pages 264-269. central nervous system (brain and spinal cord) peripheral nervous system (cranial and...
TRANSCRIPT
Pages 264-269
Central Nervous System(brain and spinal cord)
Peripheral Nervous System(cranial and spinal nerves)
Somatic(voluntary)
Autonomic(involuntary)
Sensory(afferent)
Motor(efferent)
Senseorgans
Skeletalmuscles
Cardiac andsmooth muscle,
glands
Parasympathetic Sympathetic
The relative stability of our internal environment depends largely on ANS function
Involuntary regulation of◦ Cardiac activity◦ Smooth muscles/glands
Two subdivisions:1.Sympathetic division2.Parasympathetic division
© 2015 Pearson Education, Inc.
The ANS has a chain of two motor neurons◦ Preganglionic neuron : exists in brain or spinal cord
Axon is myelinated◦ Postganglionic neuron:
outside the CNS Extends to a specific organ Axon is un-myelinated = slower response
This arrangement is different from the somatic division (voluntary motor division) which has only one motor neuron
Centralnervoussystem Peripheral nervous system Effector organs
Acetylcholine
Skeletalmuscle
Acetylcholine
Norepinephrine
Ganglion
Acetylcholine Epinephrine andnorepinephrine
Bloodvessel
Acetylcholine
Ganglion
Smooth muscle(e.g., in stomach)
Glands
Cardiacmuscle
Somatic nervoussystem
Autonomicnervoussystem
Sympatheticdivision
Para-sympathetic
division
KEY:Preganglionicaxons(sympathetic)
Postganglionicaxons(sympathetic)
Myelination Preganglionicaxons(parasympathetic)
Postganglionicaxons(parasympathetic)
Acetylcholine (Ach) is released in both divisions
◦ ACh is released by the Parasympathetic division to stimulate the effector directly
◦ ACh is released by the Sympathetic division to cause a release of: Epinephrine by the adrenal gland Norepinephrine by the postganglionic nerve fibers Either of these neurotransmitters will stimulate the
effector (heart, blood vessel, gland…)
Eye Eye
Salivaryglands
Heart
Lungs
Stomach
Pancreas
Liver andgall-bladder
Bladder
Genitals
Cervical
T1
Thoracic
L1
Lumbar
Brain stem
Cranial
Sympatheticganglia
Sacralnerves(S2–S4)
Parasympathetic Sympathetic
Skin
Salivaryglands
Heart
Lungs
Stomach
Pancreas
Liver and gall-bladder
Bladder
Genitals
Adrenalgland
REST/DIGEST FIGHT/FLIGHT
PARASYMPATHETIC Relaxes Conserves Neurotransmitter at
work is ACh
SYMPATHETIC Mobilizes Triggers:
◦ Fear, exercise, rage Neurotransmitters at
work are◦ Epinephrine◦ Norepinephrine◦ Acetylcholine
PNS: Differences Between Somatic and Autonomic Nervous Systems
© 2015 Pearson Education, Inc.
Somatic Nervous System
Autonomic Nervous System
Nerves One-neuron system; it originates in the CNS, and axons extend to the skeletal muscles served
Two-neuron system consisting of preganglionic and postganglionic neurons
Effector organ Skeletal muscle Smooth muscle, cardiac muscle, glands
Subdivisions None Sympathetic and parasympathetic
Neurotransmitter Acetylcholine Acetylcholine, epinephrine (adrenaline), norepinephrine