Nervous System Two major divisions Central Nervous System (CNS) brain and spinal cord 2. Peripheral Nervous System motor and sensory neurons around the body
Peripheral Nervous System Two Divisions Somatic - relationship with the external environment sends info from sensory detectors to brain Autonomic involved in regulation internal functions digestion, respiration, excretion, etc.
Central Nervous System
Sagittal Section of Brain cerebrum Corpus callosum cerebellum Medulla oblongata pons
Vision center – Occipital Touch, feeling, pain, temperature – Parietal Reasoning, planning, parts of speech, problem-solving – Frontal Speech, remembering scenes, talks – Temporal Movement, balance & muscle tone – Cerebellum Cardiac, respiratory,life functions – Brain Stem Emotion & Motivation-Limbic System
Sulcus and Gyrus The Sulcus are the grooves in the brain tissue The Gyrus are the “hills” in the brain tissue These allow for greater surface area for the brain = more brain power!
Neuron (Nerve Cell) Myelin Sheath Cell Body ----Nucleus Axon Dendrites Made by Schwann Cells increases speed of neural signals down the axon Cell Body ----Nucleus Axon Carry messages away from the cell body to other neurons Dendrites Carry messages to the cell body
Types of Neurons Sensory Neurons Interneurons Motor neurons Carry the impulse to the spinal cord Travels the length of the arm to the spinal cord Interneurons Impulse is transmitted to the brain and the motor neurons via synapses Travels to the brain to register pain and out to the finger Motor neurons Sends the processed information back to finger Carries impulse to the effector cells in the fingers, hand and arm
Nerve Impulses 120 meters per second = speed at which impulses travel in the body. Synapse – gap between two neurons (axon and dendrite) Impulse travels from one neuron to the next by sending chemicals (neurotransmitters) across a gap to activate the next neuron.
___3___ Membrane depolarizes to threshold ___3___ Membrane depolarizes to threshold. Voltage-gated Na+ channels open and Na+ enters the cell. ___8___ The cell returns to resting ion permeability and resting membrane potential. ___6___ K+ moves from cell to extracellular fluid (the cell is repolarizing). ___4____ Rapid Na+ entry depolarizes cell. __1, 9__ Resting membrane potential. ___5___ Na+ channels close and slower K+ channels open. ___2____ Depolarizing stimulus. ___7___ K+ channels remain open and additional K+ leaves the cell, hyperpolarizing it.
Reflex Arc Hand touches open flame or hot burner Impulse travels to spinal cord Impulse sent to brain and back to hand. Hand pulls back before pain is registered by brain 3. 2. 1. 4.
Involuntary Reflex Arcs . . . . Use only spinal cord Do not go to the brain Examples: knee jerk, eye blink,hot stove pull back
Reflex arc pathway . . . R S I M receptor receives the stimuli sensory neuron passes the impulse on I interneuron at the spinal cord processes M motor neuron acts
Know Your Neurological Disorders! Multiple Sclerosis Alzheimer’s Epilepsy Parkinson’s Amytrophic Lateral Sclerosis Huntington’s CIPA Fibromyalgia Kennedy’s Creutzfeld-Jakob