The ability to perceive sensations from the body, including touch, temperature, and pain.
2
What does the autonomic nervous system regulate?
Show answer
It regulates involuntary functions such as heart rate, digestion, and glandular activities.
3
What are neurotransmitters?
Show answer
Chemical messengers that transmit signals between nerve cells.
4
What is transduction in the context of pain physiology?
Show answer
Painful stimuli will generate action potential at the nerve ending
5
What is the process of transmission in pain physiology?
Show answer
Transfer of the sensory signal from the peripheral to the central nervous system
6
What is the final stage of pain physiology called and what does it involve?
Show answer
Modulation, which involves decreasing or suppressing the painful sensation
7
What are nociceptors and how do they activate in response to a painful stimulus?
Show answer
Nociceptors are sensory receptors that detect noxious stimuli, such as heat, cold, or mechanical damage. They activate by releasing mediators like bradykinin, substance P, and histamine, which in turn activate ion-gated transient receptor potential (TRP) channels on the axon terminals of first-order sensory neurons. This increases membrane permeability to sodium and calcium ions, leading to the excitation of the afferent nerve ending (action potential) of the spinothalamic pathway.
8
What are the key steps in the activation of nociceptors?
Show answer
The key steps are: 1) Activation of the release of mediators like bradykinin, substance P, and histamine. 2) Activation of ion-gated transient receptor potential (TRP) channels on the axon terminals of first-order sensory neurons. 3) Increase in membrane permeability to sodium and calcium ions. 4) Excitation of the afferent nerve ending (action potential) of the spinothalamic pathway.
9
What neurotransmitters are released by Aδ fibers and C-fibers in the dorsal horn of the spinal cord?
Show answer
Glutamate and substance P
10
What is the pathway for pain signal transmission from the dorsal horn to the somatosensory cortex?
Show answer
Afferent fibers → second order neurons → thalamus → somatosensory cortex
11
What is neural conduction?
Show answer
The process by which neurons transmit signals through changes in ion conduction across the cell membrane.
12
How do neurons respond to stimuli?
Show answer
By producing changes in ion conduction across the cell membrane.
13
What is membrane potential?
Show answer
The difference of ion concentration across the cell membrane.
14
What is the resting membrane potential?
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An equilibrium state resulting in a significant difference in voltage across the neural membrane.
15
What is the resting membrane potential for neurons?
Show answer
-70 mV
16
What is the resting membrane potential in neurons?
Show answer
The concentration of K+ is higher inside than outside the cell, while the reverse is the case for Na+.
17
What is the Na, K ATPase pump responsible for?
Show answer
Establishing the concentration difference of K+ and Na+ across the cell membrane.
18
What is the Resting Stage in the context of an action potential?
Show answer
The resting membrane potential before the action potential begins, freely permeable to potassium ions, and the membrane is polarized at -70 mV.
19
What happens during the Depolarization Stage of an action potential?
Show answer
Upon excitation, sodium channels open, allowing the influx of sodium ions, which increases the membrane potential to the positive direction.
20
What is the Repolarization Stage?
Show answer
After reaching a threshold of +40 mV, sodium channels close, and potassium channels are activity open. Rapid outflux of potassium ions establish the membrane repolarization.
21
What is the Refractory Period?
Show answer
Starting from depolarization till reaching the resting membrane potential, the ion channels will not respond to any new stimuli.
22
What factors influence conduction velocity in nerve fibers?
Show answer
Fiber diameter and myelination.
23
How does fiber diameter affect conduction velocity?
Show answer
Larger fiber diameter leads to lower internal resistance, resulting in faster conduction.
24
What is the role of myelin in conduction velocity?
Show answer
Myelin acts as an insulator, increasing conduction velocity.
25
What is the process called where action potentials move via discrete jumps from node-to-node in myelinated axons?
Show answer
Saltatory conduction
26
What are the voltage-gated Na+ channels only expressed at in myelinated axons?
Show answer
Nodes of Ranvier
27
What are the advantages of saltatory conduction in myelinated axons?
Show answer
Saves energy by decreasing the use of sodium/potassium pump in the axon, increases speed of nerve impulse leading to fast neural communication
28
What is the effect of an excitatory postsynaptic potential (EPSP)?
Show answer
Membrane depolarization of the postsynaptic neurons, opening the sodium channels.
29
What is the effect of an inhibitory postsynaptic potential (IPSP)?
Show answer
Membrane hyperpolarization, inhibiting an action potential by activating chloride channels.
30
What is synaptic transmission?
Show answer
The axon terminal of one neuron propagates the signal to the dendrites of another neuron.
31
What are the common neurotransmitters in chemical synapses?
Show answer
Acetylcholine, norepinephrine, epinephrine, histamine, GABA, glycine, serotonin, and glutamate.
32
What is an electrical synapse and how does it function?
Show answer
An electrical synapse is a type of synapse that transfers action potentials across gap junctions, allowing free movement of ions from one cell to the next, which facilitates extremely rapid neural communication.
33
What role do electrical synapses play in the nervous system?
Show answer
Electrical synapses play an essential role in the development and function of the nervous system.
34
What are the three main divisions of the peripheral nervous system?
Show answer
Somatic nervous system, Autonomic nervous system
35
What are the two branches of the Autonomic nervous system?
Show answer
Sympathetic and Parasympathetic
36
What are the two main subdivisions of the PNS?
Show answer
Afferent (sensory) nerves and Efferent (motor) nerves
37
What neurotransmitter is released at the neuromuscular junction?
Show answer
Acetylcholine
38
What is the function of the Somatic nervous system?
Show answer
Responsible for voluntary control
39
What is the main purpose of the Autonomic Nervous System?
Show answer
To maintain homeostasis and integrate the stress response.
40
What functions does the Autonomic Nervous System control?
Show answer
It controls involuntary functions, regulates blood pressure, GI responses to food, and bladder contraction of the urinary bladder.
41
What is the function of the Enteric nervous system?
Show answer
An extensive web-like structure that can function independently of the remainder of the nervous system, regulating digestive processes.
42
What are the functions of the Sympathetic and Parasympathetic nervous systems?
Show answer
Sympathetic: Fight or Flight reactions and exercise; Parasympathetic: Rest and Digest reactions.
43
What is the function of the hypothalamus in the central control of the autonomic nervous system (ANS)?
Show answer
The hypothalamus is the largest center that receives information from different receptors in the body. It integrates this information and sends output down the spinal cord via the hypothalamospinal tract to engage the preganglionic fibers of the sympathetic and parasympathetic nervous systems.
44
Where are the vasomotor and vasodilator centers located in the central control of the ANS?
Show answer
The vasomotor and vasodilator centers are located in the medulla.
45
What neurotransmitter is released by cholinergic preganglionic efferent fibers?
Show answer
Acetylcholine
46
What type of receptors are activated by acetylcholine in postganglionic fibers?
Show answer
Muscarinic receptors
47
Which division of the autonomic nervous system is responsible for promoting normal physiological functions including salivary, gastric, and bile release?
Show answer
Parasympathetic division
48
What is the dominant system in a stress state or the 'fight-or-flight' response?
Show answer
Sympathetic nervous system
49
Where do preganglionic neurons of the sympathetic system arise from?
Show answer
Thoracic and lumbar regions of the spinal cord (from T1 to L2)
50
What is the role of the hypothalamus in the sympathetic nervous system?
Show answer
Hypothalamus control
51
What are preganglionic fibers and what neurotransmitter do they release?
Show answer
Preganglionic fibers are short and cholinergic, releasing acetylcholine.
52
What are postganglionic fibers and what neurotransmitter do they release?
Show answer
Postganglionic fibers are long and adrenergic, releasing noradrenaline.
53
What are neurotransmitters?
Show answer
Chemical compounds that transmit signals between neurons or carry the signal from neurons to cells in the effector organs.
54
What are the types of neurotransmitters?
Show answer
Excitatory, inhibitory, or both.
55
What are the three main classes of neurotransmitters?
Show answer
Excitatory, Inhibitory, Modulatory
56
List the excitatory neurotransmitters.
Show answer
Glutamate, Acetylcholine, Norepinephrine
57
What are the inhibitory neurotransmitters?
Show answer
GABA, Glycine
58
What are the characteristics of small molecules, rapid-acting neurotransmitters?
Show answer
Amino acids, monoamines, gaseous, purines, and other
59
What are the examples of amino acids that are neurotransmitters?
Show answer
Glutamate, gamma-aminobutyric acid (GABA), and glycine
60
What are the examples of monoamines that are neurotransmitters?
Show answer
Dopamine, norepinephrine, epinephrine, serotonin, and histamine
61
What is the role of acetylcholine in the nervous system?
Show answer
Acetylcholine is a neurotransmitter of sympathetic preganglionic neurons and the entire parasympathetic nervous system. It also affects the CNS.
62
How is acetylcholine synthesized and degraded?
Show answer
Acetylcholine is synthesized by choline acetyltransferase from Acetyl-CoA and Choline. It is degraded by acetylcholinesterase.
63
What are cholinergic fibers?
Show answer
Nerve fibers that synthesize and release acetylcholine.
64
What is the neurotransmitter released by cholinergic fibers?
Show answer
Acetylcholine.
65
Which types of fibers are cholinergic?
Show answer
Somatic motor fibers to skeletal muscle, preganglionic efferent autonomic fibers of the sympathetic and parasympathetic nervous system, parasympathetic postganglionic fibers, and sympathetic postganglionic neurons that innervate sweat glands.
66
What are Muscarinic receptors subdivided into?
Show answer
M1, M2, M3, M4, and M5
67
What is the high affinity of Muscarinic receptors to?
Show answer
Muscarine
68
Where are Muscarinic receptors located?
Show answer
On the effector organs
69
What are catecholamines?
Show answer
Catecholamines are a group of neurotransmitters and hormones including norepinephrine, epinephrine, and dopamine.
70
Which two catecholamines stimulate adrenergic receptors of the SNS?
Show answer
Adrenaline and noradrenaline.
71
What is the common amino acid from which catecholamines are synthesized?
Show answer
Tyrosine.
72
What is the primary function of noradrenaline (norepinephrine) in the sympathetic nervous system (SNS)?
Show answer
Noradrenaline mediates SNS function by interacting with adrenergic receptors.
73
Which receptors does noradrenaline activate in the central nervous system (CNS) and peripheral nervous system (PNS)?
Show answer
Noradrenaline activates α1, α2, and β1 receptors.
74
How is noradrenaline inactivated in the body?
Show answer
Noradrenaline is inactivated via oxidation via monoamine oxidase (MAO) or methylation with catechol-0-methyltransferase (COMT).
75
What is dopamine?
Show answer
Dopamine is a sympathomimetic catecholamine that functions as a CNS neurotransmitter.
76
How is dopamine synthesized?
Show answer
Dopamine is directly synthesized from L-Dopa.
77
What role does dopamine play in depression?
Show answer
Dopamine deficits play a role in the pathogenesis of depression.
78
What is serotonin (5-HT) and what functions does it perform in the body?
Show answer
Serotonin (5-HT) is a monoamine neurotransmitter involved in sleep, eating, arousal, dreaming, mood regulation, and temperature/pain transmission.
79
How is serotonin synthesized in serotonergic neurons?
Show answer
Serotonin is synthesized from the amino acid tryptophan.
80
Where is serotonin found in high concentrations in the body?
Show answer
Serotonin is found in high concentrations in enterochromaffin cells throughout the GI tract, in storage granules in platelets, and throughout the CNS.
81
What is the role of glutamate in the central nervous system (CNS)?
Show answer
Glutamate is an excitatory neurotransmitter in the CNS that uses N-methyl-D-aspartate (NMDA) receptors.
82
What are the characteristics of glutamatergic neurons?
Show answer
Neurons that release glutamate are called glutamatergic neurons. They are found throughout the brain and spinal cord, and they are termed excitatory neurons.
83
What percentage of brain neurons use glutamate or GABA as their neurotransmitter?
Show answer
Around 90% of the brain neurons use either glutamate or GABA as their neurotransmitter.
84
What are the risk factors for seizures?
Show answer
Epilepsy, genetic factor, vascular (stroke, intracranial hemorrhage), infection, trauma, autoimmune, metabolic, idiopathic, neoplasm, psychiatric (family history of seizures)
85
What mnemonic can be used to remember the vascular causes of seizures?
Show answer
VITAMINS
86
What does a neurological exam include?
Show answer
Behavior, movements, and mental function tests.
87
What do blood tests detect in the context of seizures?
Show answer
Infections, genetic or metabolic conditions.
88
What do imaging and electroencephalogram (EEG) do?
Show answer
Imaging detects structural abnormalities, EEG detects electrical activity in the brain.
89
What is the difference between focal and generalized seizures?
Show answer
Focal seizures originate from a specific area of the brain, while generalized seizures affect the entire brain.
90
List the types of focal seizures mentioned in the slide.
Show answer
Simple partial, Focal impaired awareness seizure.
91
What are the types of generalized seizures listed in the slide?
What is the definition of a simple partial seizure?
Show answer
Focal seizures accompanied by preserved consciousness. May be preceded by an aura, followed by motor signs.
93
What is the duration of a focal impaired awareness seizure?
Show answer
Between 30 seconds and 2 minutes.
94
When should an ambulance be called for a seizure?
Show answer
No medical I.D. and no way of knowing whether the seizure is caused by epilepsy, person is pregnant, injured, or diabetic, seizure continues for more than 5 minutes, seizure has happened in water, second seizure starts shortly after the first has ended, consciousness does not return after the shaking has stopped.
95
What are the key factors to consider when deciding to call an ambulance for a seizure?
Show answer
No medical I.D., epilepsy, pregnancy, injury, diabetes, duration of seizure, location of seizure, recurrence of seizures, post-seizure consciousness.
96
What are anticonvulsants and how do they work?
Show answer
Anticonvulsants are drugs that reduce seizures by enhancing inhibitory GABAergic activity or modulating glutamate activity.
97
What is the surgical approach for managing drug-resistant focal epilepsy?
Show answer
The surgical approach involves focal resection of the epileptogenic cortex.
98
How does the ketogenic diet influence neuronal excitability?
Show answer
The ketogenic diet forces the body into a state of ketosis, which is associated with enhanced GABA levels and reduced neuronal excitability.
99
What is the classification of Parkinson's disease?
Show answer
Parkinson's disease (PD) is a progressive neurodegenerative disease with increased risk in the elderly population (≥65 Y).
100
What are the two rare forms of Parkinson's disease?
Show answer
Young onset PD (≥50 Y) and Juvenile PD (children).
101
What is the prevalence of Parkinson's disease?
Show answer
The second most common age-related neurodegenerative disease. Nearly 1 million are living with PD with 90,000 cases diagnosed each year.