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Human phys exam #2
chp 6,7,8, 9, 10
| Question | Answer |
|---|---|
| the nervous system is comprised of | CNS(Brain, spinal chord, BBB, CSF), PNS(afferent and efferent), ANS |
| afferent system is made of | somatic, visceral and special sensory neurons and the afferent system is signals going from the pns -->cns |
| what is the difference between humans and animals? | well developed frontal lobe, allows you to precieve things differently |
| brain dead | only the brainstem is functioning, the person that you are is not able to communicate |
| brain is made up of 3 portions | forebrain, cerebellum, brainstem |
| forebrain: cerebral hemispheres | cerebral hemispheres:in cerebrum controls preception/thought. contains 4 lobes: frontal (thought), parietal(somatosensory), occipital (visual), temporal (sound). made of white matter (meylin) and gray matter (unmeylinated portions of neurons) |
| forebrain:Thalamus | information transfer, muscle control |
| forebrain: hypothalamus | homeostasis, manages body's endocrine system |
| forebrain: limbic system | emotions |
| cerebellum | movement, learning, motor control |
| brain stem | basic functions, ie. breathing |
| cerebral ventricles | in the brain, 4 interconnected cavities that are filled with fluids |
| spinal chord | within the vertebral column, cartilage and spina chord sandwich each other and contains the dorsal horn and ventral horn |
| spinal chord: dorsal horn | portion of spinal gray matter pointing towards the back of the body, think dorsal fins of fish, located on the back of the fish` |
| spinal chord: ventral horn | located in hte front of the spinal gray matter, think vent like stochach, efferent |
| number and types of cervical vertabrae | think breakfast at 8 (8 cervical vertabrae) lunch at 12 (12 thoracic vertabrae) and dinner at 5 (5 lumbar vertabrae) |
| difference between autonomic and somatic nervous system | both are subsections of the efferent division of the PNS, somatic is more invovled in moving the body while autonomic is more involved in maintaining the body. |
| difference between autonomic and somatic nervous system: somatic system | consists of single neuron between CNS and skeletal muscle, innervates skeletal muscles, can only lead to muscle excitation |
| difference between autonomic and somatic nervous system: autonomic system | has a two neuron chain, ther eis a synapse between the CNS and target organ, innervetes many things including smooth and cardiac muscles, glands and GI neurons, can be excitatory or inhibitory |
| gangilion | synapes outside the cns, it is the synapse the neurons of the ANS use to send messages |
| parasympathetic system | rest and digest, SLUD: Salivation, Lacrimation, Urination, Defecation |
| sympathetic nervous system | fight or flight |
| dual innervation | both the sympathetic and parasympathetic affect the same parts of the pody |
| pregangilion | before the ganglion |
| post ganglion | after the ganglion |
| parasympathetic pre and post ganglionic neurons | preganglionic neurons are located only in the brainstem and sacral sections of the vertabrae and they are the longer portion, they extend further than the post ganglionic part, the post ganglionic neuron is right next to target organ |
| parasympathetic pre and post ganglionic neurons cont. | the post ganglionic cells tend to target one organ at a time, this results in in slower processing of info which makes sense for the parasympathetic system, its rest and digest |
| males are point and shoot | erection-parasympathetic || ejaculation- sympathetic |
| sympathetic pre and post ganglionic neurons | short preganglionic neurons, long post ganglionic neurons, there are many ganglia along the vertabrae, the post ganglia can effect multiple organs at the same time. this allows faster and coordinated response, good for fight/flight |
| vagus nerve | performs up to 70% of the afferent and efferent systems stuff |
| sympathetic and parasympathetic receptors: Nicotinic AchR | found on post ganglionic neurons in autonomic ganglia in neuromuscular junctions of skeletal muscle, also found in CNS targets somatic system, symp and para, works quickly, ligand gated sodium channels |
| sympathetic and parasympathetic receptors: adrenergic | responds to epinephrine and norepinephrine, gprotein receptors, generally found in the sympathetic system, affects smooth/cardiac muscle and gland cells, alpha and beta stuff, IN TARGET CELLS ONLY |
| sympathetic and parasympathetic receptors: muscarinic | parasympathetic, think muscarin --> related to mushrooms --> mushrooms look like parasols -->therefore parasympathetic!! gprotein related so works more slowly, works in CNS and in ANS but is minority, IN TARGET CELLS ONLY |
| alpha cells | constrict, favor NE > E |
| beta cells | dilate, in B1 NE = E, in B2 E>NE, in B3 NE > E. B1 prevents heart from beating too fast, B2 dilates blood vessels in lungs to allow for more oxygen, treats things like asthma |
| Blood brain barrier | things that plan to go through the blood brain barrier should be lipid soluble and small |
| how does the sensory system basically work? | there's a stimulus, it gets to the receptor membrane of a receptor cell, triggering vesicles of neurotransmitters to release on the other end of the cell, initiating a response in the next receptor cell, and so on and so forth. |
| two kinds of receptors: rapidly adapting | respond quickly to a signal but only send one or two messages, these are for "on-off" responses, ie. clothes rubbing against skin or something |
| two kinds of receptors: slowly adapting | send you continuous messages regardingthe stimulus, the signal stops sloooowly, signals prolonged events, ie. joint and muscle receptors holding you upright |
| sensation in the body | sensation --> transmission --< integration --> preception. sensation is the physical feel, the message is sent through your body, to your brain, understood, and the you perceive what just happened to you |
| proprioception | the ability to sense the position and location and orientation and movement of the body and its parts. |
| thermosensors | temperature sensitive, cation channels that are nonselective and open in response to body temperature |
| nociceptors | pain receptors, free nerve endings |
| unmodulated pain | c fiber sends pain from pns to cns, stimulates the release of substance P which eventually goes from the spinal chord to the thalamus to the brain |
| modulated pain | AB fiber modulates a secondary, inhibitory neuron which releases inhibitory NT to cancel out the substance P. both C fibers and AB fibers fire epsps/ ipsps to an inhibitory interneuron, whoever has the stronger response will decide what happens. |
| modulated pain continued | if c fiber is stronger then you do feel pain, if AB fiber is stronger then you dont. AB fibers are linked to skin mechanoreceptors, thats why pressing a hurt area reduces pain, you stimulate more mechanoskin receptors thus AB fibers have a stronger epsp |
| taste | there's only one type of taste bud, taste depends on the pH of food || sour (h+ blocks the k+ channel, depolarization of cells)|| salt (Na+ depolarizes afferent neuron) |
| taste continued | sweet/umami: triggers gprotein second messenger system that eventually blocks the k+ channels and depolarizes the receptor |
| shapes of psychoactive drugs | psychoactive drugs mimic the shape of important NT. |
| substance dependence is decided by dependence on the atleast 3 of te flollowing things for more than 12 months | look at tabe 8.3 and 8.5 |
| down regulation due to drug use | when you take drugs, you have so much signal that your body down regulates the receptors |
| cross tolerance | tolerance to one drug increases as your tolerance to another drug increases |
| what part of your body detoxifies the drugs | smooth endoplasmic reticulum in liver cells |
| drug dosage | based on your body's calculated ability to detoxify a drug |
| wernickes area | site of brain related to comprehension of language, can speak but words make no sense |
| broca's area | site of brian related to articulation of language, words don't come out right |
| dependence | addiction, has a psychological aspect and a physical dependence (withdrawal) |
| tolerance | when you need higher doses to get the same effect of drugs, down regulation causes this |
| sarcomere | a single unit of skeletal muscle, contracts down |
| heart | muscle the size of your fist, hollow, contracts everywhich way |
| agonistic muscles | move the body through space, the ones that allow you to bend your limbs |
| antagonistic muscles | return the body to its normal position |
| skeletal muscle | regular arrangement, striated appearance, multinucleated |
| cardiac muscle | branched arrangement, intercalated disks, single nuclei |
| smooth muscle | layered arrangement |
| muscle cell = muscle fiber | |
| tendons | attach muscle to bone |
| ligaments | attach bone to bone |
| structure of a sarcomere | comprised of thick filament (sandwiched between thin filaments, made of myosin, in the middle of the sarcomere), thin filaments (between the thick filament, made of actin, troponin and tropomyosin),z-line (what separates one sarcomere from the other |
| structure of a sarcomere continued | what both filaments are attached to). |
| how a contraction occurs: sliding filament mechanism | when a contraction occurs, thick and thin filaments don't change length, the thin filaments move in, towards the center of the sarcomere, creating the contraction |
| how a contraction occurs: step 1. enter calcium | calcium enters the cytoplasm. binds to troponin and opens myosin binding sites on actin, myosin crossbridges, these little heads on the thick filament, then bind with the actin molecules on thin filaments. |
| how a contraction occurs: step 2. POWER STROKE | breaking ATP into ADP gives myosin the energy to cock its head, bind to actin, which releases the strained conformation of the bridge and moves the crossbridge, called a power stroke |
| how a contraction occurs: step 3. break it off | actin and myosin are tightly bound, you need to break that if you want another power stroke. bind ATP to the myosin head, uncocking itand returning it to its rest position. ATP isn't hydrolyzed here though, just attached to weaken the actin-myosin bond |
| how a contraction occurs: step 4. hydolizing atp | the ATP on the myosin head is split, reenergizing the myosin head so its ready for another powerstroke. if calcium is present, the myosin head can attach to another actin molecule and start this all again |
| ATP has two important jobs during a muscle contraction | 1. releases energy during ATP hydrolysis to allow the crossbridge to move 2. ATP BINDING, not breaking, allows they link between the actin and myosin head to weaken so the cycle can repeat |
| troponin and tropomyosin on thin filament | tropomyosin is covering the myosin binding site on each actin molecule so crossbridges can't just attach whenever they like. troponin binds to tropomyosin and regulates the acess to myosin binding site as well. |
| calcium's role in muscle contraction | when calcium binds to troponin, it changes the proteins structure, triggering tropomyosin to move and opening the binding site. the amount of calcium, therefore, determines if you move or not |
| why aren't there inhibatory transmitters released at the neuro muscular junction | because muscle fibers only contract, there is no opposing action, inhibition of muscle contraction = relaxation and if you don't wan the muscles to contract, just don't release the AcH |
| what is the NT that triggers muscle contraction? | AcH |
| how does AcH trigger muscle contraction? part 1 | motor neurons release AcH, it goes around the sarcolemma (membrane around muscle fibers) until it finds T-tubules. AcH goes down the tubule until it binds to the DHP receptors. |
| how does AcH trigger muscle contractions? part 2 | that, in turn, triggers the ryanodine receptors and opens the sarcoplasmic reticulum (endoplasmic reticulum in muscles) which then releases calcium into the cell's cytoplasm. calcium will then go bind with troponin and do its thing. |
| how does AcH trigger muscle contractions? part 3 | to reomove ca from the muscles, energy from hydrolyzing ATP --> ADP pumps it back into the sarcoplasmic reticulum |
| motor neurons | innervate skeletal muscle fibers, located in brainstem/spinal chord, a single motor neuron can innervate many muscle fibers but each muscle fiber is controlled by a branch from only one motor neuron, no muscle fiber is controlled by more than one neuron |
| botulinum | blocks Ach release, no Ach release = no Ca release, no Ca = no muscle contractions, paralysis |
| curare | blocks nicotinic Ach receptors, no Ach accepted, no Ca release, paralysis, temporary though bc gprotein receptors are still working |
| succinylcholine | similar to Ach-esterase inhibitors. too much Ach build up, constant contractions, body doesn't get to relax so you are paralyzed or, if the diaphragm is constantly contracted, you die |
| twitch: | single contraction cycle |
| tengion: | state of contraction at the muscle |
| tetanus: | full sustained contraction |
| energy sources of atp | 1st couple seconds: Stored ATP. next 15-30 seconds: creatine phosphate phosphorylating the ADP. 10-15 seconds of glycolysis. primary source of ATP is oxidative phosphorylation |
| review of cellular respiration: glycolysis | occurs first, in cytoplasm, divides glucose into 2 3sugar molecules, makes pyruvate, 2 NADH and 2 ATP ar produced, doesn't need oxygen |
| review of cellular respiration: transition step | NAD+ turns both pyruvates into Acetyl Co-A which is taken to mitochondria for krebs cycle |
| review of cellular respiration: krebs cycle | 2 ATP made |
| fermentation | lactic acid, regenerates the Nadp, needed to make ATP, is absorbed back into the blood and taken to the liver to make glycogen, lactic acid is a byproduct of glycolysis |
| msucle fatigue | if a skeletal muscle fiber is stimulated too much, tension of the fiber decreases even though stimulus continues. lack of ATP is not a cause of muscle fatigue, ATP concentration is only slightly lower in a fatigued muscle than resting muscle |
| causes of muscle fatigue: conduction failure | buildup of K+ ions in t tubule, leads to depolarization, failure to produce action potential bc of inactivated sodium channels |
| causes of muscle fatigue: lactic acid buildup | too much anerobic respiration, lactic acid builds up, acidifiation of muscles alters proteins including actin and myosin, ca atpase pumps to sarcoplasmic reticulum are affected |
| causes of muscle fatigue: inhibition of cross bridge cycling | buildup of ADP and P in muscle slows down the cross bridge step 2 which delays crossbridge dtachment of myosin from actin, reducing overall speed of contraction |
| causes of muscle fatigue: glycogen | glycogen provides fuel for contraction, derease in glycogen definitely related to fatigue |
| types of skeletal muscle fibers: slow oxidative | low myosin atp activity, aerobic, dark meat, does the most work, fatigue resistant |
| types of skeletal muscle fibers: fast oxidative | the inbetweener, can be aerobic or glycolitic (anerobic) doesn't fatigue very quickly but does fatigue faster than slow oxidative |
| types of skeletal muscle fibers: fast glycolitic | rapid, easily fatigued, maximum contraction, chicken breast |
| most muscles are comprised of all three muscle fiber types, nor just one | |
| antagonistic muscles, | muscles that oppose directed movements |
| smooth muscle | uses cross bridges between actin and myosin filaments to generate force. but the process of contraction and the organization of the filaments is very different. troponin is not present. thin filaments are attached to dense bodies (like the z lines) |
| structure of smooth muscle fibers | spindle shaped, sheet licke layers, single nucleus, cells become globular when contracted, can contract over a wider range, less likely to fatigue, lower oxygen demanded, equally distributed thick and thin muscle |
| recruitment | order the energy sources come from. slow oxidative fibers first, then fast oxidative, then fast glycolitic. fast glycolitic is anerobic and the logic is, you already have ATP, may as well use it before you switch to anerobic respiration |
| cholinergic receptors | responds to AcH |
| what triggers the crossbridge process in smooth muscle | because there's no troponin blocking actin's binding site, the thin filament is not the switch to contraction in this case. instead an enzyme phosphorylating myosin triggers the rpocess |
| smooth muscle contraction | 1. amount of Ca in cytosol increases. calcium binds to calmodulin, protein present in cytosol of most cells. 2. calcium-calmod combo then attaches to enzyme myosin light chain kinase (MLCK), thus activating it |
| smooth muscle contraction continued | activated MLCK uses atp to phosphorylate the myosin crossbridge head, pushing the head into the cocked position and binding it to actin. as long as there's calcium to bind to calmodulin and start this, this process can continue. |
| how do smooth muscles relax? | myosin light chain phosphate will dephosphorylate the myosin head, allowing the smooth muscle to contract |
| difference between smooth muscle and skeletal muscle contraction | in skeletal muscle, the presence of calcium alters the thin filament (moving tropomyosin). in smooth muscle, adding calcium alters the thick filament ( cocking the myosin head) |
| pacemaker potential | spontaneous change in voltage in a cell |
| slow waves | some smooth muscles depolarize at regular intervals and return to normal immideately but generally smooth muscles depolarize in slow rising curves, unless theres a stiumulus (like food) in which case it starts spiking alot |
| varicosities | autonomic nerve fibers that branch into the smooth muscles, branches from a single axon can be located in and trigger several muscle cells, |
| smooth muscle activity vs skeletal muscle activity | smooth muscle activity can be increased or decreased based on neural activity while skeletal muscles only get input from motor neurons |
| cardiac muscle structure | branched, single nucleus, adjacent cells are connected by intercalated disks, desmosomes that hold cells together and where myofibrils attach. whithin the intercalated disks are gap junctions, branched appearance |
| cardiac muscle contraction | begins in response to propogation through t tubules. depolarization occurs in cardiac muscle cell through influx of ca ions from voltage gated l-type calcium channels. |
| importance of calcium in cardiac muscle | unlike skeletal muscles,sarcoplasmic reticulum,which releases even more calcium,is triggered when calcium in the cytosol binds to ryanodine and calcium rushes into cytosol. cardiac contraction dependent on the movement of xtracellular calcium into cytosol |
| importance of calcium in cardiac muscle | contraction ends when calcium concentration is low again due to calcium pumps |
| structure of a sarcomere continued. h zone sandwhiches the m line | myofibrils(striated thick and thin filaments). A line (thick filaments layer on top of each other creating a dark band in the center of the sarcomere) I band ( same thing a a band but for thin filaments) mline, in the middle of the thick filaments, center |
| for more muscle study, look at table 9-6 | |
| monosynaptic | does not have an inter neuron (knee jerk), stretch reflexes are the only known monosynaptic reflex arcs |
| polysnaptic | does have an inter neuron, except for stretch reflex, all other reflex arcs are polysynaptic |
| paralysis | loss of voluntary muscle control |
| motor control | pattern of neural activity required to properly performed movement |
| proprioception | afferent information about the position of the body and its parts in space, being able to tell where you body is and |
| voluntary movement | 1. movement accompanied by conscious awareness of what we're doing and why, attention is directed towards performing the action |
| involuntary | automatic |
| interneurons | synaptic input to motor neurons from afferent neurons/descending pathways don't go straight to the motor cells, they go through inter neurons |
| why are interneurons inmportant | important in deciding which muscles are activated and when, can act as switches that enable movement to be turned on and off on command. |
| why interneurons are important contintued | ie. pick up a hot plate and reflexes say stop it. however higher command can direct interneurons to tell you to hang on, if that plate has your dinner or something |
| stretch receptors | embedded in muscles, monitor muscle length and rate of change in muscle lenght, have peripheral endings of afferent nerves wrapped around muscle fibers |
| muscle spindle fibers: responsible for regulation | multiple stretch receptors bound together, prevents over stretching. has two kinds of stretch receptors:nuclear chain fibers( responds best to how much muscle ahs been stretched) and nuclear bag fibers ( responds to speed and magnitude at which it occurs) |
| intrafusal fibers | these modified muscles withing the spindle, with the stretch receptors in them. not large/stong enough to shorten a muscle or move joints. only job is to mantain tension on spindle stretch receptors |
| extrafusal fibers | skeletal muscle fibers that create the bulk of the muscle, generate movement and force, contracting fibers |
| muscle spindles are parallel to extrafusal fibers | an external force stretchign the muscle also pulls the intrafusal fibers, stretching them and activating their receptor. speed and amount of stimuli affect rate of receptor firing |
| stretch reflex: | excitatory synapse directly on a motor neuron that goes back to the muscle causing it to strech. look @pg302 |
| reciprocal innervation | activating neurons in one muscle simultaneously inhibits the antagonistic muscle, helps in walking |
| dual innervation | an organ receives impulses from both sympathetic and parasympathetic, usually one excites while the other inhibits |
| synergistic muscles | muscles whose contraction assists the desired movement |
| alpha motor neurons | motor neurons controlling the extrafusal muscle fibers |
| gamma motor neurons | smaller motor neurons that innervate intrafusal fibers |
| alpha gamma coactivation | alpha and gamma neurons are both right next to eacho other and activated by interneurons right nextto them, often they are coactivated, ie. excited at the same time to allow info about muscle lenght to be constantly availible for future adjustment |
| golgi tendon | shuts down the muscle reflex, keeps you from over stressing, receptors involved in monitoring body's tension, look @pg304 |
| difference between muscle spindle and golgi tendon | muscle spindle provides homeostatic control of muscle LENGTH while golgi tendon provides local homeostatic control of muscle TENSION, both this info can be used to modify future motor program |
| crossed extensor reflex (contralatera=on the opposite side of the body) | same stimuli causes opposite respones on the opposite leg. ie. the stimuli that triggers you to lift one foot also triggers you to stiffen the opposite foot so you don't fall. look @pg305 |
| withdrawal reflex (ipsilateral=on the same side of the body) | moving the limb away from harmful stimulus |
| babinski reflex | fanning of the toes, suppressed as you get older, if the babinski reflex is present in an adult, there is damage to the brain |
| REFLEXES | fixed, automatic movements triggered in response to a specific sensory stimulus usually fairly rapid, little voluntary control, but can be modulated e.g., patellar tendon, eye blink, etc. |
| RHYTHMIC MOVEMENTS: | also a combination of reflex and volition initiation and termination is voluntary, but the actual movement is more stereotyped e.g., walking, running, chewing, etc. |
| VOLUNTARY MOVEMENTS: | purposeful, goal-directed movements initiated entirely from within the CNS performance improves with practice reflex and postural movements are often initiated that compensate for the effects of the intended action on other parts of the body |
| flexor muscles | muscles whose contraction bends a joint |
| extensor muscles | muscles whose contraction extends a joint |
Created by:
hsinha93
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