Autonomic Nervous System: Anna made Flashcards
(33 cards)
Somatosensory function
- Consciously controlled
- Sensory information from tissue to CNS
- Muscle, joints, skin, special senses
Somatomotor function
- Consciously controlled
- Motor information from CNS to skeletal muscle
- Voluntary control from cerebrum
- Involuntary/reflexive from brainstem and spinal cord
Autonomic Function
- Processes regulated below conscious level
- Responds to visceral sensory inputs
- Signals from CNS to heart, smooth muscle, glands
- Maintains homeostasis
Hypothalamus
ANS control center
Sympathetic and parasympathetic responses
Influenced by frontal cortex and limbic system
Brainstem
Controls visceral reflexes
- Blood pressure regulation
- Direction of blood flow
- Cardiac activity
Spinal cord
Controls two important visceral reflexes
- Urination and defecation
ANS Ganglia
Collection of neuron al bodies found in the peripheral nervous system (synapses)
Posterior root ganglion
Cell bodies of unipolar sensory neurons
Sympathetic and parasympathetic ganglia
Synapsing of preganglionic and postganglionic neurons
Parasympathetic Division of Autonomic Nervous System
- “Sex and digest”
Regeneration of tissue, absorption of nutrients, energy diverted to digestive, reproductive, urinary, and immune systems
Sympathetic Divisions of Autonomic Nervous System
- “Fight or flight”
Emergency response, exercise, excitement
Parasympathetic “Craniosacral” Division
- Originates at cranial nerves III, VII, IX, X and sacral nerves 2, 3, 4
- Long preganglionic neurons
- Synapse with short postganglionic fibers
- Ganglions found close to organs
Terminal ganglia
- Parasympathetic
- Close to effector organ
Intramural ganglia
- Parasympathetic
- Embedded in the wall of the organ
Sympathetic “Thoracolumbar” Division
-Originates in lateral horn of spinal segment t1 to L2
-Short preganglionic neurons
-Synapses with long postganglionic neurons
-Ganglia found close to spinal column
Sympathetic chain ganglia
On either side of the spinal column
Essentially operate as a relay station for the Sympathetic Nervous System
-Myelinated presynaptic neurons originate in lateral horns of spinal cord
Three options for synapsing:
1. Synapse in ganglion with postsynaptic neuron
2. Axon passes through ganglion and continues as part of splanchnic nerve
3. Axon ascends/descends in chain to synapse at higher or lower levels and continues as part of that spinal nerve
White Rami
Myelinated preganglionic sympathetic axons from nerve to ganglion
-“Exit ramp” from nerve; “entrance ramp” to ganglion
Gray Rami
Unmyelinated postganglionic sympathetic axons from ganglion to spinal nerve
Sympathetic Spinal Nerve Pathway
- Preganglionic myelinated axons synapse in ganglion with unmyelinated postganglionic neuron
Postganglionic axons returns to spinal nerve - Targets integumentary structures
Postganglionic Sympathetic Nerve Pathway
- Myelinated preganglionic axons synapse with unmyelinated postganglionic neurons in ganglion or ascend/descend chain to synapse with postganglionic neuron
- Targets head, neck, thoracic viscera
Cardiac nerve innervates heart
Splanchnic Nerve Pathway
- Postganglionic axon passes through ganglion without synapsing
- Continues as part of splanchnic nerve
Greater splanchnic nerve
Lesser splanchnic nerve
Least (lowest) splanchnic nerve - Targets abdominal and
pelvic viscera
Adrenal Medulla Pathway
- Preganglionic axon passes through ganglion to lesser splanchnic nerve
- Targets adrenal glands
Stimulates release of adrenaline from adrenal glands
Maintains fight or flight response
Acetylcholine
Neurotransmitter of parasympathetic division
Cholinergic neurons
- All ANS preganglionic neurons
- All parasympathetic postganglionic neurons
Target cells have cholinergic receptors
Norepinephrine
“Catecholamine”
- Neurotransmitters of sympathetic division
Adrenergic neurons
- Most sympathetic postganglionic neurons are adrenergic
Target cells have adrenergic receptors