Chapter 14 The Brain and Cranial Nerves Flashcards
1
Q
Name some anatomical features of the brain. (Not structures)
A
The cranial meninges, formation and circulation of cerebrospinal fluid (CSF), cranial nerves.
2
Q
What is the primary function of cerebrospinal fluid (CSF)?
A
Protects the brain and spinal cord from chemical and physical injuries, carries nutrients, and circulates around the brain and spinal cord.
3
Q
How many pairs of cranial nerves are there in the peripheral nervous system?
A
12 pairs.
4
Q
What are the major parts of the brain?
A
- Brainstem
- Cerebellum
- Diencephalon
- Cerebrum
5
Q
What is the composition of cerebrospinal fluid (CSF)?
A
Clear, colorless liquid primarily composed of water, glucose, proteins, lactic acid, urea, cations (sodium, potassium, calcium, magnesium), and anions (chlorine and HCO3−).
6
Q
True or False: The cranial dura mater has only one layer.
A
False.
7
Q
What are the three extensions of the dura mater that separate parts of the brain?
A
- Falx cerebri
- Falx cerebelli
- Tentorium cerebelli
8
Q
What structure serves as the shock-absorbing medium for the brain?
A
Cerebrospinal fluid (CSF).
9
Q
What is the blood-brain barrier (BBB)?
A
A barrier consisting mainly of tight junctions that seal together endothelial cells of brain capillaries, preventing certain substances from entering brain tissue.
10
Q
Fill in the blank: The brain consumes about _____ of the oxygen and glucose used by the body.
A
20%
11
Q
What are the components of the diencephalon?
A
- Thalamus
- Hypothalamus
- Epithalamus
12
Q
Identify the cranial nerve responsible for smell.
A
Olfactory (I) nerve.
13
Q
What is the function of the medulla oblongata?
A
Controls autonomic functions such as breathing, heart rate, and blood pressure.
14
Q
What is the primary role of the reticular formation?
A
Regulates wakefulness, attention, and sleep.
15
Q
What structure is formed by the choroid plexus in the brain?
A
Cerebrospinal fluid (CSF).
16
Q
What happens when blood flow to the brain is interrupted for 1 or 2 minutes?
A
It impairs neuronal function.
17
Q
What are the main areas of the cerebral cortex?
A
- Sensory areas
- Association areas
- Motor areas
18
Q
Which cranial nerve is primarily responsible for vision?
A
Optic (II) nerve.
19
Q
What is the significance of the decussation in the medulla oblongata?
A
It is where 90% of the axons cross to the opposite side, affecting motor control.
20
Q
How is CSF reabsorbed into the blood?
A
Through arachnoid granulations (villi) that project into the dural venous sinuses.
21
Q
What is the average volume of cerebrospinal fluid (CSF) in an adult?
A
80 to 150 mL (3 to 5 oz).
22
Q
What are the foramina through which cranial nerves pass called?
A
Specific foramina.
23
Q
True or False: The cerebellum is located posterior to the brainstem.
A
True.
24
Q
What type of cells form the blood-CSF barrier?
A
Ependymal cells.
25
What are the three basic functions of CSF?
* Mechanical protection
* Chemical protection
* Circulation
26
What is the role of astrocytes in the blood-brain barrier?
They secrete chemicals that maintain the tightness of the tight junctions.
27
Fill in the blank: The adult brain has a mass of about _____ grams.
1300
28
What are the bulges on the anterior aspect of the medulla called?
Pyramids
## Footnote
Formed by large corticospinal tracts that pass from the cerebrum to the spinal cord
29
What do the corticospinal tracts control?
Voluntary movements of the limbs and trunk
30
What is the decussation of pyramids?
The crossing of axons where 90% of the axons in the left pyramid cross to the right side and vice versa
31
What type of nuclei are found in the medulla that control vital body functions?
Cardiovascular center and medullary rhythmicity center
32
What does the cardiovascular center regulate?
Rate and force of heartbeat and diameter of blood vessels
33
Which centers in the medulla are involved in regulating breathing?
Medullary respiratory center and pontine respiratory group
34
What is the function of the vomiting center in the medulla?
Causes vomiting, the forcible expulsion of contents from the upper digestive canal
35
What is the role of the inferior olivary nucleus?
Regulates activity of cerebellar neurons and adjusts muscle activity as motor skills are learned
36
Which nuclei in the posterior part of the medulla are associated with sensations?
Gracile nucleus and cuneate nucleus
37
What is the pathway known as that relays sensory information from the medulla to the thalamus?
Posterior column–medial lemniscus pathway
38
The gustatory nucleus is part of which sensory pathway?
Gustatory pathway from the tongue to the brain
39
Which cranial nerves have nuclei located in the medulla?
* Vestibulocochlear (VIII)
* Glossopharyngeal (IX)
* Vagus (X)
* Accessory (XI)
* Hypoglossal (XII)
40
What is the primary function of the pons?
Connects parts of the brain with one another
41
What are the two major structural components of the pons?
* Ventral region
* Dorsal region
42
What does the pontine respiratory group do?
Helps control breathing
43
Which cranial nerves are associated with the pons?
* Trigeminal (V)
* Abducens (VI)
* Facial (VII)
* Vestibulocochlear (VIII)
44
What structure connects the third ventricle with the fourth ventricle in the midbrain?
Cerebral aqueduct
45
What are the paired bundles of axons in the anterior part of the midbrain called?
Cerebral peduncles
46
What functions do the superior colliculi serve?
Reflex centers for visual activities and movements in response to visual stimuli
47
What is the role of the substantia nigra?
Helps control subconscious muscle activities through dopamine release
48
Which cranial nerves have nuclei located in the midbrain?
* Oculomotor (III)
* Trochlear (IV)
49
What is the reticular activating system (RAS)?
Ascending portion of the reticular formation involved in consciousness and arousal
50
What is a primary function of the RAS?
Maintains consciousness and prevents sensory overload
51
What happens if the RAS is damaged?
Results in coma, a state of unconsciousness from which an individual cannot be aroused
52
What does the descending portion of the RAS regulate?
Muscle tone, heart rate, blood pressure, and respiratory rate
53
What does the medulla oblongata contain?
* Sensory and motor tracts
* Cardiovascular center
* Medullary respiratory center
* Various nuclei for sensory pathways
54
What is the function of the cerebellum?
Smooths and coordinates contractions of skeletal muscles and regulates posture and balance
55
What is the hypothalamus responsible for?
* Integrating activities of autonomic nervous system
* Producing and releasing hormones
* Regulating emotional and behavioral patterns
56
The thalamus relays almost all sensory input to which part of the brain?
Cerebral cortex
57
What is the role of the corpus striatum?
Helps initiate and terminate movements, suppresses unwanted movements, and regulates muscle tone
58
Fill in the blank: The cerebellum accounts for about _______ of the brain mass.
a tenth
59
What is the primary function of the cerebellum?
To evaluate how well movements initiated by motor areas in the cerebrum are being carried out.
60
How does the cerebellum contribute to movement coordination?
It sends feedback signals to motor areas of the cerebral cortex to correct errors and smooth movements.
61
What is the shape of the cerebellum compared to?
It resembles a butterfly.
62
What are the main lobes of the cerebellum?
Anterior lobe, posterior lobe, and flocculonodular lobe.
63
What does the vermis refer to in the cerebellum?
The central constricted area.
64
What type of matter is the cerebellar cortex made of?
Gray matter.
65
What are the cerebellar peduncles?
Three paired structures that attach the cerebellum to the brainstem.
66
Which cerebellar peduncle carries impulses for voluntary movements?
Middle cerebellar peduncles.
67
What sensory information do the inferior cerebellar peduncles carry?
Sensory information from proprioceptors in the trunk, limbs, and head.
68
True or False: The cerebellum contains nearly half of the neurons in the brain.
True.
69
What is the main role of the thalamus?
Major relay station for most sensory impulses.
70
What are the seven major groups of nuclei found in the thalamus?
* Anterior nucleus
* Medial nuclei
* Lateral group nuclei
* Ventral group nuclei
* Intralaminar nuclei
* Midline nucleus
* Reticular nucleus
71
What does the hypothalamus regulate?
Homeostasis and various autonomic activities.
72
What hormones are produced by the hypothalamus?
* Oxytocin
* Antidiuretic hormone
* Releasing hormones
* Inhibiting hormones
73
What is the function of the suprachiasmatic nucleus (SCN)?
Establishes circadian rhythms.
74
What does the epithalamus consist of?
* Pineal gland
* Habenular nuclei
75
What hormone does the pineal gland secrete?
Melatonin.
76
Fill in the blank: The _____ is responsible for regulating eating and drinking.
hypothalamus.
77
What are circumventricular organs (CVOs)?
Parts of the diencephalon that monitor chemical changes in the blood.
78
What is the role of the habenular nuclei?
Involved in olfaction and emotional responses to odors.
79
What does the internal medullary lamina do?
Divides the gray matter of the right and left sides of the thalamus.
80
What is the anterior nucleus of the thalamus involved in?
Emotions and memory.
81
What is the primary function of the medial nuclei in the thalamus?
Involves emotions, learning, memory, and cognition.
82
What is the relationship between the hypothalamus and the pituitary gland?
The hypothalamus produces hormones that regulate the pituitary gland.
83
What is the reticular nucleus's function?
Monitors, filters, and integrates activities of other thalamic nuclei.
84
Which region of the hypothalamus regulates body temperature?
The hypothalamus itself functions as the body's thermostat.
85
What does melatonin regulate?
Circadian rhythms, sleep, and various physiological functions.
86
True or False: The cerebellum is located superior to the medulla and pons.
False.
87
What type of information do the ventral posterior nuclei of the thalamus relay?
Somatic sensations like touch, pressure, and pain.
88
What is the primary role of the inferior olivary nucleus?
Regulates the activity of cerebellar neurons.
89
What are circumventricular organs (CVOs)?
Regions in the brain that coordinate homeostatic activities of the endocrine and nervous systems
## Footnote
CVOs include parts of the hypothalamus, the pineal gland, and the pituitary gland
90
What is the primary function of the cerebrum?
Seat of intelligence; enables reading, writing, speaking, calculations, music composition, memory, planning, and imagination
91
What is the cerebral cortex?
A region of gray matter forming the outer rim of the cerebrum, containing billions of neurons arranged in layers
92
What are gyri and sulci?
Gyri are folds of the cerebral cortex; sulci are shallower grooves between folds
93
What is the longitudinal fissure?
The most prominent fissure that separates the cerebrum into right and left halves called cerebral hemispheres
94
What connects the two cerebral hemispheres?
The corpus callosum
95
Name the four lobes of the cerebrum.
* Frontal lobe
* Parietal lobe
* Temporal lobe
* Occipital lobe
96
What is the precentral gyrus responsible for?
Contains the primary motor cortex of the cerebrum
97
What is the postcentral gyrus responsible for?
Contains the primary somatosensory area of the cerebral cortex
98
What are the three types of cerebral white matter tracts?
* Association tracts
* Commissural tracts
* Projection tracts
99
What are the components of the basal nuclei?
* Globus pallidus
* Putamen
* Caudate nucleus
100
What is the primary function of the basal nuclei?
Help regulate initiation and termination of movements
101
What is the limbic system often referred to as?
The emotional brain
102
What are the main components of the limbic system?
* Limbic lobe
* Hippocampus
* Amygdala
* Septal nuclei
* Mammillary bodies
* Olfactory bulbs
103
What role does the hippocampus play?
Involved in memory and capable of neurogenesis
104
Where is the primary somatosensory area located?
Directly posterior to the central sulcus in the postcentral gyrus of each parietal lobe
105
What is the sensory homunculus?
A distorted map of the body represented in the primary somatosensory area
106
What is the primary visual area responsible for?
Receives visual information and is involved in visual perception
107
What is Broca's speech area?
An area of the frontal lobe responsible for speech production and understanding language
108
What happens if Broca's area is damaged?
Results in nonfluent aphasia, where a person cannot form words despite having clear thoughts
109
What is the main function of the somatosensory association area?
Integrates sensory experiences to recognize and evaluate objects by touch
110
What is the role of the facial recognition area?
Stores information about faces and allows recognition of people by their faces
111
Fill in the blank: The primary auditory area is located in the _______.
Superior part of the temporal lobe
112
True or False: The auditory association area allows you to recognize a sound as speech, music, or noise.
True
113
What area in the right hemisphere is more dominant for facial recognition?
Facial recognition area
## Footnote
This area allows you to recognize people by their faces.
114
What is the function of the auditory association area (area 22)?
Recognizes sounds as speech, music, or noise
## Footnote
Located inferior and posterior to the primary auditory area in the temporal cortex.
115
What does the orbitofrontal cortex allow you to identify?
Odors
## Footnote
This area receives sensory impulses from the primary olfactory area and discriminates among different odors.
116
What is Wernicke’s area responsible for?
Interpreting the meaning of speech
## Footnote
It recognizes spoken words and translates them into thoughts.
117
What type of aphasia is associated with damage to Wernicke’s area?
Fluent aphasia, or 'word salad'
## Footnote
Patients can speak but cannot arrange words coherently.
118
Which area integrates sensory interpretations from various association areas?
Common integrative area (areas 5, 7, 39, and 40)
## Footnote
It transmits signals for appropriate responses to sensory inputs.
119
What functions does the prefrontal cortex influence?
Personality, intellect, complex learning, recall, judgment, foresight, reasoning
## Footnote
It is an extensive area in the anterior portion of the frontal lobe.
120
What is the role of the premotor area (area 6)?
Deals with learned motor activities of a complex and sequential nature
## Footnote
It generates nerve impulses for muscle contractions in specific sequences.
121
What does the frontal eye field area (area 8) control?
Voluntary scanning movements of the eyes
## Footnote
Sometimes included in the premotor area.
122
What is hemispheric lateralization?
Functional asymmetry between the right and left hemispheres
## Footnote
Each hemisphere specializes in certain unique functions despite being nearly symmetrical.
123
What is a significant anatomical difference in the planum temporale of most individuals?
It is 50% larger on the left side than on the right side
## Footnote
This asymmetry appears in the human fetus at about 30 weeks gestation.
124
True or False: Lateralization is more pronounced in females than in males for language skills.
False
## Footnote
Lateralization seems less pronounced in females for language and visual spatial skills.
125
What are the four types of brain waves?
Alpha, Beta, Theta, Delta
## Footnote
Each type has distinct frequencies and associated states of brain activity.
126
What frequency range do alpha waves occur in?
8–13 cycles/second
## Footnote
Present in EEGs of nearly all normal individuals when awake and resting with eyes closed.
127
What does the trigeminal (V) nerve control?
Sensory and motor functions in the face
## Footnote
It is the largest cranial nerve and has three branches.
128
What is the function of the olfactory (I) nerve?
Conducts APs for olfaction
## Footnote
It is sensory and involved in the sense of smell.
129
What is the optic (II) nerve primarily responsible for?
Conducting APs for vision
## Footnote
Technically a tract of the brain, it plays a crucial role in visual processing.
130
What muscles do the oculomotor (III), trochlear (IV), and abducens (VI) nerves control?
Muscles that move the eyeballs
## Footnote
They are motor nerves that contain only motor axons.
131
What is the smallest cranial nerve?
Trochlear (IV) nerve
## Footnote
It arises from the posterior aspect of the brainstem.
132
Which cranial nerve is the largest?
Trigeminal (V) nerve
## Footnote
It is a mixed cranial nerve with sensory and motor functions.
133
What is the primary function of the trigeminal nerve?
Sensory and motor functions related to touch, pain, and temperature sensations in the face and oral cavity, as well as chewing movements.
## Footnote
The trigeminal nerve has three branches: ophthalmic, maxillary, and mandibular.
134
Which branch of the trigeminal nerve is the smallest?
Ophthalmic nerve.
## Footnote
It passes into the orbit via the superior orbital fissure.
135
What structures does the maxillary nerve innervate?
Mucosa of the nose, palate, part of the pharynx, upper teeth, upper lip, and lower eyelid.
## Footnote
It is intermediate in size between the ophthalmic and mandibular nerves.
136
What sensory information does the mandibular nerve carry?
Touch, pain, and thermal sensations from the anterior two-thirds of the tongue, cheek, lower teeth, skin over the mandible, and mucosa of the floor of the mouth.
## Footnote
The mandibular nerve is the largest branch of the trigeminal nerve.
137
True or False: The facial nerve is exclusively a sensory nerve.
False.
## Footnote
The facial nerve is a mixed cranial nerve, with both sensory and motor functions.
138
What is the role of the facial nerve's sensory axons?
They relay taste from the anterior two-thirds of the tongue and sensations from the skin in the ear canal.
## Footnote
Sensory axons pass to the geniculate ganglion before ending in the pons.
139
What are the principal functions of the vestibulocochlear nerve?
Hearing and equilibrium.
## Footnote
It has two branches: vestibular (for equilibrium) and cochlear (for hearing).
140
Where do sensory axons in the cochlear branch originate?
In the spiral organ (organ of Corti) in the cochlea.
## Footnote
The cell bodies of these sensory neurons are in the spiral ganglion of the cochlea.
141
What is the function of the glossopharyngeal nerve?
Taste sensation from the posterior one-third of the tongue, proprioception from swallowing muscles, and monitoring of blood pressure and gas levels.
## Footnote
It is a mixed cranial nerve with sensory and motor functions.
142
What type of neurons does the vagus nerve contain?
Sensory, branchial motor, and parasympathetic motor neurons.
## Footnote
The vagus nerve is distributed from the head and neck into the thorax and abdomen.
143
Which cranial nerve is responsible for the movement of head and pectoral girdle?
Accessory (XI) nerve.
## Footnote
It sends motor impulses to the sternocleidomastoid and trapezius muscles.
144
What is the primary role of the hypoglossal nerve?
Control of the muscles of the tongue for speech and swallowing.
## Footnote
It is a motor cranial nerve originating from the hypoglossal nucleus in the medulla oblongata.
145
Fill in the blank: The cranial meninges consist of the ______, ______, and ______.
dura mater, arachnoid mater, pia mater.
## Footnote
These layers protect the brain and are continuous with the spinal meninges.
146
What is the main source of blood supply to the brain?
Internal carotid and vertebral arteries.
## Footnote
Any interruption can lead to damage or death of brain cells.
147
What is the function of cerebrospinal fluid (CSF)?
Provides mechanical protection, chemical protection, and circulation of nutrients.
## Footnote
CSF is formed in the choroid plexuses and circulates through the ventricles and subarachnoid space.
148
True or False: The medulla oblongata contains nuclei associated with cranial nerves.
True.
## Footnote
It contains nuclei for the vestibulocochlear, glossopharyngeal, vagus, accessory, and hypoglossal nerves.
149
What are the major parts of the brain?
Brainstem, cerebellum, diencephalon, cerebrum.
## Footnote
These components are essential for various brain functions.
150
What part of the brainstem contains nuclei associated with the oculomotor and trochlear nerves?
The midbrain
## Footnote
The midbrain plays a critical role in visual and auditory processing.
151
What is the function of the reticular formation in the brainstem?
Helps maintain consciousness, causes awakening from sleep, and regulates muscle tone
## Footnote
The reticular formation is a network of neurons that plays a vital role in arousal and alertness.
152
Where is the cerebellum located in relation to the cranial cavity?
Inferior and posterior aspects
## Footnote
The cerebellum is critical for coordination and balance.
153
What connects the cerebellum to the brainstem?
Three pairs of cerebellar peduncles
## Footnote
These peduncles facilitate communication between the cerebellum and other parts of the brain.
154
What are the three main components of the diencephalon?
Thalamus, hypothalamus, epithalamus
## Footnote
Each component has distinct functions related to sensory and autonomic control.
155
What is the role of the thalamus?
Relay station for sensory input to the cerebral cortex and contributes to motor functions
## Footnote
The thalamus is crucial for processing and transmitting sensory information.
156
What functions does the hypothalamus control?
Autonomic nervous system, hormone production, emotional and behavioral patterns, body temperature regulation
## Footnote
The hypothalamus is essential for homeostasis and emotional responses.
157
What does the epithalamus consist of?
Pineal gland and habenular nuclei
## Footnote
The pineal gland secretes melatonin, influencing sleep patterns.
158
What is the largest part of the brain?
The cerebrum
## Footnote
The cerebrum is responsible for higher brain functions such as thought and action.
159
Name the four lobes of the cerebral hemispheres.
Frontal, parietal, temporal, occipital
## Footnote
Each lobe has specialized functions related to perception, movement, and cognition.
160
What is the primary motor area responsible for?
Controls voluntary contractions of specific muscles
## Footnote
This area is critical for executing movements.
161
What is the function of the limbic system?
Emotional aspects of behavior and memory
## Footnote
The limbic system influences emotions and memory formation.
162
True or False: The left hemisphere of the brain is primarily responsible for musical awareness.
False
## Footnote
The right hemisphere is more important for musical and artistic skills.
163
What is the primary somatosensory area involved in?
Perception of touch, pressure, vibration, itch, tickle, pain, and proprioception
## Footnote
This area is crucial for processing sensory information from the body.
164
Fill in the blank: The _______ nerve is responsible for the sense of smell.
[Olfactory (I) Nerve]
## Footnote
This sensory nerve transmits information about odors.
165
What type of nerve is the trigeminal (V) nerve?
Mixed cranial nerve
## Footnote
It carries sensory information from the face and motor fibers for chewing.
166
What is the function of the vestibulocochlear (VIII) nerve?
Sends sensory information for hearing and balance
## Footnote
This nerve is crucial for auditory and equilibrium functions.
167
What does the vagus (X) nerve regulate?
Swallowing, vocalization, heart rate, and gastrointestinal motility
## Footnote
The vagus nerve plays a significant role in autonomic functions.
168
The hypoglossal (XII) nerve promotes which functions?
Speech and swallowing
## Footnote
This motor nerve controls the muscles of the tongue.
