Module 5 What does each of the following structures do to support the function of a neuron Be sure that you are prepared to draw a neuron label its structures and describe their purpose Axon carries the impulse to the terminal Axon Hillock joins the soma and axon Dendrites receives impulses from other cells Terminal spreads cell s impulse out to other neurons Terminal Buttons links up to the dendrites of the next neuron Schwann Cells surrounds neurons to increase efficiency of impulse Soma cell body contains genetic info Synapse What is the electrical charge of a resting potential How do ions create this charge 70mV difference in Na and K concentrations between inside and outside of cell What does it mean when a neuron reaches its threshold 55mV enough Na has entered the cell to bring the potential up to the threshold potential an action potential will now fire What is an action potential How does an electric signal travel through a neuron Impulse of electrical activity fires once neuron reaches threshold potential more Na rushes into the cell Describe generally how ions entering and exiting the cell change the electrical charge of the cell and cause an electrical current Neurotransmitter binds to sodium ion channels sodium enters cell brings potential to 55 mV threshold more sodium channels open pulse travels down axon then potassium channels open sodium channels close K floods out Na stops rushing in potential becomes more negative as K leaves hyperpolarization occurs What is the absolute refractory period From the initiation of the action potential to right after the peak What causes this to happen electrically Na channels are deactivated and cannot be immediately reopened Can an action potential occur during the absolute refractory period No What is the relative refractory period Na channels are beginning to recover from inactivation What causes this to happen electrically More stimulation is needed to reach the threshold potential because less Na channels are activated and also because the resting potential is higher than usual and K will still be flowing out of the cell opposing an increase in Na Can an action potential occur during the relative refractory period Yes if the increase in potential is greater gets to 55 What is the synapse The gap separating neurons How does a signal get from one neuron to the next Signal from pre synaptic neuron causes the release of a neurotransmitter which causes an action potential in the post synaptic neuron What are the different kinds of signals a presynaptic neuron can send to a postsynaptic neuron Excitatory or inhibitory What are vesicles and what do they contain Sacs made of membrane contain neurotransmitters How do neurotransmitters excite or inhibit a postsynaptic neuron Excite cause sodium channels to open Inhibitory prevent sodium channels from opening How are ions involved in this process Binding of neurotransmitters causes sodium ions to enter cell How can a neuron be excited and inhibited simultaneously By different neurotransmitters with competing effects How does this simultaneous excitation and inhibition affect threshold Conflicting signals mean that even more excitation is required to reach the threshold and fire an action potential What is reuptake Neurotransmitters being taken back into the pre synaptic neuron by transporter proteins How are groups of nerves organized into systems and what does each system do Be prepared to draw a diagram that represents the hierarchical organization of the systems Central Nervous System CNS all information is processed and stored o Brain o Spinal Cord Peripheral Nervous System PNS brings in info and sends info out o Afferent a k a Sensory Division info to CNS sight smell touch pain o Efferent Division info from CNS into actions motor division signal through sensory neurons from CNS sent to target cells Somatic control of voluntary movement send signal to skeletal muscles to consciously move arm Autonomic involuntary responses Sympathetic fight or flight speed up heart rate Parasympathetic rest and digest slow heart rate What is a reflex arc and how does it allow the body to respond to important sensory input without the delay of having the brain process it and coordinate a response Sensory info processed at spinal cord without involving brain action taken faster than the time it takes to think about it What does it mean to say that function is localized Different parts of the brain control different aspects of behavior personality memory etc What happened to Phineas Gage and why was his case important in the discovery that function is localized A spike went through his head and only some aspects of his brain function were affected How is the brain organized in three general layers Within those layers what is the location and function of the following structures Be prepared to label a blank diagram Hindbrain o Brain stem spinal cord enters skull o Medulla heart beat breathing o Pons movement o Thalamus sensory info seeing hearing feeling touching tasting o Reticular Formation arousal o Cerebellum non verabl learning memory perception of time modulating emotions voluntary movement Midbrain contains the limbic system o Hypothalamus regulating body temp circadian rhythm hunger endocrine system o Pituitary gland o Amygdala memory consolidation fear aggression o Hippocampus learning memory Forebrain cerebrum ability to think speak and perceive o Corpus collosum o Cerebral cortex layer of interconnected neurons o Motor cortex frontal lobe voluntary movement o Somatosensory cortex frontal incoming sensory info Lobes of the Cerebrum separated by folds fissures o Frontal lobes speaking planning judging abstract thinking personality aspects o Parietal lobes sense of touch body position o Temporal lobes sound speech comprehension o Occipital lobes sight What is the homunculus What does it tell us about the relative importance of some sensory information over other information A sensory map of the body shows where more sensory information comes from Types of receptors Chemoreceptors mechanoreceptors photoreceptors thermoreceptors nocireceptors auditory receptors What is brain imaging How do each of the following help researchers learn about brain structures and functions How does each technique create an image of the brain fMRI functional Magnetic Resonance Imaging uses a circular magnet to produce cross sectional images slices CT Computerized Axial Tomography combines many 2 dimensional images
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