Transcript Module 3
Neural and Hormonal Systems Will Explain Why We FEEL…… Nervous Strong Pain Sick It all Starts with the Neuron Neuron Structure Neurons do NOT touch each other- the space in between is call the synapse. How a Neuron Fires It is an electrochemical process • Electrical inside the neuron • Chemical outside the neuron (in the synapse in the form of a neurotransmitter). • The firing is call Action Potential. The All-or None Response • The idea that either the neuron fires or it does not- no part way firing. • Like a gun Steps of Action Potential • Dendrites receive neurotransmitter from another neuron across the synapse. • Reached its threshold- then fires based on the all-or-none response. • Opens up a portal in axon, and lets in positive ions (Sodium) which mix with negative ions (Potassium) that is already inside the axon (thus Neurons at rest have a slightly negative charge). • The mixing of + and – ions causes an electrical charge that opens up the next portal (letting in more K) while closing the original portal. • Process continues down axon to the axon terminal. • Terminal buttons turns electrical charge into chemical (neurotransmitter) and shoots message to next neuron across the synapse. Action Potential How Neurons Communicate Neurotransmitters • Chemical messengers released by terminal buttons through the synapse. • We should know at least 4 types and what they do. Acetylcholine • Its function is motor movement and maybe memory. To much and you will…. Not enough and you will…. Lack of ACH has been linked to Alzheimer’s disease. Dopamine • Its function is motor movement and alertness. Lack of dopamine is associated with Parkinson’s disease. Overabundance is associated with schizophrenia. Serotonin • Function deals with mood control. Lack of serotonin has been linked to depression. Endorphins • Function deals with pain control. We become addicted to endorphin causing feelings. Agonists and Antagonists Types of Neurons Sensory Neurons Motor Neurons Inter Neurons Sensory Neurons (Afferent Neurons) • Take information from the senses to the brain. Inter Neurons • Take messages from Sensory Neurons to other parts of the brain or to Motor Neurons. Motor Neurons (Efferent Neurons) • Take information from brain to the rest of the body. Divisions of the Nervous System Sympathetic Nervous System Flight or Fight Response A Simple Reflex A Simplified Neural Network Neurons that learn to work together as a team. The Endocrine System A system of glands that secrete hormones. Similar to nervous system, except hormones work a lot slower than neurotransmitters. Hormones Neurotransmitters The Major Endocrine Glands