HUMAN PHYSIOLOGY EXTERNAL BRAIN CHAPTER I: MEMBRANE PHYSIOLOGY 1. Explain the importance of the cell membrane (LOC). Differentiate between simple and facilitated diffusion, active transport, and cotransport across a membrane (MOC). Provide examples of each and briefly describe how they work (MOC). ∙ TheWe also discuss several other topics like pierre alexis delamair
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cell membrane has hydrophilic and hydrophobic parts and a phospholipid bilayer with trans membrane proteins that allow for molecules to be moved across the membrane. o Hydrophilic head and hydrophobic tails. The tails point inward, preventing water from traveling across the membrane ∙ Simple diffusion: Does not require a carrier and easily moves through channels o Does not move against the concentration gradient o Example: Potassium moving through the channel to get outside because there is a higher concentration in the cell than outside. Moving from high to low concentrations ∙ Facilitated Diffusion: Requires a carrier and interaction with a protein ∙ Active Diffusion: Requires interaction with protein and a source of energy (ATP) o Example: Sodium trying to leave the inside of the cell against its concentration ∙ Cotransport: when a molecule attaches to another molecule that can go through the carrier protein ∙ Factors that affect diffusion o Concentration differences o Membrane electric potential o Pressure differences 2. Describe the function of the Na+/K+ ATPase pump in maintaining membrane potential (LOC). ∙Usually there is more sodium outside of the cell and more potassium inside (a banana in the ocean) ∙With the Na/K+ ATPase pump, the pump works to push sodium back outside of the cell and potassium back inside. This is why there is so much sodium outside of the cell and so much potassium inside the cell ∙Maintains the resting membrane potential and cell volume regulation as well as signal transduction 3. Define the Nernst Equation value (equilibrium potential; LOC). Determine the charge of the equilibrium potential based on the concentration and charge of a theoretical ion (HOC). Apply the concept underlying the equilibrium potential to questions about real or theoretical ions, and to explain the peaks and values of the action potential waveform (HOC). ∙Nernst potentialo Electrical potential vs. chemical potential o Voltage between two sides of a membrane o Equilibrium potential is where the electrical potential = chemical potential in which there is no net movement o Example. There is more chloride outside of the cell and the membrane potential is negative. What is the Nernst potential? The large amount of chloride ions outside of the cell will want to come into the cell but because the membrane of the cell is negative, it will be repelled: arrows moving in opposite direction so it is negative Large amounts of Sodium inside the cell with a negative membrane potential: Sodium will want to leave but because the membrane is negative and sodium is a positive ion, it will want to stay in the cell: opposite arrows so negative Negative indicates the ion is not leaving; positive indicates that the arrows are moving in the same direction and there is movement across the membrane ∙ 4. Describe the function of Na+ and K+ ion channels and their role influencing the membrane potential and electrochemical gradients during an action potential (LOC). Draw an action potential and label depolarization, repolarization and hyperpolarization and where on the action potential waveform the permeability for Na+ and K+ peaks (LOC). ∙ If the membrane loses negativity and gets closer to zero, sodium channels become activated so that sodium can make the membrane more negative ∙ Sodium channels depolarize the cell ∙ Peak of graph indicates that the sodium channels are closing and the potassium channels are opening ∙ The opening of the potassium channels leads to repolarization of the cell ∙ Hyperpolarization occurs when the voltage gated potassium channels are still open past their resting levels o Prevents an additional action potential from occurring right away ∙ Permeability vs. Conductance o Permeability: ability for ions to diffuse through membranes o Conductance: measured on the ion’s ability to create voltage across the membrane o Above 0mv, there are high amounts of sodium and high sodium conductance o Potassium is most permeable during repolarization 5. Distinguish between sodium activation and inactivation gates, chemical and voltagegated channels (LOC). ∙ At rest: o The activation gate of sodium is closes and the inactivation gates are open. o Voltage gated potassium ion channels are closed ∙ At maximum depolarization: o Voltage gated sodium channels open ∙ Chemical gated channels open when a chemical or ligand binds to them whereas voltage gated open in response to voltage differences 6. Explain the absolute and relative refractory period, relate each to the oneway nature of action potential propagation, and identify the membrane potential at which each period begins and ends (LOC). ∙ Absolute: Male orgasms o Cannot stimulate another action potential because all the sodium channels are either open or inactivated o Begins below resting and ends as the membrane becomes hyperpolarized ∙ Relative Refractory Period: Female Orgasms o Can occur as long as there is a strong enough stimulus to catch the sodium channels being reset. If the channels are reset, the action potential cannot occur o Begins below threshold, right after hyperpolarization o Requires another graded potential for an additional action potential to occur∙ Propagation of the action potential o Unmyelinated Action potentials begin at the axon hillock and prorogate to the axon terminal. Propagates in a singular direction because sodium channels become inactivated after depolarization. o Myelinated Salutatory Conduction ∙ Nodes of Ranvier occur between the myelin sheaths ∙ Lots of voltage gated sodium channels at the nodes but not in the sheaths ∙ Action potentials are regenerated at each node ∙ Myelin sheath allows for the spread of the depolarizing current Faster than continuous conduction in unmyelinated axons 7. Describe the function of Schwann cells, myelin, Nodes of Ranvier and the process of salutatory conduction on signal transmission (LOC). Use your knowledge of axon physiology to explain how axon diameter and temperature affects speed of transmission (MOC). ∙ Schwann Cells for the myelin sheath ∙ Myelin: Surrounds axons and insulates them so that the transmission of electrical impulses can occur faster ∙ Saltatory Conduction o Takes place in the myelin sheath o Increases conduction velocity of the action potentials ∙ Large diameter and hotter temperatures allow for the fastest conduction velocity 8. Describe the production of an Excitatory and Inhibitory Postsynaptic Potentials (EPSP, IPSP) via specific ion movements across the postsynaptic membrane (LOC). Differentiate between a graded potential in the soma and an action potential in the axon, and describe the allornone nature of action potentials (MOC). ∙ EPSP: more likely for an action potential to be fired o Depolarizing potential; the cations and anions ∙ Temporary depolarization of the membrane and flow of positive ions into postsynaptic cell from the opening of the ligand gated channels ∙ IPSP: due to the flow of negative ions into the cell or positive ions leaving the cell o K+, Cl o Hyperpolarizes the post synaptic neuron∙ EPSP and IPSP are graded potentials ∙ Graded vs. Action Potentials o Graded Potentials Can depolarize or hyperpolarize Ion channels can be ligand gated There is no refractory period Has summation Amplitude diminishes as you get further from the origination Can start through external stimuli or neurotransmitters Can occur in areas of synaptic contact with other cells Amplitude is proportional to the strength of the stimulus Occurs in the soma/cell body o Action Potentials Membrane is always depolarized All or none frequency Controlled by the voltage gates of potassium and sodium Have absolute and refractory periods No summation because of the all or none Amplitude is constant as it is propagated across the axon Triggered by depolarization o All or None Principle: strength by which a nerve or muscle fiber responds to a stimulus is independent of the strength of the stimulus If the stimuli reach the threshold potential, the action potential will be propagated 9. Explain the role of a synapse in establishing an action potential in a postsynaptic cell and the role of summation (temporal or spatial) of postsynaptic potentials in reaching threshold (LOC). Describe how calcium is related to neurotransmitter exocytosis. Predict how change in presynaptic action potential frequency affects neurotransmitter release and temporal summation in the postsynaptic neuron (HOC). ∙ Action potential travels down the axon where it hits the presynaptic terminal of the axon. Once at the presynaptic, it opens the Calcium channels and signals for the synaptic vesicles to diffuse across the cleft, releasing the neurotransmitters within o Neurotransmitters than bind with the postsynaptic receptors o This is the conversion of the electrical signal to a chemical signal. o In order to continue the action potential across the postsynaptic neuron, the chemical signal must once again become an electrical signal ∙ Summation determines whether the action potential will occur o Spatial Summation The signals work together as graded potentials at the trigger zone. If the signals reach threshold, action potential Multiple stimuli coming together to reach a potential that will either reach the trigger zone that can have multiple synapses at multiple locations EPSP: above threshold and elicits an action potential IPSP: below threshold because it doesn’t reach the trigger zone Different Synapses but same postsynaptic neuron at the same time! o Temporal Summation Occurs at different time points and either summate together to reach threshold or do not summate together Same Synapse by series of high frequency action potentials on presynaptic neuron ∙ Calcium and relationship to exocytosis o When an action potential reaches the axon terminal of the presynaptic neuron, the voltage gated Ca channels open. The opening of these channels signals for the release of the neurotransmitter, Acetylcholine to leave the vesicles on the release sites If calcium is inhibited on the presynaptic cleft, the neurotransmitter can not be released and the action potential can not be transmitted across o A more intense stimulus means more frequent action potentials o Higher frequency of action potentials means the Calcium channels are opening more frequently so there are more neurotransmitters being released A stronger muscle contraction requires more frequent action potentials With a higher frequency, the temporal summation will be closer together and are more likely to make it to the trigger zone 10. Differentiate between ligand agonists and antagonists, as well as between cholinergic and adrenergic receptors, and nicotinic and muscarinic cholinergic receptors (LOC). Be able to anticipate outcomes if any part of the system is damaged/manipulated/poison (HOC). ∙ Ligand Agonists vs. Antagonists o Agonists: Activates the receptors and can bind to the same receptors as the neurotransmitter o Antagonist: Can bind to the same receptor but prevents activation so the ligand gated ion channel will not open ∙ Cholinergic vs. Adrenergic o Cholinergic: uses acetylcholine Nicotinic and Muscarinic ∙ Nicotinic: found on the ion channels ∙ Muscarinic: activates the gene protein complex which results in ion channel opening and the 2nd messenger activation ∙ Nicotinic is found on postsynaptic ganglion in the parasympathetic and sympathetic divisions o Excitatory receptors ∙ Muscarinic is found on the target tissue of the parasympathetic branch o Purpose is to increase or decrease the activity of the effector cells o Adrenergic: uses norepinephrine and adrenaline Found on the target tissues of the sympathetic branch Beta and Alpha adrenergic receptors ∙ What is the difference between a hormone and a neurotransmitter o Hormones are secreted by endocrine glands and have a systematic effect Norepinephrine on the sympathetic target tissue o Neurotransmitters are released at a synapse and specific to a part of the body Acetylcholine at the cholinergic receptors HUMAN PHYSIOLOGY EXTERNAL BRAIN CHAPTER 2: G PROTEIN COUPLED RECEPTORS; MUSCLE PHYSIOLOGY 11. Describe different ways in which extracellular signaling molecules can cause intracellular effects (LOR). Draw the mechanism of Gprotein coupled receptor activation (LOC). Differentiate between Gprotein alpha subunit actions and predict the outcomes of activation or inactivation of specific GPCRs based on their alpha subunits (HOC). Predict the outcome when any aspect of the system is modified (HOC). ∙ Extracellular signaling and intracellular effects o Influx of sodium or chloride o Depolarization if there is an excitatory responseo Activation of the G protein ∙ Gprotein coupled receptor activation o GDP subunit binds to the receptor in its inactive state o Alpha disassociates from beta and gamma unit when GTP binds Inactive: GDP Active: GTP o GTP binds to an enzyme which produces the 2nd messenger Adenylatecyclase ∙ Converts the ATP cAMP o cAMP activates PKA which is used to activate proteins Phospholipase C ∙ PIP2 IP3+ DAG o IP3: binds to the calcium channels and is responsible for its release from the sarcoplasmic reticulum o DAG: activates protein kinase o Stimulatory G Protein: causes adenylate cyclase to increase the production of cAMP o Inhibitory G Protein: causes adenylate cyclase to decrease the production of cAMP o PDE deactivates cAMP which would lead to the deactivation of PKA which is used to activate certain proteins 12. Explain how an action potential in a motor neuron leads to an action potential in the associated skeletal muscle fiber (LOC). ∙ Ach released into the synaptic cleft or the motor end plate via exocytosis ∙ Ach binds to the nicotinic cholinergic receptors ∙ Influx of Na+ and some K+ efflux through ligand gated channels ∙ Motor endplate threshold is then reached so the voltage gated Na+ channels are open ∙ Action potentials occur along the sarcolemma via sequential opening of voltage gated Na+ and K+ channels’ ∙ A.P travels down the Ttubule ∙ Voltage Gated DHP receptors are activated ∙ Mechanically linked RYR on the sarcoplasmic reticulum open and release the calcium into the cytoplasm 13. Describe how an action potential in the ttubules leads to calcium release (LOC).14. Explain how binding of calcium to troponin C leads to available actin binding sites (LOC). Describe the process of cross bridge cycling and the steps involved as it relates to the hydrolysis of ATP to ADP + Pi, the release of ADP + Pi, and the binding of ATP to the myosin head (LOC). Evaluate the outcome of hypothetical scenarios, such as a lack of ATP or calcium, addition of toxins, or damage to various receptors (HOC). ∙ Calcium is released from the sarcoplasmic reticulum and then binds to the troponin C located on the actin filament. Tropomyosin is moved out of the way so that the actin binding sites become available ∙ Myosin head attaches to the actin binding site and pulls on the filament ∙ ADP and the phosphate are released and ATP is swapped in∙ Once ATP attaches, the cross bridge breaks and ATP becomes hydrolyzed again to ADP and Pi, preparing for the cocked position ∙ What would happen if there were no calcium being released from the sarcoplasmic reticulum? ∙ Troponin C would have nothing to bind to and thus tropomyosin would remain in its position and there would be no cross bridge ∙ What happens if DHP is inhibited? The RYR channel cannot be opened and thus calcium cannot be released from the sarcoplasmic reticulum 16. Accurately utilize the terminology related to the muscle's architecture (from whole muscle to myofilaments) and the specialized structures of the myocyte (ttubule, sarcoplasmic reticulum, terminal cisternae, triad). a. Musclefascicle sarcolemma t tubule sarcoplasmic reticulum myofibril sarcomere actin and myosin b. Terminal Cisterna help release the calcium 17. Name the parts of the sarcomere (A, I, H bands, M line, Z disc) and understand what each represents, and how each might change between a resting and shortened state (LOC). Describe the sliding filament theory of muscle contraction (LOC). Name and identify the contractile, supportive and regulatory proteins in a sarcomere (actin, myosin, titin, nebulin, troponin & tropomyosin; LOC). a. Contains the I band, 2 Z lines, A band and an M line i. I band: actin ii. A band: myosin iii. Actin connects at the z line iv. Z disk is where the actin filaments attach b. During a contraction v. A band stays the same length vi. Distance between the Z lines is less vii. I and H are narrow c. Sliding filament theory of muscle contraction viii. Tight binding between actin and myosin with the requirement of calcium ix. Cross bridge cycling d. Titin allows for the spring or bounce back when the muscle retracts and connects the myosin filament to the z disk in the sarcomere e. Nebulin binds to actin 19. Describe the size principle of motor unit recruitment, and apply this information to changes in Mwave amplitude and force production across different stimulus intensities and frequencies (HOC). a. Smaller motor units are recruited first because they are more excitable than the larger ones b. After threshold, the maximum number of motor units has been recruited. c. Inverse relationship between the number of motor units recruited and the force generated d. M waves measure the electrical activity that reaches the muscle ∙ If an M wave can not be seen, the threshold has probably not been reached yet so the action potential could not occur and thus an observable voltage through the muscle was very small if not any e. Three ways that graded contractions occur Multiple fiber summation/motor unit recruitment Frequency of stimulation Changing the initial length of the muscle Differentiate between the effects of stimulus intensity and stimulus frequency (HOC). Differentiate between artificial stimuli created in a peripheral nerve axon and physiological stimuli in the spinal cord (HOC). ∙ Strong stimuli depolarize the alpha motor neurons which lead to an action potential and result in contractions of the muscles ∙ If there is no stimulus, then there are no motor neurons being used ∙ Motor units are recruited from small to large ∙ A plateau in a graph indicates that all possible motor units are in use ∙ In people who have had strokes or those with weak(paretic muscles) there are fewer action potentials being fired and thus fewer motor units being recruited 20. Describe the principle of wave summation & tetany as they relate to calcium release and force production (MOC). ∙ Principle of wave summation o Increase in muscle contraction strength based on how rapidly a muscle is stimulated o The wave summation occurs because muscles that are rapidly stimulated are not able to relax between the repeated stimulations o Tetany occurs when there is a very high wave summation that increase s muscle contraction strength as a result of the calcium built up in the muscles Due to the rapid stimulation, the calcium is not removed 21. Draw and interpret a length tension curve for one sarcomere, and contrast it with the curve for whole intact muscle (LOC); include active and passive components of the tension curve for whole muscle (LOC). ∙ One sarcomere o If there is too much of an overlap between filaments, the force decreaseso Contraction decreases when the two ends of actin overlap o Full tension when the myosin center is reached ∙ Entire muscle o Increase in tension when the muscle contracts o At the sarcomeres normal length: maximum contraction o Active tension: the increase in tension decreases when the muscle stretches o Active muscles have a maximum tension at half their length while maximum tension in the passive muscles is when it is normal length 22. Draw and interpret the loadvelocity curve for skeletal muscle (MOC). ∙ As load increases, velocity of contraction decreases ∙ Maximum load is when the muscle is not contracting and thus there is minimal velocity of contraction in the muscle ∙ Inverse relationship due to a resistive force 23. Differentiate between isotonic, isometric, and isokinetic muscle contraction, and between eccentric and concentric muscle contraction (LOC). Evaluate the type of contraction occurring during a given movement when agonist and antagonist muscles are identified (MOC). ∙ The number of myosin heads tightly bound to actin will determine the load that can be opposed o Force output or strength of contraction ∙ isometric: muscle remains the same size during contraction Torque from the weight increases, causing the muscle torque to increase. This results in the muscle stretching and the overlap of filaments reduces. This creates tension but not enough to move the weight Maximal: strength of actinmyosin cross bridges does not exceed the load so there is no movement Submaximal: agonist and antagonist muscles both contract to maintain joint position, no JOINT movement ∙ Isotonic: muscle shortens but the tension is the same constant tension, variable length Occurs when the muscle torque>weighted torque from the weight causing the muscle to shorten( indicated by a bulging muscle) Concentric: strength of the actinmyosin binding EXCEEDS load sarcomeres shorten, muscles shorten, decreases in joint angle, moving against the force of gravity Eccentric: strength of actinmyosin binding DOES NOT EXCEED load Sarcomeres lengthen, muscles lengthen, increase in joint angle, moving with the force of gravity ∙ Isokinetic: movement of muscles at a consistent rate Constant velocity but variable length and tension ∙ Example: Sitting in a chair Quads(muscles on the front of the thigh) are stretched Hamstrings( muscles on the back of the thigh) are being shortened or relaxed ∙ Agonist muscles are the prime movers but are not always the muscles that are shortening ∙ Antagonist muscles oppose the agonist; typically causes relaxation of the other muscle and works to slow down or stop movement 24. Compare and contrast skeletal muscle fiber types related to speed of crossbridge cycling and fatigability, and which characteristics of the fiber lead to increased twitch speed or fatigability (LOC). Identify the three factors that determine muscle force production and describe how each impacts force production (MOC). ∙ Slowtwitch fibers o Red muscle o Have a prolonged contraction and are used for endurance o Use lots of oxygen to create ATP( aerobic) o Oxidative Metabolism with lots of mitochondria, capillaries, and myoglobin o Smaller neurons are stimulated first, creating less change to threshold o Have smaller motor units and thus fewer fibers per neuron o Slower ATPase enzyme so slower crossbridge cycling ∙ Fast Twitch Fibers o Anaerobic o Explosive power but fatigues easily o Less oxidative metabolism because there are less mitochondria, capillaries, and myoglobin o Larger neurons are stimulated last and create a larger change to the threshold o Large motor units o Found in white muscle o Faster ATPase enzymes so there is faster cross bridge cycling ∙ Cross Bridge Cycling Speed o Determined by the specific type of myosin ATPase on the myosin head and the speed at which it converts ATP to ADP and Pi ∙ 3 ways to regulate force o initial length of the muscle o Motor unit recruitment o Frequency of stimulation CHAPTER 3: NERVOUS SYSTEM 25. Understand the basic organization of the nervous system including the central nervous system, peripheral nervous system, afferent (sensory) system, and the efferent (motor) system, including the somatic system and well as the parasympathetic and sympathetic branches of the autonomic nervous system. ∙ SAME DAVE: Sensory Afferent MOTOR Efferent Dorsal Afferent Ventral Efferent 26. Understand the general functions of the spinal cord, as well as the lower or subcortical level of the brain, and higher or cortical level of the brain. ∙ Subcortical controls the unconscious functions ∙ Cortical controls storage info and memories 27. Explain or draw the pathway and components for spinal cord reflexes from the sensory receptor back to the muscles and identify the factors affecting speed of the reflex and how the magnitude of the reflex could be modified. Differentiate between intrafusal and extrafusal muscle fibers. ∙ Reflex pathway is controlled by the spinal cord which is why a decerebrated cat is still able to walk ∙ Ex. You touch a thorny rose o Skin recepotrs recognize the pain and send info to the interneurons in the spinal cord of the grey matter o Interneurons synapse with the motor neurons Excitatory tells the flexor muscle to contract while the inhibitory tells the extensor to relax ∙ Relfexes are important for their speed! ∙ Intrafusal vs. Extrafusal o Intrafusal: Serve as sensory organs that detect amount and rate of change in the length of a muscle Make up the muscle spindle o Extrafusal: skeletal muscle fibers that are innervated by alpha motor neurons Each alpha motor neuron and the extrafusal fibers innervated make up a motor unit Neuromuscular junction occurs between the motor neuron and the extrafusal fiber 28. Describe the different fibers that transmit sensory signals to the central nervous system, and how they vary regarding speed & information carried. ∙ Fast transmission include the alpha neurons which are large and myelinated ∙ Slow transmission occurs in the C neurons which are small and unmyelinatedo Controls temperature, crude touch, dull pain, and itches ∙ A alpha make up 1a and 1b which include the muscle spindles and golgi tendons o Fast and myelinated ∙ A beta and gamma= 2 for the tactile receptors o Fast and myelinated ∙ A delta: 3 temperature and deep pressure and sharp pain o Fast and myelinated 29. List the different categories of somatic sensory receptors that exist, how different receptors types initiate action potentials, and the anatomy of these neurons (i.e.: location of the cell body). Match the specific sensory input (pain, temperature, etc.) to the classification of sensory neuron. ∙ Somatosensory receptors: mechano, thermo, chemo, nocio, and electromagnetic ∙ Sensations to action potentials o Ion channels open causing a change in membrane potential 30. Explain the physiology that underlies our ability for 2point discrimination. Describe how convergence, lateral inhibition, and receptor density impact 2point discrimination. ∙ Good two point discrimination o Small receptor field per afferent neuron o High Receptor density in the skin o Lateral inhibition o Less convergence of first order neurons onto second order neurons ∙ Poor 2 point discrimination o Low receptor density and high convergence 31. Describe how the autonomic nervous system functions, and how the sympathetic and parasympathetic systems work together to produce a response. Predict outcomes based on varying contributions of the SNS and PNS. ∙ What is the difference between sympathetic postganglionic neurons and alpha motor neurons o Neurotransmitter is released, myelination, and the neuron size ∙ How is the adrenal gland different than other sympathetic outflow o No postganglionic neuron o Produces hormone which is released in circulationo More epi than norepi ∙ Along with the neurotransmitters being released by the adrenergic receptor in the sympathetic division, the adrenal gland of the sympathetic nervous system also releases a hormone into the blood. o The adrenal gland also releases epinephrine and norepreniphrine but because of its location, they are considered hormones in this case. Still stimulated by the cholinergic preganglionic fibers 32. List the differences between the sympathetic and parasympathetic neurons and neurotransmitters, and explain how these differences affect the speed & duration of response. Predict outcomes based on manipulation of the ANS (beta blockers, atropine, etc.). ∙ Why is the parasympathetic faster to respond but the sympathetic has a longer duration? o Parasympathetic has long presynaptic neurons which are myelinated and fast o Sympathetic has hormones being released into the blood which take longer to break down and also has longer postsynaptic ganglions which takes it longer to get to the target tissue. 33. Explain the basic physiology underlying synaesthesia, phantom limb pain and Capgras syndrome as described by Dr. Ramachandran in his TedTalk. ∙ Ex. Patient recognizes the face but believes the person is an imposter’ o Example of the fusiform gyrus being intact but the connect to the amygdala is severed No emotional response ∙ Synesthesia o Less trimming of the neuro connections in the brain which connect perception of various senses o Color and numbers get blended together which are both next to each other in the fusiform gyrus 34. Map out the neural pathways involved to produce a simple voluntary motor pattern: include the premotor area and primary motor cortex, cerebellum, basal ganglia, corticospinal tracts and motor neuron, in addition to the sensory feedback required to achieve a successful outcome. ∙ Example: Reaching for an apple o Premotor area creates the motor image prior to stimulating the primary motor cortex o Primary Motor cortex has cell bodies associated with the activation of muscles in each area of the body o Supplementary motor area: postural and positional muscle activation to support intendeded movement Occurs at same time as the primary motor cortex o Corticospinal tract: neurons that connect cortex to the spinal cords interneurons/motor neurons o Cerebellum works to differentiate between sensory and motor to make adjustments as necessary 35. Describe the function of the following portions of the brain, and be able to connect symptoms of brain damage to the area affected: primary motor & sensory cortices; secondary (association/supplementary) sensory, motor and premotor areas; dominant and nondominant Wernicke’s areas; angular and fusiform gyri; prefrontal lobe; Broca’s area; limbic association area; corpus callosum; hippocampus; thalamus & hypothalamus. ∙ Wernicke’s area: understanding of written and spoken language o Nondominant controls understanding of music, visual patterns, and proprioception; understanding body language and tsomatic use of limbs ∙ What happens if you have a prefrontal lobotomy? o Wont be able to form new memories Other Things to Remember ∙ Activation gates are closed at resting for sodium o During the depolarization phase, sodium gates are open for both the activation and inactivation sites ∙ Action potentials traveling along the axon of a nerve cell o When threshold is reached at the axon hillock, multiple action potentials occur in local area along the length of the axon to carry the signal to the axon terminal o Refractory periods support the one way movement of an action potential down the axon when the action potential is initiated from the axon hillock ∙ Action potentials begin at the axon hillock ∙ When a GCPR is activated, GTP replaces the bound GDP and the G alpha dissociates from the beta/gamma unit when GTP binds