Somatic and Autonomic Nervous System Flashcards
Somatic NS
Voluntary and involuntary control of skeletal muscle
Autonomic NS
Involuntary control of smooth muscle, cardiac muscle and glands
Sympathetic and parasympathetic divisions
Afferent
Sensory info. carried to the CNS
Efferent
Motor commands to muscles and glands, away from CNS
Nerves of the somatic NS
Cranial and spinal nerves
Nerves of the autonomic NS
Cranial preganglionic Spinal preganglionic Sympathetic chain ganglia Collateral ganglia Visceral postganglionic
What are plexuses of the somatic NS?
Interwoven nerve trunks
Cervical, brachial, lumbar, sacral
What are plexuses of the ANS?
Cardiac, pulmonary, oesophageal, celiac, inferior mesenteric, hypogastric
What are pyramidal (direct) tracts?
Upper motor neurons on CNS synapse with lower motor neurons in brainstem or spinal cord
Conscious control
Corticospinal and corticobulbar tracts
What do the corticospinal and corticobulbar tracts control?
Conscious control of movements below head and of head respectively
What are extrapyramidal (indirect) tracts?
Motor neurons first synapse in an intermediate nucleus in the brainstem
Subconscious control
Tectospinal, vestibulospinal, recticulospinal, rubrospinal
What does the tectospinal tract control?
Subconscious reflex movement of the head
What does the vestibulospinal tract control?
Balance and muscle tone
What does the recticulospinal tract do?
Reflex regulation
What odes the rubrospinal tract do?
Upper limb muscle tone and movement
Why form plexuses?
Widespread action
Amplification
Which are generally shorter, sympathetic or parasympathetic preganglionic neurons?
Sympathetic
Sympathetic post-ganglionic cell bodies tend to be located close to the spinal cord, while parasympathetic are more peripheral.
What travels through the dorsal ramus?
- Info. to and from the skeletal muscles, skin, smooth muscles and glands of back
- Sensory and motor
- Somatic and visceral
What travels through the ventral ramus?
- Info. to and from the ventrolateral body surface, wall and limbs
- Sensory and motor
- Somatic and visceral
What travels through the gray ramus?
Visceral motor info. to organs
What travels through the white ramus?
Visceral motor and sensory info. to and from (preganglionic) organs
What is the largest component of the ANS?
The Enteric NS which governs GI tract functions and reflexes
Where is the ENS located?
In sheaths of tissue lining the esophagus, stomach, small intestine and colon
What is a dermatome?
Map of areas of skin innervated by spinal segments
