How would loss of negative feedback influence calcium release from the ER? Calcium channel would not shut down in presence of high levels of calcium Refractory period would increase Calcium would not release from the ER IP3 would not bind to the calcium channel Calcium pumps would not reduce local cytosolic calcium concentration

How would loss of negative feedback influence calcium release from the ER? Calcium channel would not shut down in presence of high levels of calcium Refractory period would increase Calcium would not release from the ER IP3 would not bind to the calcium channel Calcium pumps would not reduce local cytosolic calcium concentration

Body Structures & Functions Updated

13th Edition

ISBN:9780357191606

Author:Scott

Publisher:Scott

Chapter11: Endocrine System

Section: Chapter Questions

Problem 3RQ

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Table1.Contractionofsmoothmusclebythreeagonists Contractileresponse(mm) Loglagonist] (M) -10 -9 -8.5 -8 -7.5 -7 -6.5 -6 -5.5 -5 -4.5 -4 agonist-1 0.2 1.8 4 9.8 14.8 18 19.6 19.4 20 20 20 20 agonist-2 0.2 1 2.6 4 7.6 8.8 9.6 9.8 10 10 agonist-3 0.2 2 5.2 10 14.8 18 19.6 20 a) Experiments were performed on the contraction of smooth muscleusingincreasingconcentrationsofthreeagonistsandtherespo nsesare given in Table 1. The maximum response of the system was 20mm contraction. Calculate the % maximum response of the systemforeachconcentrationofagonistandplotgraphsshowingthede pendence of the response on log [agonist]. Compare the threeagonists in terms of their maximal effect and their potency usingpharmacologicalterms. EIN 5
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In the given below option what step causes a sarcomere to shorten? cross-bridge formation calcium transport into SR calcium release power stroke myosin heads in high energy state
What contains troponin, is involuntary and intracellular calcium is necessary in muscle contraction? Multi unit smooth muscle Unitary smooth muscle Cardiac muscle fiber Red skeletal muscle fiber White skeletal muscle fiber only one option should be correct
What step DIRECTLY causes a sarcomere to shorten? cross- bridge formation calcium transport into SR calcium release power stroke myosin heads in high energy state
Which of the following does NOT limit normal clot growth to the sight of injury? O A) Removal and dilution of clotting factors O B) Fibrin binding to thrombin O C) Antithrombin III D) Exposed collagen fibers O E) Serotonin
The calcium binding protein in muscle is called: Actin O Troponin C Tropomyosin O Myosin
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Write note on the circled events of the excitation contraction coupling shown in the diagram below. Sarcolemma T-tubule Myosin Ca++ 4 Ca Cat 3 TN-I 2 TN-C -TN-T SR DHP receptor Actin TM SERCA RyR RK '17
Ans Column I Column II Ca binds to calmodulin 1. Elastic fibers that anchor thick filanments in place Ca binds to troponin 2. Occurs in smooth muscles only Oxidative type I muscle fibers 3. Is the primary source of Ca that drives muscle contraction Titin 4. Is a dense connective tissue that surrounds the entire muscle H zone 5. Anchors thin filaments together Z line 6. Have high concentration of mitochondria Sarcomere 7. The region of thick filaments that has no overlap with thin filaments Actin and myosin 8. Is the functional unit of skeletal muscle Epimysium 9. Occurs in skeletal and cardiac muscles Sarcoplasmic reticulum 10. Generate the mechanical force of a muscle through crossbridge cycling
The mechanism of contraction in smooth muscle is different from skeletal muscle in that the site of calcium binding differs ATP energizes the sliding process actin and myosin interact by the sliding filament mechanism the trigger for contraction is a rise in intracellular calcium the thick filaments have fewer myosin heads
Suppose theres a drug that works towards blocking the entry of calcium from the extracellular fluid. Select what would happen to the skeletal muscle contractions and the contractions of smooth muscles if these were stimulated to contract under this drug. 1- The skeletal muscle would be unable to contract/ the smooth muscle would have no change 2-The skeletal muscle contractions would decrease but would still contract/ the smooth muscle contraction decreases but still contracts 3-The skeletal muscle contractions would decrease but still contract/ the smooth muscles would not contract 4-No change in the skeletal muscle contraction/ the smooth muscle contractions decrease but still contract 5- No change in skeletal muscle contraction/ the smooth muscle is unable to contract