Lecture 17: Integrating and Coordinating Roles of the Nervous System Flashcards
What do afferent and efferent mean?
Afferent is information moving into the CNS from the PNS, efferent is information moving out from the CNS to the PNS.
What does the PNS and CNS each consist of?
CNS: Brain and spinal cord.
PNS: Cranial nerves and spinal nerves.
What is somatic and autonomic?
Somatic = things we have conscious control over. Autonomic = things we have no conscious control over, are not aware of.
What four types of information transmitted in the nervous system?
Somatic sensory, somatic motor, visceral sensory (afferent), and autonomic motor (efferent).
How many neurons between CNS and effector?
1
Where is the cell body and axon of a somatic motor neuron?
Cell body in spinal cord (CNS) and axon in spinal nerves (PNS). Often very long.
What are the effectors of a somatic motor neuron?
Skeletal muscle fibres.
What neurotransmitter is released at the synapse of a somatic motor neuron? What is this synapse called?
Acetylcholine (ACh)
Neuromuscular junction.
What is a motor unit?
A motor neuron and all the muscle fibres it innervates.
Are muscle cells ever innervated by more than one neuron?
No.
Is the axon myelinated in somatic motor division nerves?
Yes!
Where are nerves in the Autonomic Nervous System?
Neuron #1 has cell body in CNS and axon in the PNS. This connects to neuron #2 which has its cell body and axon in the PNS.
What are the effectors of the autonomic nervous system?
Smooth Muscle, Cardiac Muscle, Glands, Adipose(fat) Tissue
Where do neurons in the autonomic system synapse and what neurotransmitter do they release?
Neuron #1 (pre-ganglionic) synapses in the Autonomic Ganglion and releases acetylcholine. Neuron #2 (post-ganglionic) synapses on the effector organ and releases either acetylcholine (ACh) OR noradrenaline (NE)
What division of the nervous system are the sympathetic and parasympathetic subdivisions part of?
Autonomic
What is the sympathetic nervous subdivision?
Sympathetic: “FIGHT OR FLIGHT”. Increased heart rate, blood flow to muscles, pupil size and sweating. Decreased blood flow to skin and viscera, salivation, and gastric motility.
What is the parasympathetic nervous subdivision?
Parasympathetic: “REST & DIGEST”.
Increased gastric motility and salivation, decreased pupil size and heart rate.
What do sympathetic nerves synapse on and what neurotransmitter do they release?
The pre-ganglionic neuron has a short axon, synapses at the sympathetic ganglion (sympathetic chain ganglia, close to the CNS) and releases ACh. The post-ganglionic neuron has a long axon, synapses with the effector and releases NE.
What do parasympathetic nerves synapse on and what neurotransmitter do they release?
The pre-ganglionic neuron has a long axon, synapses at the parasympathetic ganglion (far from the CNS) and releases ACh. The post-ganglionic neuron has a short axon, synapses with the effector and releases ACh.
Which axons are myelinated in the parasympathetic and sympathetic nervous systems?
The pre-ganglionic axon.
Where do axons of sympathetic pre-ganglionic neurons leave the CNS?
At thoracolumbar levels (spinal cord).
How many pairs of sympathetic chain ganglia are there?
21-23, depending on how tall you are.
Which synapse releases norepinephrine?
The synapse of post-ganglionic sympathetic neurons.
What are the 2 types of sympathetic ganglia?
Chain and collateral ganglia
How many main collateral ganglia are there, and what do they contain?
- They contain preganglionic axons that didn’t make synapses in the chain ganglia.
Which two positions do the axons of preganglionic neurones leave the CNS?
At the cranial or brain stem and sacral or spinal cord levels.
What neurotransmitter is used by a somatic efferent neruon?
Acetylcholine
If you were told that your cranio-sacral nervous system were activated what does that tell you about your mood?
Relaxed.
