hemorrhage can be caused by a variety of conditions, but the most common and severe cases typically result from the rupture of a brain aneurysm. Subarachnoid hemorrhage usually begins suddenly, with a severe headache that develops within seconds, sometimes referred to as a thunderclap headache.
14. Which of the following vessels is NOT considered part of the Circle of Willis?
- A. anterior choroidal artery
- B. anterior cerebral artery
- C. internal carotid artery
- D. posterior cerebral artery
Show Answer
Correct answer: A
The Circle of Willis is made up of the anterior cerebral arteries, internal carotid arteries, posterior cerebral arteries, anterior communicating artery, and posterior communicating arteries. The interconnection of these vessels can allow blood flow to continue if a major vessel is blocked on one side of the brain.
15. In brain blood vessels, which cells form the tight junctions that are the main structural feature of the blood-brain barrier?
- A. glial cells
- B. smooth muscle cells
- C. endothelial cells
- D. oligodendrocytes
Show Answer
Correct answer: C
Endothelial cells line the interior of brain capillaries and form tight junctions, which are the main structural feature of the blood-brain barrier (BBB). These junctions limit the movement of substances between blood and brain tissue, helping protect the brain from toxins, pathogens, and fluctuations in blood composition.
16. Which of the following types of substances would be most likely to cross the blood-brain barrier (BBB)?
- A. Large, hydrophilic molecules
- B. Small, lipophilic molecules
- C. Charged ions
- D. medium-sized, hydrophilic molecules
Show Answer
Correct answer: B
The blood-brain barrier is a complex that surrounds most of the blood vessels in the brain. It acts as a barrier between the bloodstream and the extracellular space of the brain, allowing only certain substances like water, oxygen, and small lipid-soluble substances to easily cross from the blood into the brain.
17. The most common condition to result from a ruptured brain aneurysm is:
- A. encephalitis
- B. transient ischemic attack (aka mini-stroke)
- C. meningitis
- D. subarachnoid hemorrhage
Show Answer
Correct answer: D
The rupture of a brain aneurysm typically causes bleeding into the area surrounding the brain---a condition known as subarachnoid hemorrhage. Subarachnoid hemorrhage is an extremely dangerous situation with high rates of fatality.
18. Which artery primarily supplies the superior surface of the cerebellum with blood?
- A. dorsal cerebellar artery
- B. anterior inferior cerebellar artery
- C. superior cerebellar artery
- D. posterior cerebral artery
Show Answer
Correct answer: C
The superior cerebellar arteries supply the superior surface of the cerebellum.
19. Which of the following arteries is formed by the union of the two vertebral arteries?
- A. internal carotid artery
- B. middle cerebral artery
- C. anterior communicating artery
- D. basilar artery
Show Answer
Correct answer: D
The two vertebral arteries come together to form the basilar artery.
