The Autonomic System

Question 1

Efferent

Answer 1

Going to organs of the body (exiting the CNS)

Question 2

Afferent

Answer 2

Going from organs to brain (going at the CNS)

Question 3

Peripheral Nervous System

Answer 3

• breaks into sensory and motor
• sensory: somatic (touch), special (vision/smell), and visceral sensory (in our organs)
• motor: somatic and visceral motor

Question 4

PNS - Motor - Visceral aka Autonomic

Answer 4

• sympathetic (fight or flight)
• parasympathetic (rest and digest)

Question 5

Somatic Motor

Answer 5

• target/effectors: skeletal muscles
• voluntary
• examples: moving your biceps brachii muscle
• # of neurons in pathway: 1
• properties: myelinated
• neurotransmitter: acetylcholine
• ganglia: no

Question 6

Visceral motor

Answer 6

• target/effectors: smooth and cardiac muscles, glands
• involuntary
• example: changing heart rate, peristalsis
• # of neurons in pathway: 2 preganglionic and postganglionic
• properties: preganglionic (myelinated) and postganglionic (unmyelinated)
• neurotransmitter: preganglionic (acetylcholine) and postganglionic: (Ach or norepinephrine)
• ganglia: yes

Question 7

Sympathetic

Answer 7

• fight, flight, fright
• activates
• visceral motor axons of the sympathetic act to:
  
  • increase: heart rate (blood flow to muscles), respiration (oxygenate), perspiration (sweat glands activate in order to release watery sweat and engage cooling
  • decrease: digestion (want to conserve energy)
• dilate pupils: allow more light to come in and it increases our visual acuity
• causes widespread, long-lasting mobilization of the flight or flight response

Question 8

Parasympathetic

Answer 8

• visceral motor axons of the parasympathetic division act to:
  
  • increase: blood flow to GI system (digest), activity of salivary glands
• decrease: heart rate, and respiration (calm down)
• pupils constrict
• highly localized and shorter lived
• inhibits

Question 9

2-neuron pathway: parasympathetic

Answer 9

1. Central NS brain stem or sacral spinal cord “craniosacral”
   - long preganglionic axon
2. Peripheral NS: intramural ganglia w/in organ (will synapse at second cell)
   - short postganglionic axon
3. Target: gut tube and digestive glands

Question 10

Parasympathetic innervation via oculomotor

Answer 10

1. preganglionic cell body in brain stem
   - long preganglionic axon = oculomotor nerve
2. Synapse in ciliary ganglion
   - short postganglionic axon
3. Postganglionic nerve innervate sphincter papillae to constrict pupil

Question 11

Parasympathetic innervation via facial nerve — pterygopalatine ganglion

Answer 11

1. Preganglionic cell body in brain stem
   - long preganglionic axon = facial nerve
2. Synapse in pterygopalatine ganglion
   - short postganglionic axon
3. Postganglionic axon project to lacrimal gland, small glands of nasal cavity
   - results: lacrimal gland = crying/tears
   > Nasal glands = sniffles/mucus

Question 12

Parasympathetic innervation via facial nerve — submandibular ganglion

Answer 12

1. Preganglionic cell body in brain stem
   - long preganglionic axon = facial nerve
2. Synapse in submandibular ganglion
   - short postganglionic axon
3. Postganglionic axons project to submandibular and sublingual glands
   - results: salivation/drooling

Question 13

Parasympathetic innervation via glossopharyngeal nerve

Answer 13

1. Preganglionic cell body in brain stem
   - long preganglionic axon = glossopharyngeal nerve
2. Synapse in otic ganglion
   - short postganglionic axon
3. Postganglionic axons project to parotid salivary gland
   - result: salivation/drooling

Question 14

Parasympathetic innervation via vagus nerve

Answer 14

1. Preganglionic cell body in brainstem
   - long preganglionic axon = vagus nerve (forms plexuses)
   - all plexuses will synapse to wall of organs
2. Synapse in intramural ganglia
   - short postganglionic axon
3. Postganglionic axons project to various target organs of thorax, abdomen, and pelvis (innervates testes and ovaries)
   - results: decrease in heart rate, constriction of airways, increased activity of GI organs

Question 15

Parasympathetic innervation via pelvic splanchnic nerves

Answer 15

1. Preganglionic cell body in s2-4 spinal cord segments
   - long preganglionic axon = pelvic splanchnic nerves
2. Synapse in intramural ganglia
   - short postganglionic axon
3. Postganglionic axons project to urinary bladder and reproductive organs
   - result: contraction of bladder, erection of clitoris and penis

Question 16

2-neuron pathway: sympathetic

Answer 16

1. Central NS T1-L2 Spinal Cord
   - short preganglionic axon
2. Synapse at PNS
   > sympathetic chain ganglion: long string of ganglia
   > pre-aortic ganglion: arranged in front of the abdominal aorta
   - long postganglionic axon
3. Target blood vessels (shoot more blood out); sweat glands (cool body down)

Question 17

Sympathetic chain ganglion pathway

Answer 17

• 1st/central NS neuron: T1-L2 Spinal Cord
• sympathetic chain ganglion
• target: blood vessels of head and neck, heart and lungs, limbs and trunk, sweat glands

Question 18

Pre-aortic (prevertebral) ganglion pathway

Answer 18

• 1st /central NS neuron: T1-L2 Spinal cord
• pre-aortic (prevertebral) ganglion
• target: blood vessels of GI system, smooth muscle of GI system, adrenal, renal, pelvis and perineum

Question 19

Synapse at Same Level

Answer 19

1. 1st neuron in T1-L2 spinal cord
2. Short preganglionic axon travels through white ramus communicans
3. 2nd neuron in sympathetic chain ganglion
4. Postganglionic axon travels through gray ramus communicans to enter spinal nerve

Question 20

Ascend or Descend, then synapse

Answer 20

1. 1st neuron in T1-L2 spinal cord
2. Short preganglionic axon travels through white ramus communicans then ascends (or descends) sympathetic chain
3. 2nd neuron in sympathetic chain ganglion
4. Postganglionic axon travels through gray ramus communicans to enter spinal nerve

Question 21

Sympathetic innervation in the head

Answer 21

1. 1st neuron in T1-L2 spinal cord
2. Preganglionic axon travels through white ramus communicans then ascends sympathetic chain
3. 2nd neuron in superior cervical ganglion (every sympathetic axon going to the head is going to synapse there)
4. Postganglionic axon travels on carotid arteries to reach head; distributed to target organs via arterial branches

Question 22

leave chain without synapsing

Answer 22

1. 1st neuron in T1-L2 spinal cord
   - preganglionic axon travels through white ramus communicans then leaves sympathetic chain through a splanchnic nerve
2. Neuron in preaortic ganglion (prevertebral)
3. Postganglionic axon follows blood vessels

Question 23

Sympathetic prevertebral ganglia: celiac ganglion

Answer 23

1. Preganglionic axons from T5-T9 exit sympathetic chain w/o synapsing
2. Greater splanchnic nerve synapses at celiac ganglion
3. Long perivascular plexus that targets stomach, spleen, liver, gallbladder, part of small intestine
   - result: decreased action of GI organs

Question 24

Sympathetic prevertebral ganglia: superior mesenteric ganglion

Answer 24

1. Preganglionic axons from T10-T11 exit sympathetic chain w/o synapsing
2. Lesser and least splanchnic nerves synapse at superior mesenteric ganglia
3. Long perivascular plexus targets small intestines, part of large intestine
   - results: decreased GI activity

Question 25

Sympathetic prevertebral ganglia: inferior mesenteric ganglion

Answer 25

1. Preganglionic axons from L1-L2 exit sympathetic chain without synapsing 2. Lumbar splanchnic nerve synapses at inferior mesenteric ganglia 3. Long perivascular plexus targets distal colon, rectum, bladder, reproductive organs - results: decreased GI activity

Question 26

Locate cranial nerves on brain

Answer 26