Muscle Fibers
The prolonged contraction of a muscle caused by rapidly repeated stimuli.
A) Summation
B) Twitch
C) Tetanus
C) Tetanus
When we have fewer muscle fibers per alpha-motor neuron, we are able to have more control over fine movements.
True or False?
True.
Where is glycogen stored for endurance events?
A) Kidney
B) Muscle
C) Liver
B) Muscle
Muscle damage is reversible with rest.
True or False?
False. Fatigue is reversible with rest.
Protein is one of the major energy sources during rest and exercise.
Ture or False?
False.
Name three different types of muscle contractions.
-Concentric
- Static
Direct calorimetry vs. indirect calorimetry.
Direct: measures heat output by subject; through a calorimeter (metabolic rate)
Indirect: measures gas exchange; (energy expenditure), less expensive.
Brain, liver, heart, adjacent muscle fibers
Direct calorimetry vs. indirect
Direct: measures heat output by subject; through a calorimeter (metabolic rate)
Indirect: measures gas exchange; (energy expenditure), less expensive.
Describe smooth muscle vs. cardiac muscle.
Smooth muscle: involuntary, found in walls of most blood vessels. (non-straited)
Cardiac muscle: involuntary, walls of heart (straited)
Name at least two things that increase force production (key words: motor unit(s)).
- Recruiting more motor units
- Increasing frequency of motor unit stimulation
- Using an optimal joint angle when performing the movement
Name at least 3 things the autonomic nervous system regulates:
- breathing
- heartbeat
-digestive processes
- blood distribution
Name and compare the three main energy substrates we get from our food.
Carbohydrates: 4.1 kcal, quickly accessed, prolonged intense exercise.
Fats: 9.4 kcal, provides most energy, used during less intense exercise
Proteins: 4.1 kcal, minor energy source
Describe Economy of Effort and give an example.
Energy demands are reduced at a given pace the more skilled we are at an exercise. Ex: In a race, runner B can run faster for a given oxygen cost.
Muscle spindles vs Golgi Tendon Organs and give an example for each.
Muscle spindle: intrafusal fibers, controlled by y-motor neurons. Sense STRETCH (length). Corrects movements. Ex: heavy weight dropped into hands.
Golgi tendon Organs: sensory receptors through which muscle tendon fibers pass. Sensitive to TENSION. Inhibit contracting muscles & excite antagonist. Ex: Patellar tendon reflex
Draw or describe the Excitation-Coupling process. Full points if used all 5 key words (revealed in answer).
- Acetylcholine
- T-tubule
- Sarcoplasmic Reticulum
- Power Stroke
- Tropomyosin
Draw/describe a neuron and label its parts. Additional 20 points per DESCRIPTION given per label.
Axon hillock - responsible for summation
Axon terminal - sends signals
Nodes of Ranvier - gap in insulation, rapid conduction
Schwann Cells - myelinating cell of PNS, produce myelin sheath
Dendrites - receive signal
Axon - carries nerve impulses away from body
Nucleus - contains nucleolus and chromosomes
Describe/draw the Glycolytic cyle. Include #of NADH, #of ATP produced.
Refer to google images and notes.
Describe the two theories in our book concerning Exercise-associated muscle cramps (EAMCs). State one evidence that supports each theory.
1) Neuromuscular control theory - aspect of control between motor neuron and muscle becomes altered. Abnormal firing of motor neurons.
- electrical stimulation in labs suggests neuromuscular origin
- stretching muscle provides relief; stretching related to alpha-motor neuron
2) electrolyte depletion theory (heat cramps) - contracts extracellular fluid to compartment, increase neurotransmitter concentration and causes motor nerve terminals to be hyperexcitable.
- history shows laborers in hot & humid conditions suffer from cramping
- ingesting salt alleviated cramps
- salty sweating is evident in athletes who are prone to cramping
Compare muscle fibers I, II, and IIx. Include # of mitochondria, force to resistance, motor fiber per unit, ATPase rate and endurance.
Refer to notes.
Describe the following:
- Fascicle
- Sarcoplasm
-Myofibril
- Perimysium
- Satellite cells
- Fascicle: Bundle of muscle fibers
- Sarcoplasm: cytoplasm of muscle cells, contains ATP & phosphagens, gelatin-like interior of a muscle fiber
- Myofibril: Grouping of numerous sarcomeres
- Perimysium: Connective tissue sheath surrounding each muscle fasciculus
- Satellite cells: Located between the sarcolemma and basement membrane. Helps muscle cells adapt to growth, injury & training.
Label 3 characteristics of:
- basal ganglia
- primary motor cortex
- cerebellum
Basal ganglia: in cerebral white matter, initiated sustained & repetitive movements, help controls posture & muscle tone.
Primary motor cortex: Control of fine & discrete muscle movements, located in frontal lobe, pyramidal cells, conscious control of skeletal muscles, decisions are made here.
Cerebellum: COORDINATES & smooths movement, rapid & complex muscular activities, sensory feedback, CORRECTS
Name the rate-limiting enzymes of the 4 energy systems and whether they are anaerobic or aerobic.
ATP-PC (anaerobic) => creatine kinase
Glycolysis (aerobic & anaerobic) => phosphofructokinase
Krebs Cycle/ Citric Acid Cycle (aerobic) => isocitrate dehydrogenase
Electron Transport System (aerobic) => cytochrome oxidase
Describe the different types of pain/ discomfort we can feel after exercise. And describe what can cause each one.
Acute muscle soreness: immediately after exercise. Accumulation of H+ ions, and from tissue edema. Disappears several hrs after exercise. After heavy endurance or strength training.
Delated-Onset Muscle Soreness: Felt a day or 2 after exercise. ECCENTRIC muscle action. Structural damage, inflammatory reaction.
Exercise-induced muscle cramps EAMCs may be caused by altered neuromuscular control, fluid or electrolyte imbalances.
Muscle fatigue-associated cramps are related to sustained alpha-motor neuron activity. More spinfdle and less golgi tendon organ activity.
Heat-associated cramps involve shift in fluid from interstitial space to intravascular space, hyperescitable neuromuscular junction.
Key words: troponin, myosin, actin, nebulin, titin.