Module 8: The Nervous System Flashcards
(136 cards)
1
Q
Hypoxia
A
The medical condition in which there is an inadequate oxygen supply to the brain.
2
Q
Ischemia
A
A lack of blood supply to the brain.
3
Q
Hypoglycemia
A
A condition in which glucose levels in the blood have become so low that the brain cannot function properly.
4
Q
What are the two basic types of stroke?
A
Ischemic and hemorrhagic stroke.
5
Q
What happens in an ischemic stroke?
A
A blood clot cuts off the blood supply to part of the brain.
6
Q
What happens in a hemorrhagic stroke?
A
A blood vessel in the brain bursts, the blood supply to the neurons is interrupted, and the neurons are bathed in blood chemicals toxic to them, killing large numbers of neurons.
7
Q
What does the acronym FAST refer to?
A
It refers to the steps that should be taken to recognize a stroke. F: Face
A: Arms S: Speech T: Time
8
Q
What are some of the basic nutrients the brain needs?
A
It needs glucose, B vitamins and minerals, and essential fat.
9
Q
What are B vitamins and minerals used for in the brain?
A
It allows the neurons’ mitochondria to produce ATP efficiently.
10
Q
What is essential fat used for in the brain?
A
The neuroglia use the fat to make myelin.
11
Q
Gray matter
A
Collections of neuron cell bodies and their associated neuroglia.
12
Q
White matter
A
Bundles of parallel axons and their coverings.
13
Q
What does MRI stand for?
A
Magnetic resonance imaging
14
Q
Midsagittal section
A
A slice down the center of the brain that splits it into equal left and right halves.
15
Q
What three sections can the brainstem be split into?
A
The medulla oblongata, the pons, and the midbrain.
16
Q
Decussation
A
The anatomical crossing over of neurons from left to right.
17
Q
Where does decussation typically take place?
A
The medulla oblongata.
18
Q
What is the name of the groups of gray matter in the medulla, and what is their function?
A
They are called nuclei, and they act as control centers for the body’s vital functions.
19
Q
Vital functions
A
Those functions of the body necessary for life.
20
Q
The vasomotor area
A
The area in the medulla that controls the dilation or constriction of blood vessels throughout the body. It is a vital blood pressure control mechanism.
21
Q
Foramen magnum
A
The opening at the base of the skull through which the spinal cord and brain are connected.
22
Q
Why can a sudden blow to the head be fatal?
A
Swelling of the brain causes the medulla to be pushed through the foramen magnum, damaging the medulla, which controls the vital functions of the body.
23
Q
What is the function of the pons?
A
The pons forms a bridge between the medulla and the upper brain stem. It also has several nuclei that relay messages between the cerebrum and the cerebellum.
24
Q
How does the pons work with the medulla?
A
The pons and medulla have nuclei which work together to enable the body to switch from breathing in (inspiration) to breathing out (expiration).
25
What are the functions of the nuclei on the midbrain?
The nuclei control hearing, sight, and reflexes that cause you to turn toward the source of a sudden sound or sudden sight. The midbrain also contains nerve pathways that connect the brain stem to the upper parts of the brain.
26
What do the nuclei called reticular formation do?
They receive information from various afferent nerves, especially those of the face. They play a major role in determining the cycle of sleeping and waking.
27
Reticular activating system
The nuclei distributed throughout the brain stem called reticular formation and their interconnections.
28
What are the two major components of the diencephalon?
The thalamus and the hypothalamus.
29
Intermediate mass
The small cylinder that links the two sides of the thalamus.
30
What are the functions of the thalamus?
The thalamus is a major relay station and affects mood and body movements, especially those related to strong emotions such as fear and anger.
31
Where do afferent axons synapse with other neurons in the brain?
The thalamus.
32
What is the function of the hypothalamus?
It regulates the pituitary gland is involved in the functions of the autonomic nervous system, and controls the body temperature.
33
How does the hypothalamus regulate the pituitary gland?
It regulates the pituitary gland through neural connections and its own hormones.
34
Why is the pituitary gland often called the master endocrine gland?
It secretes many hormones that affect diverse functions such as metabolism, reproduction, urination, and response to stress.
35
What are the basic functions of the cerebrum?
It deals with higher-level brain functions, interprets signals sent from the sensory receptors to the body, reasoning, and memory.
36
Cortex
The outer surface of the cerebrum that is composed of gray matter that is deeply folded.
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Gyri
The folds of the cerebrum's cortex.
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Sulci
The grooves between the gyri of the cortex.
39
What are the functions of the cerebellum?
The cerebellum controls functions that occur without conscious thought, subconscious motor functions, equilibrium, sequencing of muscle contractions, muscle preset, and dampening.
40
Equilibrium
Balance, or the constant state of control the muscles are in to maintain a certain position.
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Sequencing of muscle contractions
The precise timing and sequencing of muscular actions that must occur for an action to be performed correctly.
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Muscle preset
A predetermined correct amount of contraction to perform a task.
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Dampening
The inhibition of motor neurons that prevents the limbs from swinging.
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What is the function of the corpus callosum?
It allows the left and right halves of the cerebrum to communicate with each other.
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What divides the cerebrum into two hemispheres?
The longitudinal fissure.
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What functions is the temporal lobe involved in?
Hearing, smell, memory, and abstract thought.
47
What functions is the frontal lobe involved in?
Motor function, smell, mood, emotions, foresight, and memory.
48
What functions is the occipital lobe involved in?
It receives and integrates visual sensory information.
49
What functions is the parietal lobe involved in?
All sensory information except smell, vision, and hearing. It receives information from receptors of touch from the entire surface of the body.
50
What functions is the primary somatic sensory area involved in?
It receives generalized sensory input from all over the body.
51
How does the primary somatic sensory area know which area of the body a signal came from?
There is a little area on the primary somatic sensory area that corresponds to almost every part of the body's surface. The primary somatic sensory area localizes the sensations that come from the body.
52
What functions is the somatic sensory association area involved in?
It determines the meaning of a sensation and has a sensory memory to refer to.
53
What functions is the visual cortex involved in?
It receives the action potentials from the optic nerves that are attached to the eyes. Action potentials are interpreted to give the basics of vision: shape, color, and size.
54
What functions is the visual association area involved in?
Action potentials from the visual cortex pass to the visual association area, which then compares the image with past experience.
55
What functions is the primary auditory area involved in?
It is responsible for the basics of sound: volume and pitch.
56
What functions is the auditory association area involved in?
It takes signals from the primary auditory area and interprets them with historical context. It also allows us to make sense out of speech.
57
Describe the process through which speech is heard and understood.
Auditory signals first hit the primary auditory area to hear the volume and pitch. Then the signals move to the auditory association area, which puts the sounds into historical context. If the sounds are recognized as speech, they are sent to Wernicke's area, where the speech is comprehended.
58
What functions is the taste area involved in?
It interprets taste.
59
What functions is the olfactory area involved in?
It interprets the signals from the nose to give us a sense of smell.
60
What functions is the primary motor area/cortex involved in?
It controls the basic skeletal movements.
61
What functions is the premotor area involved in?
It does all the preparatory work for fine motor movement and decides what action potentials must be sent, how quickly, and in what order. Impulses are generated in the premotor area and then sent to the primary motor area.
62
What functions is Broca's area involved in?
Broca's area works out the detailed sequencing that needs to take place to carry out the finest of muscle movements--those related to speech.
63
Describe the process used to generate speech.
Wernicke's area determines what words will convey the meaning you wish to impart, which generates action potentials to be sent to Broca's area. Broca's area then works out the precise sequence of muscle movements needed to produce those words, then sends action potentials to the primary motor area, which initiates the muscle movements.
64
What functions is the prefrontal area involved in?
It has the ability to reason, think things through, and foresee what is going to happen. Many aspects of personality are contained in the prefrontal area.
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Prefrontal lobotomy
A surgical procedure used to control violent or disturbed people by removing a part of the brain.
66
Commissures
Connections of neuron axons that allow the two hemispheres of the brain to communicate with one another.
67
Name some general characteristics of the left hemisphere of the brain.
It is involved in speech and active in mathematical reasoning.
68
Name some general characteristics of the right hemisphere of the brain.
It is involved in determining spatial relationships, music, and facial recognition.
69
Basal nuclei
Lumps of gray matter in the white matter of the brain underneath the cortex.
70
What two parts make up the corpus striatum?
The lentiform nucleus and the caudate nucleus.
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What basal nuclei is found in the diencephalon?
The subthalamic nucleus.
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What basal nuclei is found in the cerebrum?
The corpus striatum (lentiform nucleus and caudate nucleus).
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What basal nuclei is found in the midbrain?
The substantia nigra.
74
What do the basal nuclei do?
They are involved in the planning, initiation, maintenance, and termination of motor activity, and they maintain muscle tune and the adjustments needed to maintain posture.
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What are some symptoms of damage to the basal nuclei?
Muscle tremors, involuntary shaking, or other dysfunctions of muscle coordination.
76
The limbic system
A series of nuclei and commissures that run through the cerebrum and the diencephalon.
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What role does the limbic system have?
It influences mood, emotion, fear, the senses of pain and pleasure, and the survival instincts.
78
Describe the interaction between the hippocampus and the amygdaloid nucleus in memory.
The hippocampus stores the memory of a person's name, but the emotions attached to that person come from the amygdaloid nucleus.
79
What are ventricles in the brain?
They are hollow spaces filled with cerebrospinal fluid.
80
How do the ventricles of the brain form in a fetus?
The CNS begins development as a hollow tube, and the top of the tube develops lobes that eventually form cavities in each of the hemispheres of the brain. The bottom tube expands and forms cavities in the diencephalon and the midbrain.
81
What makes up the choroid plexuses?
The ependymal cells, their support cells, and the blood vessels that supply them with oxygen and nutrients.
82
What is the function of the choroid plexuses?
They produce CSF (cerebrospinal fluid).
83
What connects the two lateral ventricles to the third ventricle?
Two foramina called interventricular foramina.
84
What connects the third ventricle to the fourth ventricle?
A thin tube called the cerebral aqueduct.
85
Why are the ventricles of the brain connected?
The connections allow CSF to flow freely from the lateral ventricles all the way down to the fourth ventricle and then onto the surface of the brain or around the spinal cord.
86
Meninges
Three specific layers of tissue below the skull that surround and protect the brain.
87
Where is the dura mater and what is it connected to?
The dura mater is right underneath the skull, is firmly attached to the periosteum, and extends down into the major fissures of the brain.
88
Superior sagittal sinus
A vein that collects the blood that returns from the brain as well as CSF.
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Subdural space
The space between the dura mater and the arachnoid mater that is filled with a small amount of fluid that moistens the tissue.
90
Where is the pia mater?
The pia mater is below the arachnoid mater and is bound tightly to the brain.
91
What are the three layers of the meninges?
The dura mater, the arachnoid mater, and the pia mater.
92
Subarachnoid space
The space in between the arachnoid layer and the pia mater which contains web like strands of arachnoid mater and is filled with CSF.
93
Meningitis
An infection caused by either viruses or bacteria that causes an inflammation of the meninges.
94
Why is meningitis dangerous?
Meninges are very important to the protection of the brain and spinal, so an inflammation of them can block the flow of CSF and lead to pressure on the brain's neurons, which leads to paralysis, coma, and even death.
95
What is the choroid plexus made of?
Tiny "fingers" of tissue called villi.
96
What are villi made of?
Ciliated and non-ciliated ependymal cells.
97
If CSF is made in the lateral ventricles, how does it flow?
It flows under the pressure of its own production through the interventricular foramina into the third ventricle, and then down through the cerebral aqueduct into the fourth ventricle. From there it travels to the subarachnoid space and then flows up and around the brain or down the spinal cord.
98
What causes the pressure that pushes the CSF out of the ventricles and into the subarachnoid space?
More CSF is being made by the choroid plexus, which pushes out the old CSF to make room for the new.
99
Why can a blockage of CSF be deadly?
Since new CSF gets made constantly, the pressure would just build and build until the pressure on the brain destroyed neurons.
100
Why does new CSF have to be made?
CSF eventually reaches arachnoid granulations which dump CSF into the superior sagittal sinus, and then it mixes with blood and returns to the heart.
101
Cervical enlargement
An area where the spinal cord's diameter increases so that the nerves of the upper limbs can enter and exit the cord.
102
Lumbar enlargement
A region of increased diameter where the nerves of the lower limbs enter and exit the spinal cord.
103
Conus medullaris
A conelike structure of the spinal cord just below the lumbar enlargement.
104
Cauda equina
The coma medullaris and the many strands of axons that attach to it.
105
What three columns is the white matter of the spinal cord organized into?
The dorsal (posterior) column, the lateral columns and the ventral (anterior) column.
106
Fasciculi
Further divisions of the basic white matter columns of the spinal cord that are also called nerve tracts. Each fasiculus contains axons that carry action potentials of a similar type and with similar information.
107
How is the central gray matter of the spinal cord organized?
It is organized into horns.
108
What do axons from the sensory neurons synapse with?
Associations neurons in the dorsal (posterior) horn.
109
Where are the cell bodies of the motor neurons found?
The ventral (anterior) horn.
110
Where are the cell bodies of the autonomic neurons found?
The lateral horns.
111
Where does the dorsal root enter the spinal cord?
At the dorsal horn.
112
What type of signals does the dorsal root carry?
It carries afferent signals from the sensory receptors to the spinal cord.
113
Where are sensory cell bodies located?
In the dorsal (posterior) root ganglion.
114
Where does the ventral root leave the spinal cord?
At the anterior horn.
115
What type of signal does the ventral root carry?
It carries efferent action potentials from the spinal cord to the effectors.
116
Why don't the ventral roots have ganglia?
The motor neuron cell bodies are located within the gray matter of the spinal cord.
117
What is the difference between the dura mater of the brain and spinal cord?
In the brain, the dura mater is attached to the periosteum of the skull. In the spinal cord, the dura mater is not connected to the bone of the vertebral column.
118
The epidural space
The space between the vertebral column and the dura mater that contains spinal nerves, blood vessels, connective tissue, and fat.
119
What are the basic steps that occur within a reflex arc when you touch something hot?
Pain receptors in the skin are stimulated and send an afferent message to the spinal cord. The spinal cord integrates that information using the interneurons within the gray matter and makes a judgment about what to do. It then sends an outgoing message to a flexor muscle in the arm, telling it to contract and thus drawing the arm away from the hot stove.
120
Describe the diverging circuit in the reflex arc.
The afferent message travels into the spinal cord, and the axon divides and synapses with many different neuron. One neuron is the association neuron that stimulates the reflex. The other neuron sends a message to the brain.
121
What are the two primary purposes of the diverging circuit in the reflex arc?
It allows the afferent signal to initiate the reflex but also go to the brain. Thus, the reflex is both fast and able to go to the brain so we can learn from it.
122
Describe the converging circuit in a reflex arc.
Two neurons both synapse with the same effector neuron. The first neuron is the association neuron in the reflex arc. The other is a neuron coming from the brain.
123
Describe the two primary purposes of the converging circuit in a reflex arc.
It allows the effector to be controlled by both the reflex arc and the brain. A forearm, for example, can flex quickly in reaction to pain, but it can also flex in reaction to a conscious thought, as it normally does.
124
What are the two types of pathways of the spinal cord?
Motor/descending pathways and sensory/ascending pathways.
125
Where do action potentials originate when movement is initiated?
The primary motor cortex, which is on the precentral gyrus.
126
What does conscious muscle movement need to complete its task?
A direct pathway of two motor neurons and an association neuron.
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Upper motor neuron
The neuron in the motor cortex that sends action potentials down the midbrain, through the pons, and to the medulla to start a motor pathway.
128
Medullary pyramid
The point in the medulla where most of the axons cross over (decussation).
129
Lower motor neuron
The neuron that carries the action potentials to the neuromuscular junction of the muscle in a motor pathway.
130
Describe the steps of a motor pathway action potential.
Upper motor neurons, which originate in the motor cortex, send their axons down the spinal cord without a synapse. These axons cross over to the other side of the body at the medulla oblongata. They then synapse with association neurons, which then synapse with lower motor neurons, which send the action potentials to the muscle.
131
Lateral corticospinal tract
A route that travels directly from the cerebral cortex, down the side of the spinal cord, and to the muscle.
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Primary neuron
The neuron in a sensory pathway that initiates the action potential. It is activated by a very light touch.
133
Why is the thalamus called a relay station?
The secondary neurons of a sensory pathway travel up to the thalamus and synapse with tertiary neurons there.
134
Can the thalamus interpret sensory signals?
Only partially. It gives some awareness of touch, but to really interpret the signals, they must be sent to the somatic sensory area.
135
Describe what is needed for a sensory pathway to complete its job.
It needs three synapses.
136
Why do sensory pathways need more synapses than a motor pathway?
Sensory information must be regulated and sometimes inhibited because the brain cannot receive every single sensory input.
