1
Q
what is the function of the brain?
A
- to receive and integrate vast majority of sensory stimuli
- to coordinate appropriate responses
- site of intelligence, emotions, complex thinking, and formation of memories
2
Q
what are the four major sections of the adult brain?
A
- cerebrum
- cerebellum
- diencephalon
- brainstem
- brainstem is continuous w/ spinal cord
- diencephalon superior to brainstem
- cerebrum superior to diencephalon
- cerebellum posterior to brain stem
3
Q
how is the brain protected?
A
- enclosed by cranial meninges
- protected from physical damage by cranium’s bones
4
Q
what is the cranial dura mater?
A
- two layers fused tgt/ except where they enclose the venous sinuses
- also has extensions that separate major brain structures (falx cerebri)
5
Q
what are the venous sinuses?
A
vessels that drain blood from the brain to the internal jugular veins
6
Q
what is the falx cerebri?
A
an extension of the dura mater that separates the two cerebral hemispheres
- extends into longitudinal cerebral fissure
- attaches to the crista galli of the ethmoid bone
7
Q
is there an epidural space in the brain?
A
NO, no epidural space btwn cranial dura mater and the bones of the skull
8
Q
what are arachnoid granulations?
A
extensions of arachnoid mater that project into the venous sinuses
- where CSF is reabsorbed into the blood
9
Q
what are venous sinuses?
A
endothelial-lined venous channels that drain venous blood from the brain and deliver it back into internal jugular veins
10
Q
what is the cerebrum?
A
most superior portion of the brain, highly developed in humans and other primates
- divided into L/R cerebral hemispheres
- contains the lateral ventricles
- can be divided into 4 lobes
11
Q
what are the cerebral hemispheres?
A
left and right halves of cerebrum, allows for hemispheric lateralization because of slight asymmetry btwn the hemispheres
12
Q
what are the 4 lobes that can be found in each cerebral hemisphere?
A
- frontal lobe
- parietal love
- occipital lobe
- temporal lobe
13
Q
what is a fissure?
A
deep grooves found on the surface of the cerebrum
14
Q
what is a sulcus?
A
shallow groove found on the surface of the cerebrum
15
Q
the surface of the cerebrum has what kinds of convolutions in the tissue?
A
sulci, fissures, gyri
16
Q
what is a gyrus?
A
bulge of tissue found on either side of a sulcus on the surface of the cerebrum
17
Q
what is the central cerebral sulcus?
A
a prominent sulcus found on the cerebral surface that separates the frontal and parietal lobes of the cerebrum
18
Q
what is the lateral cerebral sulcus?
A
shallow groove that separates frontal lobe from occipital lobe
19
Q
what is the parieto-occipital sulcus?
A
shallow groove that separates the occipital lobe from the parietal lobe
20
Q
what is the frontal lobe?
A
lobe of cerebrum found directly below the frontal bones, contains the primary motor cortex, Broca’s area, prefrontal cortex
21
Q
what is the parietal lobe?
A
lobe of cerebrum found directly below parietal bones, contains the primary somatosensory cortex and somatosensory association area
22
Q
what is the temporal lobe?
A
lobe of cerebrum found directly below the temporal bones, contains the primary auditory cortex, and facial recognition association area
23
Q
what is the occipital lobe?
A
lobe of cerebrum found below the occipital bones, contains the primary visual cortex, and visual association area
24
Q
what is the precentral gyrus?
A
the gyrus found anterior to the central cerebral sulcus, contains the primary motor cortex
located on frontal lobe
25
what is the postcentral gyrus?
the gyrus found **posterior** to the central cerebral sulcus, contains the **primary somatosensory cortex**
located on parietal lobe
26
what is the longitudinal cerebral fissure?
the fissure found on the cerebral surface that separates the right and left hemispheres
27
what is the transverse fissure?
groove that separates cerebellum from cerebrum
28
what is the insula?
triangular area of cerebral cortex, lying deep within the lateral cerebral fissure
29
what is the cerebral white matter?
region of cerebrum directly deep to the grey matter cerebral cortex, contains myelinated axons
30
what is the cerebral cortex?
grey matter surface of the cerebrum, highly convoluted and contains billions of neurons
31
what is the cerebellum?
the 2nd largest portion of the brain, found posterior to the brain stem that evaluates how well the movements initiated by cerebral motor areas are actually being carried out
- regulates posture, balance, coordination
- highly convoluted, contains nearly half of the neurons found in the brain
- has superficial grey cortex and deep white matter
32
what is the arbor vitae?
the cerebellar white matter, its structure resembles a tree
33
what are the three major structures found in the brainstem?
- midbrain
- pons
- medulla oblongata
34
what do the midbrain and pons do together?
forms important **relay center** in the brain, transmitting sensory and motor input from spinal cord to the cerebral hemispheres to be processed
35
what is the medulla oblongata?
structure found on brainstem found immediately superior to and merges w/ the spinal cord
- regulates heartbeat, blood vessel diameter, breathing rhythm
- controls reflexes for vomiting, swallowing, coughing, etc.
- most of the large motor tracts descending from cerebrum **cross over** in medulla so skeletal muscle fibers on right side of body controlled by left side of brain
36
what is the pituitary gland?
endocrine gland located inferior to hypothalamus
37
what are some hormones secreted by pituitary gland?
- growth hormone
- antidiuretic hormone
- oxytocin
- follicle-stimulating hormone
- thyroid-stimulating hormone
- prolactin
38
what is the infundibular stalk (infundibulum)?
stalk-like structure that attaches pituitary gland to hypothalamus
39
what is the midbrain?
- reflex centers for certain visual activities
- relays impulses from receptors for hearing in inner ear to brain
- reflex centre for **startle reflex**
- involved in release of dopamine
40
what is the pons?
- bridge, connects areas of brain w/ each other
- has ventral and dorsal region
- ventral: coordinates, maximizes efficiency of voluntary motor output throughout body
- dorsal: has both ascending and descending tracts, acts as bridge btwn brain and SC
41
what is the spinal cord?
long stalk that is part of CNS that connects brain to the rest of the body
42
what is the diencephalon?
central region of brain that contains many important structures (hypothalamus, thalamus, pituitary gland) that can only be seen in sagittal section as they are enclosed by cerebrum, cerebellum, and brainstem
- inferior to cerebrum, superior to brainstem, anterior to cerebellum
43
what is the corpus callosum?
broad band of white matter immediately inferior to cerebrum that contains axons which connect right and left cerebral hemispheres
44
what is the thalamus?
major sensory relay station that transmits motor info from cerebellym to cerebrum, plays role in maintaining consciousness
- forms lateral walls of diencephalon and encloses the third ventricle
45
what is the interthalamic adhesion?
region of grey matter that connects the left and right thalamus regions
46
what is the hypothalamus?
the floor of the diencephalon that acts as major regulator for homeostasis
- monitors osmotic pressure, blood glucose, hormone levels, blood temperature
- connected w/ pituitary gland to produce hormones
- controls ANS, regulates emotions and behaviour patterns
47
what is the epithalamus?
small region superior and posterior to thalamus, roof of diencephalon
- superior to 3rd ventricle
- contains the pineal gland
48
what is the pineal gland?
small, posterior projection of endocrine tissue that secretes melatonin
49
what are some functions of melatonin?
- regulates circadian rhythm
- induces sleep
- serves as antioxidant
- inhibits reproductive fxn. of some animals
50
what are ventricles?
cavities within brain that are filled with cerebrospinal fluid
51
what are the different ventricles?
- 2x lateral ventricles
- 3rd ventricle
- 4th ventricle
52
what are the lateral ventricles?
- enclosed in the cerebral hemispheres (one lateral ventricle for each hemisphere)
- separated anteriorly by septum pellucidum
53
what is the septum pellucidum?
thin membrane that separates the two lateral ventricles anteriorly
54
what is the third ventricle?
narrow, slitlike cavity along the midline btwn the two halves of thalamus & btwn the lateral ventricles
55
what is the fourth ventricle?
cavity found between brainstem and cerebellum
56
what are choroid plexuses?
networks of blood capillaries within each of the ventricles that are lined by ependymal cells that produce and circulate cerebrospinal fluid
- capillaries provide selected substances for ependymal cells to use
57
what type of neuroglial cell produces cerebrospinal fluid?
ependymal cells
58
describe the path that cerebrospinal fluid flows in the brain's ventricles
CSF flows from the lateral ventricles → 3rd ventricle → **interventricular foramina** → **aqueduct of the midbrain** → 4th ventricle → central canal → subarachnoid space
59
what are interventricular foramina?
narrow, oval opening through which lateral ventricles communicate w/ third ventricle
60
what is the aqueduct of the midbrain?
channel through midbrain connected the third and fourth ventricles
- contains cerebrospinal fluid
- CSF flows from 3rd ventricle to aqueduct of midbrain to 4th ventricle
61
what are three functions of cerebrospinal fluid?
1. Mechanical protection: **shock-absorbing medium**, buoys brain so it floats weightlessly in cranial cavity
2. Chemical Protection: provides optimal chem. environment for accurate neuronal signalling
3. Circulation: minor exchange of nutrients and waste btwn blood and nervous tissue
62
what is the central canal of the spinal cord?
small space in spinal cord's grey commissure
- contains cerebrospinal fluid, continuous w/ brain's fourth ventricle
63
why is constant and consistent blood supply to the brain critical for normal functioning?
brain does not have ability to store glucose, O2 and glucose must be brought to the brain via internal carotid and vertebral arteries
64
what is the cerebral arterial circle?
group of blood vessels that create redundances in the cerebral blood supply to ensure that if one side of this circle becomes damaged, the other side can compensate and maintain adequate blood supply to brain tissue
- also equalizes blood pressure to the brain
65
describe the path venous blood travels in the brain
venous blood circulates through venous sinuses found btwn the 2 layers of the dura mater and leaves the brain via the **internal jugular veins**
66
anterior communicating arteries?
_oxygenated_ blood from _anterior cerebral arteries_ to _brain tissue_ via cerebral arterial circle
67
anterior cerebral arteries?
_oxygenated_ blood from _internal carotid arteries_ to _frontal lobe of cerebrum_
68
internal carotid arteries?
_oxygenated_ blood from _common carotid arteries_ to _anterior cerebral arteries_ to supply _eyeball, ears, pituitary gland_
69
posterior communicating arteries?
_oxygenated_ blood from _internal carotid arteries_ to _posterior cerebral arteries_ to supply _brain tissue_
70
posterior cerebral arteries?
_oxygenated_ blood from _posterior communicating arteries_ to _brain tissue_ via cerebral arterial circle
71
basilar artery?
_oxygenated_ blood from _vertebral arteries_ to _posterior cerebral and cerebellar arteries_ to supply _cerebellum, pons, inner ear_
72
vertebral arteries?
_oxygenated_ blood from _right subclavian artery_ to _basilar artery_ to supply _cerebellum, pons, inner ear_
73
why are choroid plexuses important to nervous system?
allows ependymal cells to produce CSF from selected substances off of filtered blood plasma delivered by the choroid plexuses
74
what are the two fxns. of the circle of WIllis?
1. equalizes blood pressure in brain
2. provides alternate path for blood to flow in case of blockages (anastomoses)
75
how many pairs of cranial nerves are there?
12
76
what is the function of cranial nerves?
- conduct impulses to and from various parts of the body included olfactory epithelium, retina of eye, muscles of eyeball and face, carotid arteries, structures in the throat, the heart and lungs, the digestive tract, and neck muscles
77
what occurs to the optic nerve in the optic chiasm, anterior to the optic tract?
**partial decussation**, optic nerves cross over and innervate other side of the head
(partial b/c axons from the medial half of each eye cross to the opposite side; axons from the lateral half remain on the same side)
78
what is the optic chiasm?
A crossing point of the two branches of the optic (II) nerve, anterior to the pituitary gland
79
what are the olfactory tracts?
axons of olfactory (I) nerve that extend posteriorly from olfactory bulbs, ending in olfactory cortex in temporal lobe
80
what are olfactory bulbs?
paired masses of grey matter where olfactory nerves end, resting on the cribriform plate of the ethmoid bone
81
what are the optic tracts?
posterior to the optic chiasm, axons of the optic (II) nerve that synapse w/ neurons of primary visual cortex in occipital lobe
82
olfactory (I) nerve
- special sensory
- innervates superior portion of nasal cavity, olfactory epithelium
- conveys impulses related to smell
83
optic (II) nerve
- special sensory
- innervates retina
- conveys impulses related to vision
84
oculomotor(III) nerve
- motor
- innervates medial rectus muscle of eye, circular muscle of iris, muscle of upper eyelids, muscles of eyeball (ciliary muscles)
- innervates medial rectus muscle, allows eye to move medially
85
trochlear(IV) nerve
- motor
- innervates superior oblique muscle
- moves eye inferiorly and laterally, rotates them medially
86
Trigeminal(V) nerve
- mixed
- opthalmic nerve: innervates anterior half of scalp
- maxillary nerve: innervates palate
- mandibular nerve: innervates anterior 2/3 of tongue and muscles of mastication
- conveys impulses for touch, pain, and thermal sensations
- mandibular nerve controls chewing movements
87
abducens(VI) nerve
- motor
- innervates lateral rectus muscle
- moves eyes laterally (abducts eyes)
88
facial (VII) nerve
- mixed
- innervates external acoustic meatus
- relays touch, thermal, pain sensations in external acoustic meatus
- innervates facial, scalp, and neck muscles
- allows for contraction of muscles for facial expressions
89
Vestibulocochlear(VIII) nerve
- special sensory
- innervates cochlea, semicircular canals, saccule
- conveys impulses related to hearing and equilibrium
- vestibular branch: equilibrium
- cochlear branch: hearing
90
Glossopharyngeal(IX) nerve
- mixed
- innervates stylopharyngeus muscle, taste buds on posterior 1/3 of tongue
- assists in swallowing
- conveys impulses related to taste
91
Vagus (X) nerve
- mixed
- innervate pharynx, larynx, soft palate
- allows for swallowing, vocalization, coughing, conveys sensations of hunger, fullness, discomfort
- innervates chemoreceptors in carotid and aortic bodies, conveys info abt CO2 and O2 lvls in blood
92
Accessory(XI) nerve
- motor
- innervates sternocleidomastoid, trapezius muscles
- coordinates head movements and pectoral girdle
93
Hypoglossal(XII) nerve
- motor
- innervates tongue muscles
- movement of tongue during speech and swallowing
94
olfactory nerve test
tests the nose
1. sit w/ eyes closed and 1 nostril plugged
2. garlic nose and coffee under nose one at a time and try to identify smell
3. perform same test w/ other nostril
95
optic nerve test
tests the retina
1.find paragraph and timer
2. read for 1 min, then count # of words read
96
oculomotor nerve test part A
tests retina and eyelids
1. sit looking straight ahead
2. cover 1 eye w/ hand
3. shine light in other eye and note change in diameter of pupil
97
oculomotor nerve test part B
tests retina and eyelids
1. open both eyes as wide as possible, noting any drooping of eyelids
98
Trochlear and abducens nerve test part A
tests the eyeball muscles
1. sit looking straight ahead
2. have partner hold pencil in front of you and move it slowly up down, medially, laterally
3. track movement of pencil w/ eyes w/o moving head
99
abducens nerve test part B
tests the eyeball muscles
1. cover left eye
2. look laterally w/ right eye
3. switch eyes and repeat
100
trigeminal nerve test part A
tests the mandibular muscles (muscles involved in mastication like temporalis, masseter)
1. clench teeth on tongue depressor while partner tries to pull it out
101
trigeminal nerve test part B
tests the mandibular muscles (muscles involved in mastication)
1. have partner hold one hand firmly under chin and try to open your mouth
102
facial nerve test part A
tests the muscles of facial expressions
1. smile and show teeth (buccinator)
2. inflate cheeks (orbicularis oris)
3. wrinkle forehead (frontalis)
4. raise one/both eyebrows
103
facial nerve test part B
tests the muscles of facial expressions
1. dip sterile cotton swap in flask of sweet soln. and swab the front of your tongue
104
vestibulocochlear nerve test part A
tests the ears and stereophonic hearing
1. sit with eyes closed
2. have partner hold ticking clock ~1m from right then left ear
is sound heard in both ears? can you determine which direction sound is coming from?
105
vestibulocochlear nerve test part B
tests the ears and vestibular senses (balance)
1. stand with feet together and eyes closed, maintaining balance
106
glossopharyngeal and vagus nerve test
- tests the uvula and mouth
1. open mouth and have partner carefully touch uvula w/ sterile cotton swab
2. open mouth and have partner hold tongue down w/ sterile tongue depressor
3. say ahhh
107
accessory nerve test part A
tests the head and neck muscles (trapezius muscle) against resistance
1. sit and have partner push down on shoulders
2. try raising shoulders
108
accessory nerve test part B
tests the head and neck muscles (sternocleidomastoid) against resistance
1. have partner hold sides of your head
2. try to turn your head to the left and right
109
hypoglossal nerve test
tests the tongue muscles
1. stick tongue out and then retract tongue, noting deviation from midline
inspect tongue for atrophy and fasciculations
110
stretch reflex of trigeminal nerve
1. have patient slightly open mouth
2. place finger on chin and strike finger w/ reflex hammer
3. normal response is no movement
111
why do you get patients to smile by telling a joke/funny story during facial nerve tests if there is weakness especially in a bilateral upper motor neuron distribution?
automatic or emotional facial expressions will be more complete than movements to command
112
gag reflex for glossopharyngeal and vagus nerve tests
- tests both sensory and motor components of IX and X nerves
1. touch the back of pharynx w/ tongue depressor and watch the elevation of the palate
113
by having a patient say "lah-pah-kah", what motor components are being tested?
motor components of CN 12, 7, 9, and 10
- vagus nerve
- facial nerve
- glossopharyngeal nerve
- hypoglossal nerve
114
how does the cerebellum test demonstrate the fxn. of the cerebellum?
- eyes closed and walking in straight line, touching nose w/ both index fingers, moving heel up and down shin of left leg
- allows us to evaluate one's posture, balance, and movement of body parts in relation to each other
- if cerebellum impaired, cannot coordinate cerebral motor's signals, leading to lack of balance, posture, and coordination
115
how does category clustering help?
chunking is organizing data into manageable & meaningful units
- We remember information best/can recall better when we can organize it into personally meaningful arrangements (words in a sentence, in categories, etc.)
116
what are some trends that occur during categorical clustering test?
- primacy effect: info in the beginning of list is remembered better
- recency effect: info at the end of list is remembered better
- Von Restorff Effect: we have a tendency to remember unique items in a list
117
