CH 11: efferent division - autonomic and somatic motor control Flashcards
What type of neuron carries out commands from the CNS to the muscles and glands of the body? How can it be further divided?
- Efferent neurons
- Further divided into:
- Somatic motor neurons: control skeletal muscles, mostly voluntary
- Autonomic neurons: control smooth muscle, cardiac muscle, glands, and some adipose tissue, mostly involuntary
***Diaphragm controlled by both!
What does the sympathetic branch of the autonomic system do?
fight or flight
What does the parasympathetic branch of the autonomic division do?
rest and digest
What type of control is primarily used in the autonomic division? (agonist, antagonist, mixed, etc)?
- antagonistic
- one branch is (sympathetic) excitatory and the other one (parasympathetic) is inhibitory
- some exceptions (sweat glands & BV only by sympathetic & rely on tonic [up regulation] control)
- sometimes they can work together and have different functions
- neurotransmitter receptor often determines response in the target tissue
What is a ganglion?
- a cluster of neuronal cell bodies outside the CNS
- equivilant in CNS is nucleus
- act as mini-integration centers
Is the autonomic ganglion closer to the CNS or the target tissue in parasympathetic?
target tissue (or more in the middle)
What neurotransmitter does the preganglionic neuron release in the parasympathetic division and what receptor on the ganglion does it bind to?
- acetylcholine
- binds to nicotinic receptors
Is the autonomic ganglion closer to the CNS or the target tissue in sympathetic?
CNS (close to preganglioninc neuron)
What neurotransmitter does the preganglionic neuron release in the sympathetic division and what receptor on the ganglion does it bind to?
- acetylcholine
- binds to nicotinic receptors
Where are the ganglions in the sympathetic and parasympathetic pathways (CNS or PNS)?
PNS
What neurotransmitter does the postganglionic neuron release in the parasympathetic division and what receptor on the target cell does it bind to?
- acetylcholine
- binds to muscarinic receptor (GPCRs —> second messenger changes)
What neurotransmitter does the postganglionic neuron release in the sympathetic division and what receptor on the target cell does it bind to?
- norepinephrine
- adenergic receptors
What is the preganglionic neuron?
- first neuron in chain with cell body in CNS
- projects from CNS to an autonomic ganglion outside the CNS
- synapses with postganglionic neuron
what is the postganglionic neuron?
- second neuron in the chain with cell body located in the autonomic ganglion
- projects from an autonomic ganglion to the target tissue
- synapses with target cell
Look at slide 13 & 14