Neurons and Biological Systems Biological bases of Behavior Brain The only time Greeks were able to study the brain is when they were dead so no functionality was tested In the 1700s Franz Gall creates phrenology Phrenology Everything about you and your personality can be measured through your head Bumps and dimples can tell something about you People with big heads are smarter in the 1700s that was a reasonable way of thinking It is a pseudoscientists The Nazis used it to prove the Jews were inferior to their Aryan blood Biological Psychologists Study the links between behavior and biology The body is composed of cells that use electrochemical communication to talk to each other Different parts of the brain control different things If you fall down and hit the back of your head your vision goes black for a second All of these functions are integrated to create our perception of the world around us Neural Communication How neurons talk to each other Neuron The brain is composed of nerve cells neurons Animal brains function similarly to human brains so studies on animals can be useful for humans The building block of the body s communication system is the neuron Sensory Neuron Afferent Bring information towards the brain and spinal cord Motor Neurons Efferent Bring information from the brain and spinal cord to muscles and glands Interneuron Neurons whose job is to communicate between the sensory and motor neurons They are found in the brain and spinal cord they are the messengers Communication between the communication Dendrites The extension off of the main part of the neuron that is connected to some type of receptor cell When something hits the receptor cell it begins to communicate a message through the entire neuron Soma The soma is near the hairy end of the neuron It is the main part of the neuron Axon The long tail like structure can be millimeters or even feet long Around the axon there are little fatty tissues that are called the myelin sheath It allows the message to travel down the length of the axon while protecting the axon and insulating it The last part of our bodies to develop so little kids often struggle to stand up because the myelin in their leg neurons hasn t developed so they cannot send the messages Cerebral Palsy people have myelin that decays much faster than the normal human body s myelin It is not a consistent string there are gaps Axon Terminal The end of the line for the axon The communication changes from and electrical message to a chemical message and will change from neuron to neuron Action Potential The message itself is called an action potential and it is transmitted down the entire neuron and onto another neuron Changes negatively charged ions to positively charged ions to carry out the message All or Nothing Principle There is no halfway of firing a neuron it either all fires or doesn t fire at all Threshold The only role the soma has An area to decide whether or not the message is worth sending Limiting the amount of information you are getting while making sure you get all of the important stuff Resting Potential There are positively charged sodium ions outside little gaps in the myelin sheath open up and allow the positively charged ions in and allow the outside to become negatively charged After this it cannot send another action potential Negatively charged inside positively charged outside Semi Permeable Membrane Only let certain things in and certain things out Refractory Period Time where it is reloading to prepare to fire again Must bring back in the negatively charged ions to reach the resting potential and fire again Synapse The space between the two neurons The message is received in the dendrites of the next neuron The process is repeated down the next neuron until it reaches the brain The neurotransmitters need to get out of the synaptic gap Neurotransmitter Chemicals that pass a message onto the next dendrite The neuron identifies the correct neurotransmitter to use to transfer information over to the dendrite of the next neuron in line through the axon terminal of the other one It s like a middle school dance they get really close to each other but never touch Reuptake As soon as the first neuron has to suck the transmitters back into the axon terminal so if the signal has to continue again it needs to have the chemicals back in to fire again Regulating the amount of chemical in the synaptic gap The only time we want anything in the synapse is when we are sending messages Agonists Things that are similar to the actual neurotransmitter but are not the same thing an alternative Fits into the gap but is not the exact same So it sends a message that shouldn t be sent Antagonists Something that blocks the flow of a message by walling off the synapse between neurons They prevent the ability to contract muscles and you cannot breathe Nervous System Run by the individual neuron our bodies electrochemical fast communication system Split into two parts Messages move 200 mph Central Nervous System It consists of the brain and the spinal cord Had over 4 billion neurons connected to over 10 000 other neurons Peripheral Nervous System The body s sensory and motor communication system Brings info to the central nervous system All of the information from out nerves muscles and glands are transmitted to the spinal cord through the PNS The optic nerve is a bunch of bundled axons in the back of the eye Neural Networks Neurons grouped together that serve a similar purpose The more you use one the better they get They start to fire together more efficiently Reflexes A reflex action is different because it is unthinking the brain plays no role but the spinal cord takes the wheel If you damage your spinal cord any information that is transmitted below that break the message will not be sent No thought process Somatic Nervous System One part of the peripheral nervous system Voluntary muscle control Autonomic Nervous System Automated Involuntary muscle control Sympathetic Nervous System Part of the automated system Controls arousal not the sexual arousal energizing the system Most closely associated with the fight or flight response Parasympathetic Nervous System Designed to inhibit energy to relax the body Also controls one autonomic function that uses energy digestion So it can create new energy Endocrine System A chemical communication system that controls hormones and glands If puberty would run like the nervous system it would be done in a split
View Full Document
Unlocking...