Lecture 18 and 19
Lecture 18 and 19 Biol 202
Popular in Human Anatomy and Physiology I
Popular in Biology
verified elite notetaker
This 4 page Class Notes was uploaded by Natasha on Sunday November 22, 2015. The Class Notes belongs to Biol 202 at St. Cloud State University taught by Schoenfuss, Heiko in Spring 2015. Since its upload, it has received 26 views. For similar materials see Human Anatomy and Physiology I in Biology at St. Cloud State University.
Reviews for Lecture 18 and 19
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 11/22/15
Biol 202 The Nervous System The Average Neuron Dendrites that look like tree roots Synaptic terminal (axon terminal) communicates with the other cells Axon hillock is where all the information comes together Starting a Nerve Impulse Depolarization a stimulus depolarizes the neuron’s membrane A depolarization membrane allows for the sodium to flow inside the membrane The exchange of ions initiates an action potential in the neuron The Action Potential If the action potential or nerve impulse starts, it is propagated over the entire axon It is an all or nothing response Potassium ions rush out of the neuron after sodium ions rush in and that repolarizes the membrane The sodiumpotassium pump restores the original configuration and this action requires ATP IMPORTANT CONCEPT (read in your text book) Look at the graph It takes 4 milliseconds before an action potential can fire again Threshold, stimulus, depolarization (or failed initiations), action potential, repolarization, refractory period, resting state Nerve Impulse Propagation The impulse continues to move toward the cell body Impulses travel faster when fibers have a myelinated sheath They cannot travel backwards It travels down to the synaptic end or axon terminal of the cell Schwann cells cannot exchange sodium and potassium ions that can only happen at the nodes of Ranvier Saltatory Impulse Conduction The impulse jumps (saltationLatin) from one Node of Ranvier to the next Stimulus can travel effectively and quickly down the length of the axon towards the axon terminal The VoltageClamp Method Squid have think neurons so you can stimulate the neurons and test them with electrodes. Continuation of the Nerve Impulse between Neurons Impulses are able to cross the synapse to another nerve o Neurotransmitter is released from a nerve’s axon terminal o The dendrite of the next neuron has receptors that are stimulated by the neurotransmitter o An action potential is started in the dendrite Nervous System Divisions Central Nervous System o Brain o Spinal Cord Peripheral Nervous System o Peripheral nerves o Nerves outside the brain and spinal cord Functional Classification of Neurons Sensory or afferent neurons o Carry impulses from the sensory receptors to the central nervous system Cutaneous sense organs Proprioceptors they detect stretch or tension Motor or efferent neurons o Carry impulses from the central nervous system to effectors (muscles and glands) Interneurons or associated neurons o Found in the neural pathways in the central nervous system o Connect the sensory neurons and the motor neurons Structural Classification of Neurons Multipolar neurons many processes extend from the cell body; all are dendrites except for a single axon Bipolar neurons two processes extend from the cell body; One is a fused dendrite, the other is an axon Unipolar neurons One process extends from the cell body and forms central and peripheral processes, which together comprise an axon Nervous Tissue: Support Cells Central Nervous System Astrocytes o Most abundant and most versatile glial cells o Star shaped o Brace neurons o Form barrier between capillaries and neurons o Control the chemical environment of the brain Microglia o Small ovoid cells with long “thorny” processes o Spiderlike phagocytes o Dispose of debris Ependymal Cells o Line central cavities of the brain and spinal cord o Circulate cerebrospinal fluid Oligodendrocytes o Line up along the thicker neuron fibers in the CNS and insulate the myelin sheaths Nervous Tissues: Support Cells in the PNS Satellite cells o Surround neuron cell bodies located in the PNS o Protect neuron cell bodies Schwann cells o Form myelin sheath in the peripheral nervous system Functions of the Nervous System Sensory input gather information o Monitor changes occurring inside and outside the body o Changes in stimuli Integration o Processes and interprets sensory input and decides what should be done at each moment Motor output o Response to stimuli o Activates effector organsthe muscles and glands Functional Classification of the Nervous System Sensory or afferent division o Nerve fibers that carry information to the central nervous system Motor of efferent division o Nerve fibers that carry impulses away from the central nervous system o Two divisions 1. Somatic nervous system – voluntary Consciously control our skeletal muscles 2. Autonomic nervous system – involuntary Heart pumping or digesting food Two subdivisions 1. Sympathetic division 2. Parasympathetic division
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'