Mod6-Obj1: Organisation of autonomic vs. somatic nervous system Flashcards
Somatic vs. autonomic
-Similarities
Both are efferent divisions that distribute motor commands
Somatic vs. autonomic
-Differences
- Neural pathways (efferent)
- Effectors
- Organ response
- Neurotransmitters
Somatic nervous system
Conducts motor impulses from motor cortex to skeletal muscles
Somatic output controls…
- Voluntary movement
- Involuntary movement (somatic reflexes)
Somatic motor pathway
Effectors innervated by lower motor neuron (LMN) that exits CNS:
- ) Via a spinal nerve
- ) Via a cranial nerve
Somatic motor pathway: via a spinal nerve
LMN cell body located in a motor nuclei of anterior grey horn
-Axon exits spinal cord via ventral root of a spinal nerve
Somatic motor pathway: via a cranial nerve
Cell body in a brainstem nucleus
Autonomic nervous system
Conducts motor impulses from the hypothalamus to cardiac and smooth muscle, glands
Autonomic output controls…
involuntary activities
- Visceral organ function
- Glandular activity
ANS: Motor pathways
- CNS interneuron
- Preganglionic neuron (connect to postganglionic)
- Postganglionic neuron (affect visceral glands)
ANS: Motor pathways
- CNS interneuron
- Preganglionic neuron (connect to postganglionic)
- Postganglionic neuron (affect visceral glands)
Autonomic nervous system controls organ function to support…
Homeostasis
ANS: Hypothalamus
Contains integrative centres (nuclei) that control autonomic activity
Hypothalamus is responsive to which other areas of the brain?
- Cerebral cortex
- Limbic system
Hypothalamus mediates ANS activity via nuclei in what area of the brain?
Brainstem i.e.) Medulla obongata
Hypothalamus mediates ANS activity via nuclei in what area of the brain?
Brainstem i.e.) Medulla obongata
ANS motor pathways: effectors innervated by 2 neuron chain
- ) Preganglionic neuron
2. ) Postganglionic neuron
ANS motor pathways: effectors innervated by 2 neuron chain
- ) Preganglionic neuron
2. ) Postganglionic neuron
Autonomic motor pathways: Preganglionic neuron
Cell body in CNS
-Axon exits CNS and synapses with postganglionic neuron in a ganglion
Autonomic motor pathways: Postganglionic neuron
Cell body in ganglion (near CNS or effector)
-Axon exits ganglion to innervate effector
Neurotransmitters: Somatic nervous system
Acetylcholine (ACh)
-Always excitatory (muscle contraction)
Neurotransmitters: ANS
Preganglionic -ACh (always excitatory) Postganglionic -Parasympathetic=ACh -Sympathetic=NA (Noradrenaline, excitatory or inhibitory)
Neurotransmitters: ANS
Preganglionic -ACh (always excitatory) Postganglionic -Parasympathetic=ACh -Sympathetic=NA (Noradrenaline, excitatory or inhibitory)
Somatic nervous system summary
-Voluntary control
Innervates skeletal muscle
-One peripheral LMN:
+Neuron cell body in CNS (motor neuron of anterior gray horn of brain stem)
+Axon extends (spinal or cranial nerves) to skeletal muscle
-Always stimulates skeletal muscle
-Controls movement
Autonomic nervous system summary
-Involuntary control
Innervates cardiac & smooth muscles, glands
-Two peripheral motor neurons:
+Preganglionic neuron cell body in CNS (motor neuron of lateral gray horn or brain stem) whereby the axon synapses with postganglionic neuron cell body in ganglion
+postganglionic neuron to effector
-Stimulates or inhibits cardiac or smooth muscle or glands
-Controls visceral organ function to support homeostasis
