Axon Sends signals to from other cells takes it away from cell body Axon Hillock Where the soma meets the axon either signals make it through there and travel on or don t Dendrites Recieves signals and brings it to the body Schwann Cells Makes up the myelin sheath of the axon Soma Body of the nucleus Synapse Space between axon terminal of one neuron and dendrites of another Terminal The end of a neuron Terminal Buttons Small buttons at the end of a neuron that release the chemical neurotransmitters What is resting potential s electric charge Resting potential is 70mV Inside of neuron is 70mV less than the outside of the neuron meaning the inside is negative related to the outside How do ions create the resting potential charge More potassium inside than sodium Although meant to be balanced out cannot due to semi permeable membrane only some ions pass through the ion channels At rest potassium can pass through easily while Chloride and Sodium have difficulty What does it mean when a neuron reaches its threshold When a neuron reaches its threshold it reaches action potential If it doesn t reach the threshold doesn t go At 55mV neuron fires action potential Describe generally how ions entering and exiting the cell change the electrical charge of the cell and cause an electrical current Stimulus has sodium ions rush into nerve through pore causing inside to become more positively charged 40mV If it reaches threshold sodium continues to go into all the nearby nerves Potassium rushes out of membrane causing voltage to return to normal What happens with the two different ion channels Ions cross over the membrane When threshold is reached much less sodium outside than inside so sodium channels open and rush into the neuron making the neuron positively charged Because of depolarization potassium channels open and rush out of the neuron reversing depolarization Absolute refractory period Polarization is so negative that action potential and firing is not possible Relative refractory period Polarization is very negative but not as negative as absolute Can go into action potential but needs a very strong push How does a signal get from one neuron to the next electrical impulses must travel down the axon to the presynaptic synapse the diffuse into the cleft and then through the postsynaptic synapse Explain the process of how a presynaptic neuron transfers info to a postsynaptic At the presynaptic neuron an electrical impulse will trigger the migration of vesicles containing neurotransmitters toward the presynaptic membrane The vesicle membrane will fuse with the presynaptic membrane releasing the neurotransmitters into the synaptic cleft The neurotransmitter molecules then diffuse across the synaptic cleft where they can bind with receptors on the postsynaptic ending Vesicles Sacks of neurotransmitters that fuse with the membrane of the presynaptic neuron How do neurotransmitters excite or inhibit a postsynaptic neuron the binding of neurotransmitters to the receptors of the postsynaptic neuron opens the sodium channels allowing sodium ions to flow in resulting in depolarization which causes action potential and the remaining neurotransmitters are hydrolyzed by enzymes in the synaptic cleft Inhibatory neurons How can a neuron be excited and inhibited simultaneously Reuptake work by making the membranes hyperpolarized meaning they are too negative that it comes to an absolute refractory point Achieve this negativity inside due to a high concentration of Chloride ions which is negatively charged Eccitatory and Inhibitory neurotransmitters can be firing simultaneously it just depends on which there is a higher concentration of If higher concentration of excitatory is present then threshold is reached but if higher concentration of inhibitory too negative to fire the absorption by a presynaptic nerve ending of a neurotransmitter that it has released but it didn t get picked up by the receptors of the postsynaptic neuron nor did it get destroyed by enzymes within the synaptic cleft They are repackaged for reusage Central Nervous System All info comes in leaves or gets stored here Consists of the brain and the spinal cord Peripheral Nervous System Consists of Afferent sensory and Efferent motor Afferent Efferent Sensory senses things through the 5 senses through sensory neurons sends that info to the CNS for the brain to interpret Motor takes info from CNS to target cells through efferent neurons involuntary natural responses as well as intentional responses Consists of somantic and autonomic Somantic voluntary movements conscious Autonomic involuntary movements Sympathetic and Parasympathetic Sympathetic Fight or flight heart rate goes up during physical activity or fear Parasympathetic Rest and digest heart rate goes down during rest Reflexive Arc sensory info processed at spinal cord resulting in action without involvement of the brain Deals with reflexes Example hand on hot stove move it right away What does it mean to say that brain function is localized Different parts of our brain control specific aspects of our behavior localized parts of the brain have different functions What happened to Phineas Gage He was taping gunpowder into a hole with a metal rod caused an explosion which shot the rod through his cheek and out of the top of his head where there was brain After this he was no longer himself He was now mean and vulgar as opposed to his typical happy self yet his memory and motor skills still worked He is a great example of how function is localized in the brain because of the things that were and weren t affected Hindbrain Brain stem medulla thalamus reticular formation pons Brain Stem most ancient and central core of the brain the stem on the inside the core Medulla automatically controls beating of heart breathing etc Pons helps coordinate several auto functions Thalamus takes in sensory infor related to seeing hearing touching and tasting Reticular Formation network inside brainstem that s essential for arousal Cerebellum responsible for non verbal learning and memory perception of time emotions and voluntary movement Midbrain Contains the lymbic system Amygdala hippocampus hypothalamus pituitary gland Amygdala Deals with emotion and memory consolidation Hippocampus Deals with memory and learing Hypothalamus Regulates body temp heart rate hunger governs endocrine system Pituitary Gland Secretes different types of hormones Forebrain Cerebrum corpus collosum cereberal cortex motor
View Full Document
Unlocking...