Transcript Biology 211 Anatomy & Physiology I

Biology 211
Anatomy & Physiology I
Autonomic Nervous System
Autonomic Nervous System
The efferent (motor) component of the peripheral
nervous system includes two types of neurons:
Somatic Neurons regulate voluntary movement
(contraction of skeletal myocytes)
Autonomic Neurons regulate involuntary functions
(rate & force of of cardiac myocyte contraction)
(contraction of smooth myocytes)
(secretion of glands)
Both types of efferent neurons run through the same
cranial or spinal nerves
Comparison: Somatic vs Autonomic efferent neurons
Somatic
Autonomic
Voluntary
Effectors: Skeletal M.
Involuntary
Effectors: Cardiac M.
Smooth M
Glands
Neurons extend from
CNS to effectors
without synapsing.
Two neurons to get from
CNS to effectors; therefore
one synapse.
"Two neuron chain"
Autonomic Nervous System
Two divisions based on:
a) Where the cell body of the first neuron is located
(Brain; Specific region of spinal cord)
b) Where the axon of the first neuron synapses with
the dendrites of the second neuron
(Far away from effector cells; Near effector cells)
First cell =
Second cell =
of Autonomic Nervous System
Preganglionic neuron starts in thoracic or lumbar
levels of spinal cord.
Preganglionic neuron synapses with postganglionic
neuron relatively far from effectors
of Autonomic Nervous System
Preganglionic neuron starts in brain or sacral level
of spinal cord.
Preganglionic neuron synapses with postganglionic
neuron very near the effector cells
Sympathetic Division
Synapse between preganglionic neuron and postganglionic
neuron can occur in either of two sets of ganglia
1)
"Chain" of
ganglia along spinal column,
next to vertebrae
2)
Near major
arteries of abdomen:
Celiac ganglion
Superior mesenteric ganglion
Inferior mesenteric ganglion
Note: A sympathetic synapse can
occur in either set of ganglia,
but not both
Parasympathetic Division
Synapse between preganglionic and postganglionic
neurons occurs in ganglia very close to the target cells:
1. Above neck: Larger ganglia
located near target organs
(posterior to eye).
(posterior to maxilla)
(near angle of mandible)
(inferior to foramen ovale)
Parasympathetic Division
Synapse between preganglionic and postganglionic
neurons occurs in ganglia very close to the target cells:
2. Below neck: Microscopic
ganglia located within
walls of target organs
such as intestines
Parasympathetic Division
Synapse between preganglionic and postganglionic
neurons occurs in ganglia very close to the target cells:
2. Below neck: Microscopic
ganglia located within
walls of target organs
such as heart
Most organs have both sympathetic and parasympathetic
innervation, each of which acts in opposition to the other.
Sympathetic:
F
F
F
F
Parasympathetic:
Most organs have both sympathetic and parasympathetic
innervation, each of which acts in opposition to the other.
For example:
Heart:
Sympathetic increases heart rate & force of contraction
Parasympathetic decreases heart rate & force of contraction
Most organs have both sympathetic and parasympathetic
innervation, each of which acts in opposition to the other.
For example:
(Heart: Sympathetic increases rate & force
Parasympathetic decreases rate & force )
Lungs:
Sympathetic dilates air passages
Parasynpathetic constricts air passages
Most organs have both sympathetic and parasympathetic
innervation, each of which acts in opposition to the other.
For example:
(Heart: Sympathetic increases rate & force
Parasympathetic decreases rate & force )
(Lungs: Sympathetic dilates air passages
Parasynpathetic constricts air passages)
Digestive System:
Sympathetic decreases activity; constricts anal sphincter
Parasympathetic increases activity; relaxes anal sphincter
Most organs have both sympathetic and parasympathetic
innervation, each of which acts in opposition to the other.
For example:
(Heart: Sympathetic increases rate & force
Parasympathetic decreases rate & force )
(Lungs: Sympathetic dilates air passages
Parasynpathetic constricts air passages)
(Digestive System: Sympathetic decreases activity
Parasympathetic increases activity)
Urinary System:
Sympathetic inhibits urination
Parasympathetic promotes urination
Most organs have both sympathetic and parasympathetic
innervation, each of which acts in opposition to the other.
For example:
(Heart: Sympathetic increases rate & force
Parasympathetic decreases rate & force )
(Lungs: Sympathetic dilates air passages
Parasynpathetic constricts air passages)
(Digestive System: Sympathetic decreases activity
Parasympathetic increases activity)
(Urinary System: Sympathetic inhibits urination
Parasympathetic promotes urination)