Week 6 notes after test
Week 6 notes after test PHYS 215
Popular in Human Physiology
Popular in Science
This 8 page Class Notes was uploaded by Jennifer Fry on Wednesday September 30, 2015. The Class Notes belongs to PHYS 215 at Ball State University taught by Zamlauski-Tucker in Summer 2015. Since its upload, it has received 14 views. For similar materials see Human Physiology in Science at Ball State University.
Reviews for Week 6 notes after test
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 09/30/15
Physiology Week 6 notes Notes for test 3 93015 The NeuromuscularJunction De nition 0 A synaptic connection formed between a motor neuron axon and a muscle ber The membrane of the muscle ber is folded in the region of contact with the axon terminal this increases the surface area There are many postsynaptic receptors packed into the region of the muscle ber membrane that is juxtaposed with the axon terminal The motor endplate o Postsynaptic membrane of the neuromuscularjunction 0 Contains a series of shallow folds that line up with the presynaptic terminal active zones Synaptic vesicles accumulate along these bands of active zones Acetylcholine is the neurotransmitter released at the neuromuscularjunction Excess acetylcholine in the synaptic cleft is destroyed 0 Broken down into choline and acetate by acetylcholinesterase o This terminates the transmission Haw newer trigger a muscle ergll fiber E ntr rtiitm Neuromusc ular junction The 11oiisrol1lliisoular junction iii Due 11cm col forms K neurotiilliscular it unnumu litm hGTi iE LELEI a norm cull Iii it neuron PHIEl a mumIt ml M l ff lili39lil 3971 gme rm ma i lE i39 1 i i g ir quot 391 quota 1 I I I quoti l I llr r r l a an 1 H l arm 13min ocn th culls 1 Iln in mmFL Jum m a I quoth mm ii era l39lELlll39 39llllli L lh39i the r 7 Hu la mi 7 j H 7 lilil l UEIIE Wm mLi39rU39lmnsmitlur Heummuseuilnr Etcctylelmlliiiie Ach z39 mtW mm NEW in cunniliilliriiciittg r x Th 3390133 li llllEEIJ Ellllii 1 I a 3 mr 39 r AChEi A I int1111 the Egg 39 lam yquot the l illsllhllll tuber Ill 1 i i u i mun Mn r 1 WE39LL Ur mm HIIT39ILlllztliL Ei lmvi ril l l Emilii 1mm nd on t minal nF mullJr ncuen l39lcutIr Enema3 Minnguy EQTMITI39I39IQ The impulse travels dawn the axon and enters the muscle at the Neuruni us cular jun ctiun causing volt age regulated calcium channels in the axon membrane to up en I39 ntnr EI39II39EIIEIIFJlE Esme tesicle Mitechcindria Emmett iE lcft Smccleimna Swim at the myti lm T tubule Ealciunl iuns frunl the e11139ac ellular uid ew in tn the aJtun terminal This causes synaptic vesicles tu fuse with the FI ES j Il ptil n1 Eltll r ane and release the tr an sn1itt er substance Acetj lechuline intu the synaptic cleft Eitcitatien Cun lrae39tin C uupling rtlhe details 4 39rf 1 J Ii illli I Filer sen binds in faceplate en the aamelernms same39lemma eaten ending Synaptic Ac etylecheline A h diffuses across the gap and attaches to receptors en the sarcelenuna This causes an action 11 etential impulse wave to h e sent along the sarculenuna spreading along the muscle bre issuance immiscth t39leupling t1c details the AEh racemes spams Hat enters and tilt leases sarenplasm thmugh the same channel creating the endmete itential EFF I End plate patents is just a change a K the membrane petcntial atquot the muscle cell ber a fl Emitslion Conimei39ion Eon line details Exm taimn Lorijlmctmn toppling the details Pay EP39P emit voltage gated lain ghg39anmella In adjacent Eaglema all reamnllenimm Diffusion oil Wait and Hi thmug l1 their rite Elhansnieis depeiart e membrane email imiti i ee E l39li potential in muscle iiilh iquot aa quota r T Action pairentlala propagated down 11 in HllJlIiEE tn llll lletEFii illquot cri muscle fiber o Acetylcholinesterase destroys acetylcholine o This terminates the action potential and response of the muscle cell Muscle Physiology 0 3 types of muscles comprise the 600 muscles in the human body 0 Smooth 0 Cardiac o Skeletalstriated 0 Smooth muscle 0 Involuntary Uninucleated one nucleus Spindleshaped Often woven with connective tissue bers Unstriated arrangement of myosin and actin is less c i 0 Contains numerous gap junctions 0 Cardiac muscle l o Primarily involuntary 0 Only in the heart 0 Contains generally one nuclei 0 Has own inherent rhythm and can contract without an stimulus 0 Has faint striations and are branched o Gap junctions are common 0 Skeletal muscle move the skeleton o Consciously controlled 0 Has very long bers cells which are unbranched 0 Contains many nuclei 0 ln transverse section has lines striations running along the sh axis of the ber 0 Properties of Muscle OOOO o Excitabilityrespond to stimuli o Conducti39v39ity able to conduct electrical charge My lam ms o ContractIIIty shorten when stimulated mimimnl Tlk a o Extensibility able to be stretched again quot 1quot mm o Elasticity able to recoil to its original length is 1 Thi l1 l m l 39 o The Muscle Fiber 0 A muscle ver is a skeletal muscle cell 39 75 4139 39 legion sa rpnmei e Samuinum o Fibers extend the entire length of a skeletal muscle 0 A muscle ber contains contractile elements called myo brils o A myo bril contains myo laments Thick laments myosin Thin laments actin The myo laments are responsible for the striations of the myo bril and can be labeled as bands Banding striations o A band dark band where thick and thin laments overlap o l Band light band thin laments only also 2 disc 0 H zone thick laments only 0 M line separates direction of myosin orientation 0 Z disc separate sarcomeres anchor laments When the surface membrane depolarizes a voltage sensor which is a part of the dihydropyridine receptor located in the transverse tubule becomes activated in membrane The dihydropyridine receptor is thought to be involved in transmitting the depolarizationevoked signal to the ryanodine receptor a receptor in the sarcoplasmic reticulum After the ryanodine receptor is activated calcium is released from the Calcium flows into m a gt line oyiosol Lj Calcium will then interact with a muscle lame 39 mu le lamem Pmi m Thick Filaments rupunilni o Myosin head groups form cross bridges o The cross bridges can attach to actin binding sites 0 The cross bridges also have myosin ATPase activity Thin Filament O 3 prOtEinS Proponir39 complex Tropornmairs G Fl il39i Troponin 39 l i n l a 391 isquot mr gt M I iiid quot if M v 39 Actin quot 39 r ACti n Portion of a min fllamam o The main thin structural protein in the sarcomere 0 Each actin molecule has a binding site that can attach with a myosin cross bridge Tropomyosin o Tropomyosin covers the actin binding sites preventing their union with myosin cross bridges Troponin o 3 binding sites Tropomyosin Actin Calcium 0 When calcium combines with troponin tropomyosin slips away from its blocking position between actin and myosin Familnlrimi 39quotnzlrl lmclrinn Fmrp ling film distnils ExileilithioiniCiontrabtimn39 quot 7 Guupling 39 Stein 1 J r Troponin changes shape and moms y awayquot from active sites tropomyosin W w EDMFIIEEE E A tlv 1MO5in active sift25 whem actin Will subsequently bind l r p 1D Tmponi n I 1 position at posing O to mlylusln Skeletal muscle contraction is a molecular phenomenon o The myosin cross bridges can bind to actin pulling these thin laments toward the center of the sarcomere This is the sliding lament mechanism The width of the A band remains unchanged The H zone is shortened horizontally The l band decreases in width as the actin overlaps more with the myosin Neither the thick nor thin laments change in length They change their position with one another The actin slides closer together between the thick laments 6 steps 0 The in ux of calcium triggering the exposure of binding sites on actin o The binding of myosin to actin o The power stroke of the cross bridge that causes the sliding of the thin laments o The binding of ATP to the cross bridge which result in the cross bridge disconnecting from actin o The hydrolysis of ATP which leads to the reenergizing and repositioning of the cross bridge 0 The transport of calcium ions back into the sarcoplasmic reticulum A whole muscle is a group of muscle bers 0 A single action potential in a muscle ber produces a twitch o Gradations of whole muscle tension Depend on the number of muscle bers contracting And the tension developed by each contracting ber The tension developed by muscle depends on the frequency of stimulation 0 Repetitive stimulation Increases its tension by twitch summation o Contractile responses twitches Add together by two actions potentials signaling a muscle ber closely together in time 0 Rapid stimulation Cannot relax between stimuli Twitches merge into a smooth sustained maximal contraction called tetanus o Twitch summation results from sustained elevation of calcium in the cytosol The tension of tetanic contraction also depends on the length of the ber at the onset of contraction O O O The optimal length is the resting muscle length At lengths other than the optimal length not all cross bridges are able to interact for muscle shortening Muscle tension also depends on the extent of fatigue and the thickness of the ber lsotonic and isometric O O O Isometric contraction Muscle tension developed is less than its opposing load Muscle cannot shorten and lift the object with that load lsotonic contraction the muscle tension developed is greater than its opposing load Muscle usually shortens and lifts and object Constant tension throughout the period of shortening The velocity of muscle shortening is inversely proportional to the magnitude of the load Skeletal muscles can perform work 0 Work is calculated by multiplying the magnitude of the load times the distance the load is moved Force x distance Much of the energy applied is converted into heat About 25 is realized work About 75 in converted to heat Bones muscles and joints interact to form lever systems 0 O O O O A lever is a rigid structure capable of moving around a pivot The pivot is the fulcrum The power arm is the part of the lever between the fulcrum and the point where an upward force is applied The load arm is the part of the lever between the fulcrum and the downward force from the load Often the velocity and distance of muscle shortening is increased to increase the speed and range of motion of the body part moved by muscle contraction The muscle must exert more force than the opposing load for this increased speed and range ATP is generated 3 ways for the muscle contraction Creatine phosphate plus ADP is converted to creatine plus ATP First source of ATP for the rst minute or less of exercise Oxidative phosphorylation generates large amounts of ATP in the mitochondria if 02 is available for the muscle cell Aerobic exercise Myoglobin which can transfer oxygen into muscle cells Glycolysis Produces lactic acid and produces muscle soreness Remember glycolysis supports anaerobic exercise 0 These are 2 types of fatigue 0 Muscle fatigue An exercising muscle can no longer respond to the same degree of stimulation with the same degree of contractile activity Why 0 Increase in inorganic phosphate Accumulation of lactic acid Depletion of energy reserves 0 Increased oxygen consumption Central fatigue occurs when the CNS can no longer activate motor neurons supplying working muscles Often Psychological and is related to biochemical changes at the synapses in the brain 0 Muscle Fiber Types 0 O The 3 types of skeletal muscle bers are Slow oxidative type I bers Fast oxidative type lla bers Fastglycolytic type llb bers Most humans have a mixture of all 3 types of bers They are classi ed by the pathway used for ATP synthesis oxidative vs glycolytic and the rapidity by which they split ATP and contract fast vs slow Oxidative bers are red with a high concentration of myoglobin Muscle bers can adapt to the different demands placed on them 0 Regular endurance exercise longdistance jogging Promotes improved oxidative capacity in oxidative bers The bers use oxygen more ef ciently o Highintensity resistance training Promotes hypertrophy of fast glycolytic bers The bers increase diameter Testosterone promotes protein synthesis for this increase 0 Eight training can convert fastoxidative bers to fastglycolytic bers 0 Skeletal muscles atrophy when not used 0 Skeletal muscles have a capacity for limited repair 0 Control for motor neuron output 0 1 Spinal re ex pathways that arise from afferent neurons 0 2 Corticospinal pyramidal motor system that arise from the primary motor cortex Mainly intricate movements of the hands 0 3 Pathways of the multineuronal extrapyramidal motor system that originate from the brain stem Mainly postural adjustments and involuntary movements of the trunk and limbs Muscle receptors 0 Muscle spindles This input can communicate changes in muscle length When stretched triggers the re ex contraction of that muscle 0 Golgi tendon organs Located in the tendons of muscles Muscle tension 0 A stretch re ex is triggered when a whole muscle is passively stretched o The classic example of the stretch re ex is the pateIIartendon or knee jerk re ex