Based only on the book for the exam There are 100 billion neurons in the brain and each neuron is made up of 5 main parts Receives signals from other neurons and sensory receptors Depending on the signal the neuron either fires or doesn t fire Contains the nucleus Integrates signals received by multiple dendrites and passes them down the axon Dendrites Soma cell body Axon single nerve fiber Myelin Sheath Carries electrochemical signals through the neuron to the other end Surrounds the axon insulating it from its surroundings Helps to speed up signal transmission Terminal Buttons Release neurotransmitters Neurotransmitters Chemical signals that neurons use to communicate with other neurons and other cells Neurons transmit signals only in one direction Dendrites to Terminal buttons Dendrites and Soma must recieve a certain amount of stimuli in order to fire when it does fire it can t stop or be reversed ALL OR NOTHING Neuron is surrounded by and filled with fluid When a neuron is at rest there are more positive charged ions on the outside then the inside this is called its resting potential A neuron is said to be at its action potential when it has enough stimulus needed to fire Positive ions fill the neuron and negative ions leave When the neuron is done firing it will be reset to its original state and go through a short refractory period where the neuron can not be fired Nervous System The nervous system can be divided into two parts The central nervous system composing the brain and spinal cord The peripheral nervous system which contains nerves that connect to the bodies muscles and glands The Peripheral nervous system can also be broken down into two parts Somatic system which composes the skeletal muscled and skin Autonomic nervous system which controls involuntary activity such as breathing This system connects the sensory system to the central nervous system The Autonomic nervous system can be broken into two parts as well Sympathetic nervous system which deals with emergency or stressful situations Fight or Flight Parasympathetic nervous system which controls all routine functions such as breathing rate Various parts of the brain can be categorized as well The brain is divided into the right and left hemispheres and the two are connected by the corpus callosum which is a mass of nerve fiber The lower portion of the brain is made up of the brain stem cerebellum and thalamus which are involved in things such as breathing circulation and balance They also relay sensory info to other parts of the brain The limbic system is also deep inside the brain but is centered It is made up of the hypothalamus amygdala and hippocampus which are all involved in emotion motivation and memory The cerebral cortex makes up the largest portion of the brain It is divided and subdivided into many different regions according to their function and location EX Pain if we touch a hot pan is processed in the sensory cortex which is located next to the motor cortex that allowed us to turn on the stove that made the pan hot While the visual cortex processes info from our eyes allowing us to see The auditory cortex processes info from our ears allowing us to hear The prefrontal cortex controls more executive actions such as thinking planning and impulse decision making Neurotransmitters in the Brain There are over 100 neurotransmitters in the brain that serve different functions EX Acetylcholine is found in the synapses between neurons and skeletal muscles serving as an excitatory signal that causes muscles to contract
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