Lab 2: Brain Anatomy and Neurophysiology Flashcards

1
Q

bilateral internal carotid arteries enter the brain:

A

carotid canals

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2
Q

Vertebral arteries enter the brain:

A

foramen magnum (base of skull)

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3
Q

why is the circle of willis critical for brain blood flow? What does the term anastomoses mean?

A

its where the internal carotid artery and vertebral artery connect so that blood can flow. Provides blood supply to the brain. Anastomoses means a natural or surgical connection between 2 structures.

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4
Q

A stroke occurs when blood flow to the brain is obstructed, often by a clot or arterial blockage, depriving neural tissue of oxygen and nutrients - cells can die within minutes. Are all blockages the same? Blockage types:

A

All blockages are not the same. Blockages are redundant, there are other ways to get blood. Blockage types:
1. Stationary blockage (thrombosis)
2. Floating blockage (embolism)
3. Hemorrhage/rupture of blood vessel

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5
Q

Symptoms of a stroke can be very different. Why so? What is lateralization?

A

different brain areas are affected (no blood flow). Diff areas control diff abilities.

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6
Q

Will all nutrients cross from the systemic circulatory system into the brain?

A

No, most proteins can’t cross cause of large size and hydrophilicity. Water soluble molecules can pass (membrane is lipid based). Toxins can’t pass.

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7
Q

Glucose, a carbohydrate macromolecule, and oxygen are permitted to pass easily through the blood brain barrier. Why is this important? Why does this happen?

A

Body needs glucose and oxygen for ATP. Carrier-mediated transport enables molecules with low lipid solubility to cross . Glucose enters by transport protein. Glucose is the brain’s primary energy.
Transcellular transport is what allows oxygen to enter the brain.

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8
Q

The blood brain barrier can become damaged from trauma or aging - what would you suspect might happen next?

A

Barrier becomes more porous, allowing bacteria and other toxins to infect brain tissue. Leads to inflammation and death. Accumulation of toxins, inflammatory cells in neural tissue.

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9
Q

You are a scientist who made a medication to cure alzheimer’s. Does Blood brain barrier positively or negatively impact delivery of medication?

A

negatively, makes it difficult to diffuse/let antibiotics pass. will deem them a foreign substance if its a new antibiotic.

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10
Q

longitudinal fissure separates:

A

2 cerebral hemispheres

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11
Q

central sulcus seperates

A

frontal and parietal lobes

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12
Q

lateral sulcus seperates

A

frontal and temporal lobes

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13
Q

precentral gyrus seperates:

A

anterior to central sulcus, primary sensory area Postcentral gyrus: posterior to central sulcus - primary motor area

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14
Q

Why does the brain have folds? Difference between sulci, gyri, fissure?

A

To inc. surface area. Sulci: shallow depression, Gyri: ridges/peaks, Fissure: deep depressions

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15
Q

Where is the central sulcus in relation to precentral gyrus. What is precentral gyrus role?

A

its anterior to precentral gyrus. Primary motor area - voluntary muscle contractions

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16
Q

Where is the central sulcus in relation to postcentral gyrus. Role of postcentral gyrus?

A

posterior to central sulcus. Primary somatosensory area

17
Q

Pathway of cerebrospinal fluid:

A

Choroid plexus of (lateral, 3rd and 4th ventricles) -> lateral, 3rd and 4th ventricle -> subarachnoid space -> arachnoid villi of dural venus

18
Q

Major role of CSF

A

protection, nutrients, shock absorption

19
Q

how can a cerebral hemorrhage progress to an ischemic stroke?

A

blood accumulates outside vessel. Increase in pressure around vasculature, vessels collapse, no blood flow = stroke

20
Q

what is cerebral atrophy? How can an ischemic stroke lead to cerebral atrophy?

A

Cerebral atrophy is a loss of brain cells and the connections between them DUring an ischemic stroke there is low blood flow to one part of the brain. No blood flow/nutrients means vessels will die. Atrophy = decrease in brain size.

21
Q

Compare healthy specimen to pathological hemorrhage specimen. What differences can you observe?

A

general thinning of cerebrum, cerebral cortex, discoloration

22
Q

Function of infundibulum?

A

connect hypothalamus and pituitary gland

23
Q

primary function of pituitary gland?

A

hormone regulation and secretion

24
Q

compare the size of olfactory bulbs in sheep with those in humans - what do you see and why?

A

bigger - sheep rely on sense of smell more (more sensitive)

25
Q

what colour are the olfactory bulbs, in comparison to the surface of the cerebral cortex?

A

lighter shade - white matter, meaning myelinated

26
Q

what does chiasm mean? what biological function does this nerve layout allow for?

A

cross/meet. allows optic nerves to cross.

27
Q

midbrain

A

(Posterior to optic chiasm, situated superior to pons, disappears under the pons)
auditory and visual processing, the regulation of the sleep wake cycle, contributing to functions such as eye movement and pain management

28
Q

pons

A

(A horseshoe shape, opposite to the cerebellum, superior to medulla)

Plays a significant role in regulating sleep cycles, processing sensory information, and coordinating facial movements and sensation through cranial nerves

29
Q

Medulla

A

(Most inferior, stem like structure, base of brain, superficially blends in with the spinal cord)

Crucial for autonomic functions such as controlling breathing, heart rate, blood pressure, as well as reflexes like swallowing and coughing

30
Q

together the midbrain, pons and medulla are called the:

A

brainstem

31
Q

cerebellum function:

A

coordination and locomotion

32
Q

Folia function:

A

increases surface area of brain, to accommodate greater number of neuronal cells

33
Q

vermis function:

A

bodily posture and locomotion

34
Q

pons function:*****

A

optimizes communication pathways to carry information to and from the cerebellum

35
Q

How is nerve velocity measured (how was experiment done)?

A

small electrical current applied to our motor neurons and contraction of muscle movement is measured

36
Q

examine the latency period (brief interval between the initiation of an action potential in a motor neuron and the onset of contraction in the muscle fibers) for the median nerve at the wrist (abductor pollicis brevis) and the median nerve at the elbow. How do those latencies differ and why do you suppose that is?

A

the AP travels further from the median elbow, more latency so less twitch

37
Q

What are the three phases of muscle twitch contraction?

A
  1. Initial/latency
    2.contraction
    3 relaxation