Skeletal Muscle
True or False: Skeletal muscle is striated and voluntary.
TRUE
This is the place where the axon terminal of a motor neuron and the sarcolemma of a muscle fiber (cell) meet.
Neuromuscular Junction
This is the point where a muscle attaches to an immovable or less movable bone.
Origin
This type of muscle is one that opposes or reverses a prime mover.
Antagonist
Name one of the five golden rules of skeletal muscle activity.
1. with few exceptions, all skeletal muscles cross at least one joint
2. typically, the bulk of a skeletal muscle lies proximal to the joint crossed
3. all skeletal muscles have at least 2 attachments: origin & insertion
4. skeletal muscles can only pull, never push
5. during contraction, a skeletal muscle insertion moves toward the origin
This item encloses a single skeletal muscle fiber.
Endomysium
What breaks down ACh into acetic acid and choline after an action potential occurs and ACh is no longer needed?
Acetylcholinesterase
Movement of a limb away from the midline.
Abduction
The triceps muscle(s) were named based on what criteria?
The number of origins ("tri" = 3)
This form of exercise results in more flexible muscles with greater resistance to fatigue.
Aerobic or endurance exercise
All muscle types produce movement, but skeletal muscle has three additional roles. What are they?
1. maintain posture/body position
2. stabilize joints
3. generate heat
3 ions are involved in generation of an action potential. Name them in the order in which they occur in the process (i.e. first to last).
1. Calcium 2. Sodium 3. Potassium
This is when the forearm rotates laterally so the palm faces anteriorly.
Supination
This muscle dorsiflexes and inverts the foot.
Tibialis anterior muscle
This is when the muscle is stimulated so rapidly that no evidence of relaxation is seen.
Fused or complete tetanus
Epimysium of skeletal muscle blends into a connective tissue attachment, which could be either _______ or _________.
Tendons or Aponeuroses
According to the sliding filament theory, when an action potential sweeps across the sarcolemma _______ are released from intracellular storage in the ________.
1. calcium ions
2. sarcoplasmic reticulum
These 2 terms are opposites. One means decreasing the angle of a joint to bring two bones closer & the other means increasing the angle between two bones.
2. Extension
This muscle flexes the neck and laterally rotates the head.
Sternocleidomastoid muscle
Creating muscle contraction is different in the single skeletal muscle fiber (cell) versus the whole skeletal muscle. What two terms do we use to describe these different ways of contraction?
1. muscle fiber (cell): all-or-none
2. whole muscle: graded responses
In class we discussed 4 special functional properties of skeletal muscles. One is irritability which is responsiveness/ability to receive and respond to a stimulus. What are the other three and what do they mean?
1. Contractility - ability to forcibly shorten when an adequate stimulus is received
2. Extensibility - ability of muscle cells to be stretched
3. Elasticity - ability to recoil and resume resting length after stretching
In class we used a row boat analogy to describe the sliding filament theory. In this analogy, what is the row boat and what is the oar?
BONUS: We also watched a video that mentioned 2 regulatory proteins not mentioned in our powerpoint. What were they?
row boat: thin filament or actin
oar: myosin heads
Bonus - troponin & tropomyosin
Ball and socket joints are common examples for three different types of muscle movement. What are they?
1. Flexion
2. Rotation
2. Circumduction
This muscle closes and protrudes the lips.
Orbicularis oris
1. Direct phosphorylation of ADP by creatine phosphate (1 ATP per CP molecule)
2. Aerobic pathway (about 32 ATP)
3. Anaerobic glycolysis & lactic acid formation (2 ATP, per glucose molecule)