Autonomic Nervous System - Lecture Notes Flashcards

Flashcards covering key concepts of the Autonomic Nervous System, including structure (preganglionic/postganglionic neurons, ganglia), divisions (sympathetic vs parasympathetic), neurotransmitters, receptors, and higher-order function features.

What is the difference between the Somatic and Autonomic Nervous Systems?

Somatic: voluntary control of skeletal muscles. Autonomic: visceral motor neurons, involuntary control of visceral organs.

What are autonomic ganglia?

Clusters of cell bodies of visceral motor neurons located outside the CNS.

Where are preganglionic neurons located?

In the brainstem and spinal cord; project to autonomic ganglia.

Where are postganglionic neuron cell bodies located?

In autonomic ganglia; they synapse with peripheral target organs.

What division is the sympathetic nervous system and what is its overall role?

Sympathetic (thoracolumbar) division; fight or flight, prepares body for stress.

Name some physiological effects of sympathetic activation.

Heightened alertness, increased metabolic rate, reduced digestion/urination, energy mobilization, increased respiration, heart rate, blood pressure, sweating, pupil dilation.

What neurotransmitter do sympathetic preganglionic neurons release?

Acetylcholine (ACh).

What are the main sympathetic ganglia types?

Sympathetic chain ganglia (paravertebral), collateral ganglia (celiac, superior/inferior mesenteric), and adrenal medulla.

What is unique about the adrenal medulla in the sympathetic system?

Neurotransmitters function as hormones with longer-lasting effects than direct innervation.

What neurotransmitter do most postganglionic sympathetic neurons release?

Norepinephrine (NE).

Differentiate cholinergic and adrenergic synapses.

Cholinergic: use acetylcholine, effects are always excitatory. Adrenergic: use norepinephrine, effects can be excitatory or inhibitory.

What are adrenergic receptors and what do they bind?

Membrane G-protein coupled receptors that bind norepinephrine and epinephrine.

Describe Alpha-1 adrenergic receptors.

Common in smooth muscle; stimulation causes excitation via release of intracellular calcium.

Describe Alpha-2 adrenergic receptors.

Found on pre- and post-synaptic neurons; stimulation lowers cAMP, producing inhibitory effects.

Describe Beta adrenergic receptors.

Stimulation increases cAMP; Beta-1 (heart/muscles) excitatory, Beta-2 (airways) inhibitory/dilatory, Beta-3 (lipolysis).

What division is parasympathetic and what is its general role?

Parasympathetic (craniosacral) division; rest and digest, conserves energy.

What is the role of the vagus nerve?

Accounts for about 75% of all parasympathetic output.

What neurotransmitter do all parasympathetic neurons release and how is it inactivated at the synapse?

Acetylcholine (ACh); inactivated by acetylcholinesterase at the synapse and by tissue cholinesterase if diffused.

What receptors mediate parasympathetic signaling and how do they differ?

Nicotinic: ligand-gated Na+ channels, excitatory; Muscarinic: G-protein coupled, excitatory or inhibitory.

Where are parasympathetic preganglionic and postganglionic neuron cell bodies located and what neurotransmitter do they release?

Preganglionic: long, in brainstem and sacral regions; release ACh. Postganglionic: short, in ganglia near/within target organs; release ACh.

What is the functional difference in pupil size between sympathetic and parasympathetic activation?

Sympathetic: pupil dilation. Parasympathetic: pupil constriction.

What are the higher-order functions characteristics?

1) Require cerebral cortex 2) Involve conscious and unconscious processing 3) Subject to adjustment over time 4) Not innate.