Lecture 17: Organisation and subdivisions of the nervous system Flashcards
The myelin sheath in the CNS is made by:
- Oligodendrocytes
The part of neurotransmission that is carried out through a chemical signal is called
- Synapse
Information that travels into the CNS is called:
- Afferent / Ascending
The part of a neuron that makes the decision about whether to propagate an action potential in response to inputs is called:
- Axon hillock
What is somatic information?
- Stuff that we are aware of / have control over
- Somatic efferent (motor)
- Somatic afferent (sensory)
What happens under autonomic control?
- Stuff we are not aware of / have no control over
- Autonomic efferent (motor)
- Autonomic afferent (sensory) / visceral sensory
What’re the two autonomic efferent pathways?
- Sympathetic
- Parasympathetic
What are the five features of the somatic motor (efferent) division?
- Voluntary control
- One neuron between CNS and effector
- Cell body in spinal cord (CNS)
- Axon in spinal nerves (PNS)
- Effectors (things that is controlled by nerve) skeletal muscle fibres
A single motor neuron has it’s cell body in the _____ (____) and it’s axon in a ______ (____).
- Spinal Cord (CNS)
- Peripheral Nerves (PNS)
What is the Acetylcholine (ACh) neurotransmitter used for?
- Communication between motor neuron and skeletal muscle
What is the name of synapse space between a neuron and muscle?
- Neuromuscular Junction
What is a motor unit?
- Neuron(s) + muscle fibre(s)
Can a single muscle fibre be innervated by several neurons?
- NO
What are the features of the Autonomic Nervous System?
- Involuntary control
- Two neurons between CNS and effector
- Neuron #1 has cell body in CNS and axon in PNS
- Neuron #2 has cell body in PNS and axon in effector cell
What are the features of Neuron #1 (Autonomic)?
- Synapse in Autonomic Ganglion
- Myelinated
- Pre-ganglionic neuron
- Neurotransmitter = ACh
- Call body in CNS
- Axon extends outside CNS
What are the features of Neuron #2 (Autonomic)?
- Cell body in PNS (autonomic ganglion)
- Axon extends to effector organ
- Synapse on effector organ
- Neurotransmitters = ACh / Noradrenaline
- Unmyelinated (because axons = small, don’t need myelin to speed up conduction velocity)
What is the function of the sympathetic autonomic system?
- Prepares the body for acute/stress responses
- Fight of flight
What are the effects of the sympathetic nervous system?
- Increased heart rate
- Constricted blood vessels
- Decreased gastric motility / salivation
- Increased pupil size / sweating
What are the effects of the parasympathetic nervous system?
- Decreased heart rate / pupil size
- Increased gastric motility / salivation
What is the function of the parasympathetic autonomic system?
- Prepares the body for rest and digest
In the sympathetic nervous system what neurotransmitter is secreted by neuron #2 to the effector?
- Noradrenaline / Norepinephrine
In the parasympathetic nervous system what neurotransmitter is secreted by neuron #2 to the effector?
- Acetylcholine (ACh)
What are the axon size differences in parasympathetic and sympathetic neurons?
- In a parasympathetic neuron
#1 has a short axon #2 has a long axon
- In a sympathetic neuron
#1 has a long axon #2 has a short axon
What occurs in the sympathetic chain ganglia?
- Synapse between neuron #1 (preganglionic) and neuron #2 (postganglionic) takes place
There are _____ divisions in the parasympathetic nervous system, exit from CNS
- Two (Cranial + Sacral)
