Ch.14 Flashcards
Involuntary Division of the Motor Division of the PNS
Regulates smooth muscle, cardiac muscle and glands
Somatic Nervous System
- Sensory Input: Special senses and somatic senses
- One neuron pathway: Single neuron from CNS synapse directly effector ograns: skeletal muscle in PNS to release Ach –> stimulatory effect
All somatic motor neurons release
ACh
Control of Motor Output
Somatic Nervous System (SNS)
Voluntary control from cerebral cortex with contributions from basal ganglia, cerebellum, brain stem and spinal cord
All Preganglionic fibers in Autonomic Nervous System (ANS) release
Autonomic Nervous System (ANS)
ACh
All post ganglionic axons in Autonomic Nervous System (ANS) release
Autonomic Nervous System (ANS)
ACh OR norepineephrine (NE)
- Sympathetic postganglionic fibers release NE
- Parasympathetic postganglionic fibers release ACh
Sensory Input
Autonomic Nervous System (ANS)
Mainly from interoceptors
Control of Motor Output
Autonomic Nervous System (ANS)
Involuntary control from the limbic system; hypothalamus, brain stem, and spinal cord
Automatic Nervous system: Sympathetic
- “Fight or Flight” – mobilizes body for action
1. preganglionic neurons from CNS synapse with postganglionic fibers in an autonomic ganglion in PNS to release Ach
2. Unmyleinated postganglionic axon from ganglia releases norepinephrine to effector organs: Smooth muscle, glands, cardiac muscle and increased or decreased muscle contraction - Stimulatory or inhibitory, depending on neurotransmitter and receptors on effector organs
Automatic Nervous system: Parasympathetic
- “Rest, Repose, Digest” – conserves energy
1. preganglionic neurons from CNS synapse with postganglionic fibers in an autonomic ganglion in PNS to release ACh
2. Unmyleinated postganglionic axon from ganglia releases ACh to effector organs: Smooth muscle, glands, cardiac muscle and increased or decreased muscle contraction - Stimulatory or inhibitory, depending on neurotransmitter and receptors on effector organs
Agonists
- if sympathetic stimulates the gland to secrete –> the parasympathetic inhibits the gland’s secretion
Parasympathetic Division
- Axons emerge from CNS at level of cranial nerve and sacral spinal nerves
- Ganglion is near or within the effector
- Preganglion axon is long, postganglion axon is short
CN (3) III Oculomotor
Parasympathetic Division
focus on close objects at cranial level
CN (7) VII Facial
Parasympathetic Division
causes salivary and tear glands to secrete at cranial level
IX Glossopharyngeal
Parasympathetic Division
causes salivary glands to secrete at cranial level
X Vagus
Parasympathetic Division
Thoracic and abdominal organs (heart, lungs, liver, gallbladder, stomach, pancreas, etc.) at cranial level
Sacral Level
Parasympathetic Division
- Cell bodies in lateral horns of sacral spinal cord
- Axons through ventral root and into ventral rami to urinary (not kidney), reproductive, and some digestive organs
Sympathetic division
- Preganglion neuron cell bodies are in the lateral horns of the spinal cord
- Axons emerge from the thoracic and lumbar regions of the spinal cord
- Axons of preganglion neurons pass through ventral root and into white rami communicantes and enter the sympathetic trunk ganglion (usually 23 pairs)
The three optional paths of sympathetic division
Once in the sympathetic chain ganglion, there are 3 optional paths
- synapse at the same level
- synapse at a higher or lower level
- synapse in a distal collateral ganglion anterior to the vertebral column
Iris (eye muscle)
Sympathetic: Pupil dilation
Parasympathetic: Pupil constriction
Salivary glands
Sympathetic: Saliva production reduced
Parasympathetic: Saliva production increased
Oral/Nasal mucosa
Sympathetic: Mucus production reduced
Parasympathetic: Mucus production increased
Heart
Sympathetic: Heart rate and force increased
Parasympathetic: Heart rate and force decreased
Lung
Sympathetic: Bronchial muscle relaxed
Parasympathetic: Bronchial muscle constricted
Stomach
Sympathetic: Peristalsis reduced
Parasympathetic: Gastric juice production increased, motility increased
Small intestine
Sympathetic: Motility decreased
Parasympathetic: Digestion increased
Large intestine
Sympathetic: Motility decreased
Parasympathetic: Secretions and motility increased
Liver
Sympathetic: Increased conversion of glycogen to glucose
Parasympathetic: none
Kidney
Sympathetic: Decreased urine secretion
Parasympathetic: Increased urine secretion
Adrenal medulla
Sympathetic: Norepinephrine and epinephrine secreted
Parasympathetic: none
Bladder
Sympathetic: Wall relaxed, sphincter closed
Parasympathetic: Wall constricted, sphincter
relaxed
Neurtransmitter effect on taregt depends on:
type of receptor
ACh Receptors: Nicotinic
- found on all postganglion neurons, the adrenal medulla cells, and skeletal muscle cells
- Excitatory
ACh Receptors: Muscarinic
- Found on all parasympathetic effector cells, sweat glands, and blood vessels
- Effect depends on subclass (inhibits heart, stimulates GI organs)
Adrenergic Receptors (NE): Alpha
- Stimulates vasoconstriction and increases sweat production
- Inhibits digestion
Adrenergic Receptors (NE): Beta
- Stimulates heart
- Relaxes airways
Spinal cord
ANS Regulation
defecation, micturition
Brain Stem
ANS Regulation
- Medulla: HR, vessel constriction, GI activity
- Pons: respiration
- Midbrain: pupil size
Hypothalamus
ANS Regulation
HR, Bp, temp, ion balance
Cortex
ANS Regulation
through biofeedback, meditation, people can control some involuntary body functions
