Autonomic Nervous System Flashcards
Somatic
Conscious or voluntary regulation
Fibres do not synapse after they leave the CNS (single neuron from CNS to effector organ)- synapse when they reach effector organ
Innervates skeletal muscle fibres, always stimulatory
Autonomic
Functions without conscious awareness (involuntary)
Fibres synapse once at a ganglion after they leave the CNS (two-neuron chain). Motor control
Innervates smooth muscle, cardiac muscle, and glands; either stimulates or inhibits depending on where its organised
Parasympathetic
Cranial nerves to head, thorax and abdomen
Sacral outflow to pelvic organs
The vagus nerve to thorax and abdomen
Sympathetic
Cranial nerves to eye
Thoracolumbar nerves running adjacent to spinal cord
-The sympathetic chain
-Other ganglia
-Post ganglion did fibres
Somatic motor neurone
Generally comes out on cranial nerve or spinal
ACh used as a neurotransmitter
Autonomic motor neuron
Preganglionic neuron —> autonomic ganglion —> ppstganglionic neuron
Slower conduction in postganglionic neuron
ACh is the neurotransmitter at the autonomic ganglion
Neroadrenaline or ACh are neurotransmitters between the postganglionic neurone and effectors
Causes contraction of smooth or cardiac muscle, stimulation or inhibition of glandular secretion
Functions of the autonomic nervous system
Thermoregulation
Response to Exercise and stress
Digestion
Competition
Sexual function and bladder function
Outputs of ANS
Parasympathetic
-Cranial outflow
-Sacral outflow
Sympathetic
-Adrenal amplification
Enteric nervous system
Controls gut and digestion
Operates separately from parasympathetic and sympathetic nervous system
Parasympathetic
Hitches a ride on cranial nerves II, VII, IX, X
Apart from sacral outflow, S1, S2 through fibres pass
Sympathetic
White and grey rami communicates, sympathetic chain
Splanchnic nerves (non-myelinated) to large thoracic-abdominal plexi- where the secondary synapses take place
Slide 18-21
The adrenal medulla
Causes secretion of adrenaline and noradrenaline
Massive amplification of flight or fight
Parasympathetic cranial outflow
Preganglionic fibres run via:
-CN III
-CN VII
-CN IX
-CN X
Cell bodies located in cranial nerve nuclei (where the parasympathetic response starts) in the brain stem
The enteric nervous system
Coordinates GI function
Enteric system can work independently from ANS
Sympathetic
Preganglionic neuron
Neurotransmitter is ACh
At ganglion nicotinic receptors receives ACh
Postganglionic neuron
Neurotransmitter is Noradrenaline
At effector cell (smooth muscle/gland) adrenergic receptors receive NE
Sympathetic receptor sub types- nordarenaline
Alpha: alpha 1, alpha 2
Beta: beta 1, 2, 3
