A & P Physiology of muscle contraction Flashcards
The function of acetylcholine esterase is to
stops the process of muscle contraction
True or false. The chemical bonds in glucose provides the supply of energy contained in a creatine phosphate molecules
False
Contraction causes:
Only the sarcomere to shorten
Define synape
The place where a nerve cell meets either another nerve cell or effector organ
Effector organ
The organ the nerve controls
Neuromuscular junction
A special type of synapse where the axon of a nerve muscle meets a muscle cell
Which of the following produces the least amount of energy for muscle contraction:
Creatine phosphate
True or false. A fast twitch muscle would be expected to have a fast rate at which glucose is converted into ATP
False
The function of ACh (acetylcholine) is to:
Cause an action potential occurs in the muscle cell
Rigor mortis happens?
Because ATP is needs to myosin and actin to released since ATP is not present in a dead body, myosin and actin cannot release until the myofilament decay.
Describe the transmission of a nerve impulse across the neuromuscular junction.
- Motor neuron receives signal to stimulate movement
- Synaptic vesicles move to end of neuron and release Ach
- Ach attaches to receptors
- Generic cation channels open, stimulating contraction
- Enzyme breaks down Ach, stopping contractions
Aerobic cellular respiration
Glucose reacts with oxygen forming ATP
Muscle tone
Relaxed muscles are in a state of slight contraction
Synaptic cleft
The small space between effector organ and axon of the nerve cell
Glycolysis/ Anaerobic respiration
Glucose is converted into pyruvic acid which supplies energy to cells.
What is the role of tropomyosin in muscle contraction?
To prevent myosin from continuing to slide up the actin filament
What is the role of acetylcholine in calcium release?
Stimulates cellular contraction by opening voltage-gated ion channels
Muscle component from largest to smallest
muscle, fascicle, muscle fibers, myofibrils, sarcomeres, & myofilaments
Location of Sarcomere
In between the z line
What is an aponeurosis?
A thin flat tendon-like sheet that anchors a muscle or connects it to the part that muscle moves
Sliding Filament theory
Step 1:The sarcoplasmic reticulum stimulated to release calcium ions
Step 2: Calcium is released from the sarcoplasmic reticulum
Step 3: Calcium ions bind to troponin
which causes troponin to destabilize tropomyosin which exposes the myosin bind on actin
Step 4: Myosin becomes phosphorylated which means myosin can do work also known as high energy conformation of myosin
Step 5: Myosin binds to actin know as crossbridge attachment
Step 6: Powerstroke which is ADP and P are released from myosin head which makes myosin lose their energy and turn back to original state
Step 7: Crossbridge detachment is new molecule of ATP binds and myosin and actin unbinds and muscle relaxes
Fast Glycolytic Fibers
- largest in diameter and contain the most myofibrils which can generate the most powerful contractions.
- low myoglobin content, relatively few blood capillaries, and few mitochondria.
- appear white in color because have very few myoglobin.
- large amounts of glycogen and generate ATP mainly by glycolysis.
- large size and their ability to hydrolyze ATP rapidly, FG fibers contract strongly and quickly.
- The fast‐twitch fibers are adapted for intense anaerobic movements of short duration, such as weight lifting or throwing a ball.
- they fatigue quickly.
- Strength training programs that engage a person in activities requiring great strength for short times increase the size, strength, and glycogen content of fast glycolytic fibers.
Fast oxidative fibers
intermediate in diameter.
- large amounts of myoglobin and many blood capillaries, pinkish red appearance.
- generate considerable ATP by aerobic cellular respiration.
- which gives them a moderately high resistance to fatigue.
- intracellular glycogen level is high, so they also generate ATP by anaerobic glycolysis.
- are “fast” because the ATPase in their myosin heads hydrolyzes ATP three to five times faster than the myosin ATPase in SO fibers.
- twitches of FOG fibers reach peak tension more quickly than those of SO fibers but are briefer in duration—less than 100 msec.
- contribute to activities such as walking and sprinting.
Slow oxidative fibers
smallest in diameter.
- least powerful.
- dark red- large amounts of myoglobin and many blood capillaries. many large mitochondria.
- generate ATP mainly by aerobic cellular respiration.
- “slow” because the ATPase in the myosin heads hydrolyzes ATP relatively slowly and the contraction cycle proceeds at a slower pace than in “fast” fibers.
- slow speed of contraction.
- Their twitch contractions last from 100 to 200 sec, and they take longer to reach peak tension.
- resistant to fatigue and are capable of prolonged, contractions for many hours.
- adapted for maintaining posture and for aerobic, endurance‐type activities such as running a marathon.
Which muscle twitch fatigue faster
Fast twitch
Which muscle twitch uses doesn’t use a lot if energy
Slow twitch
