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Neurons I bet your neurons are all fired up now! Slide 2 The Nervous System Neuron = Nerve = Slide 3 Types of Neurons - carry outgoing messages from the brain and spinal cord to the muscles and glands - neurons within the brain and spinal cord that communicate internally and between sensory inputs and motor outputs - carry messages from tissues and sensory organs to the brain and spinal cord for processing Slide 4 Neurons Slide 5 How neurons communicate Electro-Chemical process 1.Electrical within a neuron Action Potential Information is pushed through the axon based on process of positive and negative charges of electrical atoms (ions) 2. Chemical between neurons Neurotransmitters (chemicals) - Neurotransmitters can either Messages are sent at a speed of 2-200 mph Slide 6 How does a neuron fire Step 1 : neuron is charged and ready to fire Polarized outside, inside (Na+) (Cl- & K+) Selectively permeable Step 2: the minimum energy needed to generate an action potential - the process of making a neuron receiving neurotransmitters more likely to generate an action potential must be greater than -the process of making the neuron receiving neurotransmitters less likely to fire an action potential Step 3: Action potential - Sodium (Na+) rushes in creating a positive charge on the inside and outside of the axon neurons can only send message in one direction at the same speed and strength - Potassium (Ka+) flows out creating a positive charge on the inside and negative charge on the outside of the axon. Step 5: - the recharging period that must occur to ready a neuron to generate another action potential Sodium/Potassium pumps push Sodium (Na+) out and Potassium in (Ka+) bringing axon back to resting potential Slide 7 Slide 8 Action Potential Slide 9 Electrical Transmission The Action Potential http://outreach.mcb.har vard.edu/animations/ac tionpotential_short.swf Slide 10 Between Neuron Communication the chemical messengers that carry information across the synapse between one neuron and then next are released from terminal buttons on the sending neuron Can be: Excitatiatory Neurotransmitters Inhibitory Neurotransmitters the small gap between neurons which neurotransmitters travel across to send a message to the receiving neurons dendrites the process of the sending neurons terminal buttons taking back excess neurotransmitters from the synaptic gap Slide 11 How do neurons communicate with each other? The chemical process Slide 12 How Neurons Communicate Slide 13 Synaptic Transmission http://learn.genetics.utah.e du/content/addiction/rewar d/neurontalk.html Slide 14 Drugs can be.. Agonists- mimic neurotransmitters Antagonists- block neurotransmitters Reuptake Inhibitors- block reuptake Slide 15 Acetylcholine (ACH) Deals with motor movement, memory and learning. Too much and you will. Too little and you will Lack of AcH has been linked to disease. Black widow Botox Curare Slide 16 Dopamine Deals with motor movement and alertness/attention, emotion, rewards. Lack of dopamine - linked to Too much - Slide 17 Serotonin Regulates sleep, dreaming, mood, pain, aggression, appetite and sexual arousal - Lack of serotonin Slide 18 Endorphins Involved in pain control and mood elevation. Examples: Slide 19 Norepenephrine Helps control alertness and arousal Undersupply can depress mood Slide 20 GABA Major neurotransmitter meaning it keeps the neuron from firing (slows CNS) Undersupply linked to Alcohol consumption causes Slide 21 Glutamate Meaning It causes Oversupply can over stimulate brain, producing MSG Slide 22 Agonists and Antagonists http://thebrain.mcgill.ca/flash/i/i_03/i_03_m/ i_03_m_par/i_03_m_par_cocaine.html#dro gues Slide 23 Agonist and Antagonists Examples: Agonists Antagonists Slide 24 The Nervous System Slide 25 Central Nervous System Brain Spinal chord Interneurons Slide 26 Peripheral Nervous System All nerves that are not encased in bone. Everything but the brain and spinal cord. Slide 27 Somatic Nervous System Controls Uses motor (efferent) neurons. Slide 28 Autonomic Nervous System Controls Lungs, stomach, intestines, liver, kidney, heart sympathetic and the parasympathetic Slide 29 Sympathetic Nervous System Response. Arouses and expends energy Causes: Slide 30 Parasympathetic Nervous System Response Automatically slows the body down after a stressful event. Causes Slide 31 Slide 32 Reflexes Reflex - Normally, sensory (afferent) neurons take info up through spine to the brain. Some reactions occur when sensory neurons reach just the interneurons in the spinal cord = reflex Survival adaptation. Slide 33 A Simple Reflex Slide 34 A Simplified Neural Network Neurons learn to work together as a team. Neurons that fire together, wire together = Slide 35 The Endocrine System A system of glands that secrete hormones. Similar to neurotransmitters. Neurotransmitters Hormones Slide 36 The Endocrine System A system of glands that secrete hormones. Similar too Neurotransmitters Neurotransmitters Hormones NeurotransmittersHormones Location Speed Slide 37 Figure 3A.11 The endocrine system 2011 by Worth Publishers Master Gland:- Hypoglycemia Hyperglycemia Overactive = Underactive = Controls pituitary gland Sends info to CNS Adrenaline or epinephrine and norepinephrine Estrogen Testosterone