AUTONOMIC NERVOUS SYSTEM Flashcards
ANS
-ANS usually operates without conscious control
-hypothalamus and brainstem regulate ANS reflexes
Interceptors
-sensory receptors in blood vessels, organs, muscles and the nervous system monitors conditions in the internal environment
Dual innervation
-organs receive both sympathetic and parasympathetic impulses
-usually antagonists
Sympathetic division
-exercise, excitement and emergency
-functions to prepare the body for physical activity or a stressful situation
Thoracolumbar division
Parasympathetic division
-helps the body relax and perform vital functions
-conserves energy and replenishes stores
-maintains homeostasis at rest
-“rest and digest”
Craniosacral division
Ganglia
-clusters of cell bodies that result in an enlarged portion
-found in PNS
-called nuclei in the CNS
In sympathetic = sympathetic trunk ganglia and prevertebral ganglia
Sympathetic trunk ganglion:
-along either side of the spinal cord
-innervate organs above the diaphragm
Prevertebral ganglia:
-anterior to the spinal cord
-innervate below the diaphragm
-celiac, mesenteric ganglions
In parasympathetic = terminal ganglia
-located near target organs or within the wall of effector
-parasympathetic preganglionic neurons are long, postganglionic neurons are short
Preganglionic neurons
-postganglionic neuron in unmyelinated
-can excite or inhibit effectors
-can release wither acetylcholine or norepinephrine
Postganglionic neurons
Parasympathetic division:
-presynaptic neurons synapse with 4 or 5 post-synaptic neurons which supply a single visceral layer
Sympathetic division:
-terminate in several different visceral effectors
-response is widespread
-preganglionic neurons are highly branched
-may synapse with > 20 post-synaptic neurons
Neurotransmitters
-Acetylcholine
-Norepinephrine
Acetylcholine – detected by cholinergic receptors
-at all ganglia
-used in all of the synapse of the sympathetic and parasympathetic ganglia
-cholinergic receptors
-two subtypes:
1.Nicotine:
-found in ganglia
-Ach binding is always
excitatory
2.Muscarinic:
-found in synapses with the
effector organs in the
parasympathetic NS
-at all effectors in
parasympathetic and some
in sympathetic
-usually excitatory
sometimes inhibitory
Norepinephrine – detected by adrenergic receptors
-at some effectors in sympathetic except sweat glands (Ach)
-androgenic
-excitatory or inhibitory
Agonists
-substances that bind and activate a receptor
-ex. nicotine or muscarine
Antagonist
-substances that bind and block a receptor
-ex. atrophine (blocks muscarine ACH receptors)
SLUDD ACRONYM
acronym
-Salivation increases
-Lacrimation increases
-Urination increases
-Digestion increases
-Defecation increases
And decreases:
-rate and force and heartbeat
-airway size
-breathing rate
Be able to compare the somatic and autonomic nervous systems in terms of control of motor output, motor neuron pathway, neurotransmitters used, and the effectors (see table 15.1).
Be able to list the effects of the sympathetic and parasympathetic divisions on the effector organs
COME UP WITH ANSWER
Be able to differentiate between sympathetic and parasympathetic as in the following table:
