Week 11: Autonomics (Mastrangelo Tues 2025)

TA Names

Careena, Ethan, & Ian

Autonomic Nervous System

Controls involuntary responses

Sympathetic Division

• Fight or Flight

• Short Preganglionic Fibers

• Long Postganglionic Fibers

• Norepinephrine

• Metabolism

• Alertness

Parasympathetic Division

• Rest & Digest (Feed & Breed)

• Long Preganglionic Fibers

• Short Postganglionic Fibers

• ACh (Acetylcholine)

Somatic

Motor neurons from the CNS that are responsible for voluntary movement (i.e they innervate skeletal muscles)

Autonomic

Motor neurons of the CNS synapse on the visceral motor neurons in the autonomic ganglia (2 neuron pathway) that are responsible for involuntary movements (think cardiac and smooth muscle, and glands)

Ganglion

Cluster of cell bodies

What has a 1 motor neuron system?

Somatic Nervous System (CNS → Motor Neuron → Muscle)

What has a 2 motor neuron system?

Autonomic Nervous System (CNS → Preganglionic Neuron → Ganglion → Postganglionic Neuron → Muscle/Glands)

Sympathetic Neurotransmitter

Norepinephrine

Parasympathetic Neurotrasmitter

ACh (Acetylcholine)

Peripheral Autonomic Nervous System Main Function

Involuntary control of the body → smooth muscle, cardiac muscle, glands

What does the peripheral autonomic nervous system regulate?

• Digestion

• Urination

• Respiration

• Heart Rate

• BP

• Maintaining Homeostasis

What are some secondary functions of the peripheral autonomic nervous system?

• Responding to stimuli

• Getting goosebumps

• Sweating

• Teary eyes

• Mouth watering

• Internal Pain sensations
  

What releases neurotransmitters?

Postganglionic neurons

In the sympathetic nervous system, where are cell bodies of preganglionic neurons located?

In the grey matter of the spinal cord- segments T1-L2. Thoracolumbar division.

In the sympathetic nervous system, where are cell bodies of postganglionic neurons located?

• Sympathetic chain ganglia

• Collateral ganglia

• Adrenal Medulla

In the parasympathetic nervous system, where are cell bodies of preganglionic neurons located?

Located in brainstem and sacral region of the spine (S2- S4). Craniosacral division.

In the parasympathetic nervous system, where are cell bodies of postganglionic neurons located?

• Ciliary ganglion

• Pterygopalatine ganglion

• Submandibular ganglion

• Otic ganglion

Preganglionic neurons located in the gray matter of brain stem…

Exit through cranial nerves III, VII, IX to synapse with ganglion in head. Vagus nerve (X) synapses with ganglion in the thoracic cavity or in target organs (heart, lungs, etc).

Preganglionic neurons located in sacral division of spinal cord…

Exit through ventral rami, travel to the splanchnic nerve, then synapse with ganglion on pelvic organs.