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Physiology- Drexel CRNA 2027 > Neuro > Flashcards

Neuro Flashcards

Final (102 cards)

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1
Q

What is the synaptic transmission?

A

the process by which impulses are communicated between neurons.

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2
Q

What type of sensory stimulus do free nerve endings receive (4)?

A

Free nerve endings receive various sensory stimuli such as touch, temperature, pain, and proprioception.

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3
Q

What types of input does the somatosensory system provide?

A

touch, temperature, proprioception, and pain.

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4
Q

What does “selective blockade” refer to in the context of the somatosensory system

A

ability to block specific types of sensory input based on type, location, or density.

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5
Q

How is sensory input converted to an impulse?

A

the process of transduction by sensory receptors.

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6
Q

How is the impulse conducted to the CNS

A

synaptic transmission

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7
Q

: What role do neurotransmitters play in synaptic transmission?

A

A: Neurotransmitters are the mechanisms by which impulses travel through the brain and between sensory and motor pathways.

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8
Q

How does chronic pain affect the threshold for action potentials?

A

Chronic pain causes depolarization, which narrows the gap between resting potential and threshold potential, making it easier to create an action potential with minimal stimulation.

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9
Q

What is a dendrite and what is its primary function?

A

A dendrite is a branched extension of a neuron that receives and transmits electrical impulses from other neurons or sensory stimuli to the neuron’s cell body.

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10
Q

How do dendrites contribute to the processing of signals in a neuron?

A

Dendrites receive incoming signals, including neurotransmitters and sensory stimuli, and transmit these signals to the neuron’s cell body, where they are processed and potentially generate an action potential.

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11
Q

Why are the structural features of dendrites important for their function?

A

branched structure and numerous dendritic spines of dendrites increase their surface area, allowing them to receive and integrate a large number of signals from other neurons or sensory inputs.

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12
Q

How does an impulse travel from the dendrite to the axon terminal?

A

An impulse travels from the dendrite to the nucleus, then to the axon hillock, and through the axon, which is surrounded by the myelin sheath.

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13
Q

What types of sensory input do dendrites receive?

A

Dendrites receive sensory input such as touch, pressure, substance P, and prostaglandins.

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14
Q

What happens to an impulse once it reaches the cell body?

A

continue as an action potential or stop at this point.

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15
Q

What is synaptic transmission? and 2 types

A

Synaptic transmission is a method by which cells communicate with other cells, either chemically or electrically.

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16
Q

What are the two types of synaptic transmission and how do they differ?

A

Synaptic transmission can be electrical, mediated through direct gap junctions, or chemical, where the gap junctions have no direct connection and involve neurotransmitter release.

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17
Q

What occurs during the chemical synaptic transmission process when an action potential reaches the presynaptic terminal?

A

Depolarization of the presynaptic terminal causes voltage-sensitive Ca++ channels to open, allowing Ca++ to enter the cell and stimulate exocytosis of neurotransmitter vesicles into the synaptic cleft.

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18
Q

What are the four key processes of synaptic transmission, and how can they be targeted for pain management?

A

Release of neurotransmitter: Can be stopped to block transmission.

Diffusion of neurotransmitter: A passive process; cannot be stopped.

Binding to post-synaptic receptors: Can be targeted by blocking receptors.

Inactivation of neurotransmitter: Can be blocked or modified through re-uptake or inactivation mechanisms.

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19
Q

What is the effect of excitatory synapses on the probability of action potentials in the post-synaptic cell

A

A: Excitatory synapses increase the probability of action potentials by raising the voltage of the post-synaptic membrane and bringing it closer to the action potential threshold.

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20
Q

What is the effect of inhibitory synapses on the post-synaptic cell?

A

reduce the probability of action potentials by decreasing or hyperpolarizing the membrane potential of the post-synaptic cell.

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21
Q

At what membrane potential is an action potential typically triggered?

A

-40 mV.

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22
Q

How does depolarization affect the release of neurotransmitters?

A

Depolarization increases the flow of Ca++ into the presynaptic terminal, which enhances neurotransmitter release. A longer action potential duration results in more Ca++ influx, and increased extracellular Mg++ can reduce neurotransmitter release by competing with Ca++.

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23
Q

What causes synaptic delay in neurotransmission?

A

caused by the time needed for fusion and exocytosis of the neurotransmitter vesicles, although the time for transmitter diffusion and post-synaptic channel activation is negligible.

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24
Q

ow is acetylcholine (ACh) inactivated after its release into the synaptic cleft?

A

After its release into the synaptic cleft, acetylcholine (ACh) is inactivated by being hydrolyzed by acetylcholinesterase (AChE). Additionally, ACh can be actively pumped back into the presynaptic terminal or diffuse away from the synapse.

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25
What is the function of nicotinic ACh receptors in skeletal muscle end plates?
Nicotinic ACh receptors, activated by nicotine and inhibited by curare, have binding sites for ACh and chemically gated ion channels. When ACh binds, it makes the channel permeable to Na+ and K+, leading to cell depolarization and action potential propagation.
26
What is the role of neurotransmitters in chemical synapses across the nervous system?
Neurotransmitters are the mechanism of communication in chemical synapses, facilitating communication in all parts of the nervous system
27
What are the effects of an imbalance between excitatory and inhibitory neurotransmitters?
an excess of inhibitory neurotransmitters can produce predictable symptoms of over-inhibition, while an excess of excitatory neurotransmitters can lead to symptoms of over-excitation. Some neurotransmitters can function as both excitatory and inhibitory depending on the context.
28
Name two neurotransmitters that are both excitatory and inhibitory.
Norepinephrine (primarily excitatory but inhibitory in some brain areas) serotonin (excitatory in the raphe nuclei; inhibitory in the cerebral cortex).
29
List some major inhibitory neurotransmitters and their effects. DEGABA
Dopamine Enkephalins Gamma-aminobutryic Acid GABA glycine, endorphins, dinorphins
30
What are some major excitatory neurotransmitters and their effects? GASP!
Glutamate-most abundant excitatory neurotransmitter in the brain Acetylcholine (AcH) Substance P = pain
31
How does an excitatory post-synaptic potential (EPSP) contribute to the initiation of an action potential?
An EPSP must depolarize the membrane to the threshold level for an action potential to be initiated. It is a cumulative effect of excitatory signals.
32
What is the impact of inhibitory post-synaptic potentials (IPSPs) on action potential initiation?
IPSPs hyperpolarize the membrane, reducing the magnitude of the EPSP and decreasing the chance of reaching the action potential threshold.
33
What are the three types of sensory neurons and their general functions?
General Somatic Afferent (GSA): Widespread branches throughout the body; alert the CNS to pain, touch, and temperature; primary fast response includes withdrawal. Special Somatic Afferent (SSA): Found in muscles, tendons, and joints; senses position and movement; important for body awareness. General Visceral Afferent (GVA): Fewer and more limited distribution; receptors are on visceral organs; senses fullness and discomfort; pain is diffuse and unlocalized.
34
How do General Somatic Afferent neurons function and what do they detect?
General Somatic Afferent neurons have widespread branches throughout the body and detect pain, touch, and temperature. They alert the CNS to potential danger and initiate a primary fast response, such as withdrawal.
35
What is the role of Special Somatic Afferent neurons and where are they located?
Special Somatic Afferent neurons are located in muscles, tendons, and joints, and they sense the position and movement of body parts, aiding in body awareness and proprioception.
36
Describe the function and challenges associated with General Visceral Afferent neurons.
General Visceral Afferent neurons are located on visceral organs and are less precise compared to general somatic afferents. They sense fullness and discomfort, and the pain is diffuse and hard to localize, making it difficult to pinpoint the exact source of discomfort or pain.
37
What is the primary function of the sensory unit (first-order neurons)?
The sensory unit perceives and conducts information about stimulus discrimination, tactile discrimination, thermal sensation, and position sensation via the dorsal root ganglia.
38
What are the three types of fibers in the dorsal root ganglia and their functions?
Type A Fibers: Largest, myelinated, fastest; conduct touch, temperature, pain, and pressure. Type B Fibers: Conduct mechanical pain from subcutaneous structures. Type C Fibers: Unmyelinated, small diameter, slower; conduct temperature, mechanical, and chemical pain.
39
What are the two main ascending pathways for sensory information and their primary functions?
Dorsal Column-Medial Lemniscal Pathway: Discriminative touch, precise localization, and stereognosis using three neurons. Anterolateral Pathway: Crude touch, pain, and temperature sensations, with subdivisions including:
40
what are the 2 subdivisons of the anterolateral pathway, and where do they terminate ?
Paleospinothalamic Tract: Poorly localized, involved in chronic pain and autonomic responses. -fibers terminate prior to thalamus Neospinothalamic Tract: Well-localized, provides information about stimulus localization. -terminate in the thalamus
41
What is the primary function of central processing (3rd-order neurons) in the sensory system?
Central processing controls perception, motor responses, and attenuation of sensory information.
42
Where does precise localization of sensory information occur in the brain? (3rd order neuron)
Precise localization occurs in the somatosensory cortex, located in the post-central gyrus of the parietal lobe.
43
What types of receptors are involved in tactile sensation and their functions? (4)
Meissner’s Corpuscles: Found in non-hairy skin; detect light touch and low-frequency vibration. Merkel’s Disks: Detect sustained pressure; slow to adapt. Ruffini’s Endings and Pacinian Corpuscles: Deep receptors; detect persistent strong and steady signals. A-delta Fibers: Rapidly transmit tactile information to the CNS.
44
How does thermal sensation differ from tactile sensation in terms of adaptation and local anesthetic sensitivity?
Thermal sensation, which perceives cold, warmth, and pain, adapts more slowly than tactile sensation and is more quickly blocked by local anesthetics.
45
What is the role of proprioceptive receptors in position sensation?
Proprioceptive receptors, located in muscles, joints, and tendons, provide static and dynamic sense of body position, transmitted via the discriminative pathway without interruption.
46
What is a motor unit?
A motor unit consists of a motor neuron and the muscle fibers it innervates. When stimulated, all muscle fibers in the unit contract simultaneously.
47
What is the role of the spinal cord in motor organization?
The spinal cord can initiate motor responses independently through spinal reflexes.
48
What are the two descending motor pathways from the brainstem and their functions?
Medial Pathway: Controls balance; targets axial and proximal muscles. Lateral Pathway: Controls purposeful movement; targets distal muscles and limbs.
49
What are the functions of the Primary Motor Cortex, Pre-Motor Cortex, and Supplemental Motor Cortex? brainstem fxn
Primary Motor Cortex: Controls precise and discrete movements. Pre-Motor Cortex: Involved in motor planning. Supplemental Motor Cortex: Activates muscles before movement.
50
Q: What does the Motor Homunculus represent? (Brainstem)
A: The Motor Homunculus shows the mapping of motor control in the brain, with larger areas for body parts requiring more motor control, like the hands.
51
Q: What are the roles of the Cerebellum and Basal Ganglia in motor control? independent subcortical feedback
Cerebellum: Coordinates and times movements in real time. Basal Ganglia: Plans and refines movement, impacting its grace.
52
name 4 brainstem reflexes
‣ pupillary ‣ gag ‣ corneal reflex ‣ vestibule-oculocephalic
53
Where are the basal nuclei located, and what are they called in the central nervous system?
Basal nuclei are deep within the cerebral hemispheres, lateral to the thalamus. In the central nervous system, they are referred to as basal nuclei (not ganglia).
54
Name the main components of the basal nuclei.
Caudate Subthalamic Nucleus- indirect Substantia Nigra-= direct Globus Pallidus Putamen
55
What is the function of the pyramidal tracts?
Pyramidal tracts control voluntary movement and are named for their pyramidal shape.
56
What does the Corticobulbar Tract control, and which cranial nerves are involved?
CN III, IV, VI: Eye movements CN V: Mastication CN VII: Facial expression CN IX, X: Swallowing CN XII: Tongue movements
57
cranial Nerve mneumonic Olympic Opium Occupies Troubled Triatheletes After Finishing Vegas Gambling Vacations Still High
I- O-Lympic (Olfactory) II- O-Pium (Optic) III- O-Ccupies (occulomotor) IV- T-Roubled (Troclear) V- T-RIatheletes (trigeminal) VI- A-fter (Abducens) VII- F-inishing (Facial) VIII- V-Egas (Vestibulocochlear) VIII- G-ambling (Glossopharyngeal) IX-S-till (Spinal Accessory) X- H-igh (Hypoglossa)
58
What are the two main divisions of the Corticospinal Tract and their functions?
Lateral Corticospinal Tract: Decussates (crosses over) in the medulla, descends into the spinal cord, and ends in the ventral horn for voluntary movement control. Anterior Corticospinal Tract: Remains ipsilateral (same side) until it reaches the spinal cord, then ends in the ventral horn for voluntary movement control.
59
Q: What is the role of the Extrapyramidal Tracts?
: Extrapyramidal tracts control involuntary movements and are regulated by the basal ganglia and cerebellum.
60
What are the two components of the Pyramidal Tracts and their functions?
Corticobulbar Tracts: Transmit from the cerebral cortex to the motor nuclei of cranial nerves, controlling facial and oral movements. Corticospinal Tracts: Transmit from the cerebral cortex to lower motor neurons (LMNs) in the spinal cord, controlling voluntary movements.
61
What are Upper Motor Neurons (UMNs) and their function?
UMNs connect the cerebral cortex to the spinal cord and synapse upon another neuron in the CNS.
62
What are Lower Motor Neurons (LMNs) and their function?
A: LMNs connect the spinal cord to the periphery and synapse upon muscles or glands in the PNS.
63
What is the role of the Interneuron in motor pathways?
A: Interneurons (if present) act as a bridge between UMNs and LMNs, facilitating communication between them. Some UMNs and LMNs may communicate directly without interneurons.
64
Q: Where do Upper Motor Neurons (UMNs) originate and where do their axons descend?
A: UMNs originate in the primary motor cortex and their axons descend through the internal capsule and brainstem.
65
Q: What is the role of the reticular formation in UMN pathways?
A: The reticular formation receives collateral branches from UMN axons and its descending neurons inhibit lower motor neurons in the spinal cord, modulating motor control.
66
Q: How does a UMN lesion affect the body depending on its location relative to the decussation?
Rostral to the Decussation (e.g., cerebral cortex or brainstem above the caudal medulla): Causes contralateral hemiparesis or hemiplegia. Caudal to the Decussation (e.g., spinal cord): Causes ipsilateral hemiparesis or hemiplegia below the level of the lesion.
67
What are the clinical signs of Lower Motor Neuron (LMN) lesions? (4)
Flaccid paralysis Hyporeflexia Hypotonia Muscle atrophy
68
What occurs in Combined Upper Motor Neuron (UMN) and Lower Motor Neuron (LMN) lesions, such as in Brown-Sequard syndrome?
LMN signs in muscles innervated by the affected spinal segments. UMN signs below the level of the spinal cord injury.
69
What is Brown-Sequard syndrome?
A: A condition resulting from a hemi-section of the spinal cord, affecting both the corticospinal tract (UMNs) and LMNs, causing mixed UMN and LMN signs.
70
Q: What are the main components of the primary motor pathway?
A: Cortex, brainstem, and spinal cord.
71
Q: How are voluntary motor impulses transmitted?
A: Voluntary impulses are transmitted from the cortex to cranial nerves via the corticobulbar pathway and to LMNs via the corticospinal pathway (lateral and anterior), with decussation occurring in the spinal cord.
72
Q: How are involuntary motor impulses transmitted?
A: Involuntary impulses are transmitted from the brainstem to the spinal cord.
73
Q: What is the ultimate effect of motor impulses on the motor unit?
excitation or inhibition
74
Q: What does the Central Nervous System (CNS) include?
brain and spinal cord
75
Q: What does the Peripheral Nervous System (PNS) include?
neurons OUTSIDE of the brain/spinal cord
76
Q: What is the role of the Afferent Division of the nervous system?
A: It brings sensory information FROM the periphery TO the brain and spinal cord.
77
Q: What is the role of the Efferent Division of the nervous system?
A: It carries signals AWAY from the brain and spinal cord.
78
Q: What does the Somatic System control?
A: Skeletal muscle and everything under our conscious control.
79
Q: What does the Autonomic Nervous System (ANS) control?
A: Smooth muscle and functions not under conscious control. gets done "automatically"
80
Q: What are the two divisions of the Autonomic Nervous System?
sympathetic-fight or flight paraysmpathetic- rest and relax
81
What is the basic structure of the autonomic nervous system (ANS)
A 2-neuron visceral efferent (away from the CNS) system consisting of a pre-ganglionic neuron and a post-ganglionic neuron.
82
Q: Where do the cell bodies of the pre-ganglionic neurons in the Sympathetic Nervous System originate?
thoracic and lumbar regions of the spinal cord
83
Q: What is the function of ganglia in the autonomic nervous system?
A: Ganglia serve as relay stations between the pre-ganglionic neuron and the post-ganglionic neuron.
84
Q: Where do the post-ganglionic neurons in the Sympathetic Nervous System have their cell bodies?
ganglia- and terminate on EFFECTOR ORGANS
85
Q: Where do the cell bodies of the pre-ganglionic neurons in the Parasympathetic Nervous System originate?
brainstem or sacral region of spinal coord
86
Q: Where do the post-ganglionic neurons in the Parasympathetic Nervous System terminate?
on effector organs
87
Q: What is dual innervation in the autonomic nervous system (ANS)?
A: Most organs are innervated by both the sympathetic and parasympathetic divisions of the ANS.
88
Q: Which division of the ANS is associated with "fight or flight" responses?
A: The Sympathetic Nervous System.
89
Q: Which division of the ANS is associated with "rest and digest" responses?
A: The Parasympathetic Nervous System.
90
Q: How does the Somatic Nervous System differ from the ANS in terms of motor neuron pathways?
A: The Somatic Nervous System uses a single motor neuron that travels directly from the CNS to the skeletal muscle without mediation by a ganglion.
91
Q: What is the primary difference in control between the Somatic Nervous System and the Autonomic Nervous System?
A: The Somatic Nervous System is under conscious control, while the Autonomic Nervous System is not.
92
Q: What is the primary function of neurotransmitters in the nervous system?
facilitate communication between nerve cells at ganglia and between nerve cells and effector organs.
93
Q: Which neurotransmitters are primary signals for the autonomic nervous system (ANS)?
A: Norepinephrine (NE) and Acetylcholine (ACH).
94
Q: What is unique about Acetylcholine (ACH) in the somatic nervous system?
A: ACH is the only neurotransmitter at the neuromuscular junction.
95
Q: Name two neurotransmitters associated with useful drugs.
A: Norepinephrine (NE) and Acetylcholine (ACH).
96
Q: What is Epinephrine and how is it different from neurotransmitters?
A: Epinephrine is a hormone released by the adrenal medulla, not a neurotransmitter.
97
Q: What type of receptors are activated by Norepinephrine (NE)?
A: Adrenergic receptors.
98
Q: What are the two main types of adrenergic receptors?
alpha beta
99
Q: What type of channels are Nicotinic receptors associated with?
ligand gated ion channels
100
Q: What type of receptors are activated by Acetylcholine (ACH) other than Nicotinic receptors?
muscarinic receptors
101
Q: How do Muscarinic receptors differ from Nicotinic receptors in their signaling mechanism?
A: Muscarinic receptors use a G protein-coupled mechanism and involve a slower second messenger cascade, while Nicotinic receptors mediate fast synaptic transmission.
102

Physiology- Drexel CRNA 2027 (2 decks)

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