Exam 6 Material 2 17 14 Visual System Info energy waves 7 21 Type photoreceptors Components of the eye o Cornea and lends focus image 7 26 glasses poorly shaped eyeball o Retina transforms into signal Receptors at back Afferent in front Where afferents exit no receptors blind spot Coding o 2 kinds of receptors 1 Rods activated more in low light conditions dim light 2 Cones bright light Lose color as light gets dimmer Black and white rods Colors cones Color Vision based on three cone pigments blue green and red 7 32 What about yellow Multiple cones are activated Color blind Issue with cones but not missing cones lacking pigments curves 7 32 are shifting o Most common red green colorblind o 10 20 of white males are color blind Chemosensory System Info dissolved chemicals Type chemoreceptors Components o External taste and smell o Internal pH O2 Co2 ect Taste in mouth and throat why you get an after taste with some foods o Lots of surface area more receptors 7 47 o Categories of taste 1 Salt Na channels tasting salty 2 Sour H blocks K channels 3 Sweet sugars bind turn sugar into energy 4 Bitter various substances bind things we don t want to typically ingest compounds you don t want too much in your body because too much toxic ex Bitter beer face too much beer is BAD 5 Umami glutamate MSG binds enjoyable flavor flavorful MSG will always be preferred need Umami to run cell metabolic pathway 6 Likely adding a fat receptor soon Olfaction in nasal passages 7 48 o Receptors Differ in type and quantity Last only about two months why you get used to smell of house but can smell your friends houses Perception How we interpret these signals cerebral Often signals combine e g taste o Ex This is why you can t taste soup when you re sick Better at detection than consciously aware Supports and moves skeleton Types of Muscle 1 Skeletal 9 1 striated To bone via tendons Voluntary control 2 Cardiac 9 1 striated Heart muscle Sheets surrounding organs Make organs smaller bigger Contraction alters flow Autonomic involuntary Involuntary control autonomic 3 Smooth muscle 9 1 not striated aka smooth 2 19 14 Anatomy of a Skeletal Muscle Muscle organ Myofibers o Muscle cell fiber o Multi nucleated Myofibrils o Bundles Myofilaments o Basic structue o Thick myosin o Thin actin Sacroplasmic reticulum SR o Surrounded myofibrils Holds Ca 2 Transverse tubules TT o Plasma membrane extensions IF channels Mitochondria tons 9 6 Anatomy of a Myofilament Z line disc thin connections Sarcomere functional unit z to z change in size I band only thin light band change in size A band length of thick dark band no change in size M line midpoint between z s H zone only thick change in size Myofilaments o Actin thin filament double helix chain myosin site Tropomyosin bound to actin long Troponin bound to tm and actin small Ca 2 site 9 3 o Myosin thick filament golf clubish actin and ATP sites Cross bridge flexible causes movement o At rest tropomyosin blocks actin myosin binding 9 3 9 11 Innervation of Muscle Motor neurons o AKA somatic efferents o Axon ending branch 1 N many M 1 M 1N Motor unit o 1 neuron its myofibers 9 7 o 9 8 9 9 Muscle Function Contraction o AP conducted along PM into TTs o In SR voltage gated Ca 2 channels open o Ca 2 binds to troponin o Tropomyosin moves myosin site exposed o Myosin ADP and PI binds to actin 2 21 14 Muscle Function Continued Crossbridge Cycling series of conformaton changes 9 15 o Myosin ADP and PI binds actin bind a protein to a protein shape change o changing binding site shape changes the affinity o Releases ADP and PI changing shape makes it harder for them to hold onto ADP and PI so they come off o Flex of cross bridge o Ex Pulling a rope o ATP binds myosin o Myosin releases actin o ATP to ADP and PI o Deflex cock of cross bridge Moves only 10um Rigor Mortis o If not ATP myosin remains bound to actin Sarcomere shortening sliding within 9 14 o Thicks pull this toward M line o Filaments DO NOT contract change in size 9 13 o Unchanged A band 9 14 o Shortened Saracrome I band and H zone Relaxation pump 9 12 and 9 11 o Removal of Ca 2 from tropoin o Tropomyosin blocks myosin binding site o No cross bridging Duration o AP trigger 1 2 ms o Latent period 9 10 Increase in Ca 2 in cell o Contraction up to 100ms Decrease in Ca 2 in cell o Muscles need a lot of ATP Dissociation of myosin from actin 9 15 Energize the cross bridge same ATP ATPase pump to return Ca 2 to SR o Ca 2 returned to SR via an ATPase pump create gradient by using ATPase
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