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A-BIOL 1191 LECTURE > CH 14 > Flashcards

CH 14 Flashcards

1
Q

what are the four main parts of the adult brain?

A
  • cerebrum
  • cerebellum
  • diencephalon
  • brainstem
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2
Q

what are the protective coverings and barriers of the brain?

A
  • cranial meninges
  • bones of the skull
  • cerebrospinal fluid
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3
Q

what are the cranial meninges?

A

CT coverings continuous w/ spinal meninges, sharing common names w/ them

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4
Q

what is the difference between the cranial and spinal dura mater?

A

the superficial cranial dura mater has two layers:

  • outer periosteal layer
  • inner meningeal layer
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5
Q

what are some differences btwn the cranial and spinal meninges?

A
  • cranial dura mater has 2 layers, spinal dura mater has 1 layer
  • no epidural space btwn dura mater and bones of the skull
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6
Q

what are the extensions of dura mater that separates parts of the brain?

A
  • falx cerebri
  • falx cerebelli
  • tentorium cerebelli
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7
Q

what is the falx cerebri?

A

extension of the cranial dura mater that separates the right and left hemispheres of the brain

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8
Q

what is the falx cerebelli?

A

extension of the cranial dura mater that separates the left and right hemispheres of the cerebellum

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9
Q

what is the tentorium cerebelli?

A

extension of the cranial dura mater that separates the cerebellum and the cerebrum

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10
Q

what is the blood-brain barrier?

A

barrier btwn blood and the brain that maintains the selective permeability of brain tissue to substances in blood

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11
Q

what forms the blood-brain barrier?

A
  • continuous capillaries (w/o fenestrations) w/ tight junctions btwn endothelial cells
  • Astrocytes associate tightly w/ capillaries and secrete substances to maintain tight junctions
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12
Q

which arteries supply oxygenated blood to the brain?

A
  • anterior L/R internal carotid arteries
  • posterior L/R vertebral arteries
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13
Q

which veins drain deoxygenated blood from the brain?

A

dural venous sinuses drain venous blood into the internal jugular veins

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14
Q

how is neuronal activity and blood flow to the brain related?

A

as activity of neurons increase, blood flow to the brain also increases

increased perfusion (extent of blood flow)

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15
Q

what is the blood-brain barrier permeable to?

A
  • lipid-soluble substances
    – steroid hormones
    –nonpolar molecules (O2 and CO2)
  • some water-soluble substances
    – water
    – glucose
    – some ions (slow transport only)
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16
Q

what is the blood-brain barrier impermeable to?

A
  • proteins
  • antibiotics
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17
Q

What could disrupt the function/structure of the blood-brain barrier?

A
  • tumours
  • trauma to vessels and brain tissue
  • infection (meningitis, rabies)
  • radiation
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18
Q

what is the result of a compromised blood-brain barrier?

A
  • brain tissue now permeable to more substances, can lead to damaged tissue
  • brain hemorrhaging
  • more infection
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19
Q

what is the composition of CSF?

A

consists mainly of water plus glucose, ions, proteins, lactic acid, urea, and some leukocytes

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20
Q

where is CSF located in the brain?

A

the ventricles, it continuously circulates around them and through spinal cord

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21
Q

what are the four ventricles of the brain?

A
  • 2x lateral ventricles
  • third ventricle
  • fourth ventricle
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22
Q

what separates the two lateral ventricles?

A

thin membrane - septum pellucidum

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23
Q

where is the third ventricle located?

A
  • between the two halves of the thalamus, superior to the hypothalamus
  • connected to the lateral ventricles by two interventricular foramina
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24
Q

where is the fourth ventricle located?

A

between the brainstem and the cerebellum

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25
Q

what are the functions of cerebrospinal fluid?

A
  • mechanical protection: absorbs shock and permits brain and spinal cord to float weightlessly
  • chemical protection: maintains the specific optimal electrochemical environment required for accurate neuronal signalling
  • circulation: circulates nutrients and waste
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26
Q

where is CSF synthesized?

A

in choroid plexuses lining ventricles of the brain

  • ependymal cells filter blood plasma and secrete the filtered substance as CSF
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27
Q

what are choroid plexuses?

A

capillary networks in the brain’s ventricles where ependymal cells fliter blood plasma and secrete CSF

  • secretion is also bidirectional
  • ependymal cells are joined by tight junctions, forming blood-CSF barrier
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28
Q

how is CSF circulated through the ventricles?

A

CSF from choroid plexuses of lateral ventricles → interventricular foramina → third ventricle, choroid plexuses of third ventricle → aqueduct of midbrain → fourth ventricle

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29
Q

how is CSF circulated starting from the fourth ventricle?

A

subarachnoid space:
- fourth ventricle → median or lateral apertures → subarachnoid space

central canal:
- fourth ventricle → central canal (they are continuous w/ e/o)

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30
Q

what are apertures?

A

three openings in the roof of the fourth ventricle where CSF flows into and then through the subarachnoid space around brain and spinal cord

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31
Q

what are the three different apertures?

A
  • 1x median aperture
  • 2x lateral apertures
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32
Q

how is CSF reabsorbed?

A

through arachnoid granulations, extensions of the arachnoid mater that project into the dural venous sinuses and are especially prominent in superior sagittal sinuses

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33
Q

why is CSF volume relatively constant?

A

rates of filtration and reabsorption of CSF is also relatively constant

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34
Q

what is hydrocephalus?

A

condition caused by increased CSF pressure

  • may be caused by tumours, inflammation, or malformation
  • pressure on delicate brain and spinal cord tissues compresses them, altering their functions
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35
Q

how do you treat hydrocephalus?

A

drain excess CSF to relieve pressure, usually via surgical insertion of a shunt

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36
Q

what does the brainstem consist of?

A
  • medulla oblongata
  • pons
  • midbrain
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37
Q

what is the reticular formation?

A

network of grey (cell bodies) and white (myelinated axons) matter tracts within the brainstem with both sensory and motor fxns.

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38
Q

what is the medulla oblongata?

A
  • continuous w/ spinal cord
  • forms inferior portion of brainstem
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39
Q

what is the function of the medulla oblongata’s white matter?

A

contains all sensory and motor tracts that run btwn brain and spinal cord

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40
Q

what are the medulla oblongata’s pyramids?

A

enlarged corticospinal tracts found on anterior side of medulla oblongata that controls voluntary movements of limbs and trunk

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41
Q

what is the decussation of pyramids?

A
  • at junction of MO with spinal cord
  • 90% of axons on one side cross to the opposite side
  • why one side of the brain controls the movements of the opposite side of the body
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42
Q

how does the medulla oblongata control multiple body functions?

A

nuclei such as cardiovascular centre, respiratory centre, and vomiting, coughing, etc. centres are found in the medulla oblongata

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43
Q

what is an olive?

A

bulges just lateral to each pyramid of the medulla oblongata that contains a nucleus

  • receives info from cerebral cortex, midbrain, and spinal cord
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44
Q

what is the function of the inferior olivary nucleus?

A

neurons in the inferior olivary nucleus extend their axons into the cerebellum to regulate muscle activity

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45
Q

what are the gracile and cuneate nuclei?

A

nuclei in the medulla oblongata that integrates information of somatic sensations (pain, touch, pressure, conscious proprioception)

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46
Q

what is the pons?

A

“bridge”, connects parts of the brain with each other via tracts
connects:
- L/R of cerebellum
- nerve impulses controlling voluntary skeletal movements from cerebral cortex to cerebellum

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47
Q

what are some nuclei found in the pons?

A
  • pontine nuclei
  • respiratory group
  • vestibular nuclei
  • nuclei for cranial nerves 5-8
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48
Q

what is the midbrain?

A

mesencephalon

  • extends from pons to diencephalon
  • contains cerebral aqueduct
  • contains sensory tracts, motor tracts, and nuclei (for visual and auditory info)
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49
Q

what are tectum?

A

posterior portion of midbrain w/ 4 bumps
- 2x superior colliculi
- 2x inferior colliculi

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50
Q

what are the superior colliculi?

A

2 bumps on posterior portion of pons that are reflex centers for visual stimuli

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51
Q

what are the inferior colliculi

A

2 bumps on posterior portion of pons that are reflex centers for auditory stimuli

  • controls the startle reflex
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52
Q

what are peduncles?

A

anterior portion of the midbrain containing three paired tracts

  • ascending axons carry sensory info to thalamus
  • descending tracts run btwn cerebrum, pons, medulla oblongata, and spinal cord
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53
Q

what are the three paired tracts in the midbrain’s anterior cerebral peduncles?

A
  • corticospinal
  • corticobulbar (brainstem nuclei)
  • corticopontine
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54
Q

what is the substantia nigra?

A

large and darkly pigmented nuclei in midbrain, neurons release dopamine to help control subconscious muscle activity, roles in reward and addiction

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55
Q

what are red nuclei?

A

nuclei found in midbrain that are red due to rich blood supply
- axons from cortex and cerebellum synapse here to coordinate muscular movements of limbs

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56
Q

what cranial nerves/ nuclei are found in the midbrain?

A

cranial nerves 3 and 4, oculomotor and trochlear

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57
Q

what is the reticular activating system?

A

ascending portion of the reticular formation

  • controls visual, auditory, mental activity, pain/touch/pressure sensing and consciousness
  • controls arousal, attention, alertness, sensory overload
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58
Q

what is arousal?

A

ability to wake up from sleep

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59
Q

what is sensory overload?

A

ability to filter excessive auditory/visual stimuli

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60
Q

what does the descending portion of the reticular activating system control?

A

muscle tone via cerebellum and spinal cord

  • also regulates heart rate, blood pressure, and respiratory rate
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61
Q

what does inactivation of the reticular activating system lead to?

A

sleep

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62
Q

what does damage to the reticular activating system lead to?

A

coma, due to lack of arousal

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63
Q

what does the reticular activating system not help process?

A

olfactory stimuli, meaning you won’t be able to wake up from smells (like a burning house)

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64
Q

what is the cerebellum?

A

highly convoluted portion of brain that is posterior and inferior to cerebrum

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65
Q

what is the cerebellum’s grey matter cortex?

A

superficial portion of cerebellum made of grey matter

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66
Q

why is the cerebellum highly convoluted?

A

for increased surface area, cerebellum is 10% of brain’s mass but contains 50% of brain’s neurons

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67
Q

what are cerebellar peduncles?

A

white matter tracts that attaches cerebellum to the brainstem and coordinates muscle movements

  • myelinated for rapid communication for coordination
  • inferior, superior, and middle peduncles
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68
Q

what is the vermis?

A

the central body of the cerebellum that separates the cerebellum into left and right cerebellar hemispheres

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69
Q

what are cerebellar fissures?

A

grooves on cerebellum that divide the hemispheres into lobes

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70
Q

what are the lobes of the cerebellum?

A
  • anterior lobe
  • posterior lobe
  • flocculonodular lobe
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71
Q

what do the anterior and posterior lobes of the cerebellum do?

A

controls subconscious movements

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72
Q

what does the flocculonodular lobe of the cerebellum do?

A

controls equilibrium and balance

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73
Q

what are the functions of the cerebellum?

A
  • determines accuracy of muscle movements and initiates adjustments
  • smooths out movements
  • corrects errors
  • helps w/ learning complex movement sequences (like choreography)
  • regulates posture and balance
  • some nonmotor fxns. in learning, memory, etc. due to connections to cerebral cortex
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74
Q

what does damage to cerebellum result in?

A

ataxia

  • problems in balance, stiffness
  • uncoordinated movements and gait
  • slurred, mumbling speech
  • may be due to trauma/drugs
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75
Q

what is the diencephalon?

A

“core” of brain tissue, covered by cerebral hemispheres
- consists of thalamus, hypothalamus, epithalamus

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76
Q

what is the thalamus?

A
  • 80% of diencephalon
  • relays signals from spinal cord and brainstem → primary sensory cortex
  • transmits signals from cerebellum → primary motor cortex
  • plays a role in consciousness
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77
Q

what is the interthalamic adhesion?

A

grey matter that joins right and left halves of the thalamus in 70% of humans

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78
Q

what are the thalamic nuclei?

A

don’t need to memorize

seven major groups that form diff. connections to cerebral cortex:
- anterior nucleus
- medial nuclei
- lateral group
- ventral group
- intralaminar nuclei
- periventricular nucleus
- reticular nucleus of prethalamus

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79
Q

what is the hypothalamus?

A
  • inferior to thalamus
  • plays major part in maintaining homeostasis
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80
Q

what are the nuclei found in the hypothalamus?

A
  • posterior hypothalamic area
  • intermediate hypothalamic area
  • anterior hypothalamic area
  • preoptic area
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81
Q

what is the posterior hypothalamic area?

A

contains nuclei for olfaction, feeding reflexes (licking, swallowing)

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82
Q

what is the intermediate hypothalamic area?

A

contains infundibular stalk, regulates anterior pituitary gland fxn.

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83
Q

what is the infundibular stalk?

A

found in hypothalamus, connects hypothalamus to pituitary gland

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84
Q

what is the anterior hypothalamic area?

A

contains axons from paraventricular and supraoptic nuclei that transport ADH and oxytocin to posterior pituitary

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85
Q

what is the preoptic area?

A

anterior part of hypothalamus that helps regulate certain autonomic activities (e.g. body temp)

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86
Q

what are the functions of the hypothalamus?

A
  • control of the ANS
  • hormone production
  • regulation of emotional and behavioural patterns
  • regulation of eating and drinking
  • control of body temp
  • regulation of circadian rhythms and states of consciousness
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87
Q

how does the hypothalamus function in control of the ANS?

A

axons from hypothalamus extend to sym. and para. nuclei in brainstem and spinal cord

  • stimulates smooth/cardiac muscle contraction and secretions from glands
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88
Q

how does the hypothalamus function in hormone production?

A
  • hypothalamus releases hormones into capillary network → carried to anterior pituitary → stimulates/inhibits secretion of anterior pituitary hormones
  • cell bodies in paraventricular and supraoptic nuclei produce ADH and oxytocin →transported through infundibulum stalk and released by the posterior pituitary gland
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89
Q

what hormones do cell bodies in paraventricular and supraoptic nuclei secrete?

A
  • antidiuretic hormone
  • oxytocin
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90
Q

how does the hypothalamus function in regulating emotional and behavioural patterns?

A

works w/ limbic system to express rage, aggression, pain, pleasure, sexual arousal

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91
Q

how does the hypothalamus function in regulating eating and drinking?

A

hypothalamus contains thirst center, feeding center, and satiety center

  • certain cells that can sense osmotic pressure changes are stimulated by increase of osmotic pressure of ECF and cause thirst sensation → drinking water restores normal osmotic pressure
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92
Q

how does the hypothalamus function in controlling body temperature?

A

hypothalamus functions as body’s thermostat

  • when blood temp flowing through hypothalamus changes, ANS responses are activated to restore homeostatic temperature
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93
Q

how does the hypothalamus function in regulating circadian rhythms and states of consciousness?

A

suprachiasmatic nucleus receives visual input from retina to synchronize biological rhythms to 24-hr cycle
- suprachiasmatic nucleus serves as body’s internal biological clock

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94
Q

what is the epithalamus?

A

portion of diencephalon that is superior and posterior to thalamus
- contains pineal gland and habenular nuclei

95
Q

what is the pineal gland?

A

endocrine gland found in epithalamus, secretes melatonin to regulate circadian rhythms

96
Q

what are the habenular nuclei?

A

nuclei found in epithalamus that regulate emotional responses to olfactory stimuli

97
Q

what are the circumventricular organs?

A
  • located around the third ventricle
  • includes parts of hypothalamus, pineal gland, pituitary gland, etc.
  • lacks a BBB
98
Q

what is the fxn. of the circumventricular organs?

A

coordinates endocrine and nervous responses to maintain homeostasis (BP, fluid volumes and compositions, hunger, thirst, etc.)

  • maybe site of HIV dissemination
99
Q

what is dissemination?

A

initial infection occurs to new organs in the body

100
Q

why do the circumventricular organs lack a blood-brain barrier?

A
  • circumventricular organs have to sense signals from blood circulating around it in order to coordinate endocrine responses and maintain homeostasis
101
Q

what are the three parts of the cerebrum?

A
  1. outer cerebral cortex (grey matter)
  2. inner cerebral white matter
  3. deep grey matter nuclei
102
Q

what is the functions of the cerebrum?

A

produces intelligence, learning, imagination, and memory

103
Q

what are cerebral gyri?

A

extensively folded ridges on cerebral cortex

104
Q

what are cerebral sulci?

A

shallow grooves that divide individual gyri

105
Q

what are interlobal sulci?

A

intermediate grooves that divide cerebrum into lobes

106
Q

what are cerebral fissures?

A

deep grooves that divide the brain into hemispheres/parts

107
Q

what is the longitudinal cerebral fissure?

A

deepest and most prominent groove on brain that defines the cerebral hemispheres

108
Q

what is the corpus callosum?

A

white matter tracts that connects the cerebral hemispheres together

109
Q

why do each lobes process sensory input and output motor functions to the opposite side of the body?

A

decussation of pyramids in brainstem, 90% of axons cross over midline and innervate opposite side of body

110
Q

what is the central cerebral sulcus?

A

divides frontal lobe from parietal lobe

111
Q

what is the lateral cerebral sulcus?

A

separates frontal lobe from temporal lobe

112
Q

what is the parieto-occipital sulcus?

A

divides parietal lobe from occipital lobe

113
Q

what is the function of the frontal lobes?

A

cognitive fxns, control of emotions, voluntary movement

114
Q

what is the function of the parietal lobes?

A

processes information about temperature, taste, touch, movement, proprioception

115
Q

what is the function of the occipital lobes?

A

processes visual information

116
Q

what is the function of the temporal lobes?

A

processes memories and integrates them with sensations of taste, touch, sound, and sight

117
Q

what is the function of the temporal lobes?

A

processes sensory input of taste (gustation)

118
Q

what are the different tracts that can be found in the cerebral white matter?

A
  1. association tracts
  2. commissural tracts
  3. projection tracts
119
Q

what are association tracts?

A

in cerebral white matter, conducts nerve impulses between gyri in same hemisphere

  • ipsilateral, doesn’t cross midline
120
Q

what are commissural tracts?

A

in cerebral white matter, conducts nerve impulses between corresponding gyri in opposite hemispheres

  • contralateral, crosses midline
121
Q

what are the different kinds of commissural tracts?

A
  • corpus callosum
  • anterior commissure
  • posterior commissure
122
Q

what are projection tracts?

A

in cerebral white matter, conducts nerve impulses from cerebrum to other parts of brain/spinal cord

123
Q

what is the internal capsule?

A

thick band of white matter containing both ascending and descending tracts that acts as a projection tract

124
Q

what is the corpus striatum?

A

group of nuclei buried deep within each cerebral hemisphere

  • globus pallidus
  • putamen
  • caudate nucleus
125
Q

what composes the lentiform nucleus?

A

globus pallidus and putamen

126
Q

what are the functions of the corpus striatum?

A
  • receives input from cerebral cortex and sends output back to motor cortex via thalamus
  • also communicates w/ substantia nigra
  • helps start and stop movements (activity in corpus striatum can be detected before movements)
  • helps control muscle tone, subconscious movements, and posture (e.g. swining arms, spontaneous laughter)
  • affects attention, memory, planning
  • coordinates w/ limbic system to regulate emotional behaviours
127
Q

what is the fornix?

A

white matter bundle that connects the components of the limbic system
- forms floor of diencephalon
- wraps around and up the corpus callosum

128
Q

what is the limbic system?

A

collection of structures from cerebrum, diencephalon, and midbrain

  • ## involved in establishing emotional states (pain, pleasure, docility, affection, anger) and olfaction and memory
129
Q

what happens when amygdala is damaged in humans?

A

humans unable to recognize fear/anger in other humans

130
Q

what is the hippocampus?

A

found in limbic system, involved in memory storage and retrieval

  • contains cells that are capable of mitosis
131
Q

what is a lobotomy?

A
  • removal of a portion of the brain, often to treat “hysterical” women into docility
  1. remove part of scalp
  2. drill burr holes and remove portion of cranium
  3. remove amygdala and other brain structures (portions of temporal lobe)
132
Q

what are the cerebral cortex’s primary sensory areas?

A

where sensory info from peripheral receptors arrives to cerebral cortex

  • receives touch, pressure, vibration, itch, tickle, temp, pain, and proprioception info
  • includes the primary somatosensory, visual, auditory, gustatory, and olfactory cortexes
133
Q

what are sensory association areas?

A
  • lies nearby the primary sensory areas
  • facilitates sensory info processing along w/ other brain centers (recognition & awareness)
134
Q

what is a somatosensory map/sensory homunculus?

A

misshapen map of body formed by peripheral sensory receptors linking to sensory areas

  • each sensory area receives stimuli from specific part of the body
135
Q

what determines how much area of the sensory homunculus is devoted to a body part?

A

the number of receptors found on a body part

136
Q

what is the primary visual cortex?

A

receives impulses that convey information for vision (shape, colour, movement)

  • found on posterior tip of occipital lobe
137
Q

what is the primary auditory cortex?

A

interprets basic characteristics of sound (rhythm and pitch)

  • found on superior part of temporal lobe, near lateral cerebral sulcus
138
Q

what is the primary gustatory cortex?

A
  • receives impulses for taste
  • located in the insula
139
Q

what is the primary olfactory cortex?

A
  • receives impulses for smell
  • found in temporal lobe on medial aspect (peel back and look inside)
140
Q

what are the motor areas?

A

governs voluntary muscular movement

  • formed by anterior portions of each cerebral hemisphere
  • primary motor cortex
  • premotor cortex
  • Broca’s area
  • Frontal eye field
141
Q

why does each region of the primary motor cortex control specific skeletal muscles on the contralateral side of the body?

A

decussation of pyramids in brainstem

142
Q

what is the number of neurons devoted to a muscle group dependent on in the primary motor cortex?

A

dependent on whether the area is responsible for fine/skilled movements (more neurons) or gross movements (less neurons)

143
Q

what is the premotor cortex?

A

motor association area anterior to primary motor cortex
- controls complex, learned, sequential, and coordinated movements (typing, etc.)
- fine-tune movements
- serves as memory bank for how to do these movements

144
Q

what is the frontal eye field?

A

controls voluntary scanning movements of eyes (e.g. reading a line of text)

  • partially in and anterior to premotor cortex
145
Q

what is Broca’s area?

A
  • helps control articulation of speech (ability to speak)
  • controls production of speech
  • located in left frontal lobe
146
Q

what happens if Broca’s area is damaged?

A

person has Broca’s aphasia, person cannot speak but can understand

147
Q

what is aphasia?

A

communication dysfunction, including inability to speak, understand, or write

148
Q

what is the function of association areas?

A

concerned w/ complex integrative functions such as memory, emotions, reasoning, will, judgement, personality traits, and intelligence

  • different association areas connected to e/o by association tracts
  • nerve impulses are transmitted from primary areas to association areas
149
Q

why are association areas usually nearby to the primary areas?

A

nerve impulses are transmitted from primary areas to association areas, connected to each other by association tracts

150
Q

what is the somatosensory association area?

A
  • receives input from primary somatosensory cortex and thalamus
  • integrates and interprets sensations
  • can determine exact shape/texture of object by feel alone (proprioception)
  • stores past somatic sensory experiences (memories)
  • posterior to somatosensory area
151
Q

what is the visual association area?

A
  • in occipital lobe
  • receives sensory input from primary visual cortex and thalamus
  • relates present and past visual experiences (object recognition)
152
Q

what is the facial recognition area?

A
  • receives input from visual association area
  • stores information about faces, allowing you to recognize people by sight
  • found in inferior temporal lobe (right hemisphere, usually dominant)
153
Q

what is the auditory association area?

A
  • allows for recognition of sound as speech, music, or noise
  • located inferior and posterior to primary auditory area, in temporal cortex
154
Q

what is the orbitofrontal cortex?

A
  • receives sensory impulses from primary olfactory area
  • allows us to identify and distinguish different odours
  • located in lateral part of frontal lobe
155
Q

what is Wernicke’s area?

A
  • broad association area in left temporal and parietal lobes
  • interprets meaning of speech by recognizing spoken words
  • comprehension of speech, translation of words to thought
  • writing, recognizing, understanding written words
156
Q

what is the function of areas in right hemisphere corresponding to Broca’s area and Wernicke’s area?

A

add emotional content to language

157
Q

what is Wernicke’s aphasia?

A

can speak, but cannot arrange words coherently, lacks speech comprehension
- can also have hard time w/ writing thoughts

158
Q

what is the common integrative area?

A

association area that surrounds somatosensory, visual, and auditory association areas
- integrates sensory interpretation → formation of thoughts based on sensory input from different brain areas
- transmits signals to parts of brain for appropriate responses

159
Q

what is the prefrontal cortex?

A

extensive area of anterior frontal lobe
- well-developed in primates
- many connections w/ other brain regions
- regulates personality, intellect, recall, initiative, judgment, foresight, reasoning, conscience, intuition, mood, future planning, abstract ideas

160
Q

what is hemispheric lateralization?

A

functional & structural asymmetry of the cerebral hemispheres, established early in development, during gestation

  • may be less pronounced in biological females
161
Q

what results in less pronounced lateralization in females?

A

more commissural tracts

162
Q

what results in hand preferences when writing?

A
  • hemispheric lateralization
  • bigger areas in one hemisphere controlling dominant hand than other hemisphere
163
Q

what are the functions of the right hemisphere?

A

visual, creative, spatial skills

  • musical & artistic awareness
  • space & pattern recognition
  • face recognition, facial expression recognition
  • generating emotional content of language
  • producing mental picture of spaces
  • identifying, discriminating btwn odours
164
Q

what are the functions of the left hemisphere?

A

verbal, logic, language

  • reasoning
  • numerical, scientific skills
  • ability to use and understand sign language
  • spoken, written language
165
Q

what does damage to broca’s/wernicke’s area in right hemisphere do?

A
  • speaking in a monotone
  • inability to generate emotional inflection in speech
166
Q

what does damage to left hemisphere often result in?

A

aphasia

broca’s and wernicke’s area found in left hemisphere

167
Q

what are brain waves?

A

electrical activity in brain due to many neurons of brain sending millions of nerve impulses

168
Q

what is an electroencephalogram?

A

digital output of brain waves made after placing electrodes on forehead and scalp to produce electrical signals

169
Q

what are the four types of brain waves?

A
  • alpha waves
  • beta waves
  • theta waves
  • delta waves
170
Q

what are alpha waves?

A

electrical waves made while awake but not fully alert, resting with eyes closed, absent during sleep

171
Q

what are beta waves?

A

small and frequent electrical waves made while awake, mentally active, fully alert

172
Q

what are delta waves?

A

electrical waves occurring only during deep sleep in adults

173
Q

what are theta waves?

A

electrical waves that indicate emotional stress in adults

174
Q

olfactory (I) nerve

A
  • sensory
  • receives olfactory stimuli from olfactory mucosa of nasal cavity → olfactory bulb → synapses w/ neurons that form olfactory tracts → primary olfactory area in temporal lobe
175
Q

optic (II) nerve

A
  • sensory
  • receives visual stimuli from eyeball’s retina
176
Q

describe the path visual stimuli take to get to the primary visual cortex

A

ganglion cells axons form optic nerve → merge and some axons cross in optic chiasm → optic tracts → thalamus → primary visual cortex

177
Q

why do some ganglion cells’ axons go to the midbrain?

A

to synapse w/ motor neurons that control eye movements

178
Q

where does the optic nerve enter the brain?

A

through the optic foramen

179
Q

describe how visual stimuli is transduced

A

visual stimuli sensed by photoreceptors (rods and cones) in retina, → bipolar cells → ganglion cells → optic nerve

180
Q

where do optic tracts end?

A

MOST end in lateral geniculate nucleus in the thalamus
- they synapse w/ neurons and axons of these neurons extend to primary visual cortex

SOME end in superior colliculi and motor nuclei of brainstem
- synapse w/ motor neurons controlling extrinsic and intrinsic eye muscles

181
Q

oculomotor (III) nerve

A
  • motor
  • innervates extrinsic muscles to move eyeballs and upper eyelid
  • also as autonomic motor output to constrict pupils

superior: innervates superior rectus, levator palpebrae superioris

inferior: innervates medial rectus, inferior rectus, inferior oblique muscles, ciliary muscle, circular muscle of iris

182
Q

trochlear (IV) nerve

A
  • motor
  • innervates superior oblique muscle of eyeball
183
Q

trigeminal (V) nerve

A
  • mixed
  • 3 branches: opthalmic, maxillary, mandibular

sensory: receives sensory stimuli from skin over upper eyelids, lacrimal glands, cornea, mucosa of nose, upper teeth, palate, lower teeth, 2/3 of tongue

motor: innervates muscles of mastication to control chewing movements

184
Q

what is the opthalmic branch of the trigeminal (V) nerve?

A

receives stimuli from sensory axons from skin over upper eyelids, lacrimal glands, cornea

185
Q

what is the maxillary branch of the trigeminal (V) nerve?

A

receives stimuli from sensory axons in mucosa of nose, upper teeth, palate

186
Q

what is the mandibular branch of the trigeminal (V) nerve?

A

receives stimuli from sensory axons in lower teeth, 2/3 of tongue

187
Q

where do sensory axons of trigeminal (V) nerve terminate?

A

they enter through trigeminal ganglion and terminate in nuclei of pons

188
Q

what is trigeminal neuralgia?

A

nerve pain of CN V, can result in shingles, muscle weakness, loss of sensation in face

  • 1st sign of multiple sclerosis
189
Q

abducens (VI) nerve

A
  • motor
  • innervates lateral rectus muscle of eyeball
190
Q

what can damage to CN III, IV, and VI lead to?

A

strabismus

191
Q

what is strabismus?

A

disorder where eyes do not line up in same direction

192
Q

what is sensory functions of facial (VII) nerve

A
  • extend from taste buds of anterior 2/3 of tongue, extending to thalamus, then to gustatory areas of cerebral cortex
  • extend from external acoustic meatus in skin to relay touch, pain, thermal sensations
193
Q

what is motor functions of facial (VII) nerve?

A
  • innervates muscles of facial expression and stapedius msucle
194
Q

what is the function of brachial motor axons of the facial (VII) nerve?

A

innervates middle ear, facial, scalp, and neck muscles

195
Q

what is the function of parasympathetic motor axons of the facial (VII) nerve?

A

regulates autonomic glandular function, ends in two ganglia that extends to the lacrimal glands, palatine glands, nasal glands, oral cavity glands

196
Q

what is Bell’s palsy?

A

damage to facial (VII) nerve

197
Q

vestibulocochlear (VIII) nerve

A
  • special sensory
  • receives impulses for hearing and equilibrium
198
Q

what is the function of the vestibular branch of the vestibulocochlear (VIII) nerve?

A
  • receives impulses for equilibrium
  • extends from semicircular canals, and vestibule of inner ear
  • ends in vestibular nuclei in pons and cerebellum
199
Q

what is the function of the cochlear branch of the vestibulocochlear (VIII) nerve?

A
  • receives impulses for hearing
  • originates in spiral organ in cochlea of inner ear
  • extends to nuclei in medulla oblongata and ends in thalamus
  • motor fibres regulate hair cells in inner ear
200
Q

what is the sensory axons of the glossopharyngeal (IX) nerve?

A
  • originates from tastebuds on posterior 1/3 tongue
  • proprioceptors for swallowing muscles
  • baroreceptors
  • chemoreceptors
  • external ear
  • cell bodies located in superior and inferior ganglia
  • pass through jugular foramen and ends in medulla oblongata
201
Q

what is the motor neurons of the glossopharyngeal (IX) nerve?

A
  • originates from nuclei in medulla oblongata
  • exits skull through jugular foramen
202
Q

what do the branchial motor axons of CN IX do?

A

innervate stylopharyngeus muscle for swallowing

203
Q

what do the parasympathetic motor axons of CN IX do?

A

stimulate parotid gland for saliva secretion

204
Q

what is the sensory axons of CN X?

A

originate from:
- the skin of external ear for touch, pain, and thermal sensations
- few taste buds in epiglottis and pharynx
- proprioceptors in muscles of neck and
throat
- baroreceptors in carotid sinus
- chemoreceptors in carotid and aortic
bodies
- visceral sensory receptors in organs in thoracic and abdominal
cavities

205
Q

what do branchial motor axons of CN X do?

A

innervate muscles of pharynx, larynx, soft
palate (for swallowing, vocalization, coughing)

206
Q

what do parasympathetic motor axons of CN X do?

A

supply lungs heart, glands of digestive canal, smooth muscles of passageways and intestine (visceral organs)

207
Q

accessory (XI) nerve

A
  • motor
    –cranial accessory part of CN X
    – spinal accessory motor axons originate from anterior grey horn of C1-C5, ascending skull through foramen magnum
  • innervates sternocleidomastoid and trapezius muscles to coordinate head movement
208
Q

hypoglossal (XII) nerve

A
  • motor
    – somatic motor axons supply tongue muscles (during speech and swallowing)
209
Q

An elderly relative suffered a CVA (stroke) and now has difficulty moving her right arm, and she also has speech problems.

What areas of the brain were damaged by the stroke?

A

Movement of the right arm is controlled by the left hemisphere’s primary motor cortex, located in the precentral gyrus.

Speech is controlled by the Broca’s area in the left hemisphere’s frontal lobe just superior to the lateral cerebral sulcus.

210
Q

Nicky has recently had a viral infection and now she cannot move the muscles on the right side of her face.

In addition, she is experiencing a loss of taste and a dry mouth, and she cannot close her right eye.

What cranial nerve has been affected by the viral infection?

A

Nicky’s right facial (VII) nerve has been affected; she is suffering from Bell’s palsy due to the viral infection.

The facial nerve controls contraction of skeletal muscles of the face, tear gland and salivary gland secretion, as well as conveying sensory impulses from many of the taste buds on the tongue.

211
Q

You have been hired by a pharmaceutical company to develop a drug to regulate a specific brain disorder.

What is a major physiological roadblock to developing such a drug, and how can you design a drug to bypass that roadblock so that the drug is delivered to the brain where it is needed?

A

You will need to design a drug that can get through the brain’s blood–brain barrier (BBB). The drug should be lipid- or water-soluble.

If the drug can open a gap between the tight junctions of the endothelial cells of the brain capillaries, it would be more likely to pass through the BBB.

Targeting the drug to enter the brain in certain areas near the third ventricle (the circumventricular organs) might be an option as the BBB is entirely absent in those areas and the capillary endothelium is more permeable, allowing the blood-borne drug to more readily enter the brain tissue.

212
Q

What are the three layers of the cranial meninges, from superficial to deep?

A

dura mater, arachnoid mater, and pia mater

213
Q

Where is CSF reabsorbed?

A

reabsorbed by the arachnoid granulations that project into the dural venous sinuses.

214
Q

What part of the brainstem contains the pyramids?

A

The medulla oblongata contains the pyramids

215
Q

what part of the brainstem contains the cerebral peduncles?

A

the midbrain contains the cerebral peduncles

216
Q

What is the functional consequence of decussation of the pyramids?

A

Decussation = crossing to the opposite side.

each side of the cerebrum controls muscles on the opposite side of the body.

217
Q

What is the importance of the cerebral peduncles?

A

the cerebral peduncles are the main sites through which tracts extend and nerve impulses are conducted between the superior parts of the brain and the inferior parts of the brain and the spinal cord.

218
Q

Which structures contain the axons that carry information into and out of the cerebellum?

A

The cerebellar peduncles carry information into and out of the cerebellum.

219
Q

What structure usually connects the right and left halves of the thalamus?

A

In about 70% of human brains, the interthalamic adhesion

220
Q

What are the four major regions of the hypothalamus, from posterior to anterior?

A

the posterior hypothalamic area, intermediate hypothalamic area, anterior hypothalamic area, and preoptic area.

221
Q

Which tracts carry impulses between cerebral gyri of the same hemisphere? Between cerebral gyri in opposite hemispheres? Between the cerebrum and thalamus, brainstem, and spinal cord?

A
  • Association tracts connect cerebral gyri of the same hemisphere
  • commissural tracts connect cerebral gyri in opposite hemispheres
  • projection tracts connect the cerebrum with the thalamus, brainstem, and spinal cord
222
Q

what is a major function of the corpus striatum/basal nuclei in the cerebrum?

A
  • A major function of the corpus striatum is to help regulate initiation and termination of movements
  • subconscious contractions of skeletal muscles (true laughter, automatic arm swings)
223
Q

Which part of the limbic system functions with the cerebrum in memory?

A

The hippocampus is the part of the limbic system that functions with the cerebrum in memory

224
Q

Where do axons in the olfactory tracts terminate?

A

Axons in the olfactory tracts terminate in the primary olfactory area in the temporal lobe of the cerebral cortex.

225
Q

Where do most axons in the optic tracts terminate?

A

Most axons in the optic tracts terminate in the lateral geniculate nucleus of the thalamus.

226
Q

Which branch of the oculomotor (III) nerve is distributed to the superior rectus muscle? Which is the smallest cranial nerve?

A

The superior branch of the oculomotor nerve is distributed to the superior rectus muscle; the trochlear nerve is the smallest cranial nerve.

227
Q

How does the trigeminal (V) nerve compare in size with the other cranial nerves?

A

The trigeminal nerve is the largest cranial nerve.

228
Q

Where do the motor axons of the facial (VII) nerve originate?

A

Motor axons of the facial nerve originate in the pons.

229
Q

What structures are found in the vestibular and spiral ganglia?

A

The vestibular ganglion contains cell bodies from sensory axons that arise in the semicircular canals, saccule, and utricle; the spiral ganglion contains cell bodies from axons that arise in the spiral organ of the cochlea.

230
Q

Through which foramen does the glossopharyngeal (IX) nerve exit the skull?

A

through the jugular foramen

231
Q

Where is the vagus (X) nerve located in the neck region?

A

The vagus nerve is located medial and posterior to the internal jugular vein and common carotid artery in the neck.

232
Q

How does the accessory (XI) nerve differ from the other cranial nerves?

A

The accessory nerve is the only cranial nerve that originates from both the brain and spinal cord.

233
Q

What important motor functions are related to the hypoglossal (XII) nerve?

A

Two important motor functions of the hypoglossal nerve are speech and swallowing.

A-BIOL 1191 LECTURE (12 decks)

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