Unit 3
Term | Explanation | Application/Example/Extension | |||||||||||||||||||||||||||||
Neurons | Neurons are the building blocks, or messengers, which travel throughout the nervous system allowing communication | ||||||||||||||||||||||||||||||
Parts of a Neuron | Dendrites- the part of a neuron which receives information from other neurons | As dendrites grow in size, like a bush growing in size, then communication between neurons will be quicker because neurotransmitters do not travel very far to the next neuron. Neurons don’t regenerate | |||||||||||||||||||||||||||||
Axons- part of a neuron where neural impulses take place, which enables information to be sent to other neurons | The longest part of a neuron | ||||||||||||||||||||||||||||||
Myelin sheath- insulates, or covers the axon, which helps to speed up communication | When myelin sheath starts to disintegrate, or disappear then multiple sclerosis could develop | ||||||||||||||||||||||||||||||
Nodes of Ranvier- are gaps in the myelin sheath | |||||||||||||||||||||||||||||||
Neurotransmitters- chemical messengers that travel across a synapse from one neuron to another influencing whether an action potential will occur | |||||||||||||||||||||||||||||||
Synapse- the gap between neurons that neurotransmitters cross | |||||||||||||||||||||||||||||||
How Neurons Communicate | Neurons are able to communicate through an action potential, which is a brief electrical charge that travels through a neuron allowing a neurotransmitter, or messenger, to exit the neuron and go to another neuron | ||||||||||||||||||||||||||||||
Neural Impulse (action potential) | Resting potential- each neuron sits, or rests at a -70 charge, which is the only time the neuron is capable of firing an action potential | Like the water in your toilet at a constant level waiting to be flushed. | |||||||||||||||||||||||||||||
Process Begins Process Finishes | Depolarization- a message from another neuron causes the inside of the neuron to become positive as sodium starts to enter | Threshold- through the process of depolarization the inside becomes positive; once this charge exceeds the threshold, which is the minimum level of stimulation necessary to cause an action potential, then the neuron fires. | Think about the threshold as the height requirement to ride an amusement park roller coaster. If you are above the height line then you can ride (same as a charge being above the threshold) allowing an action potential to occur | ||||||||||||||||||||||||||||
All-or-none potential- a neuron will fire each time with the same amount of intensity | Similar to when you fire a gun- the bullet comes out the same way every time you pull the trigger | ||||||||||||||||||||||||||||||
Repolarization- occurs right after the action potential as potassium moves out of the inside of the cell restoring the inside back to a negative charge | Think about RE-polarization as RE-storing the charge back to -70 | ||||||||||||||||||||||||||||||
Hyperpolarization- occurs right after the process of repolarization because the inside of the cell’s charge becomes too low, or below the -70 charge. | Hyperpolarization is referred to as a refractory period, as during this period the neuron can’t fire until the charge returns back to -70 | A refractory period is similar to the moment after you flush a toilet- until the water returns back to its original level you can’t flush again, similar to a neuron returning back to -70 before it can fire another action potential | |||||||||||||||||||||||||||||
Excitatory message- makes it more likely the neuron will depolarize, causing an action potential | Inhibitory message- makes it more likely neuron will hyperpolarize, not causing an action potential | Remember excitatory means to EXCITE- when the neuron becomes excited it fires an action potential. | |||||||||||||||||||||||||||||
Inhibit means to stop, or slow down an action potential | |||||||||||||||||||||||||||||||
Nervous Systems | Central nervous system | Includes the brain and spinal cord | Interneurons- neurons located within and only travel and communicate in the central nervous system | Remember the spinal cord in centrally located in your body | |||||||||||||||||||||||||||
Peripheral nervous system | The Peripheral nervous system connects the body to the central nervous system | ||||||||||||||||||||||||||||||
Parts of the Peripheral Nervous System | Somatic nervous system- part of the peripheral nervous system which controls voluntary movements | An example of the somatic nervous system would be moving your arm- you are voluntarily moving your arm | |||||||||||||||||||||||||||||
Autonomic nervous system- part of the peripheral nervous system which controls involuntary movements | An example of the autonomic nervous system is your heart rate, which occurs involuntary or automatically | ||||||||||||||||||||||||||||||
Parts of the Autonomic nervous system | Sympathetic nervous system- part of the autonomic nervous system that speeds up the body | An example of the sympathetic nervous system would be your heart racing, or speeding up as you almost get into a car accident. S-ympathetic= S-peed up the body | |||||||||||||||||||||||||||||
Parasympathetic nervous system- part of the autonomic nervous system that calms the body down | An example of the parasympathetic nervous system would be your heart-rate retuning back to its normal rate as the accident is over. P-utting back heart rate= P-arasympathetic | ||||||||||||||||||||||||||||||
Neurons and Nerves | Neural Chain- how the brain communicates with the body | Sensory neurons- are neurons that travel within the peripheral nervous system and sense information from the environment | Interneurons- are neurons that communicate within the central nervous system | Motor neurons are neurons that travel within the peripheral nervous system; carry information out to muscles and glands, causing movement | |||||||||||||||||||||||||||
Presynaptic neuron- neuron that sends, or releases a neurotransmitter | Reuptake- presynaptic neuron absorbs back excessive, or unused, neurotransmitters in the synapse | Reuptake process is like a vacuum- the sending neuron sucks back excessive NTs to later be used- if NTs stay in the synapse for a period of time, then problems could occur, like depression. | |||||||||||||||||||||||||||||
Postsynaptic neuron- neuron that receives a neurotransmitter | |||||||||||||||||||||||||||||||
Nerves are neural cables, or “roads,” comprised of axons that are part of peripheral nervous system, which enable communication back to the central nervous system | Nerves are like ropes. Ropes are intertwined with string and nerves are intertwined with axons. | ||||||||||||||||||||||||||||||
Afferent nerves- carry information TO the central nervous system | Sensory neurons- neurons that travel within afferent nerves and SEND information to the central nervous system | Remember the word SAME Sensory neurons travel through Afferent nerves Motor neurons travel through Efferent nerves | |||||||||||||||||||||||||||||
Efferent nerves- carry information FROM the central nervous system | Motor neurons- neurons that travel within efferent nerves and carry information AWAY from the central nervous system | ||||||||||||||||||||||||||||||
Tie it all together: If you were to put your finger in hot water (1) a sensory neuron would detect this hot water travel through an afferent nerve up the peripheral nervous system, towards the central nervous system where (2) an interneuron would take the information, then the brain would process the information, releasing (3) a motor neuron that would travel through an efferent nerve back down the peripheral nervous system, causing your finger to pull out of the hot water. | |||||||||||||||||||||||||||||||
Types of Neurotransmitters | Neurotransmitter | Function | Problems | ||||||||||||||||||||||||||||
Acetylcholine | Muscle action, learning, memory | Lack of can lead to Alzheimer’s disease | |||||||||||||||||||||||||||||
Dopamine | Learning, attention, emotion- pleasure | Too much dopamine leads to schizophrenia, and too little dopamine could lead to Parkinson’s disease | |||||||||||||||||||||||||||||
Serotonin | Mood, hunger, sleep, arousal | Lack of linked to depression | |||||||||||||||||||||||||||||
Norepinephrine | Alertness and arousal | Lack of linked to depression | |||||||||||||||||||||||||||||
GABA | Inhibitory neurotransmitter- slows down brain activity | Lack of linked to seizures, tremors, and insomnia | |||||||||||||||||||||||||||||
Glutamate | Major excitatory neurotransmitter- involved in memory | Too much could lead to migraines or seizures | |||||||||||||||||||||||||||||
Endorphins | Pain control and pleasure | Too much pain medication could lead to lack of endorphin supply | |||||||||||||||||||||||||||||
Drugs that affect Neurotransmitters | Agonist is a drug designed to mimic, or perform the same actions as a neurotransmitter- often used when there is not enough of a neurotransmitter | Agonist is like a key that fits a lock and is able to unlock it- the same as an agonist fitting the receptor site of a neuron and mimicking the NT | |||||||||||||||||||||||||||||
Antagonist is a drug designed to block a neurotransmitter- often used when there is too much of a neurotransmitter | Antagonist is like a key that fits a lock but does not turn the lock, hence not opening the door- the key is now stuck in the lock, preventing any other key from entering | ||||||||||||||||||||||||||||||
Endocrine System | The endocrine system is another type of communication system that uses a set of glands which produce hormones (like neurotransmitters) that circulate through the bloodstream, enabling communication. | The endocrine system uses the bloodstream making it much slower than the nervous system, which uses electricity | |||||||||||||||||||||||||||||
Hypothalamus- part of the brain that links the brain to the endocrine system through control of the pituitary gland | |||||||||||||||||||||||||||||||
Pituitary gland- “master gland” that controls all other glands | Think of the pituitary gland as “master P” | ||||||||||||||||||||||||||||||
Thyroid gland- involved in metabolism | |||||||||||||||||||||||||||||||
Adrenal glands- help trigger “fight-or-flight” response | |||||||||||||||||||||||||||||||
Parts of the Brain | Brainstem- oldest part of the brain; responsible for survival; comprised of the hindbrain and midbrain | If you were to look at a car seat you would notice that it is positioned to hit the top part of the heard, rather than the brainstem, as this could cause serious-to-fatal injury. | |||||||||||||||||||||||||||||
Midbrain- controls certain types of automatic behaviors | |||||||||||||||||||||||||||||||
Hindbrain- an extension of spinal cord involved in blood pressure, heart rate, breathing, and other vital life functions; includes the medulla, reticular formation, cerebellum, and pons | |||||||||||||||||||||||||||||||
Medulla- controls heartbeat and breathing | |||||||||||||||||||||||||||||||
Reticular formation- controls wakefulness and arousal | “Pay particular (reticular) attention” | ||||||||||||||||||||||||||||||
Cerebellum- coordinates movements, balance | “Sara-bellum has good balance” | ||||||||||||||||||||||||||||||
Pons- coordinates movements on the left and right side of the body; dreams | Think about playing ping PONg- hitting back and forth as the pons controls right and left movements | ||||||||||||||||||||||||||||||
Forebrain- responsible for complex behaviors and mental abilities | |||||||||||||||||||||||||||||||
Hypothalamus- maintains eating, drinking, body temperature | “The man’s part of the brain”- loves pizza and beer | ||||||||||||||||||||||||||||||
Limbic system- regulates memory, fear, aggression, hunger, and thirst | “My emotions are in LIMBO” | ||||||||||||||||||||||||||||||
Hippocampus- processes new memories | Hippos have great memory | ||||||||||||||||||||||||||||||
Amygdala- linked to fear and emotion | “Don’t ever make AMY mad” | ||||||||||||||||||||||||||||||
Thalamus- relay center for sensory information except smell | The “secretary” of the brain- sends information to proper place. | ||||||||||||||||||||||||||||||
Cerebral cortex- most sophisticated area of the brain | Very similar to a CPU unit of a computer- the processor | ||||||||||||||||||||||||||||||
Cerebral hemispheres- the left and right side of the cerebral cortex | |||||||||||||||||||||||||||||||
Corpus callosum- connects the two hemispheres | Like a cord that connects two computers | ||||||||||||||||||||||||||||||
Split-brain- refers to people who have had their corpus callusum severed/ Roger Sperry found to reduce epileptic seizures | |||||||||||||||||||||||||||||||
Each hemisphere is divided into four lobes. | Association areas are present on all 4 lobes and are responsible for higher mental functions such as learning, speaking, remembering, and thinking | ||||||||||||||||||||||||||||||
Frontal lobes- largest lobe- involved in planning, thinking, emotional control, and muscle movement | People will often hit themselves in the front of the head and say, “I am so stupid”- makes sense- it is the thinking portion of the brain. | ||||||||||||||||||||||||||||||
Motor cortex- controls voluntary movements | The right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body | ||||||||||||||||||||||||||||||
Parietal lobes- located top of the hear- processes body information- touch | In duck-duck-goose people “pat” others on the top of the head | ||||||||||||||||||||||||||||||
Occipital lobes- located back of the head- processes visual information | Think about the eye store, D.O.C. cipitial, or remember, “O-h, I C (see) | ||||||||||||||||||||||||||||||
Temporal lobes- processes auditory information | You listen to the “tempo” or the beat | ||||||||||||||||||||||||||||||
Spatial ability and Language | Lateralization- notion that each hemisphere is responsible for specific abilities and tasks | ||||||||||||||||||||||||||||||
Right hemisphere- handles nonverbal- spatial, musical, and visual- recognition tasks | Left hemisphere processes language which includes the Broca’s and Wernicke’s areas | ||||||||||||||||||||||||||||||
Broca’s area- involved in spoken language | Think about “boco” in Spanish- means mouth, or “broken” speech | ||||||||||||||||||||||||||||||
Wernicke’s area- processes the ability to understand language, communication | Think about Professor Wernicke- no one can understand him | ||||||||||||||||||||||||||||||
Aphasia- refers to the inability to speak or understand | It is possible for someone to not be able to speak- Broca’s aphasia, but understand and vice versa. | ||||||||||||||||||||||||||||||
Imaging the brain | CAT Scan- X-ray photographs of the brain | MRI- uses magnetic fields that produce computer images of the brain | |||||||||||||||||||||||||||||
EEG- measures electrical activity of the brain- often used to measure brain waves during sleep | PET scan- measures brain activity through injecting radioactive glucose while the brain is performing functions | ||||||||||||||||||||||||||||||
Lesioning- involves destroying a piece or part of the brain | |||||||||||||||||||||||||||||||