Study Guide for Exam 3 - Human Anatomy Physiology | BSCI 201, Study notes of Physiology

Download Study Guide for Exam 3 - Human Anatomy Physiology | BSCI 201 and more Study notes Physiology in PDF only on Docsity! REVIEW SHEET FOR LECTURE EXAM 3 – The third lecture exam will be on the Muscular system only. The third lecture exam is on FRIDAY November 19th as scheduled in the syllabus. Muscular System 1) Define: endomysium, perimysium, epimysium, fascicles, tendons, sarcolemma, sarcoplasm, sarcoplasmic reticulum, myoglobin, sarcomere, Z line, H zone, A band, I band, Triad, motor unit a) ENDOMYSIUM CT membrane that wraps each Skeletal Muscle fiber b) FASCILE is a group of endomysium covered skeletal muscle fibers c) PERIMYSIUM CT membrane that wraps the Fascile i) A bundle of perymisum covered fasciles form the SKELETAL MUSCLE d) EPIMYSIUM Coarse CT membrane that wraps the Skeletal Muscle e) TENDONS attaches skeletal muscles; either Directly or Indirectly to the skeleton [ most are attached indirectly] i) 2 advantages to indirect attachment (1) The rope-like tendons can fit into small spaces to reach bones (2) Skeletal muscles that course over the joints will be protected if tendons run directly over the joint site skeletal muscles will be damaged at the joint sites as the joints move f) SARCOLEMMA Plasma Membrane of the muscle fiber g) SARCOPLASMCytoplasm of the muscle fiber h) SARCOPLASMIC RETICULUMspecialized smooth endoplasmic reticulum that stores/releases calcium into the sarcoplasm; the expanded ends of SR are called TERMINAL CISTERNAE i) MYOGLOBIN a red pigment that binds and stores oxygen j) TRIADComposed of transverse tubule in between 2 terminal cisternae i) Function for the Release of Calcium ions into the sarcoplasm when the sarcolemma depolarizes k) T-Tubule involutions of the sarcolemma into the sarcoplasm l) MOTOR UNITS is the motor neuron and all the skeletal muscle fibers it innervates via its axonal terminals m) Z line  anchors/stabilizes thin filaments n) SARCOMERE is the distance between 2 successive Z lines i) Are the structural units of skeletal muscle; shortening of sarcomeres results in skeletal muscle contraction. o) A band is referred to as the THICK filaments aka MYOSIN p) I band region not overlapping with the A band; THIN filaments aka Actin q) H zone region of the A band that does not overlap the thin filaments r) M line is a Line bisecting the H zone i) Anchors the A bands in the sarcomere s) Motorneurons innervate all skeletal muscles i) Parts of the PNS; when stimulated generate electrical signals called ACTION POTENTIALS= transmitted action potentials are referred to as Nerve impulses ii) Gives off end branches called AXONAL TERMINALS each axonal terminal of a motor neuron makes contact with only one skeletal muscle fiber with the skeletal muscle. Each skeletal muscle fiber in a skeletal muscle is contact by ONLY one Axonal terminal. 2) Describe the neuromuscular junction. What is the motor end plate? a) Neuromuscular Junction is the junction between the Axonal Terminal and the Sarcolemma of the skeletal muscle fiber. i)Small space between the axonal terminals and the motor end plate is called the NEUROMUSCULAR ( synaptic )CELFT b) Motor End Platethe region of the sarcolemma directly involved in forming the neuromuscular junction= is highly folded and expresses receptors that bind a neurotransmitter called ACETYLCHOLINE. 3) Actin and Myosin…….. my stuff a) Thick,thin,thick,thin arrangement give the skeletal muscle a striated appearance b) Skeletal Muscle Fibers i) 80% composed of Myofibrils run the entire length of the skeletal muscle (1) Myofibrils composed of smaller filaments called MYOFILAMENTS[ 2 types] (a) THICK composed of MYOSIN (i) Structure rod-like Tail that ends in 2 GLOBULAR HEADS (b) THIN composed of ACTIN 4) Name the 3 proteins in a thin filament. What is the function of tropomyosin in a relaxed skeletal muscle? a) ACTIN i) Double helical structure that forms the core of the thin filament contains binding sites for Myosin b) TROPOMYOSIN i) In a relaxed skeletal muscle it spirals about the actin blocking myosin binding sites on actin i) Stored ATP in skeletal muscle fibers stored ATP can support only 5 secs of skeletal muscle activity ii) Creatine Phosphate (CP) unique in muscle cells especially in skeletal muscle fibers (1) CP phosphorylates ADP to give ATP, ADP + CP  ATP iii) Catabolism ( breakdown ) of glucose in the absence of oxygen = ANAEROBIC CATABOLISM of glucose [ aka glycolysis ] (1) Will yield 2 molecules of ATP + Pyruvic Acid [ when oxygen is absent, pyruvic acid is converted into LACTIC ACID lactic acid contributes to Muscle Fatigue; which halts skeletal muscle contraction iv) AEROBIC Catabolism of Glucose in the presence of oxygen; which produces 36-38 ATP molecules and is more efficient in generating ATP to supports muscle v) contraction, but it involves more steps than anaerobic catabolism d) how is the generated ATP used in skeletal muscle contraction? i) ATP is hydrolyzed by ATPase to produce ADP and Pi to activate myosin heads ii) ATP is required for crossbridge detachment iii) ATP is required for the sequestration of calcium ions back into the SR (active transport) 9) Define the sliding filament mechanism - list structures that a) shorten b) remain the same when a skeletal muscle contracts. a) Sliding of THIN Filaments in sarcomere toward the M lines in the H zones causes SHORTENING of Sarcomeres as the Z lines are pulled inward. b) Skeletal fibers shorten skeletal muscle shortens 10) Discuss the factors that affect the strength of skeletal contraction a) Size of motor unit activated larger motor units generate more force than smaller ones b) Number of motor units activated force increases as the number of motor units activated increases i) RECRUITMENT= Smaller motor units are activated first followed by larger motor units c) Frequency of skeletal muscle activation if action potentials are developed at a higher rate such that the skeletal muscle fibers do not have time to sequester calcium ions into the SR more and more calcium ions remain in the sarcoplasm resulting in stronger and stronger skeletal muscle contraction this effect is referred to as TEMPORAL or WAVE SUMMATION. i) When the skeletal muscle contraction levels off ( ‘plateau’)  TETANY ii) The response contraction of a s motor unit to a single action potentialTWITCH 11) MY STUFF on muscle contraction a) INCREASED CONTRACTILE FORCE i) Marge number of muscle fibers activated ii) Large muscle fibers iii) Asynchronous titanic contraction iv) Muscle and sarcomere length slightly over 100% of resting length b) INCREASED CONTRACTILE VELOCITY i) Small load ii) Predominance of Fast Glycolytic ( fatigable) fibers c) INCREASED CONTRACTILE DURATION i) Small load ii) Predominance of slow-oxidative ( fatigue resistant) fibers 12) Name and give the characteristics of the 3 types of skeletal muscle fibers: [ Slow oxidative, fast oxidative, fast glycolytic] a) Which type is fatigable and why? Which type is also known as red fiber and why? i) Slow Oxidative fibers are known as Red Fiber ii) Fast Glycolytic fibers are known as White Fibers iii) 3 types based on (1) Speed of contraction – 2 types (a) Slow fibers and fast fibers due to the speed at which Myosin ATPase hydrolyzes ATP (2) Major Pathway for ATP production – 2 ways (a) Aerobic respiration= oxidative fibers (b) Anaerobic respiration using more glycogen= glycolytic fiber types b) FAST GLYCOLYTC is FATIGABLE i) Are the largest fibers; and use aerobic respiration leads to LACTICE ACID build, which causes muscle fatigue (1) ARE FOR INTENSE BUT SHORT LIVED ACTIVITIES SUCHAS WEIGHT LIFTING. c) SLOW OXIDATIVE is fatigue RESISTANT i) Use aerobic respiration to generate ATP ii) Suited for endurance type activities; marathon runner (1) Training at higher altitude will make body compensate by making more Hemoglobin; coming to sea level to run a marathon has an advantage (a) Efficient use of oxygen (b) More Red fibers/ Slow oxidative fibers 13) Define isometric and isotonic contractions. a) Isometric contraction i) Force ( tension ) generated by the muscle is increasing at a constant muscle length ( “isometric” = same length); occurs when the weight exceed the force generated by the muscle b)Isotonic contraction i) Muscle shortens at a relatively constant force ( isotonic= same force); force generated by skeletal muscle exceeds the weight so the skeletal muscle contracts and does work by lifting the weight 14) MINE AGAIN : effects of exercise on skeletal muscle and stuff a) Matured skeletal muscle grows BY hypertrophy INCREASE in size of the skeletal muscle fibers ( cells) in the skeletal muscle  skeletal muscle fibers are MULTINUCLEATE cells and therefore they have the ability to undergo Mitosis, which would have resulted in Hyperplasia. As skeletal muscle grows by Hypertrophy, the larger skeletal muscle generates MORE FORCE= “ the bigger the skeletal muscle, the greater the force it generates” b) Skeletal muscle not activated or used will undergo muscle atophy decrease in skeletal muscle size decrease force generated by the skeletal muscle c) Aerobic or endurance exercise i) Increase in capillaries ii) Increase in mitochondria iii) Increase in myoglobin content iv) Overall endurance improves= increases In samina d) Resistance Excerise i) Changes in skeletal muscles: (1) Increase in size of the skeletal muscles= hypertrophy of skeletal muscles occur due increase in the number of myofibril within each muscle fiber ii) Increase in glycogen content iii) Overall, builk muscle generates more force= increase in muscular strength 15) Compare and contrast the structures and mechanism of contraction for skeletal and smooth muscles. What is the function of calmodulin in smooth muscle contraction? a) Structures and mechanism of contraction for smooth muscle i) Excitation-contraction coupling in smooth muscle cells (1) The sarcolemma is depolarized by the pacemaker activity (2) Calcium channels open up in the Sarcolemma and calcium ions enter the cell from the extra cellular fluid in the Caveolae. Hence, Calcium channel blockers can inhibit smooth muscle contraction. Calcium ions are released from the SR in the smooth muscle cell (a)Calcium ions to support or initiate smooth muscle contraction come from two sources (i) From the Extracellular Fluid (ii)From the SR (3) The calcium ions bind to CALMODULIN to form Calcium-Calmodulin complex (4) Calcium-Calmodulin complex activates Kinase called MYOSIN LIGHT CHAIN KINASE ( MLCK) (5) Activiated MLCK attach phosphate to the myosin heads results in activation of the myosin heads (6) Activated myosin heads bind to their sites on actin ( in a smooth muscle cell the myosin binding sites on actin are always accessible; although Tropomyosin is present it does not block myosin binding sites on actin) (7) The attached activated myosin heads from CROSS BRIDGES and as the phosphate dissociate form the cross bridge, the cross bridge undergoes a change in orientation termed the POWER STROKE which causes the thin filaments to