PSB2000 Neuroscience Quiz Study Guide The structures that make up a neuron and their functions soma cell body the metabolic center of the neuron dendrite the short processes emanating from the cell body which receive most of the synaptic contacts from other neurons axon a nerve fiber that typically conducts electrical impulses away from the neuron s cell body The long narrow process that projects from the cell body axon terminal distal terminations of the branches of an axon myelination the fatty insulation around many axons nodes of Ranvier the gaps between sections of myelin nucleus is a group of neurons in CNS and ganglion is a group of neurons in PNS synapse is where 2 cells meet Know directionality of information flow through these structures Dendrites collect electrical signal cell body integrates incoming signals and generates outgoing signal to axon axon passes electrical signals to dendrites of another cell or to an effector cell The structure of a synapse pre synaptic cells the signal passing neuron comes into contact with the membrane of the target the postsynaptic cell Both sites contain molecular machinery that links the two together and carries out the signaling process Usually the presynaptic part is located on the axon but some postsynaptic parts are on the dendrite or soma neurotransmitters the molecules that are released from active neurons that influence the activity of other cells exocytosis form of active transport cell transports molecules such as proteins out of the cell by expelling them in an energy using process The process of neurotransmitter release When a neuron is at rest synaptic vesicles that contain small molecule neurotransmitters tend to congregate near the voltage activated calcium channels At many synapses one action potential causes the release of neurotransmitter molecules from one vesicle The electrical properties of a neuron depolarization vs hyperpolarization Depolarized when a cell becomes less negative Hyperpolarized when a cell becomes more negative EPSP IPSP EPSP or excitatory postsynaptic potential makes a postsynaptic neuron more likely to generate an action potential acetylcholine and glutamate IPSP or inhibitory postsynaptic potential makes a postsynaptic neuron less likely to generate an action potential GABA action potential how does it depend on ions All or nothing occurs at the nodes of ranvier threshold is reached voltage gated NA channels open concentration gradient causes NA to flood into the neuron voltage gated NA channels close voltage gated K channels open electrical gradient causes K to flood in causing hyperpolarization Electrical impulse down an axon depends on sodium goes in and potassium goes out moving through channels in the axon s membrane All or nothing signal that conveys information over distances in the nervous system Starts out hyperpolarized stimulation or synaptic input positive charge travels down axon and open voltage gated sodium channels sodium travels Because membrane is depolarized potassium channels open Potassium flows out of axon and returns to original state Divisions of nervous system Central vs peripheral Central brain and spinal cord Peripheral nerves outside brain and spinal cord Develops into autonomic NS and somatic NS Autonomic vs Somatic Somatic NS nerves going from sense organs to CNS and from CNS to muscles and glands Motor and sensory Autonomic NS automatically control heart intestines and other organs Develops into enteric sympathetic and parasympathetic NS General functions of brain structures brainstem regulation of heart rate breathing sleeping and eating includes the medulla pons and midbrain thalamus relay station for sensory information on its way to cortex filter for sensory info hypothalamus communicates with pituitary gland involved in feeding drinking temperature regulation and sex Involved in drive related behaviors and maintenance of homeostasis amygdala responsible for emotions survival instincts and memory hippocampus memory formation basal ganglia facilitate or inhibit cortical activity motor control memory and emotional expression cerebellum balance coordination direction of movement Movement sensory timing balance and postural control medulla controls vital reflexes damage can be fatal Structures of cortex major structures in each lobe and functions Frontal lobe executive functions planning working memory motor cortex movement Broca s area language Parietal lobe somatosensory cortex touch spatial organization Temporal lobe auditory cortex spoken language comprehension visual association cortex Wenike s area for spoken language cortex Occipital lobe vision primary and secondary visual cortex Spinal cord conveys messages to and from the brain organizes reflexes what side of the body does each hemisphere get input from The hemisphere of the brain controls the opposite side of the body right hemisphere left side of body which side is language typically lateralized to Left hemisphere
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