Gross Brain-Wilson Flashcards

1
Q

What is a tract?

Gray Matter
White Matter
Nerves
Tract

A

in CNS but synonymous to nerves in PNS

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2
Q

What consists of the CNS?

A

brain and spinal cord

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3
Q

What consists of the PNS?

A

cranial and spinal nerves

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4
Q

What are the primary brain vesicles?

A
  • prosencephalon (forebrain)
  • mesencephalon
  • rhombencephalon (hindbrain)
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5
Q

What does do the primary brain vesicles become?

A

prosencephalon:

  • telencephalon (cerebral cortex)
  • dicencephalon (anything with thalamus in its name

mesencephalon:
- midbrain

rhombencephalon

(hindbrain) :
- metencephalon (pons)
- myelencephalon (medulla)

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6
Q

Entire NS develops from a neural tube?

A

central canal of neural tube is lumen of the spinal cord that will become the ventricular system of the brain filled with CSF

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7
Q

What is the brainstem made up of?

A
  • midbrain
  • pons (metencephalon)
  • medulla (myelencephalon)
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8
Q

What is gray matter in the spinal cord?

A

surrounds the lumen
consists of neurons
-in the brain organized into nuclei
-organized into a dorsal horn for sensory function and ventral horn for motor function

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9
Q

What is white matter in the spinal cord?

A
  • axons coming and going to the cell bodies in the gray matter
  • appears white because most of the axons are myelinated
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10
Q

What is the organization of the gray matter in the spinal cord?

A
  • dorsal: sensory
  • ventral: motor

dorsal/ventral organization extends all the way to the brainstem but becomes a bit blurry in the brain

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11
Q

The adult brain consists of what 4 parts?

A
  1. brain stem
  2. cerebellum
  3. Diencephalon
  4. Cortex
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12
Q

What are the 3 parts of the brainstem?

A
  • continuation of the spinal cord which is medulla oblongata
  • pons: has a ventral potbelly
  • midbrain: part of the brain between the lower brainstem diencephalon and and the cortex
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13
Q

Where is the landmark used to distinguish the transition of the spinal cord to the medulla oblongata?

A

the decussation of the pyramids

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14
Q

What are the boundaries of the medulla oblongata?

A
  • caudal: decussation of the pyramids which is . the gradual transition from the spinal cord and extends below the foramen magnum
  • rostral: pontomedullary junction
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15
Q

What are the function of the medulla oblongata?

A
  • cardiac center that controls the force and rate of heartbeat and rate of breathing
  • respiratory center that controls the contraction and relaxation of the diaphragm (controls the rhythm and rate of breathing)

the diaphragm is skeletal muscle so you have complete voluntary control but the rhythm generator of that contraction and relaxation are located in the medulla

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16
Q

What happens when you have a stroke that affects the medulla oblongata?

A

you will affect the breathing and cardiovascular centers

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17
Q

What are the pyramids and what is contained in them?

A

two long columns of axon traveling from the cortex to the spinal cord

-contained in them are the corticospinal tract (supresses the extensor Babinski response in the adult )

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18
Q

What is the corticospinal tract?

A

a tracts of axons that goes from the cortex where the cell bodies are located
and the axons descend through the diencephalon route, brainstem, spinal cord innervating motor neuron in the ventral horn

-allows for voluntary control of movement moving away from reflex type of movement (you can learn new movements)

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19
Q

What is the reason for the swelling of the olives in the medulla oblongata?

A

inferior olivary complex inside the medulla which has close connections to the cerebellum and that is involved in motor learning

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20
Q

What are the dorsal columns?

A
  • carry sensory fibers for fine touch, vibration, an proprioception
  • these fibers ascend from the spinal cord to terminate in the medulla
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21
Q

What are the ascending sensory systems and where are they located in the brain?

A

they are the dorsal columns which are located in the medulla on the posterior side right underneath the cerebellum

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22
Q

What are the 4 cranial nerves that originate from the medulla?

A

CN IX, X, XI, XII

-CN XII (hypoglossal nerve): originates in the groove between the pyramids and inferior olives; series of rootlets that very very fine and come together to form CN XII

below CN originate dorsal to the olive
- CN IX: the very first root that comes off of the olive (large)

  • CN X: arises as a series of rootlets, not just one
  • CN XI (accessory nerve): is divided into two parts: a cranial* part and a spinal part that originate from the cervical spinal cord
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23
Q

What are the 3 CN that originate from the pontomedullary junction?

A

CN VI, VII, VIII

CN VI (abducens nerve): most medial nerve; innervates lateral rectus muscle)

CN VII (facial nerve): comes off of the pons; control muscles of facial expression

CNVIII: the acoustic and vestibular nerve for hearing and balance

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24
Q

What is the does the pons contain and what CN is associated with it?

A

middle cerebellar peduncle : massive tract of axons carrying info from cortex through the pons up to the cerebellum

-main root of the CN V (trigeminal nerve): will find a trigeminal ganglion not attached to the brain itsel; it is a sensory ganglion (V1, V2, V3)

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25
Q

What is the function of the pons?

A

relays signals between the cerebral cortex and cerebellum

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26
Q

The tube of the neural tube forms the ventricular system of the brain. Where is the fourth ventricle found in the brain?

A

dorsal to the medulla and pons

  • it SEPARATES the medulla/pons from the cerebellum
  • filled with CSF (remember the lumen of the neural tube becomes the ventricular system of the brain filled with CSF)
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27
Q

What is the function of the middle cerebellar peduncle?

A
  • connects pons with cerebellum; carrying cortical info via the pons to the cerebellum
  • cell bodies (neurons) are found in the pons and their axons go to the cerebellum
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28
Q

Because of the presence of the cerebellum, the roof plate is split and the central canal enlarges to become the 4th ventricle over the pons and medulla.

A

the cerebellum develops from the roof of the medulla and as it enlarges, the medulla flattens out

-the general embryonic origin of sensory and motor nuclei seen in the spinal cord is maintained

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29
Q

What are the parts of the midbrain?

A
  • superior colliculus for visual oculomotor reflexes
  • inferior colliculus for auditory relay center

they all together come to form the corpora quadrigemina

relay center so that when ??????

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30
Q

Which nerve exits the brain immediately caudal to the inferior colliculus?

A

CN IV (trochlear nerve)

  • CN IV originates from the dorsum of the midbrain
  • this is the only CN that exits the brain DORSALLY; all the other nerves exits ventrally or ventrolaterally)
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31
Q

Cerebral peduncle

A

a column of axons in the midbrain that includes the corticospinal tract with axons coming from cortex go through pons to reach the pyramids

CST important for voluntary movements

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32
Q

What other nerve is associated with the midbrain?

A

CN III (occulomotor nerve)

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33
Q

What is the cerebral aqueduct?

A

the brain has a ventricular system
-the large 4th ventricle becomes very narrow and becomes the cerebral aqueduct: a channel carrying CSF from the 3rd to 4th ventricle

-its not just axons but also contains other neuronal structures

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34
Q

What is the tectum?

A

the roof over the cerebral aqueduct

-it is found dorsal to the cerebral aqueduct

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35
Q

What is crus cerebri?

A

the anterior portion of the cerebral peduncle that contains descending motor tracts (e.g. corticospinal, corticobulbar).

-they are axons coming from cortex going to the spinal cord, the pons, or to the brainstem

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36
Q

Where is substantia nigra

(Parkinson’s disease)?

A

part of the cerbral peduncle

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37
Q

What is the periaqueductal gray responsible for?

A
  1. visceral pain response

2. fight flight

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38
Q

What is tegmentum?

A

the core of nuclei and tract that you find near the midbrain and pons ????

it is DIFFERENT FROM TECTUM

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39
Q

What are the parts of the cerebellum?

A
  • central part: vermis
  • lateral expansion: left and right cerebellar hemisphere

CEREBELLUM sits on top of the 4th ventricle

40
Q

What is the function of the cerebellum?

A
  • a comparator of intended with the actual movement and generates an error signal when there is a mismatch (that makes an adjustment on the ongoing movement to bring it back to the original intent of the movement)
  • maintains equilibrium/balance and posture
  • coordinates and smooths movements

-compares the movement the cortex and the other parts wants to do versus to what the body actually does

41
Q

What are parts of the diencephalon?

A
  • central part: thalamus
  • below the central: hypothalamus
  • epithalamus
42
Q

What is the function of the thalamus?

A
  • is a sensory relay center for information en route to the cortex
  • sensory input coming into the cortex stops first at the thalamus
43
Q

Specific thalamic nuclei project to specific areas of cortex. What are these specific nuclei?

A
  • medial geniculate nucleus for auditory relay to the auditory cortex
  • lateral geniculate nucleus for visual relay to the occipital/visual cortex
44
Q

What is the only nerve that originates from the diencephalon and is associated with the thalamus?

A

CN II (optic nerve)

–the left and right optic nerve from the eyes join to form the optic chiasma

45
Q

Why is CN II NOT a true nerve?

A

It is a tract of the CNS!!

  • the retina develops as a diverticulum of the forebrain (optic vesicle)
  • axons of CN II are surrounded by glia, not Schwann cells or oligodendrocytes
  • CN II is surrounded by meninges
46
Q

Why is the optic nerve vulnerable to multiple sclerosis?

A

-diseases that affect glial cells if its affects schwann cells the optic nerve will not be as affected

if you have MS the oligodendrocytes because of embryonic origins will be susceptible ????

conditions that can affect optic nerve Haplodema

47
Q

What is the EXCEPTION to the thalamus as the sensory/motor/limbic relay center for info en route to the cortex?

A

olfactory system: it’s a very old system

48
Q

Epithalamus

A

right in the middle of the tectum and thalamus

pineal gland: 3rd eye????

  • circadian rhythms
  • secretes melatonin)
  • involved in sexual cycles in non-primates
49
Q

Where is the 3rd ventricle located?

A

separates the left and right diencephalon

50
Q

Hypothalamus

A
  • VISCERAL control center of the brain
  • has a direct connection to the pituitary gland
  • hormones via the pituitary
  • autonomic nervous . system
  • feeding and drinking
  • sleep-wake cycles
  • sexual activity
  • temperature regulation (fever, chills)
  • memory
51
Q

Comparison of Cortex of human and rate Cerebral cortex

A

HUMAN

  • over 3/4 of our brain is represent the cortex (77%)
  • surface area of our cortex is 2,500 cm^2
  • huge expansion of the diencephalon

RAT

  • 31% of brain is cortex
  • surface area of cortex is 6 cm^2
52
Q

How is it possible to get a huge expansion of our cortex into our small skull?

A

you take the large cortex and compress it into gyri

  • the surface of the cerebral cortex is not smooth but characterized by numerous folds forming gyri separated by sulci
  • between gyri are sulci or valleys
53
Q

Why the gyri and sulci in the human brain?

A
  • the convolutions of the surface of the cortex greatly increases its surface area and computational power
  • If its surface did not have gyri/sulci but was smooth (like a rat), it would be 10X or more larger
  • the PATTERN of gyri and sulci is very similar between people with “particular gyri” having specific functions
  • when there are lesions you can predict which gyri location is affected ???
54
Q

How are cortical lobes named?

A

are named according to the bones of the neurocranium that cover them

55
Q

What divides the cortex into different regions: fronatal, parietal, temporal, and occipital lobes?

A

sulci and fissures

56
Q

What is the most prominent fissure that separates the temporal lobe from the frontal and parietal lobe?

A

lateral fissure (sulcus)

57
Q

What separates the frontal lobe from the parietal lobe?

A

central sulcus

58
Q

What is the function of the pre-occipital notch and parieto-occipital sulcus?

A

parieto-occipital sulcus: separates the occipital lobe and the parietal cortex

pre-occipital notch: draw a line between the pre-occipital notch and the end of the parieto-occipital sulcus; this line separates the occipital lobe from the temporal lobe

59
Q

How do we define the central sulcus?

A

the central sulcus ends in a CUL-DE-SAC prior to the lateral sulcus

-so the sulcus doesn’t touch the lateral fissure like the other sulci nearby

60
Q

What is not bilateral in the brain?

A

ventricular system and ???1:31:30

61
Q

What is the calcarine sulcus?

A

landmark on the occipital lobe

  • surrounding this sulcus is our primary visual cortex
  • very important

-it separates the lingual gyrus (area 17) from the cuneus gyrus (17)

62
Q

Describe the overall shape of the ventricular system of the brain.

A
Lateral ventricle:
-anterior horn 
-inferior horn (goes into temporal)
-posterior horn
???1:34:15
63
Q

What separates the temporal and occipital lobe from the cerebellum?

A

transverse (cerebral) fissure

64
Q

What divides the brain into right and left hemispheres?

A

longitudinal fissure

65
Q

Characterize the structure and function of the cortex.

A
  • structural symmetrical
  • functionally asymmetrical

LEFT BRAIN

  • language
  • numerical skills
  • reasoning abilities
  • considered more analytical than the right side

RIGHT BRAIN (Artistic)

  • processes new, unfamiliar faces
  • decodes and processes patterns, music, spatial relations
  • takes in the “whole”
  • considered more creative than the left side

WHEN you have a stroke depending on the left or right affects the consequences you’ll see

66
Q

Each hemisphere controls the CONTRALATERAL side of the body.

A

FACTS!!!

67
Q

What connects the right and left cerebral hemispheres?

A

corpus callosum (white matter)

  • so NO cell bodies just large amounts of myelinated axons
  • allows communication between the hemispheres
  • cut the corpus callosum: the connection is severed
68
Q

What are the parts of the corpus collosum?

A
  • genu
  • body
  • splenium
69
Q

Frontal cortex

A
  • lateral fissure

- central sulcus (is everything in front of this sulcus)

70
Q

Central sulcus is the landmark for what?

A
  • precentral gyrus: origin of the CST; AKA Brodmann’s area 4
  • postcentral gyri AKA Brodmann’s areas 3, 1, 2
71
Q

What is the function of the precentral gyrus and the postcentral gyrus?

A

precentral gyrus: the primary motor cortex controlling voluntary movement of skeletal muscle

postcentral gyrus: the primary somatosensory ascending from SC from the cranial nerve cortex receiving inputs conveyed by general sensory systems

72
Q

The entire brain has a topography.

A
  • both the motor and somatosensory systems are topographically organized
  • their cortical maps form a motor and a somatosensory homunculus (a picture of a “little man”
73
Q

Describe the relative amount of cortical tissue devoted to motor and somatosensory functions.

A

the relative size of the regions is not proportional to the size of the cortical tissue
(small hand has a large space in the pre-central gyrus???)

-the density of sensory receptor (touch) for the hands and fingers are very dense (we pay more attention to our hand than our big toe_

74
Q

The frontal cortex has what 3 gyri?

A
  • superior frontal gyrus
  • middle frontal gyrus
  • inferior frontal gyrus

they form parallel gyri

75
Q

What is in the inferior frontal gyrus?

A

Broca’s motor speech area

  • motor control of producing fluid speech is lost if there is lesion at this site
  • only found on the left side of the brain

-within the Broca’s area you have semantic processing (meanings) and phonological processing (sounds)

76
Q

What is the pre-frontal cortex?

A

-executive functions

  • very most rostral part of the brain
  • becomes fully functional when a person has reached teen years or early 20s
  • part of the limbic cortex

-response to complex and difficulty problems

77
Q

What is the orbitofrontal cortex?

A
  • part of the pre-frontal cortex that sits on top of the orbital
  • is part of the limbic system
  • has a round contour

-emotion and reward in decision making

78
Q

Characterize the homunculus of the post-central gyrus.

A

just like the pre-central gyrus just sensory this time
-the density of the cortical matter allocated to a region is proportional to the amount of sensory receptors you find in that region

79
Q

What are the gyri you find in the temporal lobe?

A
  • superior temporal gyrus (Wernicke’s Speech Area)
  • middle temporal gyrus
  • inferior temporal gyrus
80
Q

Wernicke’s (Speech) area

A
  • near the back of the lateral fissure
  • primarily where we have comprehension of speech
  • superior temporal gyrus and plantum temporale
  • found only on the left side
  • planum temporale is the cortical area just posterior to the auditory cortex (Heschl’s gyrus) within the Sylvian fissure. It is a triangular region which forms the heart of Wernicke’s area, one of the most important functional areas for language
81
Q

What are the structures deep in the lateral fissure?

A
  • transverse temporal gyrus of Heschl (an extension of the superior frontal gyrus) for primary auditory cortex
  • in front of that is the Insula which gives idea of self and empathy
  • most internal gyrus is the parahippocampal gyrus
  • uncus (medial hooking)

hippocampus is for short-term and working memory

82
Q

What gyrus surrounds the corpus callosum?

A

cingulate gyrus which is part of the limbic system as well as the pre-frontal cortex (limbic system)

83
Q

Deep to the cortical gray matter are deep gray matter called?

A

basal ganglia: the gate keeper; sits at the gate and determine which what can come in or go out

-if you have damage to the basal ganglia you end up with wild movements

84
Q

What does the brain and spinal cord float in to reduce traction exerted upon nerves and blood vessels?

A

CSF

85
Q

What are the functions of the ventricular system?

A
  • houses the CSF
  • cushions- dampens the effect of trauma
  • removes metabolites from CNS
  • provides stable ionic environment, nutrients
86
Q

What produces CSF?

A

choroid plexus

-is constantly producing CSF about half a liter a day

87
Q

Where is the choroid plexus found?

A
  • lateral ventricles
  • 3rd ventricle
  • 4th ventricle
88
Q

What is the function of the choroid plexus?

A

-helps to maintain the extracellular environment of the brain

89
Q

What is the net flow of the CSF?

A
  1. lateral ventricles
  2. 3rd ventricle
  3. cerebral aqueduct
  4. 4th ventricle
  5. subarachnoid space (space btw the pia and dura mater)
90
Q

What is the communication between the lateral and 3rd ventricle?

A

foramen of Monro (the little hole beside septum pellucidum)

  • CSF flows from the lateral ventricle to the 3rd ventricle through the foramen of Monro (very narrow channel)
91
Q

What separates the left and right lateral ventricles?

A

septum pellucidum

92
Q

CSF drains from the 4th ventricle into the subarachnoid space via?

A

one foramen of Magendie (central)

two foramina of Luschka (found in the lateral half of the 4th ventricle)

93
Q

What is hydrocephalus?

A

when CSF production is greater than absorption (get pooling of CSF in the ventricles)

-swelling of the brain

94
Q

Non-communicating hydrocephalus

A

When there is blockage in the flow of CSF, usually at:

  1. usually at foramen of Monro or (swelling of lateral ventricle)
  2. cerebral aqueduct (swelling of 3rd ventricle)
95
Q

There are no lymph node in the brain!!

A

Brain does not have a lymphatic system.

-One of the functions of the ventricular system is to flush out interstitial fluids to be reabsorbed back into the venous system

96
Q

What does CSF contain?

A

consists of water, protein, peptides, sugar, leukocytes, lymphocytes, (bacterial and viral meningitis, or encephalitis increase cell numbers), electrolytes, Na, K, Mg, Ca

97
Q

What are conditions involving CSF?

A
  • hydrocephaly

- meningitis