Bio 215 Unit 4- Autonomic nervous system and general senses

Divisions of the ANS (autonomic nervous system)

• sympathetic

• Parasympathetic

Sympathetic

• fight or flight (emergency situations)

• thoracolumbar outflow- leave via thoracic and lumbar spinal nerves

• ganglia near vertebral column

Parasympathetic

• rest and digest

• craniosacral outflow- leave via cranial nerves and sacral spinal nerves

• Ganglia on or near target organ

Pre ganglionic and postganglionic secrete what

• acetylcholine

• except postganglionic sympathetic neurons (2nd neuron)- secrete epinephrine (E) or Norepinephrine (NE)

Neurons leave spinal nerve and synapse with postganglionic neurons in one of 3 types of ganglia near the vertebral column:

1. sympathetic trunk ganglia

2. collateral ganglia

3. adrenal gland

Sympathetic trunk

• a chain of ganglia running on each side of the vertebral column

• handles all abdominal visceral organs

Collateral Ganglia

• several ganglia found at the base of 3 main abdominal arteries on aorta (celiac, superior mesenteric, and inferior mesenteric ganglia

• postganglionic neurons travel along arteries to abdominal organs

Adrenal gland

Parasympathetic Division

Types of mechanoreceptors

• tactile receptors

• Baroreceptors

• proprioceptors

Tactile receptors

• found in the skin

• Free nerve endings - touch pressure and itch

• Root hair plexus nerves - movement of hair

• Tactile corpuscles - fine touch most abundant in eyelids, lips, fingertips, nipples and external genitalia

• Lamellar corpuscles - deep touch