Week 4 Vocabulary

Question 1

Stroke

Answer 1

a disruption in the blood supply to the brain that leads to neurological dysfunction. Strokes are the #1 cause of neurological visits to the hospital, and the #1 neurological cause of death.

Question 2

Altitude Sickness

Answer 2

at higher altitudes, air is thinner due to lower pressure. This leads to each breath taking in less oxygen, although it is still the same % oxygen relative to other gases. People who travel to higher altitudes may feel general symptoms such as headache, nausea, and fatigue. Over time, the body adjusts to low oxygen by producing more red blood cells.

Question 3

Hemoglobin

Answer 3

the oxygen “carrier” of red blood cells.

Question 4

Epithelial Cells

Answer 4

the cells that make up blood vessels.

Question 5

Unfenestrated Epithelium

Answer 5

a special type of blood vessel barrier found in the brain that creates the blood-brain barrier. The epithelial cells are bound together by tight junctions that only allow a filtered form of blood to reach the brain. This filtered blood is known as cerebrospinal fluid.

Question 6

fMRI

Answer 6

a medical imaging technique that measures blood flow within the brain. This allows determination of which brain regions are more active, as they will be consuming more oxygen and demanding increased blood flow.

Question 7

Cerebral Perfusion Pressure (CPP)

Answer 7

the net pressure that promotes cerebral blood flow to the brain. It can be determined by the equation: CPP = MAP - ICP.

Question 8

Mean Arterial Pressure (MAP)

Answer 8

the average blood pressure within the arteries. Higher MAP increases CPP.

Question 9

Intracranial Pressure (ICP)

Answer 9

the pressure placed on the brain, blood, and everything else within the skull. Higher ICP decreases CPP.

Question 10

Syncope

Answer 10

the medical term for fainting. It involves a loss of consciousness, and a loss of postural tone (falling down).

Question 11

Autoregulation

Answer 11

the ability of the arteries of the brain to maintain cerebral blood flow over a wide range of mean arterial pressures. This ensures that the brain receives a continuous and consistent supply of oxygen and nutrients. Importantly, the range of autoregulation can shift during exercise.

Question 12

Foramen Magnum

Answer 12

the hole at the base of the skull where the brainstem meets the spinal cord. Also the site of entry for the vertebral arteries.

Question 13

Vertebral Arteries

Answer 13

supply blood to the posterior circulation.

Question 14

Basilar Artery

Answer 14

supplies blood to the pons in the brainstem. Formed by the joining of the vertebral arteries.

Question 15

Posterior Circulation

Answer 15

supplies blood primarily to the brainstem.

Question 16

Internal Carotid Arteries

Answer 16

supply blood to the anterior circulation. Enter the brain at a site next to the optic chiasm.

Question 17

External Carotid Arteries

Answer 17

supply blood to the face and scalp. These arteries are not a part of the brain’s blood supply.

Question 18

Anterior Circulation

Answer 18

supplies blood primarily to the forebrain.

Question 19

Anterior Cerebral Artery (ACA)

Answer 19

a branch of the internal carotid artery, one on each side of the brain. This artery travels along the medial surface of the forebrain.

Question 20

Middle Cerebral Artery (MCA)

Answer 20

a branch of the internal carotid artery, one on each side of the brain. This artery dives into the Sylvian Fissure that separates the temporal lobe from the frontal and parietal lobes. It supplies blood to the majority of the convexity of the brain, and is the most common site of stroke.

Question 21

Posterior Cerebral Arteries (PCA)

Answer 21

these arteries are continuations of the basilar artery that provide blood to the occipital lobes. This means that strokes here will likely impair vision in the opposite visual world.

Question 22

Anterior Communicating Artery (ACommA)

Answer 22

one artery that connects the two anterior cerebral arteries.

Question 23

Posterior Communicating Arteries (PCommA)

Answer 23

two arteries, one one each side, that connect the internal carotid artery to the posterior cerebral artery.

Question 24

Circle of Willis t

Answer 24

he circle of arteries at the base of the brain that connects the posterior and anterior circulations. This allows the brain to protect itself from one or even multiple occlusions by diverting blood from other arteries. There is great variability between individuals.

Question 25

Topography

Answer 25

when we discuss brain topography, we are referring to the functions of various brain regions. Understanding brain topography allows us to determine where in the brain a stroke has occurred.

Question 26

Convexity of the Brain

Answer 26

this is the outer surface of the telencephalic hemispheres. It is supplied primarily by the middle cerebral artery.

Question 27

Ischemic Stroke

Answer 27

this type of stroke is caused by an interruption in the blood supply. The two primary causes of ischemic stroke are an embolus

Question 28

Embolus

Answer 28

anything that travels through the bloodstream and blocks blood flow. Three common causes of emboli are blood clots, plaque, and fat emboli.

Question 29

Hemorrhagic Stroke

Answer 29

this type of stroke is caused by blood leaking into the skull. The two primary causes are a burst aneurysm or an arteriovenous malformation.

Question 30

Berry Aneurysm

Answer 30

this is a special type of aneurysm that commonly forms in the Circle of Willis.

Question 31

Arteriovenous Malformation (AVM)

Answer 31

these are congenital malformations that are most often asymptomatic. They are fragile and prone to breaking, which may lead to hemorrhagic stroke if they occur in the brain.

Question 32

Penumbra

Answer 32

the region of neurons just outside the stroke area that do not die immediately following a stroke, but are at an increased risk of dying. Treatment following stroke is designed to save these neurons.

Question 33

Central Sulcus

Answer 33

the divide between the frontal and parietal lobes. On the frontal side lies the primary motor cortex, on the parietal side lies the primary somatosensory cortex.

Question 34

Sylvian Fissure

Answer 34

the divide between the temporal hemisphere and the frontal and parietal lobes. The middle cerebral artery travels in this space.

Question 35

Epidural Hematoma

Answer 35

this intracranial bleed typically occurs following a blow to the head. There is generally a lucid, or conscious, interval following the injury. Blood builds up between the dura and the skull, and unfortunately this increases intracranial pressure and if left untreated is potentially deadly.

Question 36

Potential Space

Answer 36

a potential space that does not normally exist, but could exist. An example of this is the epidural space between the dura and the skull.

Question 37

Subdural Hematoma

Answer 37

rupture of the veins traveling through the meninges that leads to blood accumulation in the space between the dura and the arachnoid mater. This often occurs in elderly individuals who have more brittle veins, and is often asymptomatic as the bleed is slow and blood can be resorbed.

Question 38

Subarachnoid Hemorrhage

Answer 38

this is a bleed between the arachnoid and pia mater, often occurring due to a burst aneurysm or AVM. Because the subarachnoid space contains nociceptors that can lead to pain, patients often present with a sudden onset “worst headache of my life.”

Question 39

Falx Cerebri

Answer 39

folds of dura that dive between the telencephalic hemispheres.

Question 40

Tentorium

Answer 40

separates the occipital lobes from the cerebellum.

Question 41

Infratentorial Space

Answer 41

region below the tentorium that consists primarily of the brainstem.

Question 42

Supratentorial Space

Answer 42

region above the tentorium that consists primarily of the forebrain.

Question 43

Uncus

Answer 43

medial piece of temporal lobe.

Question 44

Tentorial (Uncal) Herniation

Answer 44

occurs when the uncut herniates under the tentorium. This is a medical emergency because it presses on the brainstem. Patients may present with ptosis and a down-and-out eye because the uncus may press on the oculomotor nerve.

Question 45

Falcine Herniation

Answer 45

occurs when a piece of the forebrain herniates under the falx cerebri. These are typically asymptomatic.

Question 46

Tonsilar Herniation

Answer 46

occurs when the cerebellum slips out of the foramen magnum. This is often a medical emergency as the cerebellum presses on the spinal cord, but in smaller herniations it may actually be asymptomatic.

Question 47

Mass Effect

Answer 47

this occurs when pressure increases in one compartment eventually increase pressure across the brain’s bulkheads (the falx cerebri and tentorium).

Question 48

Hydrocephalus

Answer 48

blockage of CSF flow through the ventricles of the brain, typically in the flow from the forebrain to the hindbrain, can lead to increased intracranial pressure. This is most common in babies, and can lead to expansion of their soft skull.

Question 49

Ventricles

Answer 49

spaces within the brain where CSF is produced and flows from the forebrain, to the hindbrain, to the subarachnoid space surrounding the brain and spinal cord.