Introduction to the Nervous System Dallas Smuin Megan Veglia

Learning Objectives 1.Students will explain the general structures and functions of the mammalian nervous system, including the central nervous system, the peripheral nervous system, the cranial nerves, and the ventricular system. 1.Students will utilize the neuron doctrine coined by Santiago Ramon y Cajal to explain how neurons communicate with each other to carry information throughout the nervous system. 2.Students will be able to identify the basic functional unit of the brain and describe the function of the major components of the neuron. 1.Students will describe how scientists and physicians use technology to view the living brain, including CT, MRI, and fMRI.

LO 1: Students will explain the general structures and functions of the mammalian nervous system, including the central nervous system, the peripheral nervous system, the cranial nerves, and the ventricular system.

Structure of Nervous System 2 portions: o Central Nervous System (CNS) Brain, spinal cord o Peripheral Nervous System (PNS) All nerve structures outside the CNS that connect the CNS to the rest of the body Autonomic o Sympathetic (fight or flight) o Parasympathetic (rest and digest)

Structure/Function of CNS (Brain) Cerebral hemispheres (Cerebrum) o Structure: 2 parts: gray and white matter o Gray matter: cell bodies o White matter: axons Ventricles—storage spot of nutrition and fluid Cerebellum Brain Stem

Structure/Function of CNS (Brain) Cerebral hemispheres o Function: Higher order thinking Movement Language Sensory processing Smelling (olfaction) Learning/memory Cerebellum Brain Stem

Structure/Function of the CNS (Brain) continued: Cerebral hemispheres Cerebellum o Function: Balance Some cognitive function i.e. attention and language Brain Stem

Structure/Function of the CNS (Brain) continued: Cerebral hemispheres Cerebellum Brain Stem o Structure: Composed of: o Medulla oblongata o Pons o Midbrain Continuation of the spinal cord

Structure/Function of the CNS (Brain) continued: Cerebral hemispheres Cerebellum Brain Stem o Function: Conduction—relays information from brain to body and body to the brain CN III-IX emerge from the brainstem In charge of autonomic nerve control of major organs (i.e. heart beating, lung breathing)

Ventricular System Composed of: o Lateral ventricles CONNECTED VIA interventricular foramen to the: o Third ventricle CONNECTED VIA cerebral aqueduct to the: o Fourth ventricle goes to the central canal  spinal cord CSF is inside ventricles o Function: Chemical stability Protects against minor jolts and knocks to the head

Structure of PNS Divided into: o Autonomic (involuntary) Sympathetic Parasympathetic o Somatic (voluntary) Motor and sensory innervation Composed of efferent (EFFECTOR) and afferent nerves

Cranial Nerves I—olfactory II—optic III—oculomotor IV—trochlear V—trigeminal VI—abducent VII—facial VIII—vestibulocochlear IX—glossopharyngeal X—vagus XI—accessory XII—hypoglossal

LO 2: Students will utilize the neuron doctrine coined by Santiago Ramon y Cajal to explain how neurons communicate with each other to carry information throughout the nervous system.

Ramon and Cajal Late 17 th century Discovered “Axonal Growth Cone” o dynamic, actin-supported extension of a developing neuron seeking its synaptic target o Nerve cells are “not CONTINUOUS but CONTIGUOUS” o zY zY

LO 3: Students will be able to identify the basic functional unit of the brain and describe the function of the major components of the neuron.

Neuron Structure: o

Structure (Continued) Dendrites (MICROPHONE) o Branched projections of the neurons that propagate the signal from the previous axon Cell body (AMPLIFIER) o Nucleus Axon (SPEAKER) o Axon (synaptic) terminals o Myelin Sheath

Myelin Sheath The insulating envelope of myelin that surrounds the core of a nerve fiber or axon The myelin sheath facilitates the transmission of nerve impulses It is formed from the cell membrane of the Schwann cell in the peripheral nervous system and from oligodendroglia cells. Nodes of Ranvier—gaps in myelin sheath through which the electrical signal “jumps”

WITH SHEATH: m/s WITHOUT SHEATH: m/s

CLINICAL CORRELATE: Multiple Sclerosis Autoimmune demyelinating disease 30/100,000 people globally (2-2.5 million) 18,000 deaths in 2012 Symptoms show in late 20s and early 30s Signs and Symptoms: o Loss of sensitivity o Change in sensation (tingling, pins and needles) o Muscle spasms o Difficulty with coordination and balance

LO 4: Students will describe how scientists and physicians use technology to view the living brain, including CT, MRI, and fMRI.

CT (X-ray Computed Tomography)

MRI (Magnetic Resonance Imaging)

fMRI (Functional MRI)

CT vs MRI