Feb 5, 2026	PSY 340 Brain and Behavior Class 10: Structure of the Vertebrate Nervous System  OUTLINE

A. Terminology to Describe the Nervous System

 

Central Nervous System (CNS)

• Brain
• Spinal Cord  

Peripheral Nervous System (CNS)

Any nerve that does not belong to the CNS 

• Somatic Nervous System (SNS)

• Autonomic Nervous System (ANS)

• Enteric Nervous System (ENS): Usually seen as part of ANS (more below)
  

Directions in the Nervous System

 

Rostral from ROSTRUM - A bird's beak [& the prow of a ship]

Dorsal from DORSUM - An animal or person's back

Ventral from VENTER - The belly or abdomen

• A ventriloquist speaks from the belly.

Caudal from CAUDA - The tail of a horse

• The origin of the word, coward, since one sees the tail of the horse when a horse rider flees from battle
  

Superior is ABOVE while Inferior is BELOW
Proximal is NEAR while Distal is FAR

Ipsilateral occurs on the same side
Contralateral occurs on the other side

• Lamina (laminae, pl.)
• Column
• Tract (Projection)
• Nucleus (nuclei, pl.)
• Ganglion (ganglia, pl.)
• Gyrus (gyri, pl.)
• Sulcus (sulci, pl.)
• Fissure

B. The Spinal Cord

Bell-Magendie law

• sensory information enters by way of the dorsal roots (in the back)
  

• motor information to the muscles and glands exits by way of the ventral roots (out the front)
  

• dorsal root ganglion (ganglia, plural)

• "Gray matter" in middle = cell bodies
• "White matter" surrounding = insulated axons

C. Autonomic Nervous System (ANS)

1. Sympathetic Nervous System

The sympathetic branch of the ANS prepares the body for action: fight or flight.

2. Parasympathetic Nervous System

The parasympathetic branch of the ANS helps to restore the body, build up energy & supplies needed in the future, and relax.

3. Drugs & the ANS

• Norepinepherine in PNS
• Acetylcholine [Ach] in SNS
• OTC drugs either suppress the PNS and/or stimulate the ANS leading to dry mouth & increased heart beating.

4. GI Tract and Enteric Nervous System (ENS)

• GI Tract
  
  
• ENS: lines walls of GI tract organs. Can function independent of CNS
  
  
• Food propulsion, nutrient handling, blood flow, immunological defense
  
  
• Microbiome (organisms in GI tract) can have effect upon behavior via signals to CNS
  

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The Brain: Divisions

Hindbrain Midbrain Forebrain Thalamus Hypothalamus & Pituitary Gland Basal Ganglia Basal Forebrain Hippocampus Cerebral Cortex (in the next class)

Hindbrain Chase with his older brother

Medulla (oblongata) Pons (the "bridge") Ascending reticular formation/ascending reticular activating system Raphe system: major serotonin system Cerebellum ("little cerebrum" or "little brain" with ca. 70 billion neurons) Movement & balance Time-related behaviors (rhythm, drum playing) Simple learning & conditioning NEW: role in cognition, language, & affect (emotion) Anterior: motor & movement Posterior: cognition, language, affect Rapid model building of body interacting with the world around it Agenesis of the Cerebellum [No or partial cerebellum at birth] Chase Britton - Boy Without a Cerebellum (and Pons) YouTube Video Update (9/17/2013): Chase was 6 years old, had begun 1st grade (he was in kindergarten 2012-13), plays with his older brother Alex on his iPad, can count to 30, reads short words, and has a service lab/Great Dane dog named "Missa". Update (8/14/14): Chase attended and met with Lady Antebellum at the Erie County Fair this year.  Updates in Dec. 2019 & May 2020. Chase was 12-13 years old, uses both a wheelchair and a special walker. He is also legally blind His father, David E. Britton, unfortunately died of stomach cancer at age 50 in May, 2020.  2026 No new updates on Chase who would now be 18-19 years old Chinese Woman, 24, found to lack cerebellum (2014) A 24-year-old woman in China went to the hospital complaining of a headache and was found to have been born without a cerebellum. Feng Yu et al. (2014) 45-year-old man in India found to lack cerebellum (2018) However, in all closely-studied cases of "agenesis of the cerebellum" there appears to be mild to serious levels of cognitive and/or motor impairment.

Midbrain

Tectum ("roof") Superior Colliculus ("upper little hill"): Visual orientation Inferior Colliculus ("lower little hill"): Auditory orientation Tegmentum ("floor covering" or "rug") Ascending sensory & descending motor tracts pass through Regulation of movement (e.g., eyes) Pain modulation Substantia Nigra ("dark substance") DA neurons required for smooth muscle control Loss = Parkinson's disease

Forebrain

Outer surface = Cortex (Latin = Bark of tree) [in next class] Limbic System (linked set of structures beneath the cortex including olfactory bulb, hypothalamus, hippocampus, amygdala, & cingulate gyrus) Thalamus ("antechamber") Hypothalamus ("beneath the thalamus") Pituitary Gland Basal Ganglia caudate nucleus, putamen, globus pallidus Basal Forebrain nucleus basilis Hippocampus ("sea horse") Lobes of the Cerebral Cortex - Covered in next class

Ventricles and Cerebrospinal Fluid (CSF) cerebrospinal fluid [CSF]: Clear, colorless, watery substance akin to blood plasma shock absorber or cushion and support for the weight of the brain nutrition (vitamins, hormones) waste removal CSF is formed by the choroid plexus within the ventricles CSF flows throughout the ventricles and around the extracelluar space of the brain CSF is reabsorbed into the blood stream via the meninges Hydrocephalus

 

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This page was first posted February 6, 2005