Muscular & Neurotransmission system
A bundled group of myofibrils is called _________.
Muscle Fiber
True or False. Explain.
Action potential travels along an axon into neuron.
False. Action potential travels along a neuron, then axon into the axon terminal.
Alterations in muscles include what change?
Diametre, length, vascularity, fibre type
What are 3 things muscles need to contract?
ATP
Ca2+
ACh (acetycholine- neurotransmitter)
Muscle fatigue is ________ state where muscle is unable to contract d/t _________ of ATP.
a. emotional; increase
b. physiological; deficit
c. psychological; deficit
d. physiological; increase
b. physiological; deficit
True or False, explain.
When troponin is activate, Actin pulls itself along the myosin to shorten the Sarcomere.
False. Myosin heads binds to actin and pulls it.
When troponin binds with calcium ions, it undergoes what type of change?
Conformational
True/ False. Explain.
Hyperplasia of muscle cells can be artificially induced.
True. Injection of hormone or hormone like substances, e.g., anabolic steroids such as trenbolone.
True or False. Explain.
The body does not need to produce energy as we constantly store ATP.
False. We have little ATP stored in muscle therefore continuous synthesis is required to perform daily activities.
Slow oxidative fibres are _____ fibres, _____ in blood supply, and energy production is _______.
a. white; poor; aerobic
b. red; rich; anaerobic
c. red; rich; aerobic
d. pink; rich; anaerobic
c. red; rich; aerobic
What are the phases of muscle contraction?
Latent, Contraction, Relaxation.
What is the threshold that must be reached for action potential to occur?
-55mV
What is the most likely response to regular and intense physical training?
Hypertrophy
What does direct phosphorylation of ADP mean?
It is when ADP turns to ATP through the coupled reaction between Creatine phosphate and adenosine diphosphate.
What are the force of contraction influenced by? (hint: there are 4 factors)
1. No. of myofibres stimulated
2. relative size of the muscle
3. frequency of stimulation
4. degree of muscle stretch
True/ False, explain.
If there is a shortage of tropomyosin, surplus troponin will fill the role instead.
False. Troponin C is engaged by Ca2+ which releases tropomyosin. They're both necessary to complete a single task, rather than being interchangeable.
Stimulation of a motor unit results in muscle contraction. What would be the result of simultaneous stimulation of multiple motor units?
Stronger contraction
True/ False. Explain.
All muscle fibres are innervated by at least one motor neuron.
True.
List in order from slowest to fastest pathways for ATP synthesis. List how much each system yields.
1. Aerobic respiration - 36 ATP/ glucose molecule
2.Anaerobic glycolysis - 2 ATP/ glucose molecule
3. Phosphagen system - 1 ATP/ glucose molecule
List 3 metabolic characteristics of Fast Oxidative Fibres.
- aerobic metabolism
-high oxidative capacity
-intermediate glycolytic capacity
What is the general sequence of AP propagation?
Depolarization wave spreads in all directions --> opens more gated Na+ channels --> Na+ rushes in at more points along the sarcolemma --> AP propagation.
True/ False. Explain.
Rigor mortis is the condition wherein the detachment of cross-bridge attachments is no longer possible.
True
Initial contraction after a period of inactivity is weaker than those that occur after the same stimuli is repeated a number of times. "Warming up" makes you stronger. What is this effect called?
Treppe effect
One product of metabolism is heat, which means that muscular individuals generate ______ so we don’t feel _______ as quickly.
more heat; cold
In oxygen debt, when depleted, what must myofibres do to replenish energy?
rest