Functional Information Flow Flashcards
What are the types of information transmitted?
Somatic and Autonomic
What is somatic information?
The stuff we are aware of/have control over.
- Somatic Efferent: voluntary muscle control
- Somatic Afferent: sensory information we are aware of
What is autonomic information?
The stuff we are not aware of/have no control over.
- Autonomic Efferent: Involuntary muscle control
- Autonomic Afferent: Sensory information we don’t know about
What does the somatic efferent division consist of?
- Upper motor neuron (completely in CNS)
- cell body in brain
- axon in spinal cord (is myelinated) - Lower motor neuron (goes from CNS to PNS)
- cell body in spinal cord
- Axon in spinal nerve (in myelinated)
Effectors (things the nerves go to and control) = skeletal muscle fibres
How is somatic efferent: communication with effector cells done?
The neuromuscular junction. Between the pre-synaptic cell (lower motor neuron) and the post-synaptic cell (effector, muscle) the neurotransmitter is Acetylcholine (ACh)
Summarise the somatic efferent division
- Voluntary movement
- Two neurons between brain and effector
1. Upper motor neuron
2. Lower motor neuron - Axons are myelinated
- Neurotransmitter = Acetylcholine
- Effector = skeletal muscle
What are the two divisions of the autonomic efferent nervous system?
Sympathetic and Parasympathetic
What are the effectors of the autonomic efferent nervous system?
Smooth muscle, cardiac muscle, glands, adipose (fat) tissue
What are the charactaristics of Neuron #2 in the autonomic efferent nervous system?
- Cell body in CNS
- Axon extends in PNS
- Myelinated
- Synapse in Autonomic Ganglion
- Pre-Ganglionic neuron
- Neurotransmitter = Acetylcholine (ACh)
What are the characteristics of Neuron #3 in the autonomic efferent nervous system?
- Cell body in PNS, autonomic ganglion
- Axon extends in PNS, to effector organ
- Unmylenated
- Synapse on effector organ
- Post-ganglionic neuron
- Neurotransmitter = ACh or norepinephrine
What does the sympathetic subdivision of the autonomic nervous system do?
- Prepares the body for acute stress/responses.
- “Fight or flight” system.
Effects include: Increased heart rate, constricting blood vessels to skin and viscera (so increased blood flow to muscles), increased pupil size, increased sweating
Neurotransmitter is: NOREPINEPHRINE
What does the parasympathetic subdivision of the autonomic nervous system do?
- Prepares the body for restful situations
- “rest and digest” system
Effects include: decreased heart rate, increased gastric motility, increased salivation
What are the structural differences between sympathetic and parasympathetic nervous systems?
Sympathetic: Neuron #2 has a short axon, sympathetic ganglion is close to the CNS, Neuron #3 has a long axon.
Parasympathetic: Neuron #2 has a long axon, parasympathetic ganglion is far from the CNS, Neuron #3 has a short axon.
Describe the sympathetic nervous system exit from CNS and position of ganglia
Pre-gangliotic neuron:
1. Cell body in thoracolumbar levels of spinal cord (CNS)
2. Axon is short
3. Axon terminals and synapse in sympathetic ganglion
Post-gangliotic neuron:
3. Cell body in sympathetic ganglion
4. Axon is long
What are the sympathetic chain ganglia?
21-23 pairs of ganglia on either side of the vertebral column, the place where pre-ganglionic (neron #2) axons synapse, onto post-ganglionic (neuron #3) input zone.
- post-ganglionic cell bodies in ganglion
- long axons extend into body
- unmyelinated
