Neuro Flashcards
What is acetylcholine?
Acetylcholine (ACh) is a neurotransmitter between neurons and from neurons to effector cells.
Function of Acetylcholine:
gets released into the synaptic cleft, due to the presence of action potential in the presynaptic neuron.
what happens to acetylcholine when it enters the synaptic cleft?
It binds to acetylcholine gated Na+ channels, allowing sodium to enter the post synaptic cleft causing depolarisation and may lead to production of a action potential.
How and why is acetylcholine degraded?
Acetylcholine is degraded by an enzyme call Acetylcholinesterase (AChE). This is to stop the transmission of action potentials when not required.
What happens if acetylcholine isnt degraded?
(the continued production of Action Potentials)
Neutransmission will not stop. Acetylcholine may increase in concentration in the synpatic cleft, and lead to excessive synaptic transmission.
What is a nerve agent?
Nerve agents are chemicals that interfere with the nervous system. Therefore it inhibits the breakdown of acetylcholine, a neurotransmitter used by the somatic and autonomic nervous systems.
why might nerve agents cause uncontrolled skeletal muscle contraction and constriction of pupils?
In the somatic motor pathway, this will lead to excessive excitation of a muscle cell, causing uncontrollable contraction.
In the autonomic nervous system (the parasympathetic system) it will lead to pupil constriction.
role of dorsal ramus:
carries info to the dorsal side of the body
What is Peripheral nerve structure?
Nerves are wrapped in epinerium, fasicles are wrapped in perinerium, axons are wrapped in endonerium
The ventral/anterior root contains what?
efferent axons
what level does the spinal cord end?
L1
What are the 3 white matter tracts in the brain?
Commissural , projection, association
What are the commissural , assocation and projection tracts?
Commissural = axons crossing from 1 side to other side of the brain (coordinates RHS with LHS)
Projection = axons from cerebrum to other areas of central nervous system
Association = axons between areas on the same side of the cerebrum (long or short distance)
what lobe is responsible for detecting vision?
occipital lobe
the corpus callosum is an example of what?
A commissural tract
What is the division between the cerebrum and cerebellum?
the transverse fissure
what type of white matter communicates within the same hemisphere of the cerebrum?
Association tracts
how do you measure action potential velocity?
Using conduction studies equation: velocity = distance/time
what is somatic sensation?
the bodys ability to sense stimuli
what are the 4 morphological types of sensory neurons?
Multipolar, bipolar , unipolar, anaxonic
what is sensory signal transduction ?
Process of converting sensory signals from environment into electrical signals that can be transmitted and interpreted by the brain.
4 types of general sensory receptor:
mechanoreceptor, nociceptors, thermoceptors, chemoreceptors
What is a tonic receptor?
slow adapting receptors, that is continually active to reflect background level of stimulation. Frequency changes when stimulus intensity changes.
what is a phasic receptor?
fast adapting receptor, that is normally silent, responds briefly to change, e.g touch and temperature.
what are the following 4 types of information about a stimulus that are encoded by sensory systems?
- modality - type of receptor activated
- intensity - stimulus strength
- duration - time period which stimulus exists
- location - place in body where receptors are activated
in the stretch reflex pathway, reciprocal inhibitory neurons are required in order to control the movement. TRUE OR FALSE?
FALSE - in the WITHDRAWAL reflex pathway, reciprocal inhibitory neurons are required in order to control the movement.
