14-1: Overview Flashcards
The Autonomic Nervous System is the branch of the ___Nervous System that conveys information from the ____ to ____.
Efferent; CNS; cardiac and smooth muscles or gland
The Peripheral Nervous System has 2 branches: ___.
afferent and efferent
The Efferent Nervous System has 2 branches: ___.
autonomic and somatic
What are 5 ways that the ANS differs from the SNS?
effectors: skeletal muscle | smooth muscle, cardiac muscle, and glands
type of control: voluntary | involuntary
pathway: ONE motor neuron btwn CNS and effector | TWO motor neurons btwn CNS and effector
action on effector: always excitatory | excitatory or inhibitory
neurotransmitter: acetylcholine | acetylcholine or norepinephrine
What are some examples of autonomic activity?
size of pupil dilation of blood vessels heart rate movement of digestive tract secretion of saliva emptying of bladder
Autonomic pathways almost always consist of 2 ____ neurons: ___ and ___, which synapse at ___.
motor; preganglionic neuron; postganglionic neuron; autonomic ganglion
preganglionic neuron
cell body in the brain or spinal cord, and its myelinated axon passes out of the CNS as part of a cranial or spinal nerve
postganglionic neuron
lies entirely outside of the CNS. Cell body is in an autonomic ganglion and unmyelinated axon leaves the ganglion and synapses with a visceral effector
autonomic ganglion
where pre and postganglionic neurons synapse
The autonomic ganglion has the ____ of ____; the dorsal root ganglia has ___ of ___.
cell bodies; motor neurons and synapses; cell bodies; sensory neurons
parasympathetic division
concerned with activities that conserve and restore energy during times of rest (food digestion and absorbtion into body) - normally in control
sympathetic division
involves spending energy when the body is under physicial or emotional stress (eg. exercise, rage, fear)
In the fight or flight response:
- pupils ___
- heart rate and blood pressure ____
- blood vessels to skin and viscera ____
- vessels to skeletal and cardiac muscle ____
- breathing becomes ___; airways ____
- blood sugar level ____
- pupils dilate
- heart rate and blood pressure increase
- blood vessels to skin and viscera constrict
- vessels to skeletal and cardiac muscle dilate
- breathing becomes rapid and deep - airways dilate
- blood sugar level increases
Dual innervation
most organs get nerve fibers from both sympathetic and parasympathetic division. The two cause opposite effects - if one stimulates an organ, the other inhibits it
heart rate: SANS ____, PANS ___
intenstinal motility: SANS ____, PANS ____
heart rate: SANS increase and PANS decreases
intestinal motility: SANS decreases and PANS increases
Sympathetic neurons originate in the ______; parasympathetic neurons origin in the ______.
thoracic and lumbar regions of spinal cord; brainstem and sacral region of the cord
Sympathetic has ___ preganglionic fibers and ___ postganglionic fibers; parasympathetic has ___ preganglionic and ___ postganglionic
SANS: short pre; long post
PANS: long pre; short post
Sympathetic ganglia lie ___ to the spinal cord and parasympathetic are ___ to the cord.
close; far
PANS preganglionic neurons
have cell bodies located in the nuclei of cranial nerves III, VII, IX, and X (in the brainstem) and in the laterla horns of spinal segments S2 to S4
How many nerves are controled by the PANS?
7 total - 4 cranial (III, VII, IX and X) and 3 sacral
The autonomic ganglia in the PANS is a ____ and in the SANS is a ____.
terminal ganglion; paravertebral chain ganglion
SANS preganglionic neurons
have cell bodies in the lateral horns of spinal cord segments T1 to L2
How many nerves are controled by the SANS?
14 spinal nerves
paravertebral chain ganglion
series of 23 ganglia in a vertical row on each side of the vertebral column; they form the “sympathetic trunk”
When a preganglionic axon reaches a paravertebral ganglion:
- It can synapse with a post ganglionic neuron in the ____ paravertebral ganglion
- It can go ____ the chain and synapose with a postganglionic neuron in a ___ paravertebral ganglion
- It can pass through the ganglion and synapse with a postganglionic neuron in a ____, located ___ to the vertebral column
- same
- up and down; different
- prevertebral ganglion; anterior
neurotransmitter
these chemicals are released at the synapses between neurons and the neuromuscular or neuroglandular junctions
What are the two types of autonomic nerve fibers?
cholinergic (secretes acetylcholine) and adrenergic (norepinephrine)
Where are the cholinergic fibers?
all somatic motor neurons
all preganglionic axons
all parasympathetic postganglionic axons
(and a few sympathetic postganglionic axons to sweat glands and some blood vessels)
Where are the adrenergic fibers?
most sympathetic postganglionic axons
Effects of cholinergic fibers are ___.
short lived and local (since ACh is quickly inactivated by acetylcholinesterase)
Effects of adrenergic fibers are ___.
long lasting and more widespread (since norepinephrine enter the blood and is slowly inactivated)
Receptors are found ____.
on viscera and the cell bodies of postganglionic neurons
What are the types of cholinergic and adrenergic receptors?
cholinergic: nicotinic and muscarinic
adrenergic: alpha and beta
nicotinic receptor
found on cell bodies of all post ganglionic neurons and skeletal muscles
Effect is always stimulation
muscarinic receptors
occur on all effector cells stimulated by postganglionic, chonlinergic fibers (all parasympathetic)
effect is either excitatory or inhibitory (usually excitatory, but slows down heart rate)
alpha receptor
When NE binds to these, the organ is usually stimulated
beta receptor
when NE binds to these, the organ is usually inhibited
What is an exception to the alpha-beta receptor rule?
The beta1 receptors of the heart are excitatory
