Neuronatomy Module 1 Flashcards
1
Q
What is neuroanatomy?
A
The anatomy of the nervous system
Neuroanatomy provides an overview of the anatomy and physiology of the nervous system.
2
Q
What are the two main divisions of the nervous system?
A
- Central Nervous System (CNS)
- Peripheral Nervous System (PNS)
The CNS consists of the brain and spinal cord, while the PNS connects the CNS to receptors, muscles, organs, and glands.
3
Q
What is the main function of the central nervous system?
A
To process information and send information to the peripheral nervous system.
4
Q
What are the main structures of the CNS?
A
- Brain
- Spinal cord
5
Q
What is a neuron?
A
The main structural and functional cell of the nervous system.
6
Q
What do glial cells do?
A
Support neurons and perform various functions within the CNS.
7
Q
What are the types of glial cells mentioned?
A
- Astrocytes
- Oligodendrocytes
8
Q
What is the role of astrocytes?
A
Provide nutrition for neurons, regulate synaptic connectivity, remove cellular debris, and maintain the blood-brain barrier.
9
Q
What is the function of oligodendrocytes?
A
Wrap extensions of their cytoplasm around nerve fibers to form myelin sheaths.
10
Q
What are the three major functions of the nervous system?
A
- Monitors changes (sensory input)
- Processes and interprets sensory input (integration)
- Causes a response (motor output)
11
Q
What is the difference between a nerve and a nerve fiber?
A
A nerve fiber is the axon of a single neuron, while a nerve consists of groups of fibers enclosed in connective tissue.
12
Q
What are the layers of connective tissue in a nerve?
A
- Endoneurium
- Perineurium
- Epineurium
13
Q
What are the three categories of nerve fibers based on their diameter and conduction velocities?
A
- A-fibers
- B-fibers
- C-fibers
14
Q
Which type of nerve fibers have the largest diameters and fastest conduction velocities?
A
A-fibers
15
Q
What is the primary function of the cerebral hemispheres?
A
Process sensory and motor information from the contralateral side of the body.
16
Q
What connects the two hemispheres of the brain?
A
Corpus callosum
17
Q
What is cerebral dominance?
A
The concept that one hemisphere of the brain is more developed and controls specific functions like language and memory.
18
Q
What percentage of the population has left hemisphere dominance?
A
90%
19
Q
What are the four lobes of the cerebral cortex?
A
- Frontal lobes
- Parietal lobes
- Temporal lobes
- Occipital lobes
20
Q
What functions do the frontal lobes perform?
A
- High-level cognitive functioning
- Emotions
- Executive control
- Memory storage
- Voluntary eye movement
- Motor control
21
Q
What can seizures from the frontal lobes produce?
A
Weakness in certain muscles, including those needed for speech.
22
Q
What is the role of the vagus nerve?
A
Influences organs of the chest and abdomen.
23
Q
What are neurotransmitters?
A
Chemical messengers that transmit signals across synapses.
24
Q
What can modify, enhance, or prevent neurotransmission?
A
Several factors such as drugs, diseases, and physiological changes.
25
What is synaptic transmission?
The process by which neurotransmitters are released and bind to receptors.
26
Fill in the blank: The _______ is a bridge of myelinated fibers that connects the two cerebral hemispheres.
corpus callosum
27
True or False: Neurons can divide and regenerate after injury.
False
28
What may the frontal lobes produce in certain muscles?
Weakness in certain muscles, including those needed for speech.
29
What is a characteristic of seizures originating from the motor cortex?
Seizures of the motor cortex may result in speech arrest, and tonic-clonic movement of one side of the face
or limbs. They may also cause sudden thrashing movements during sleep or head jerking to one side.
-They cannot be treated surgically as this is considered eloquent cortex.
30
What is the primary function of the parietal lobes?
Sensation; the sensory cortex is housed in these lobes.
31
What are the characteristics of seizures in the parietal lobes?
Predominantly sensory attacks with many characteristics.
32
Which lobes control the ability to understand spoken and written language?
Temporal lobes.
33
What is temporal lobe epilepsy characterized by?
Recurrent seizures, including a variety of sensory changes, frequently followed by postictal confusion.
34
What is the role of the thalamus in the CNS?
Acts as a sorting out center for impulses and is sometimes called a gateway to the cortex.
35
What functions does the hypothalamus regulate?
Blood pressure, heart contractions, digestion, respiration, body temperature, hunger, thirst, sleep, and endocrine function.
36
What are the three major components of the brainstem?
Midbrain, pons, and medulla oblongata.
37
What neurotransmitter is produced in the locus ceruleus?
Norepinephrine.
38
What involuntary functions does the medulla oblongata control?
Digestion, breathing, and heart rate.
39
What is the cerebellum's primary function?
Processes inputs to help create smooth coordinated movements.
40
What does the spinal cord provide between the body and brain?
A two-way pathway.
41
What does the limbic system include?
Hypothalamus, thalamus, amygdala, and hippocampus.
42
True or False: The limbic system is a specific structure.
False.
43
What are the two main divisions of the nervous system?
Central nervous system (CNS) and peripheral nervous system (PNS).
44
What types of cells support neurons in the CNS?
Glial cells, including astrocytes and oligodendrocytes.
45
What is the primary role of sensory nerves?
Carry impulses toward the CNS.
46
Fill in the blank: The _______ system is often referred to as the 'emotional brain'.
Limbic
47
What is the function of mechanoreceptors?
Generate nerve impulses when deformed by mechanical changes.
48
What is the size of the spinal cord approximately?
¾-inch thick.
49
What does the reticular activating system control?
Alertness and sleep.
50
What are the two types of PNS nerves based on impulse direction?
Sensory (afferent) and motor (efferent) nerves.
51
What do receptors do?
Respond to changes in the environment and send afferent information to the CNS.
52
What is the function of the cerebellum in terms of movement?
Coordinates muscle contractions to enable smooth movements.
53
What type of fibers do mixed nerves contain?
Both sensory and motor fibers.
54
What are receptors?
Specialized structures designed to respond to changes in the environment and send afferent information to the CNS.
55
Name the types of receptors based on the stimuli they respond to.
* Mechanoreceptors
* Thermoreceptors
* Photoreceptors
* Nociceptors
56
How fast can nerve impulses travel?
As fast as 100 meters per second.
57
What are the two parts of the motor division?
* Somatic nervous system
* Autonomic nervous system (ANS)
58
What does the somatic nervous system do?
Conducts efferent impulses to skeletal muscles, enabling voluntary movement.
59
What does the autonomic nervous system (ANS) control?
Conducts involuntary efferent impulses to the heart, smooth muscles, and glands.
60
What are the two divisions of the ANS?
* Sympathetic division
* Parasympathetic division
61
What is the primary neurotransmitter of the sympathetic division?
Norepinephrine.
62
What physiological effects does the sympathetic division have?
* Increases respiration
* Increases blood pressure
* Increases heart rate
* Decreases gastrointestinal secretions and motility
63
What is the primary neurotransmitter of the parasympathetic division?
Acetylcholine.
64
What physiological effects does the parasympathetic division have?
* Decreases respiration
* Decreases blood pressure
* Decreases heart rate
* Increases gastrointestinal secretions and motility
65
How many pairs of cranial nerves are there?
12 pairs.
66
Which cranial nerves attach to the forebrain?
The first two: olfactory and optic nerves.
67
What is the function of the olfactory nerve?
Conveys the sense of smell.
68
What is the function of the optic nerve?
Carries afferent impulses for vision.
69
What muscles does the oculomotor nerve supply?
Four of the six muscles that move the eyeball in its orbit.
70
What is the function of the trochlear nerve?
Connects to eye muscles that loop through a pulley-shaped ligament in the orbit of the eye.
71
What are the three branches of the trigeminal nerve?
* Ophthalmic
* Maxillary
* Mandibular
72
What is the function of the abducens nerve?
Controls eye muscles that abduct the eyeball.
73
What does the facial nerve innervate?
Facial muscles, enabling facial expressions.
74
What is the role of the vestibulocochlear nerve?
Involved in hearing and balance.
75
What does the glossopharyngeal nerve connect to?
Pharyngeal muscles involved in swallowing and salivary glands.
76
What is unique about the vagus nerve?
It extends into the abdomen and innervates various organs.
77
What is the function of the accessory nerve?
Supplies motor fibers to the larynx, pharynx, and soft palate.
78
What muscles does the hypoglossal nerve innervate?
Some tongue-moving muscles.
79
What is the primary role of the vagus nerve?
Brings sensory information from the body to the brain.
80
What is the conduction velocity of the vagus nerve in children?
Does not reach adult levels until 8 to 12 years old.
81
What does the nucleus of the tractus solitarius (NTS) do?
Processes afferent branches of the vagus nerve.
82
What are the three major pathways that vagal fibers relay information to?
* Autonomic and motor areas
* Reticular formation
* Forebrain
83
What does the vagus nerve regulate?
Body functions and behavior patterns.
84
What physiological effects do vagal medullary centers mediate?
Visceral reflexes including coughing, swallowing, vomiting, and blood pressure.
85
What is the role of the hypothalamus in relation to sensory information?
Helps control endocrine and digestive functions using sensory information from abdominal organs.
86
What do afferent nerves do?
Carry impulses toward the CNS.
87
What do efferent nerves do?
Carry impulses away from the CNS.
88
What are the two divisions of the motor division?
* Somatic nervous system
* Autonomic nervous system
89
What type of impulses does the somatic nervous system conduct?
Voluntary impulses.
90
What type of impulses does the autonomic nervous system conduct?
Involuntary impulses.
91
What is the role of sympathetic nerves in the ANS?
Prepare the body for action.
92
What is the role of parasympathetic nerves in the ANS?
Prepare the body for rest.
93
How many cranial nerves are there?
12 cranial nerves.
94
Where do 10 of the cranial nerves originate?
In the brainstem.
95
What area do most cranial nerves serve?
The head and neck area.
96
Which cranial nerve extends into the abdomen?
The vagus nerve.
97
What does the vagus nerve innervate?
* Pharynx
* Larynx
* Heart
* Lungs
* Digestive organs
98
What is the nucleus of the tractus solitarius (NTS)?
Where afferent branches of the vagus nerve terminate for initial processing.
99
What is the process of neurotransmission?
A presynaptic neuron sends an action potential down its axon to the axon terminal.
100
What is the synapse?
The tiny gap that separates the axon terminal of one neuron from the dendrites of another.
101
What is an action potential?
An electric signal sent down the axon.
102
What must happen for a signal to cross the synapse?
The electrical signal must be converted to a chemical signal.
103
What happens when enough receptors are activated on a postsynaptic neuron?
It generates a new action potential.
104
How many synaptic inputs can each neuron receive?
Up to 1,000 synaptic inputs.
105
What does the term 'polarized' refer to in neurons?
The unequal balance of charged particles across the cell membrane.
106
What is resting membrane potential?
The state of a neuron at rest, with a lower concentration of positive ions inside compared to outside.
107
What triggers depolarization in a neuron?
The opening of ion channels allowing sodium ions to rush in.
108
What is repolarization?
The process of restoring the original resting potential after an action potential.
109
What happens after the action potential moves down the axon?
The axon returns to its original negatively charged resting state.
110
What are synaptic vesicles?
Structures that contain neurotransmitters in the axon terminal.
111
What are the three methods of neurotransmitter removal from the synapse?
* Diffusion
* Enzymatic degradation
* Reuptake
112
What are channel-linked receptors?
Receptors composed of protein subunits around a central pore that open to allow ions in.
113
What happens when an excitatory neurotransmitter binds to a channel-linked receptor?
The receptor changes shape, allowing ions to enter.
114
What is the difference between channel-linked receptors and G protein-linked receptors?
Channel-linked receptors are fast and open immediately; G protein-linked receptors are slower and activate secondary messengers.
115
What is hyperpolarization?
When a neuron becomes more polarized compared to its normal resting state.
116
What is the role of neurotransmitters in synaptic transmission?
They bind to receptors on the postsynaptic neuron to regulate ion channel openings.
117
What is the main function of G protein-linked receptors?
To regulate ion channel openings through second messengers.
118
What is the duration of time that ionotropic receptors remain open?
One millionth of a second or less.
119
How long do G protein-linked receptors typically stay open?
Hundreds of millionths of a second.
120
What roles do G protein-linked receptors play?
* Learning
* Gene activation
* Protein production
* Producing widespread metabolic changes.
121
What can influence the excitability of neurons?
How sensitive they are to firing.
122
What prevents the eruption and spread of a seizure among neurons?
* Neuron’s hyperpolarized state
* Surround inhibition created by nearby inhibitory neurons.
123
What happens if surround inhibition is lost?
Groups of neurons can be ‘recruited’ into hypersynchronized firings, causing a seizure.
124
What are neurotransmitter receptor subtypes?
Different types of receptors that a neurotransmitter can bind to, causing different effects.
125
Give an example of a neurotransmitter and its receptor subtypes.
Serotonin (5-HT) has several subtypes, including 5-HT1A, 5-HT2, and 5-HT3.
126
What is receptor up-regulation?
Increasing the number of receptors a neuron produces.
127
What is receptor down-regulation?
Decreasing the number of receptors a neuron produces.
128
What are agonists?
Substances that mimic the action of a neurotransmitter, activating the receptor.
129
What is the function of antagonists?
Block the action of a neurotransmitter at its receptor site.
130
How many chemicals are known or suspected to be neurotransmitters?
About 50.
131
What are the three general categories of neurotransmitters?
* Amino acids
* Biogenic amines
* Neuropeptides.
132
What is GABA?
The major inhibitory neurotransmitter of the central nervous system.
133
What can enhance the actions of GABA?
* Alcohol
* Benzodiazepine drugs.
134
What is the role of glutamate in the CNS?
It is the major excitatory neurotransmitter.
135
What can excessive levels of glutamate cause?
Cell death, such as that caused by a stroke.
136
What does acetylcholine primarily do in the body?
It is the major neurotransmitter of the parasympathetic nervous system.
137
Where does norepinephrine originate?
In the locus ceruleus.
138
What are some functions of serotonin?
* Sleep
* Appetite
* Nausea
* Migraine headaches.
139
What do channel-linked receptors do?
Neurotransmitters bind to protein subunits, opening a central ion channel.
140
How do G protein-linked receptors influence ion channels?
An activated G protein controls the production of second messengers that influence ion channels.
141
What is the action potential?
A brief change in the membrane potential caused by the rapid opening and closing of ion channels.
142
What is the role of astrocytes?
Facilitating nutrient exchange between capillaries and neurons and mopping up residual potassium ions and neurotransmitters.
143
What type of nerves are afferent nerves?
Nerves of the PNS that carry impulses from receptors in the body toward the CNS.
144
What is the axon terminal?
End region of an axon; site of synaptic contact with another cell; also called the presynaptic terminal
145
What structures make up the brainstem?
Midbrain, pons, and medulla oblongata
146
What does the carotid sheath enclose?
Vagus nerve, carotid artery, internal jugular vein, sympathetic nerves
147
Define the cell body of a neuron.
Area of a neuron containing the nucleus; region where metabolism occurs and incoming signals are integrated
148
What is the central nervous system (CNS)?
One of two main divisions of the nervous system; consists of the brain and spinal cord
149
Describe the cerebellum.
Large, cauliflower-like organ that provides precise timing and patterns of skeletal muscle contraction needed for smooth coordinated movements
150
What is the cerebral cortex?
Convoluted surface of the brain, covering the left and right cerebral hemispheres; origin of most cognitive abilities and conscious behavior
151
What are the cerebral hemispheres?
Left and right hemispheres that are the most prominent features of the brain; collectively called the cerebrum
152
What is the corpus callosum?
Large tract of myelinated nerve fibers that connect the left and right hemispheres
153
How many pairs of cranial nerves are there?
Twelve pairs
154
What is the function of dendrites?
Branching extensions from the neuronal cell body; receive information from other neurons and convey them to the cell body
155
Define depolarization.
Process during neurotransmission in which positive sodium ions rush into the axon, reducing the negative potential of the cell membrane
156
What structures are included in the diencephalon?
Thalamus and hypothalamus
157
What is down-regulation in neurons?
Decreased production of receptors by a neuron in response to excessive neurotransmitter levels in the synaptic cleft
158
Define efferent nerve.
Nerves of the peripheral nervous system that carry impulses away from the central nervous system; also called motor nerves
159
What does the forebrain consist of?
Diencephalon (thalamus and hypothalamus) and telencephalon (cerebral hemispheres and cerebral cortex)
160
What role does the frontal lobe play?
Key role in thoughts and executive control over other brain functions
161
What is GABA?
Major inhibitory neurotransmitter of the CNS; substances that inhibit its actions can cause relaxation, sedation, and sleep
162
What are glial cells?
Cells of the CNS providing structural support, insulation, and nutrients to neurons
163
Define glutamate.
Major excitatory neurotransmitter of the CNS; plays a role in learning and memory
164
What is glycine?
Neurotransmitter that is generally inhibitory in nature
165
What is a G protein-linked receptor?
Major type of neurotransmitter receptor that regulates ion channel openings through a series of second messengers
166
What is gray matter composed of?
Brain tissue composed of the cell bodies of neurons
167
What are gyri?
Elevated ridges of tissue in the cerebral cortex
168
Define hyperpolarization.
Increase in the electrical charge across the cell membrane; can prevent the neuron from firing
169
What is the hypothalamus responsible for?
Regulating many body functions such as blood pressure, heart contractions, digestion, and sleep
170
What is the limbic system known for?
Interacting with higher areas of the cerebral cortex, creating a relationship between feelings and thoughts
171
What is the function of the locus ceruleus?
Secretes the neurotransmitter norepinephrine and projects throughout the brain
172
What does the medulla oblongata control?
Involuntary functions including digestion, breathing, and control of heart rate
173
What is the midbrain's role?
Controls many sensory and motor functions, including eye movement
174
What is a neuron?
Basic structural and functional cell of the nervous system; involved in transmitting nerve impulses
175
What is neurotransmission?
Process by which neurons transmit signals; involves electrical and chemical transmission
176
Define neurotransmitter.
Chemical messenger released by a presynaptic neuron that binds with receptors on a postsynaptic neuron
177
What is norepinephrine?
Primary neurotransmitter of the sympathetic nervous system; increases respiration and heart rate
178
What are nuclei in the CNS?
Clusters of functionally related cell bodies
179
What is the nucleus of the tractus solitarius (NTS)?
Group of nuclei in the medulla that receive input from the vagus nerve and project vagal fibers to higher brain areas
180
What is the occipital lobe responsible for?
Involved in vision
181
What do oligodendrocytes do?
Wrap around neuron fibers, forming a protective insulating myelin sheath
182
What is the role of the parabrachial nucleus?
Receives vagal inputs and projects them to higher areas of the brain
183
What does the parasympathetic division prepare the body for?
Rest
184
What does the parietal lobe control?
Muscles of the leg, hip, trunk, arm, hand, face, tongue, and vocal cords
185
What neurotransmitter is primarily involved in preparing the body for rest?
acetylcholine
186
What is the parietal lobe responsible for?
Controls muscles of the leg, hip, trunk, arm, hand, face, tongue, and vocal chords, as well as sensation
187
What does the peripheral nervous system (PNS) consist of?
Nerves that connect the brain and spinal cord to receptors, muscles, organs, and glands in the body
188
Define polarized in the context of a cell.
Separation of electric charge along two parts of a cell, atom, or molecule
189
What anatomical structure is the pons?
Bulging structure between the midbrain and medulla that conveys information about movement
190
What is a postsynaptic neuron?
The neuron that is receiving chemical signals from the presynaptic neuron
191
What is a presynaptic neuron?
The neuron that is sending a message to another cell through the release of neurotransmitters
192
What is the primary motor cortex responsible for?
Carries out the initial processing of motor (movement) information in the brain
193
What are raphe nuclei?
Cluster of neuronal cell bodies that project fibers upwards to all areas of the brain that secrete serotonin
194
What are receptors?
Specialized structures connected to sensory nerves that respond to changes in the environment
195
What is repolarization?
The return of the membrane potential to its initial negatively charged resting state after neurotransmission
196
Define resting membrane potential.
Charge that a neuron maintains across its cell membrane when at rest
197
What is the reticular formation?
Group of nuclei that helps control alertness and sleep
198
What is reuptake in neurotransmission?
Process by which neurotransmitters are removed from the synapse and drawn back up into the transmitting neuron
199
What is the somatic nervous system?
Subdivision of the motor division of the PNS that enables voluntary movement
200
What is the spinal cord's role?
Provides a two-way conduction pathway to and from the brain and controls movements of the limbs and trunk
201
What are sulci?
Shallow grooves of tissue in the cerebral cortex
202
What is surround inhibition?
Region around a group of neurons created by inhibitory neurons to prevent the spread of seizure activity
203
What does the sympathetic division do?
Prepares the body for action, such as the 'fight or flight' response
204
What is a synapse?
Specialized site of communication between two neurons
205
Define synaptic cleft.
Extracellular gap between the presynaptic and postsynaptic cells at the synapse
206
What is synaptic transmission?
Communication between two neurons or a neuron and a gland or organ, mediated by neurotransmitters
207
What are synaptic vesicles?
Small membranous sacs in the axon terminal of a neuron that contain neurotransmitters
208
What is the function of the temporal lobe?
Controls understanding of spoken and written language, involved in hearing and verbal memory
209
What is the thalamus?
Rounded structure that mediates sensations, movements, cortical arousal, learning, and memory
210
What is up-regulation?
Increased production of receptors by a neuron in response to insufficient neurotransmitter levels
211
What are viscera?
Large interior organs found in the major body cavities, especially in the abdomen
212
What is white matter composed of?
Bundles of myelinated axons
213
