autonomic SP24

Describe the difference between somatic and autonomic pathways.
Identify the differences between sympathetic and parasympathetic pathways.
Describe the significance of the adrenal gland as it relates to the ANS.
Identify the neurotransmitters released at both pre and post-synaptic neurons in both divisions of the ANS.
Describe the role of neurotransmitters at their site of release.
Given a specific bodily action, describe the neurons and neurotransmitters involved in that action.

Autonomic Nervous System (ANS): Contains two neurons from the CNS to effectors.
- Presynaptic neuron: Cell body in the CNS.
- Postsynaptic neuron: Cell body in peripheral ganglion.
Somatic Efferent Innervation:
- Myelinated fibers directly to effectors, primarily skeletal muscles.
- Uses Acetylcholine (ACh) at the neuromuscular junction.
Autonomic Efferent Innervation:
- Myelinated preganglionic fiber and unmyelinated postganglionic fiber.
- Targets visceral effectors like cardiac muscle, smooth muscle, and glands using ACh or norepinephrine (NE).

Known as "fight, flight or fright" response; also referred to as the thoracolumbar system.
Neurons located in the lateral horn of gray matter from spinal segments T1-L2.
Effects include:
- Increased heart rate, respiratory rate, and glucose release from liver.
- Pupil dilation and vasoconstriction leading to increased blood pressure.
Neurotransmitters:
- Norepinephrine is released by most postganglionic fibers.
- Acetylcholine is released by preganglionic sympathetic fibers.

Known as "rest and digest" response; referred to as the craniosacral system.
Preganglionic neurons located in the brain stem and sacral levels (S2-S4).
Effects include:
- Decreased heart rate and bronchial constriction.
- Stimulates digestive activity and gland secretion (saliva, tears).
Neurotransmitters:
- Acetylcholine at both preganglionic and postganglionic synapses.

Located above the kidneys; includes the adrenal medulla which is significant in the sympathetic nervous system.
Synapses occur within the adrenal gland, resulting in body-wide release of epinephrine and norepinephrine during stress ("adrenaline rush").

Primarily regulated by CNS:
- Medulla Oblongata: Manages cardiac, vasomotor, and respiratory functions.
- Hypothalamus: Regulates visceral functions.
- Limbic System & Cerebral Cortex: Influence emotional responses that can affect autonomic functions.

Cholinergic: Release acetylcholine (e.g., preganglionic sympathetic & parasympathetic fibers, postganglionic parasympathetic fibers).
Adrenergic: Release norepinephrine (e.g., postganglionic sympathetic fibers).

Secreted by nearly all sympathetic postganglionic neurons; receptors are termed adrenergic receptors.
Alpha-adrenergic receptors: Generally excitatory (α1 & α2).
Beta-adrenergic receptors: Generally inhibitory (β1 for heart, β2 for bronchioles and blood vessels).

Antagonistic effects of sympathetic and parasympathetic pathways can be observed:
- Increase and decrease in heart rate.
- Pupil dilation (sympathetic) vs constriction (parasympathetic).

Nicotinic: Location includes all ANS post-ganglionic neurons and skeletal muscle.
Muscarinic: Found on parasympathetic target tissues (e.g., salivary glands, heart).

Alpha-1 and Alpha-2: Target various smooth muscle and glandular organs, affecting vasodilation and vasoconstriction.
Beta-1 and Beta-2: Target heart and smooth muscles, influencing heart rate and respiratory airflow.

Chart contrasting sympathetic and parasympathetic effects on various organs (e.g., heart, lungs, pupils, digestive tract).
- Sympathetic: Increases rate and force of heart, bronchodilation, reduced gut activity.
- Parasympathetic: Decreases heart rate, promotes digestion, constricts bronchioles.

Sympathetic Division: Preganglionic fibers release ACh; most postganglionic fibers release NE. Prepares body for stressful situations.
Parasympathetic Division: Preganglionic and postganglionic fibers release ACh. Promotes restorative processes in the body.