Lecture 13 Flashcards by rRNA rRNA

What is the most common sensory pathway and what does it transmit?

Dorsal Column, transmits fine touch and pressure

The dorsal column pathway is crucial for the sensation of fine touch and proprioception.

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What are the main motor pathways in the nervous system?

Lateral and Anterior corticospinal

These pathways are responsible for voluntary motor control.

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What are the two types of pain pathways mentioned?

Fast Pain (Anterolateral) and Slow Pain

cross spinal cord at area of injury

Fast pain is associated with sharp sensations- take lateral pathway

while slow pain is characterized by dull, aching sensations - C fibers- take anterior pathway

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What neurotransmitter is exclusively used in the fast pain pathway?

Glutamate

Glutamate is a key neurotransmitter for transmitting fast pain signals.

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What is the primary location for fast pain synapses?

Lamina 1 (Lamina Marginalis)

This location is significant for the transmission of sharp pain signals.

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Which fibers are responsible for fast pain transmission?

A delta fibers

A delta fibers are myelinated and transmit signals quickly.

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What type of pain is processed in Lamina 2, 3, and sometimes 5?

Slow Pain

This type of pain is also known as dull or achy pain.

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What neurotransmitters are involved in slow pain pathways?

Glutamate
CGRP (Calcitonin Gene-Related Peptide)
Substance P

These neurotransmitters contribute to the slower transmission of pain signals.

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What is the difference in localization between fast and slow pain?

Fast pain is well localized; slow pain is poorly localized

Fast pain signals are transmitted alongside precise sensory information- terminates at thalamus(diencephalon) then cortex

while slow pain often does not reach the somatosensory cortex- terminates in brain stem (reticular formation)

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What term is used for the ‘new’ pain pathway?

Neospinothalamic Tract

This pathway is associated with fast pain transmission.

Spinothalmic tract is a part of anterolateral pain pathway.

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What term is used for the ‘old’ pain pathway?

Paleospinothalamic Tract

This pathway is associated with slow pain transmission.

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What is the primary function of the Descending Inhibitory Complex (DIC)?

To modulate or suppress pain transmission

The DIC is an essential part of the body’s natural pain control system.

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What neurotransmitter is known to increase the activity of the descending pain suppression system?

Serotonin (5-HT)

Increased serotonin can enhance the effectiveness of pain management strategies.

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Where does the first synapse for fast pain occur?

Lamina 1 (Lamina Marginalis)

This is crucial for the rapid transmission of sharp pain signals.

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What is the ascending tract for slow pain?

Anterior spinothalamic tract

This tract is responsible for transmitting slow pain signals to the brain.

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What is a characteristic of the slow pain pathway’s neurotransmitter release?

Slower release and activation

This contributes to the prolonged sensation of slow pain.

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What is the role of the Vestibulospinal tract?

Helps maintain eye fixation during body movement

This tract is important for balance and coordination.

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What is the significance of the Tract of Lissauer?

Facilitates reflex pathways involving multiple spinal levels

This tract is important for complex reflex actions.

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What is the primary location of the descending tracts in the spinal cord?

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Anterior part of the spinal cord

-descending - motors- anterior tracts

-ascending - sensory- posterior tract

These tracts are located near pain synapses.

Fill in the blank: The fast pain pathway is also known as the _______.

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Neospinothalamic Tract

This pathway is characterized by rapid transmission of sharp pain.

Fill in the blank: The slow pain pathway is referred to as the _______.

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Paleospinothalamic Tract

This pathway is associated with dull, achy pain sensations.

True or False: Slow pain signals are often well localized.

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False

Slow pain signals are typically poorly localized.

What neurotransmitter is released by the third-order descending neuron at the spinal cord level?

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Enkephalins

Enkephalins bind to opiate receptors on pain transmission neurons.

What is the effect of enkephalins binding to their receptors on pain transmission neurons?

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Increases potassium permeability and hyperpolarizes the neurons

opens k channels making pre and post synaptic cells less excitable

This makes it harder for pain neurons to transmit pain signals.

Which class of drugs works by mimicking enkephalins?

Opiates (e.g., Morphine) ## Footnote Opiates bind to the same receptors as enkephalins.

What is the role of Serotonin Reuptake Inhibitors (SSRIs) in pain management?

They enhance the activity of the descending inhibitory complex (DIC) ## Footnote This leads to increased enkephalin release and greater pain suppression.

What is Tramadol primarily believed to affect?

Serotonin pathways ## Footnote Tramadol acts as a serotonin reuptake inhibitor.

What are the two primary types of glutamate receptors involved in ascending pain transmission?

* AMPA Receptors * NMDA Receptors

What is the primary function of AMPA receptors when activated?

Activated by glutamate Allow sodium (Na+) to flow into the cell ## Footnote This leads to depolarization and action potential generation in the postsynaptic neuron.

What is required for NMDA receptors to open?

*Prior depolarization of the cell Ampa receptors activated by glutamate- allow Na in- causing depolarization - moving magnesium around - allowing NMDA receptors to open which allow some Na in BUT MOSTLY CA+ — leads to potentiation ## Footnote Magnesium ions block the NMDA channel at rest.

What happens when calcium (Ca2+) enters the NMDA receptor?

Activates second messenger systems and protein kinases ## Footnote This is involved in pain wind-up and can contribute to chronic pain.

What effect does Ketamine have on NMDA receptors?

Blocks NMDA receptor channels ## Footnote It dissociates patients from pain sensations without shutting down the nervous system.

What is the role of magnesium in relation to NMDA receptors?

It blocks NMDA receptors at rest ## Footnote Magnesium supplementation can help keep NMDA receptors closed.

What is the relationship between ethanol and NMDA receptors?

Ethanol interacts with NMDA and GABA receptors ## Footnote It contributes to sedative and pain-reducing effects.

What is the primary neurotransmitter released by the third-order pain suppression neuron?

Enkephalin

What happens when enkephalins bind to receptors on the presynaptic and postsynaptic pain transmission neurons?

More potassium channels open, making neurons hyperpolarized ## Footnote This makes it more difficult for both sending and receiving neurons to activate.

What is the function of the CSF circulatory system?

Refresh and maintain the CSF surrounding neurons ## Footnote It ensures a stable environment and offers protection from trauma.

What are the three layers of the meninges?

* Pia mater * Arachnoid mater * Dura mater

Where is the majority of CSF located?

Under the arachnoid layer In subarachnoid space

What are arachnoid trabeculae?

Columns supporting the arachnoid layer ## Footnote They help provide separation for CSF.

What is the function of the choroid plexus?

Produces CSF - choroid plexus = clumps of ependymal cells ## Footnote Ependymal cells in the ventricles are responsible for CSF production.

What condition is caused by obstruction in the CSF pathways?

Hydrocephalus ## Footnote It leads to enlarged ventricles and increased osmotic pressure.

What is the interventricular foramen also known as?

Foramen of Monroe

What is the cerebral aqueduct also known as?

Aqueduct of Sylvius

What are the lateral and median apertures associated with?

Drainage openings in the fourth ventricle ## Footnote They allow CSF to exit the ventricular system. Lateral aperatures = foramen of Lusaka Median aperature = foramen of megendi

What is the central canal?

An opening that runs down the entire spinal cord ## Footnote It is lined with ciliated cells that help propel new CSF.

Lecture 13 Flashcards

(46 cards)