Finding our Way through the Nervous System Some basic terms to guide our examination

Traditional Divisions KW 2-13

Nerves (PNS) and Tracts (CNS) KW 2-12

Cell Bodies and Axons PNS axons = nerves Ex: cranial nerves cell bodies = ganglion Ex: dorsal root ganglion CNS Axons = tracts Ex: Pyramidal tract cell bodies = Nucleus Ex: Lateral Nucleus

Dorsal and Ventral KW 2-3

Pear Sections

Frontal Section KW 2-8

Saggital Section KW 2-10

Lobes of the Brain KW 1-1

How Reflexes gave Birth to Psychology

CNS and PNS KW 1-2

Spinal Cord KW 2-28

Dermatomes KW 2-27 C6 C7 C8

Freud’s Discovery Patient reported numbness in hand. Glove Anesthesia Does this sensory loss correspond to dermatomes? No! Loss must have another cause.

Spinal Reflex Interaction of the PNS nerves and Spinal cord (CNS) Rapid response Protect the body Important for movement

Spinal Cord KW 2-28

Afferent (sensory) and Efferent (motor) KW 2-4

Knee-jerk Reflex KW 2-26

Spinal Cord Section

Spinal Reflex (sketch) Dorsal Ventral Sensory Nerve Motor Nerve Mixed Nerve White Matter Grey Matter

Withdrawal Reflex

Diseases that can affect reflexes Multiple Sclerosis (Motor and/or sensory). Amyotrophic Lateral Sclerosis (ALS) also know as Lou Gehrig’s disease (Motor). Polio (Motor). Tabes dorsalis (degenerative syphilis) sensory tracts in spinal cord.

Sclerosis Multiple Sclerosis: spinal pathways for sensation and movement. Myelin destroyed and repaired. Variable. Amyotrophic Lateral Sclerosis: motor cell bodies and pathways. Progressive.

Neurosyphilis Parasitic infection Several forms Occur decade after initial infection Tabes Dorsalis: attack on sensory pathways in spinal cord Paresis: degeneration of the cortex

Polio Viral infection. Infects motor nerves. Destroys cell bodies. Other motor cells try to compensate by branching out Post polio syndrome

Learned Reflex First model of experimental psychology

Ivan Pavlov Nobel prize in 1904 for studies on the digestive system Classical conditioning Learned reflex

Pavlov’s Classic Experiment Before Conditioning During ConditioningAfter Conditioning UCS (food in mouth) Neutral stimulus (tone) No salivation UCR (salivation) Neutral stimulus (tone) UCS (food in mouth) UCR (salivation) CS (tone) CR (salivation)

Behaviorism John B. Watson >Impressed by Pavlov’s work >Good model for experimentation >viewed psychology as objective science –avoid reference to unobservable mental processes

Internal control systems

Functional Divisions KW 2-13

Autonomic System KW 2-29

Emotional Arousal Autonomic nervous system controls physiological arousal Sympathetic division (arousing) Pupils dilate Decreases Perspires Increases Accelerates Inhibits Secrete stress hormones Parasympathetic division (calming) Pupils contract Increases Dries Decreases Slows Activates Decreases secretion of stress hormones EYES SALIVATION SKIN RESPIRATION HEART DIGESTION ADRENAL GLANDS

Fight/Flight or Rest/Digest Autonomic Nervous System –the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart) Sympathetic Nervous System –division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations Parasympathetic Nervous System –division of the autonomic nervous system that calms the body, conserving its energy

Cranial Nerves KW 2-14

Med Student’s Chant On Old Olympus Towering Top A Finn And German Viewed Some Hops