List AND describe the functions of skeletal muscles
List AND describe the characteristics of skeletal muscle
Responsiveness (excitability)- to chemical signals, stretch and
electrical change across the plasma membrane
Conductivity- local electrical change triggers a wave of excitation that travels along muscle fiber
Contractility-shortens when stimulated
Extensibility- capable of being stretched
Elasticity- returns to its original resting length after being stretched.
Describe the number and location of nuclei in a myofiber
Make sure you understand the difference between a myofiber and a myofibril!
Describe the location of the T tubules, sarcoplasmic reticulum, and terminal cisternae. What is the function of each of these structures?
Describe the location of the sarcoplasmic reticulum (SR) and the function.
Describe the location of the terminal cisternae and the function.
What is an aponeurosis? Where are some regions in the human body might you find one? How does an aponeurosis differ from a tendon?
What is the function of a Titin protein? What two regions of the sarcomere does it connect?
Label the following regions of a sarcomere:
Describe AND draw the relationship between the following proteins in a sarcomere during muscle contraction AND muscle relaxation:
What happens to the sizes of the following bands/regions of sarcomere during contraction AND relaxation?
Explain, in detail, the concept of a motor unit. How would the arrangement of a motor unit differ for fine control vs. strength control?
A motor neuron and the muscle fibers it innervates
*dispersed throughout the muscle
*when contract together causes weak contraction over wide area
*provides ability to sustain long-term contraction as motor units take turns resting (postural control)
1.) Fine control
small motor units contain as few as 20 muscle fibers pernerve fiber
i.e. eye muscles
2.) Strength control
*gastrocnemius muscle has 1000 fibers per nerve fiber (recruitment)
Describe, in detail, all of the components of a neuromuscular junction (NMJ) including:
a. synaptic knob is the swollen end of the nerve fiberb.
Junctional folds: located on the sarcolemma, functions to increase surface area for ACh receptors and contains acetylcholinesterase to break down ACh and relax musclesc.
Synaptic cleft: tiny gap between nerve and muscle cell; function is a space for reactions to occurs
Basal Lamina: thin layer of glycoprotein and collagen all over muscle fibers
Acetylcholine: chemical component released from neuron to produce a stimulusf.
Acetylcholine receptors sense the ACh being released into the synaptic gap and open channels to allow chemicals in for the muscle to contract.
Acetylcholinesterase breaks down the ACh causing the muscle to relax
Briefly summarize the four actions necessary for muscle contraction and relaxation.
1.Excitation - action potentials in the nerve lead to formation of
action potentials in a muscle fiber
2. Excitation-Contraction Coupling - action potentials on the sarcolemma activate myofilaments.
3. Contraction - shortening of a muscle fiber or at least the formation of tension.
4. Relaxation - return of a muscle fiber to its resting length
Diagram AND explain in words ALL of the steps involved in muscle contraction AND relaxation. Yes, this will take you some time. You should know by now how you learn best, so choose a method that works for you. The more times you go through this and the more detail you include, the better off you will be!
Discuss HOW some of the neuromuscular toxins covered in class affect the NMJ.
Discuss HOW myasthenia gravis leads to progressive weakness
Explain, in detail, why an individual becomes rigid soon after death, but then days later, becomes floppy. Make sure to include the roles of ATP and calcium in your explanation.
Explain the phenomenon of “all or none” when describing muscle contraction.
What does recruitment mean in terms of muscle contraction?
What are the three phases of twitch AND what is happening on the molecular and cellular level during each of these phases?
Compare and contrast unfused and fused tetanus. Make sure to mention “treppe” and wave summation in your answer.
Compare and contrast isotonic and isometric muscle contraction. Give some examples of each.
What is the difference between a concentric and eccentric isotonic contraction?
Explain what is meant by the statement that, “A muscle is never entirely relaxed.” Yes, this question is asking you to talk about muscle tone.
Compare and contrast, in detail, what is occurring on a molecular and cellular level for immediate, short term, and long term energy needs of a muscle.
long: Aerobic respiration needed for prolonged exercise
36 ATPs/glucose molecule
After 40 seconds of exercise, respiratory and cardiovascular systems must deliver enough oxygen for aerobic respiration
oxygen consumption rate increases for first 3-4 minutes and then levels off to a steady state
Limits are set by depletion of glycogen and blood glucose, loss of fluid and electrolytes
What is creatine phosphate in terms of a supplement? Specifically, who is it going to benefit? Why?
Describe on a molecular and cellular level what is occurring when a muscle becomes fatigued.
What types of things would an endurance athlete be concerned with? Explain!
Describe what is occurring when a muscle goes into “oxygen debt.” Make sure to explain EPOC in your response.
Compare and contrast slow twitch and fast twitch muscle fibers.
-Slow oxidative fibers, Smaller diamter, more mitochondria, myoglobin and capillaries,adapted for aerobic respiration and resistant to fatigue, Slow to contract, soleus and postural muscles of the back-Have large diameter, large glycogen reserves, few mitochondria, Fast glycolytic,rich in enzymes for phosphagen and glycogen lactic acid systems sarcoplasmic reticulum releases Ca quickly, contractions are quicker, fatigue quick
How exactly do strength workouts increase muscle size?
What is DOMS? What exactly causes it?
How does endurance training prepare an athlete for an Ironman triathlon? Explain what is going on at the molecular and cellular level!
Compare and contrast skeletal muscle, cardiac muscle, and smooth muscle making sure to include the following in your comparison. This question may be more appropriate for the lab portion of this course: