Exam 2

  1. Describe the thick and thin filament
    • Thick: Golf club shaped protein and several hundred make one, made of myosin
    • Thin: Has actin, tropomyosin, and troponin
  2. What is the role of calcium in the skeletal muscle contractions
    Ca++ binds to troponin pulling tropomyosin off the binding site allowing actin and myosin to bind
  3. How does muscle shortening occur and what do you call his theory
    • Sarcomere shortens and the overlap between  the thick and thin filaments increase
    • Sliding filament mechanism
  4. What are the 3 phases of the cross-bridge cycle
    Binding, power stroke, and detachment
  5. What must happen first before the cross bridge cycle can occur
    Ca++ must bind to troponin to pull tropomyosin off of the binding site so binding can occur
  6. Where does Ca++ come from in skeletal muscle
    Sarcoplasmic reticulum
  7. How did Ca++ get out of the SR in skeletal muscle
    An AP traveling down the T-Tubule activating the DHP-R then RR allow Ca++ channels to open in the SR
  8. What 3 roles does ATP have in skeletal muscle
    • Energize myosin head
    • Detaches myosin head from actin
    • Actively transports Ca++ back to SR
  9. What 2 things happen to cause muscle relaxation
    • Ache removes Ach and calcium 
    • Tropomyosin goes back to binding site
  10. What is a muscle twitch
    Weak contraction produced by a single fiber in response to a single action potential
  11. What is a: motor unit, recruitment, and asynchronous recruitment
    • Motor Unit: Neuron innervates multiple muscle fibers
    • Recruitment: Strength & precision of contraction dependent on size of motor unit and number of units activated
    • Asynchronous: Prevents fatigue, only a portion of motor units are used and alternates motor unit activity
  12. List 4 factors that affect the tension a muscle can generate
    • Frequency of stimulation
    • Length of muscle fiber at onset
    • Fatigue
    • Thickness of fiber
  13. What is the difference between twitch summation and tetany?
    • Twitch Summation: Second AP arrives before a twitch is over
    • Tetanus: The muscle has no chance to relax
  14. What are three sources of ATP in the muscle?
    • Creatine phosphate
    • Oxidative phospholyration
    • Glycolysis
  15. List 3 examples of muscular fatigue in skeletal muscle
    • Central fatigue
    • Psychological fatigue
    • Neuromuscular fatigue
  16. Compare and contrast skeletal and smooth muscle's thin filament
    • Smooth: No troponin
    • Skeletal: Actin, tropomyosin, and troponin
  17. Describe smooth muscle activation
    • Calcium binds to calmodulin
    • Calmodulin activates myosin kinase
    • Kinase pulls phosphate from ATP giving ADP leading to cross-bridge
  18. What is the different between multi-unit and single-unit smooth muscle activation
    • Multi-Unit: neurogenic
    • Single-Unit: Myogenic
  19. Compare and contrast cardiac muscle vs skeletal and smooth muscle
    • All: Sliding filament mechanism
    • Cardiac & smooth: Myogenic sarcomeres and unicellular
    • Skeletal & Cardiac: Striated and have thin filament
    • Skeletal: Has neurogenic sarcomeres
  20. What are 2 types of cells of cardiac muscles
    • Autorythmic 
    • Contractile
  21. Describe AP in autorythmic cells
    • Decrease in K+ permeability and increase Ca++ permeability
    • Due to transient voltage-gated channels causing the AP to occur and LL voltage gated channels to take place
  22. Describe the normal autorythmic conducting system
    • Sinoatrial node 
    • Atrioventricular node
    • Bundle of his
    • Purkinje fibers
  23. What is unique about the contractile cardiac muscle cell's AP and what causes this
    • Plateau in AP
    • Slow lasting voltage-gates Ca++ channels
  24. The plateau of contractile cardiac muscle cell results in a ling refractory period. Why is this significant?
    • Prevents tetanus 
    • Important for synchronizing contractions
  25. What is systole and diastole?
    • systole: contraction/emptying
    • diastole: relaxation/fill
  26. What ECG wake corresponds with ventricular systole
    QRS wave
  27. What causes blood to flow from now heart chamber to the next
    Pressure in atria exceeds pressure in ventricle to pass through valve
  28. What is an isovolumetric period of the cardiac cycle?
    Volume in the chambers stay the same
  29. What is stroke volume and how do you calculate it
    • Volume of blood pumped out of ventricle with each contraction of heart
    • Calculated: EDV-ESV=SV
  30. hat is the cadiac output and how do you calculate it
    • The volume of blood per minute from each ventricle
    • Calculated: HR*SV=CO
  31. What 2 systems affect the heart rate and what changes do they cause
    • Parasympathetic: Decrease heart rate
    • Sympathetic: Increase heart rate
  32. How do we intrinsically and extrinsically regulate stroke volume
    • Intrinsically: Venous return and length-tension relationship
    • Extrinsically: Sympathetic stimulation and epinephrine
  33. What variables determine flow rate
    • Pressure Gradient and resistance
    • Radius
    • Viscosity
    • Vessel lenght
  34. What 3 variables determine resistance of a vessel and which has most influence
    • Radius: Most influential
    • Viscosity
    • Length
  35. What is the function of arteries besides transporting blood
    Pressure reservoir
  36. What is the function of arterioles besides transporting blood
    • Regulates blood pressure
    • Determines Cardiac Output
  37. What is the function of capillaries besides transporting blood
    exchange materials by diffusion
  38. What is the function of veins besides transporting blood
    Blood reservoir
  39. Define systolic pressure, diastolic pressure, pulse pressure, and mean arterial pressure
    • Systolic pressure: Mac pressure during ventricular systole
    • Diastolic pressure: Min pressure when blood is draining out
    • Pulse pressure: Difference between systolic and diastolic pressure in mmHG
    • Mean Arterial Pressure: Main driving force for blood flow and drives it forward
  40. What are 2 types of changes that arterioles make to alter resistance
    • Vasoconstriction
    • Vasodilation
  41. Intrinsic and extrinsic factors regulate arteriole tone but each has different aspects of blood flow. What do intrinsic regulators control?
    What do extrinsic regulators control?
    • Intrinsic: Control local influences on the resistance of arterioles
    • Extrinsic: Control Blood pressure
  42. Give some examples of chemical intrinsic factors
    • EDRF
    • Endothelin
    • Histamine
  43. Why is blood velocity slowest in the capillaries
    Capillaries have a small radius
  44. What is the purpose of a metarteriole
    Regulate movement through capillary
  45. List the forces that control filtration and reabsorption at a capillary and indicate which ones favor filtration and which ones oppose filtration
    • Hydrostatic: Favor filtration
    • Oncotic: Oppose filtration
  46. List 3 functions of lymphatic system
    • Return excess filtered fluid
    • Return filtered proteins
    • Defense against disease by lymph nodes
  47. List 5 extrinsic factors that aid in venous return
    • Sympathetic stimulation
    • Increased skeletal muscle activity
    • Respiratory pump
    • Cardiac Suction
    • Valves
  48. What 3 factors determine blood pressure
    • Cardiac output
    • Total peripheral resistance
    • Blood volume
  49. What factors would be used to regulate blood pressure on a short term basis? Long term?
    • Short term: Cardiac Output and TPR
    • Long term: Adjust blood volume
Card Set
Exam 2