Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Copyright Notice! This PowerPoint slide set is copyrighted by Ross Koning and is thereby preserved for all to use from plantphys.info for as long as that website is available. Images lacking photo credits are mine and, as long as you are engaged in non-profit educational missions, you have my permission to use my images and slides in your teaching. However, please notice that some of the images in these slides have an associated URL photo credit to provide you with the location of their original source within internet cyberspace. Those images may have separate copyright protection. If you are seeking permission for use of those images, you need to consult the original sources for such permission; they are NOT mine to give you permission. Biology: life study of What is Life? Properties of Life Cellular Structure: the unit of life, one or many Metabolism: photosynthesis, respiration, fermentation, digestion, gas exchange, secretion, excretion, circulation--processing materials and energy Growth: cell enlargement, cell number Movement: intracellular, movement, locomotion Reproduction: avoid extinction at death Behavior: short term response to stimuli Evolution: long term adaptation Neuron Structure and Function ©1996 Norton Presentation Maker, W. W. Norton & Company The leaves of Mimosa pudica are touch responsive using pulvini (pressure-based movement) This stimulus (touch) causes an action potential! This system is not centralized and thus local stimulation gives mostly local response. ©1996 Norton Presentation Maker, W. W. Norton & Company The neural network in a Hydra A slightly more centralized nerve system in jellyfish: Neural ring around opening of medusa is the “central” system for coordinating swimming motions Peripheral nerves connect to cnidoblast, so when a nematocyst is fired, a signal goes back to the nerves in the mouth to direct it to potential prey ©1996 Norton Presentation Maker, W. W. Norton & Company In flatworms there is an evolutionary progression from: …to a cephalized system with two major longitudinal nerves. …a nerve net as in the hydra. ©1996 Norton Presentation Maker, W. W. Norton & Company ©1996 Norton Presentation Maker, W. W. Norton & Company The nerve system in round worms has less than 300 nerves, but a complex map with a centralized area and a large ventral nerve In earthworms, the two ganglia are dorsalized, but connect to the major ventral nerve cord. The first few segments have many sensory neurons ©1996 Norton Presentation Maker, W. W. Norton & Company The rest of the segments have individualized nerve connections ©1996 Norton Presentation Maker, W. W. Norton & Company This is the sea slug, Aplysia, a marine mollusc ©1996 Norton Presentation Maker, W. W. Norton & Company The morphology of a sea slug: ©1996 Norton Presentation Maker, W. W. Norton & Company The sea slug’s gills are vulnerable to fish attack at the siphon: ©1996 Norton Presentation Maker, W. W. Norton & Company After the touch by the fish, the siphon is “instantly” withdrawn into the mantle: ©1996 Norton Presentation Maker, W. W. Norton & Company This cartoon shows the nerve system that operates in this touch response: Sensory nerves connect sensors to motor neurons at the ventral nerve cord…with sufficient signal, the motor neurons fire, muscles contract and the siphon and gills are withdrawn. ©1996 Norton Presentation Maker, W. W. Norton & Company The squid giant neuron has been heavily studied: ©1996 Norton Presentation Maker, W. W. Norton & Company Insect larvae have double-ganglia in the anterior segments and a dual ventral nerve cord extending to the posterior segments Insects have a ventral nerve cord is a double item with ganglia along its length. A large ganglion in the head segments serves as the brain. http://www.anselm.edu/homepage/jpitocch/genbios/33-33-InsectAnatomy-L.gif These are invertebrate neurons. You can tell because the cell body is outside the path of electrical flow from dendrite to axonic synapse. ©1996 Norton Presentation Maker, W. W. Norton & Company The basic form of neurons (nerve cells): The interneuron receives the conflicting information and, with sufficient positive inputs,responds by sending a signal to the target motor neuron ©1996 Norton Presentation Maker, W. W. Norton & Company In a simple system, many sensory neurons receive touch information. Some send “I am touched” signals, others are sending “I am not touched” signals. The sensory synaptic terminals can connect with the dendrites or the cell body of the interneuron. Again, when sufficient information exceeds a threshold, the interneuron sends a signal down its axon ©1996 Norton Presentation Maker, W. W. Norton & Company The interneuron can receive inputs from many sensory or other neurons. ©1996 Norton Presentation Maker, W. W. Norton & Company Here is a SEM of a cell body in Aplysia with many synaptic connections: These synaptic connections are indirect: The synaptic vesicles release transmitter substances across the synaptic cleft. Receptors in the post-synaptic cell membrane receive the transmitters and respond… …if a nerve cell, by sending an electrical action potential down the cell ©1996 Norton Presentation Maker, W. W. Norton & Company The electrical stimulus travels down the axon. ©1996 Norton Presentation Maker, W. W. Norton & Company Here is the TEM of the synapse, corresponding with the cartoon: serotonin GABA acetyl choline ©1996 Norton Presentation Maker, W. W. Norton & Company Differential responses to inputs is explained by different transmitter substances being released ©1996 Norton Presentation Maker, W. W. Norton & Company In vertebrate neurons, the cell body is IN the information pathway: ©1996 Norton Presentation Maker, W. W. Norton & Company A motor neuron synapses on several muscle fibers (cells) ©1996 Norton Presentation Maker, W. W. Norton & Company The neuro-muscular junction: Acetyl Choline vesicles containing acetyl choline presynaptic membrane synaptic cleft postsynaptic membrane muscle cell responds with contraction exocytosis ©1996 Norton Presentation Maker, W. W. Norton & Company H3C-COO-CH2-CH2-N+(CH3)3 ©1996 Norton Presentation Maker, W. W. Norton & Company A pectoral reflex arc: ©1996 Norton Presentation Maker, W. W. Norton & Company A pelvic reflex arc: ©1996 Norton Presentation Maker, W. W. Norton & Company Reflex arcs are connected to the CNS too: OUCH! (late!) The beauty of the reflex is that you take defensive action BEFORE it registers in your brain that you have a problem! Autonomic Nerve System-“self-naming” system Norepinephrine Acetylcholine Fright Calming Fight Flight HOHO- -CHOH-CH2-NH2 ©1996 Norton Presentation Maker, W. W. Norton & Company Operates without conscious thought Involves opposing nerve systems instead of opposing muscles H3C-COO-CH2-CH2-N+(CH3)3