bio seminar Flashcards
What are nociceptors?
Nociceptors are sensory neurons that detect damage, which the brain interprets as pain.
They have free nerve endings and are not traditional neurons.
What is the role of sodium channels in nociceptors?
Nociceptors have special sodium channels (Na+) that open in response to stimuli such as temperature, chemicals, and pressure, allowing Na+ to enter the neuron and cause depolarization.
What is the resting potential of a neuron?
Resting potential is typically -70mV, with more Cl- than Na+ inside and more Na+ than Cl- outside the neuron.
What happens when a nociceptor is stimulated?
Na+ channels open, allowing Na+ to flow into the neuron, causing depolarization and leading to an action potential.
What is the dorsal root ganglion?
The dorsal root ganglion is where the cell bodies of sensory neurons, including nociceptors, are located near the spinal cord.
What neurotransmitter is primarily involved in the central nervous system (CNS)?
Glutamate is the primary excitatory neurotransmitter in the CNS.
What is the function of the Periaqueductal Grey (PAG)?
The PAG plays a crucial role in pain modulation by initiating the descending analgesic process and is activated in response to stress, pain, or opiates.
What is the default condition of interneurons in the PAG?
Interneurons in the PAG are spontaneously active, firing action potentials due to their resting membrane potential being close to the threshold.
What effect do endogenous opioids have on interneurons in the PAG?
Endogenous opioids hyperpolarize interneurons, inhibiting their activity and leading to disinhibition of projection neurons.
What neurotransmitters are released by the raphe magnus neurons?
The raphe magnus neurons release serotonin and noradrenaline, which can have excitatory or inhibitory effects.
What is the role of inhibitory interneurons in the spinal cord?
Inhibitory interneurons release neurotransmitters like GABA or endorphins to block incoming pain signals from nociceptive neurons.
What is the process of disinhibition in pain modulation?
Disinhibition occurs when inhibitory interneurons are inhibited, allowing projection neurons to fire action potentials and transmit pain signals.
What are the clinical implications of opiate drugs?
Opiate drugs mimic the action of endogenous opioids, activating the PAG and descending analgesic pathways to reduce pain perception.
Fill in the blank: The PAG initiates the descending analgesic process by increasing output to the _______.
raphe nuclei.
True or False: Stress can reduce pain perception by triggering endogenous opioids in the PAG.
True.
What happens in the spinal cord during pain signal suppression?
Inhibitory interneurons dampen the activity of nociceptive neurons, preventing pain signals from being sent to the brain.
What is the significance of the action potentials generated by projection neurons?
Action potentials run down the axon of projection neurons from the PAG to the raphe magnus, transmitting pain modulation signals.
What neurotransmitter is primarily associated with excitatory synapses in the descending analgesia circuit?
Glutamate.
