Autonomic Nervous System Flashcards

Somatic vs. Autonomic Nervous Systems

• Conscious Control:

  • Somatic: Consciously controlled.

  • Autonomic: Not consciously controlled.

• Target Muscle Types:

  • Somatic: Skeletal muscles.

  • Autonomic: Smooth, cardiac muscles, and glands.

Lower Motor Neurons: Somatic vs. Autonomic

• Number of Neurons:

  • Somatic: One neuron from the spinal cord to skeletal muscle.

  • Autonomic: Two neurons (pre- & postganglionic) connect spinal cord to effector organ.

• Neurotransmitters:

  • Somatic: Acetylcholine (ACh).

  • Autonomic: Acetylcholine (ACh) or Norepinephrine (NE).

• Myelination:

  • Somatic: Heavily myelinated.

  • Autonomic: Preganglionic lightly myelinated; postganglionic unmyelinated.

Autonomic Nervous System Integration Center

• The hypothalamus serves as the integration and command center.

Sympathetic vs. Parasympathetic Nervous Systems

• Origins:

  • Sympathetic: Thoracolumbar (T1-L2).

  • Parasympathetic: Craniosacral (brainstem & S2-S4).

• Functions:

  • Sympathetic: "Fight or flight."

  • Parasympathetic: "Rest and digest."

Sympathetic vs. Parasympathetic Effects

• Pupils:

  • Sympathetic: Dilation (mydriasis).

  • Parasympathetic: Constriction (miosis).

• Heart Rate:

  • Sympathetic: Increases.

  • Parasympathetic: Decreases.

• Airways:

  • Sympathetic: Bronchodilation.

  • Parasympathetic: Bronchoconstriction.

• Digestion:

  • Sympathetic: Decreases.

  • Parasympathetic: Increases.

• Reproduction:

  • Sympathetic: Ejaculation/orgasm.

  • Parasympathetic: Erection/engorgement.

Cholinergic Receptors

• Types:

  • Nicotinic

  • Muscarinic

• Location:

  • Nicotinic: Postganglionic neurons, adrenal medulla, skeletal muscle.

  • Muscarinic: Effector organs stimulated by postganglionic cholinergic fibers.

Adrenergic Receptors

• Types:

  • Alpha (\alpha) receptors: \alpha1 and \alpha2

  • Beta (\beta) receptors: \beta1, \beta2, and \beta_3

• Location:

  • Alpha receptors: