Autonomic Nervous System (2) Flashcards
Exam 2
Central Nervous System information
- brain and spinal cord
- integrative function
Peripheral Nervous System information
- nerves leading to/from CNS
- pathway of signal input/output
- connects CNS to: sense organs, muscles, and glands
- two divisions
What are the two divisions of the PNS?
- Afferent (sensory) - somatic and visceral divisions
2. Efferent (motor) - somatic and autonomic division
Spinal Cord info
- cylinder of nervous tissue
- enclosed in vertebral canal
- foramen magnum to first lumbar vertebra
What are the regions of the spinal cord and why are are they named what they are?
- cervical
- thoracic
- columnar
- sacral
(named for where the spinal nerves emerge
Posterior (dorsal) horns definition
receiving points for sensory information
Lateral Horns Definition
location of somas of somatic motor neurons exiting gray matter
Somatic Nervous System definition
voluntary control of movements
controls skeletal muscle and includes somatic reflexes
Autonomic Nervous System definition
involuntary control system
controls visceral functions and visceral reflexes
Autonomic Nervous system is self-governed and includes….
glands, cardiac and smooth muscle, cutaneous blood vessels, sweat glands, and pilorector muscles
Visceral Motor Division information
- not somatic
- generally involuntary
- not necessary to function (modify based on need)
Visceral Reflexes are needed to ____
survive
Visceral reflexes include basal functions. What are basal functions?
unconscious, automatic, stereotyped responses
Unconscious processes are used to bring things back to _____
homeostasis
What are the steps to the visceral reflex of when you have high blood pressure?
- Receptor: stretch receptors
- Afferent (Sensory): cranial nerve to the medulla oblongata
- Integration: information integrated with other information (sensory) fibers
- Efferent (Motor): carry response (vagus nerve) to effector
- Effector: heart told to slow down which leads to blood pressure being reduced
(restores blood pressure to normal)
What are the two divisions of the ANS?
- Sympathetic Division
2. Parasympathetic Division
What does the sympathetic division do?
“fight or flight”
adapts for physical activity
What does the parasympathetic division do?
“rest and digest”
controls normal body maintenance
_____ effects on some targets; ____ effects on others
excitatory
inhibitory
Autonomic Tone definition
balance shifts with changing needs of body
CNS Components:
- control centers: hypothalamus and brain stem
- motor neurons: spinal cord
PNS Components:
nerve fibers: cranial/spinal
What is a ganglion?
Swelling, usually near end of nerve
What does a ganglion contain?
contains cell bodies of peripheral neurons
In some ganglions: neurons form synaptic connections and act as ____ ____ in the PNS
information processing
Somatic Pathway Definition
axon of motor neuron in brainstem/spinal cord reaches directly to skeletal muscle (myelinated axon)
Autonomic Pathway Definition
signal must travel across two pathways:
- Preganglionic neuron
- Postganglionic Neuron
All (efferent) sympathetic ____ fibers from the thoracic and first two lumbar segments of the spinal cord (_____ region [division])
preganglionic
thorocolumbar
Which fibers in the sympathetic division are short?
preganglionic fibers
Which fibers in the sympathetic division are long?
postganglionic fibers
Paravertebral Ganglion definition
connected to spinal nerves via two branches: communicating rami
Preganglionic Fibers information
- myelinated
- enter ganglia through white communicating rami
Postganglionic Fibers information
- unmyelinated
- leave ganglia via gray communicating rami
What are the three steps once preganglionic fibers enter the sympathetic chain?
- end in ganglion: synapse with postganglionic neuron
- travel up and down: synapse with postganglionic neurons at different levels
- Pass through chain without synapsing (splanchnic nerves)
What are the three ways postganglionic fibers leave the sympathetic chain?
- Spinal Nerves
- Sympathetic Nerve Route
- Splanchnic Nerve Route
Origin of CNS in sympathetic
thoracolumbar
Origin of CNS in parasympathetic
craniosacral
location of ganglia in sympathetic
paravertebral ganglia adjacent to spinal column and prevertebral ganglia
location of ganglia in parasympathetic
terminal ganglia near or within target organs
fiber lengths in sympathetic
short preganglionic
long postganglionic
fiber lengths in parasympathetic
long preganglionic
short postganglionic
Neuronal divergence in sympathetic
extensive
neural divergence in parasympathetic
minimal
effects of system in sympathetic
often widespread and general
effects of system in parasympathetic
more local and specific
