Physiology Flashcards
In the PNS, what cells are responsible for producing myelin?
Schwann cells
What lie between each individual myelin sheath?
Nodes of Ranvier
What is the primary excitatory transmitter in the CNS?
Glutamate
What are the 2 main inhibitory transmitters in the CNS?
Gamma aminobutyric acid (GABA) and glycine
What holds the pre and post-synaptic membranes together,? Whilst also maintaining the synaptic cleft
A matrix of fibrous extracellular protein
Describe spatial summation
When many inputs converge upon one neurone and the net potential determines the output.
Describe temporal summation
When a single input from one axon has a high enough frequency to overpower its counter-signal and determine the output.
What type of physiological receptors are involved in touch, pressure, vibration and proprioception?
Mechanoreceptors
List 4 substances which chemical nociceptors receptors respond to
- Prostaglandins
- Bradykinin
- Serotonin
- Histamine
The dorsal column is composed of which 2 tracts?
- Fasciculus gracilis
- Fasciculus cuneatus
Sensory input to T6 and below, travels down which tract specifically?
Fasciculus gracilis
Describe the flexor reflex
Noxious stimulus causes limb to flex by contraction of flexor muscles via excitatory interneurons and relaxation of extensor muscles via excitatory and inhibitory neurones.
Describe Gate Control Theory
Stimulation of ABeta-fibres dampens down the pain response invoked by nociceptors via stimulation of an inhibitory interneurone.
What are opiates?
Substances which are extracted from opium, or of similar structure to opium.
What are opioids?
Any agent (including endogenous peptides) that act upon opiod receptors.
