Human Physiology Test 2: Muscle Function

  1. Name the Neurotransmitter in muscle? Name of the synapses?
    Acetylcholine. Cholinergic Synapses
  2. Name two type of cholinergic receptors.
    • Nicotinic- Ionotrophic
    • Muscarinic- Metabotrophic
  3. Name two type of Adrenergic Receptors
    • Alpha-Norepinephrine
    • Beta- Epinephrine
  4. Name the two divisions of the peripheral nervous system and what they control.
    • Autonomic- Involuntary
    • Somatic- Voluntary
  5. What is the Neuromuscular Junction?
    Synapse between motor neuron and muscle
  6. Describe the process of muscle contraction
    • 1. AP travels down Motor Neuron from Ventral Horn
    • 2. AP causes Acetocholyine to be released
    • 3. AP binds to nicotinic receptor & depolarizes (Via Ionotrophic Channels)
    • 4. AP causes release of Calcium from Sarcoplasmic Reticulum
    • 5. Calcium binds to Troponin triguring the release of tropomyosin. 
    • 6. Cross Bridge Cycling occurs
    • 7. Calcium actively transported back into SR.
  7. Name sources of ATP
    • Creatine Phosphate --> Creatinine
    • Oxidative Phosphorylation in present of O2
    • Anaerobic- 2 net ADP
  8. Name the parts of the somatic nervous system
    • Gray Matter- Cell Bodies
    • White Matter- Myelinated Axons
    • Motor Neurons
    • Spinal Canal
    • Ventral Horn- Origin of MN
    • Dorsal Horn
  9. Name the organization of Skeletal Muscle
    • 1. Fascicles- Bundle of Fibers
    • 2. Fibers- Individual Cells
    • 3. Myofibrils- Several make one fiber (Made of Protein Filaments)
    • 4. Sarcomeres- Smallest Unit of contraction
  10. Anatomy of the muscle.
    • Sarcolemma- Muscle Membrane
    • Sacroplasm- Cytoplasm (Multinucleated)
    • Sarcoplasmic Reticulum- ER: Stores Calcium
    • Transverse (T) Tubules- Invaginations of sarcolemma
  11. Arrangement of Sarcomere
    • 1) z Line (Protein)
    • -Actin Attaches to Zline. ZL to ZL = Sarcomere
    • 2. I Band
    • -Region with 0 thick filaments. Spans one z line
    • 3. A Band
    • -Thick n Thin overlap
    • 4. H Zone- Only Thick filament
    • 5 M Line- Protein that anchors thick filaments.
    • 6. Titin- Coiled Protein -M Line --> Zline
    • See Figure in book.
  12. Describe Actin
    • Thin filament. Made of G Protein (Globular) Polymerize to form strands.
    • Troponin
    • Tropomyosin
  13. Describe Myosin
    • Thick Filament. Golf Club
    • ATPase site
    • Fibrous protein. (Tail is a double helix)
  14. What is the sliding filament theory
    • -Sarcomere Shortens. z-line to z-line.
    • -Fibers do NOT shorten.
    • -H-zone and iband shorten
  15. Name the steps of crossbridge cycling
    • 1. ATP hydrolyzed to ADP
    • -Myson binds to actin
    • 2. Pi is released, head hinges
    • 3. ADP is released, still hinged (rigor)
    • 4. ATP Binds (Myosin detaches)
    • 5. High Energy State, myosin head is cocked.
  16. What is a twitch?
    A single muscle fiber activated by 1 AP
  17. What is the latent period?
    All the events that occur prior to sarcomere shortening
  18. What is a contraction?
    Phase in which X Bridge cycling occurs.
  19. What is Relaxation?
    Calcium is actively transported back into the Sarcoplasmic Reticulum
  20. What is an isometric contraction?
    Same length (Load is greater than Tension)
  21. What is an isotonic contraction?
    Same Tension (Tension is greater than load)
  22. Name the factors affecting force on fibers
    • Frequency of Stimulation
    • Fiber Diameter
    • Changes in Fiber Length
  23. What are the different types of stimulation frequency?
    • Treppe- Independent twitches that get stronger
    • Summation- summing twitches=greater contraction
    • Tetanus- Constant contraction due to several AP's
  24. What is recruitment?
    Use of more fibers to create more force
  25. Which muscle units fire first?
    Smaller units.
  26. Describe the relationsihp between muscle shortening velocity & load
    • Higher load lower velocity
    • Higher latent period when load is heavier
  27. What are the three primary Fiber types
    • Slow Oxidative
    • Fast Oxidative
    • Fast Glycolytic
  28. Contrast Fast vs Slow Fibers
    Fast Fibers contain higher mysoin ATPase activity= Higher velocity of contraction
  29. Name the two metabolic types of fibers
    • Oxidative- Oxidize PO4, presence of 02 (Aerobic) Typically smaller
    • Glycolytic: Anaerobic: White Meat
  30. What is fatigue?
    Decline in a muscles ability to maintain a constance force of contraction despite stimulation
  31. How does high intensity exercise cause fatigue?
    • -Increase in lactic acid (lowers PH)
    • -Compresses blood vessels
    • -Depletes acetylcholine
    • -loss of glycogen
    • -buildup of inorganic phosphate
    • -Central Fatigue
  32. How does a muscle adapt to use?
    • -Cell Changes in size
    • -Atrophy (Smaller) (Denervation atrophy=motor neuron lost)
    • -Hypertrophy- Increase in size
  33. What are joints?
    Spots where tendons attach muscle to bone
  34. Name two kinds of receptors that control overall muscle activity
    Sensory Receptor & Proprio Receptors
  35. What are EFF and IFF and how are they innervated?
    • EFF- Extrafusal fiber. Innervated by alpha motor neurons
    • IFF- Intrafusal Fiber. Innervated by gamma motor neurons
  36. Which Muscle fibers detect change in muscle length?
    Intrafusal fiber
  37. What is stretch reflex?
    Negative feedback that keeps muscle at optimum length
  38. Describe a stretch reflex
    • 1. Stimulus hits tendon
    • 2. Muscle spindle detects change & Sends signals to S.C via afferent neurons.
    • 3. Afferent synapse to efferent
    • 4. Efferent neurons synapse onto fibers
  39. What is the Golgi Tendon Organ
    • Located within Tendons
    • Sensory Neuron in callagen fibers
    • Controls motor neurons
    • Detects changes in tension
  40. Where is smooth muscle located?
    Lining of intestines & GI Tract & blood vessels & Uterus
  41. Characterize Smooth Muscle
    • Actin & Myosin (But different)
    • No Sarcomeres
    • Arranged diagnally
    • Connected by gap junctions
    • No troponin
    • Slower contraction (Slow myosin ATPASE)
  42. Describe the excitation contraction coupling process of smooth muscle
    • 1. Initiated by calcium
    • 2. Triggers release of more calcium from SR
    • 3. Calcium binds to Calmodulin & Activated mysosin light chain kinase
    • 4. Myosin is phosphorylated
    • 5. Myosin ATPase active
    • 6. Cycling.
  43. Describe Neural regulation of smooth muscle
    • Innervated by Autonomic NS (Parasym or sym)
    • Receptors determine effect of NT
    • Does not require an AP (myogenic)
Card Set
Human Physiology Test 2: Muscle Function