Anatomy of the Brain & Cranial Nerves Flashcards
1
Q
The brain receives information about the ___ and ___ environment
A
internal and external
2
Q
the brain makes decisions regarding: ___, ___, ___, ___ and ___
A
muscular movements, glandular secretions, heart and respiration rate, social interactions and the regulation of homeostasis
3
Q
Similar to the spinal cord, the brain is organized with __ surrounding a ___
A
central gray matter surrounding a fluid filled cavity
4
Q
surrounding the gray matter are ___
A
large white matter tracts for carrying ascending and descending information
5
Q
there is a second region of gray matter found ___ to the white matter - where is it found?
A
gray matter found superficial to the white matter in the cerebral cortex
6
Q
sensory inputs converge where? what does this allow for?
A
sensory inputs converge in the cerebral cortex, allowing us to make sense of our environment
7
Q
what is formed 4 weeks after fertilization?
A
the neural tube
8
Q
what is the neural tube
A
it is a hollow tube that forms all of the cells found in the brain and spinal cord
9
Q
the walls of the neural tube become what? the cavity in the tube becomes what?
A
the walls become the neurons and glial cells while the hollow cavity becomes the central canal in the spinal cord and he series of interconnected ventricles
10
Q
the growth of the ___ from the neural tube outpaces the other regions of growth
A
cerebrum
11
Q
what are the brain’s six major divisions?
A
- cerebrum (2 hemispheres)
- Diencephalon
- Midbrain
- Pons
- Medulla Oblongata
- Cerebellum
12
Q
what 3 parts of the six major divisions make up the “brainstem”
A
the midbrain, the pons, and the medulla oblongata
13
Q
the central gray matter is also called ___ and surrounds a fluid filled cavity also called __
A
nuclei ; ventricles
14
Q
many of the body’s sensory input have a specialized region of the ___ dedicated to ___
A
cortex dedicated to their processing of information
15
Q
the specialized cortices are ___ allowing for ___ of the senses and a highly ___ ___ of reality
A
the cortices are interconnected allowing for integration of the senses and a highly detailed perception
16
Q
in addition to the 2 types of gray matter, there is a very large amount of ___ ___ containing ___ traveling to and from the brain’s ___ and ___
A
white matter containing axons that travel to and from the brain’s nuclei and cortex
17
Q
the axons communicate between 1. __ and 2. ___ through ___
A
they communicate between specific regions of the brain and between the brain and spinal cord ; they do it through the highly ordered tracts that the axons are organized into
18
Q
what are ventricles
A
the are a series of chambers within the 2 hemispheres of the cerebrum that travel down the center of the brain to the spinal cord
19
Q
what do ventricles contain?
A
fluid known as cerebrospinal fluid or CSF
20
Q
what does CSF do
A
nourishes and protects the brain
21
Q
where is the CSF produced
A
it is produced from blood at the choroid plexuses, which are found in the walls of the ventricles
22
Q
a set of paired ventricles lying within the cerebral hemispheres are called the ___
A
lateral ventricles
23
Q
what is the septum pellucidum
A
it is the thin membrane that separates the lateral ventricles
24
Q
each lateral ventricle connects to a ___ by an ___
A
3rd ventricle by an inter-ventricular foramen
25
what surrounds the 3rd ventricle?
the diencephalon
26
the 3rd ventricle narrows to form the __
cerebral aqueduct
27
the cerebral aqueduct passes through the ___
midbrain
28
what shape is the 4th ventricle
diamond-shaped
29
what borders the 4th ventricle
the pons border the 4th ventricle anteriorly and the cerebellum borders the 4th ventricle posteriorly
30
the 4th ventricle narrows substantially to become what?
the central canal of the medulla and spinal cord
31
the brain is surrounded by the bones of the skull and a series of ____ called ____
membranes called meninges (singular = meninx)
32
the most superficial of the meninges is the ___
dura mater
33
the dura mater does what
provides a resilient layer around the brain
34
the dura mater's two sublayers divide to form routes for blood called the ___
dural venous sinuses
35
what is the function of the dural venous sinuses
they function as veins, draining blood away from the brain and scalp
36
the ____ is on the innermost surface of the dura mater
the arachnoid mater
37
the arachnoid mater's fine strands extend across the ____ to the deepest meninx called the ____
subarachnoid space to the deepest meninx called the pia mater
38
the subarachnoid space is filled with ___ to provide a ___ to surround the brain
CSF to provide a watery cushion surrounding the brain
39
what absorbs excess CSF
the dural venous sinuses absorb excess CSF through arachnoid granulations
40
what are arachnoid granulations
extensions of the arachnoid mater that help the dural venous sinuses to absorb CSF
41
major regions of the brain are separated by
dural folds
42
what is the longitudinal fissure
the separation between the two cerebral hemispheres
43
where can the falx (sickle) cerebri be found
within the longitudinal fissure
44
within the falx cerebri there is a large dural venous sinus close to the skull called the ____
superior sagittal sinus
45
another major dural fold is the ___ (hint: tent-like)
tentorium cerebelli
46
where can the tentorium cerebelli be found
in the transverse fissure
47
what is the transverse fissure
a deep crevasse that divides the cerebrum from the cerebellum
48
what is the 1st step of circulation
CSF is produces in the choroid plexuses
49
what are the choroid plexuses
blood vessels in the walls of the ventricles
50
what is the 2nd step of circulation
small openings in the ventricular system allow CSF to escape and enter the continuous subarachnoid space that surrounds the entire brain and spinal cord
51
what is the 3rd step of circulation
in the subarachnoid space, CSF has its greatest protective role, providing a cushion of fluid capable of dissipating forces that impact the skull and vertebral column
52
what is the 4th step of circulation
from the subarachnoid space, CSF returns to the blood and specialized regions of the subarachnoid mater called arachnoid granulations penetrate the dural venous sinuses surrounding the brain
53
what are the five lobes of the cerebral hemispheres
1. frontal
2. parietal
3. occipital
4. temporal
5. insular
54
which lobe is the most difficult to visualize
the insular lobe - it is tucked away in the lateral sulcus
55
a thin layer of gray matter called the ___ lies on the surface of the cerebral hemispheres
cerebral cortex
56
the surface of the cerebrum is covered in ridges called ___, grooves called ___ and major grooves called ____
gyri (gyrus = singular)
sulci (sulcus = singular)
fissures
57
what divides the frontal and parietal lobes
the central sulcus
58
what separates the right and left hemispheres
the longitudinal fissure
59
what divides the temporal lobe from the frontal and parietal lobes
the lateral sulcus
60
what divides the parietal and occipital lobes
the parieto-occipital sulcus
61
what allows for an expansive network of synapses in the brain
the large surface area created by the lobes and intricate folding pattern created by the gyri and sulci
62
the cortex is organized into
functional regions
63
what are motor areas and where are they found
they are regions that produce voluntary movement throughout the body and send instructions to the motor division of the peripheral nervous system; they are found in the frontal lobe
64
where is the primary motor cortex located
the precentral gyrus on the frontal lobe of each hemisphere
65
what is the primary motor cortex
the region that issues motor commands to the body
66
like motor areas, there are also regions concerned with receiving information from ___
the senses
67
where do the general senses (touch, temperature and pain) of the body arrive in the brain?
they arrive at the primary sensory cortex
68
where is the primary sensory cortex located
on the postcentral gyrus of the parietal lobes
69
special senses project to other parts of the __
cortex
70
where is the primary visual cortex
occipital lobe
71
where is the primary auditory cortex
temporal lobe
72
where is the primary olfactory cortex
temporal lobe
73
where is the primary gustatory (taste) cortex
insular lobe
74
what are multimodal association areas
these are areas that integrate inputs from multiple senses and allow us to make meaning of the information we receive
75
where can you find the multimodal association areas
throughout the cortex
76
what is the best understood multimodal association area and what is it important for
the best understood is the prefrontal cortex - a region important in social interactions and personality
77
white matter is found where
beneath the cortex
78
white matter contains ___ that make tracts and allow for what
it contains axons that form tracts and allow the passage of information to and from the cortex
79
there are __ directions that bundles of axons can take
3
80
what are the 3 directions the bundles of axons in the white matter can take
1. commissural tracts
2. projection tracts
3. association tracts
81
what are commissural tracts
they connect the cortex to the cortex of the opposite hemisphere - the vast majority of tracts cross at the corpus callosum but a smaller commissure is visible inferior to the corpus callosum called the fornix (or arch)
82
what are projection tracts
they connect the cortex to lower brain regions or to the spinal cord; these fibers control muscles and relay senses to/from most of your body
83
what are association tracts
these tracts connect the cortex to adjacent regions of the same hemisphere
84
where can the basal nuclei (or basal ganglia) be found
they lie close to the ventricles in the deepest recesses of the cerebral hemispheres
85
what do the basal nuclei do
they are clusters of gray matter that are mainly responsible for regulation of movement initiation and the coordinated control of antagonistic muscle pairs (biceps v. triceps for ex. )
86
how are basal nuclei related to Parkinson's disease
Parkinson's results from the over-activity of these nuclei - people w/ parkisons have uncontrolled muscles contracting on both sides of joins leading to tremors/difficulty initiating movements
87
what region of the brain is directly affected by Parkinson's
the midbrain - the region that regulates activity of the basal nuclei
88
what is the diencephalon
it is a brain region that includes 3 major structures of the adult brain
89
what are the 3 major structures included in the diencephalon
the thalamus, the epithalamus, and hypothalamus
90
during development the epithalamus has 2 parts - what are they
the pineal gland and the choroid plexus
91
what does the pineal gland (or body) do
it produces melatonin which prepares the body for sleep
92
what does the choroid plexus do
it produces CSF - choroid plexuses may be found in all of the ventricles - only the plexus of the 3rd ventricle is part of the epithalamus
93
what is the thalamus
this brain region is often called the relay station because it is the site of synapse for nearly all sensory pathways; signals are routed from the spinal cord or lower brain regions to the appropriate region of the cerebral cortex
94
the thalamus has two __ shaped halves with the __ __ between them
egg-shaped halves with the 3rd ventricle between them
95
what is the interthalamic adhesion
a small spot where the two halves of the thalamus make contact through the 3rd ventricle (only found in 70% of brains)
96
where is the hypothalamus and what is it made of
below the thalamus ; it contains several nuclei that regulate many bodily functions
97
what are the 5 functions of the hypothalamus
1. autonomic control - governs the activity of the autonomic nuclei in the brainstem
2. emotional center - initiates "gut reaction" to various stimuli including hunger, thirst, sex, anger, fear, rage
3. body temperature control - initiates sweating or shivering
4. sleep cycle control
5. pituitary control - releases hormones that control the release of other hormones from the pituitary gland
98
where is the midbrain
it is a narrow region between the pons and thalamus
99
what is inside the midbrain
there are two pairs of pigmented nuclei
100
what are the two pairs of pigmented nuclei in the midbrain and what do they do
1. the red nucleus - coordinates gross limb movements
2. the substantia nigra - controls the basal nuclei; dopamine releasing neurons degenerate in parkinson's leaving the basal nuclei unregulated
101
what are cerebral peduncles
they are large bundles of axons containing projection tracts that permit communication between the cerebral hemispheres and lower parts of the central nervous system
102
what are superior colliculi
they are nuclei on the posterior side of the midbrain that initiate visual reflexes ( ex. the coordination of eye and head movements when tracking a moving object)
103
what are inferior colliculi
they are nuclei on the posterior midbrain that receive auditory information and coordinate reflexive actions in response to sounds
104
together the superior and inferior colliculi form the what?
corpora quadrigemina (corpora = bodies; quadrigemina = four twins)
105
what are the pons
they contain mostly tracts of white matter
106
many tracts pass vertically through the pons and form the ___ of the midbrain
cerebral peduncles
107
some tracts that arrive at the pons enter the cerebellum through large bundles called the ___
cerebellar peduncles
108
what is the cerebellum
the cerebellum receives information from the cerebral hemispheres about tis intent to initiate movements and it receives info from sensory receptors in muscles and joins that provide info about the body's position
109
what are proprioceptors
sensory receptors in the muscles and joints
110
what calculates coordinated movements of the body
the cerebellum
111
what is called "little brain" and why
the cerebellum ; b/c it has 2 hemispheres that have an outer cortex and inner white matter
112
what is the arbor vitae
it is the name of the white matter in the cerebellum that exhibits a distinct tree-like branching pattern
113
the cortex of the cerebellum is folded into little ridges called ___
follia (singular = folium)
114
what is the vermis (= the worm)
the miniature 3rd lobe at the center of the cerebellum
115
in addition to the mostly white matter tracts in the medulla oblongata several important __ are present
nuclei
116
nuclei in the medulla oblongata send and receive info from the ___ nervous system
autonomic
117
what are the 3 types of centers in the medulla oblongata that send and receive info
1. the cardiovascular centers - they regulate heart rate and blood vessel diameter
2. respiratory centers - control depth and rate of breathing
3. various autonomic centers - reflex centers for the gastrointestinal tract
118
what are the most striking external features on the medulla oblongata
the large ridges on the anterior surface called the medullary pyramids
119
what do the medullary pyramids contain
very large descending "corticospinal tracts" which contain axons that direct voluntary movements of the body
120
what are the two important functional components of the brain that span anatomical boundaries
the limbic system and the reticular formation
121
what is the reticular formation
a loosely organized series of nuclei extending throughout the brainstem that play an important role in filtering sensory information on its way to the cortex
- keeps all the different stimuli from all your receptors from your conscious thought
122
what is the limbic system
it includes structures in the cerebral cortex, basal nuclei, thalamus, and hypothalamus: all these structures coordinate to recognize social cues and elicit emotions and memory
123
emotional overstimulation from the limbic system can have an affect on autonomic targets (like nausea, vomiting) - why?
because the hypothalamus is involved in both emotion and autonomic control and the hypothalamus is apart of the limbic system
124
where are the cranial nerves
on the inferior surface of the brain
125
cranial nerve 1 is the ___
olfactory nerve - a very short nerve running from the nasal epithelium through the cribriform plate of the ethmoid bone. it synapses within the olfactory bulbs
126
what is the olfactory tract
the visible structure on the surface of the brain - it is an extension of the cerebral hemisphere
127
where is the olfactory bulbs
at the distal end of the olfactory tracts ; they are where the olfactory nerve synapses
128
Cranial nerve 2 is the __
optic nerve - it carries information from the retina of the eye to the optic chiasm and then the optic tracts carry information to the brain
129
what is the optic chiasm
where about half of the fibers cross to the opposite side
130
how many cranial nerves are there
12
131
what is the mnemonic to remember the first letter of nerves
```
Oh
Once
One
Takes
The
Anatomy
Final, a
Very
Good
Vacation
Sounds
Heavenly
```
132
Using the mnemonic, name the 12 cranial nerves
```
Olfactory
Optic
Oculomotor
Trochlear
Trigeminal
Abducens
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Spinal Accessory
Hypoglossal
```
133
What is the mnemonic to remember whether the cranial nerves are motor, sensory or both
```
Some
Say
Marry
Money
But
My
Brother
Says
Big
Business
Makes
Money
```
134
using the mnemonic, say whether the nerves are motor, sensory or both
Olfactory - Sensory (from olfactory epithelium)
Optic - Sensory (from retina)
Oculomotor - Motor (to most extrinsic eye muscles)
Trochlear - Motor (to extrinsic eye muscle)
Trigeminal - Both; motor to chewing muscles; sensory from face, oral and nasal cavities
Abducens - Motor (to extrinsic eye muscle)
Facial - Both: motor to facial expression muscles; sensory from taste buds
Vestibulocochlear - Sensory (from inner ear)
Glossopharyngeal - Both: motor to pharynx; sensory from taste buds
Vagus - Both: motor and sensory to thoracic and abdominal organs
Spinal Accessory - Motor (to neck muscles)
Hypoglossal - Motor (to tongue muscles)
