General Info, Sympathetic & Parasympathetic Nervous Systems

What is the autonomic Nervous System? What is it mainly used for?

Nervous system OUTSIDE of the Brain and Spinal Cord. Mainly used for unconscious actions and reflexes.

What type of muscle does the ANS innervate?

Smooth Muscle

What are the CNS control points for the ANS, and what do they do?

Hypothalamus —> Hunger, Temp, water

Pons → Respirations (breathing rate), cardiovascular

Medulla Oblongata → Respiratory, Cardiovascular

Where do cell bodies in the ANS originate?

WITHIN the CNS (either brain or Spinal Cord)

• They synapse with cell bodies outside the CNS, innervating targert

Sequence of Innervation for ANS?

CNS → Pregangliotic Neuron → Autonomic Ganglion → Postgangliotic Neuron → Target Tissue

Function of the Sympathetic Nervous System, and when is it dominant?

Fight/Flight, Dominant during Stress

• Homeostatic

Function of Parasympathetic Nervous System, and when is it dominant?

Rest/Digest, Dominant during Rest

• Homeostatic

Where does the Pathway start in the Sympathetic Nervous System? What are the characteristics of the nerves?

• Pathway starts in the Spinal cord

• LONG nerve Projections to target that travel SHORT distances

  • need to be short for quick reactions during stress

Where does the Pathway start in the Parasympathetic Nervous System? WHat are the characteristics of the nerves>

• Pathway starts in the Brain

  • SHORT nerve projections to target that travel LONG distances

What signaling molecules does the Sympathetic Nervous system use?

Epinepherine and Acetylcholine

What signaling molecules does the parasympathetic nervous system use?

Acetylcholine

What type of control does the ANS utilize?

Antagonistic Control (increase in sympathetic, decrease in parasympathetic, vise versa)

What is Somatic Motor division?

Voluntary movement

What is the path taken in the Somatic Motor Division? What types of receptors?

Single neuron in the CNS → long myelinated axon → Skeletal muscle

• More sympathetic because of the long myelinated axon

Has multiple different acetylcholine receptors (Nicotinic, Muscarinic)

What is Acetylcholine?

Excitatory neurotransimtter used in sympathetic, parasympathetic and somatic systems.

What is cholinergic signaling

Idea that a different receptor elicits a different response (regardless of signaling molecule)

How do the different receptors act (antagonist and agonist)?

Act agnoistically (causing a physiological response when binding with a receptor).

Act antagonistically (inhibiting a physiological response when binding with a receptor)

What are Nicotinic Receptors? How is it used?

• Ligand Ion-Gated Channels.

  • Excitatory (usually) receptors

• Composed of 5 subunits

• Used agonistically and anatgonistically, used differently in somatic, parasympathetic, sympathetic systems.

What are muscarinic receptors?

GPCR gated (g-protein coupled receptors)

• Involved in neuromodulation

  • Muscarine = Poisonous mushroom

USES NICOTINIC RECEPTORS FOR PREGANGLION → POSTGANGLION

What are Adrengernic receptors?

Used by Epi

• Has many functions and targets, but stimulates all of them

• ONLY in the sympathetic (since only Epi used)

USES NICOTINIC RECEPTORS FOR PREGANGLION → POSTGANGLION

What are the different “second” postsynaptic ganglia in the sympathetic pathway? Where are they, What do they target?

Chain Ganglia → Next to spinal cord

• Targets head, heart, lung tissues and glands

Collateral Ganglia → Abdominal cavity

• Targets GI tract, pancreas, liver, colon

Adrenal medulla → Modified Chain Ganglia

What is unique about the Adrenal medulla?

When stimulated, the ENTIRE thing is stimulated, producing Epi and NorEpi

• Causes the whole entire scale of fight/flight

What are ANS reflexes, and how do they work? What are two types of reflexes?

Rapid, focused pathways to detect and fix changes in body homeostasis

• Barcoceptor Reflex

• Pupil Dialation

What is the barcoceptor reflex?

• detects sudden changes in the effects of gravity (lightheadedness when you stand up
  quickly)

  • Uses Adrengernic Receptors (so ONLY in Sympathetic)

What is the Pupil Dialation Reflex?

Pupil dialating based on light present, protecting it from birght light and allowing vision in dim light

• Bright Light —> Pupil constricts via Parasympathetic

• Dim Light —> Pupil dilates via Sympathetic