Week 19 Flashcards
(31 cards)
What is the role of the agonist muscle?
Generates the majority of the force to cause the desired action.
Define antagonist muscle.
Muscle that brings about the opposite reaction.
What is a synergist muscle?
Aids the prime mover during the desired reaction or inhibits the opposing action.
What are the components of a simple lever mechanism?
- A rigid bar or rod
- Fulcrum or pivot
- An object moved against resistance
- Force that supplies energy for the movement
What is the origin of a muscle?
The bone that does not move when the muscle shortens.
What is the insertion of a muscle?
Movable end of the muscle.
What is the belly of a muscle?
The fleshy portion of the muscle in between the attachment sites.
What occurs at the neuromuscular junction?
The muscle fibre membrane forms a motor end plate specialized for muscle contraction.
What is the function of synaptic vesicles at the neuromuscular junction?
They store neurotransmitter molecules.
How many ACh receptors are present in the motor end plate membrane?
30 million ACh receptors.
What initiates the contraction of a skeletal muscle fibre?
Stimulation by a motor neuron.
What is the sliding filament model?
A mechanism describing how myosin and actin filaments slide past each other during muscle contraction.
What does ATP do during muscle contraction?
Provides energy for the myosin heads to return to their original position.
What is an isotonic contraction?
A contraction in which a muscle shortens to overcome resistance.
What is an isometric contraction?
A muscle contraction without motion.
List the three types of muscle tissue.
- Skeletal muscle tissue
- Smooth muscle tissue
- Cardiac muscle tissue
What are the functions of muscle tissue?
- Movement
- Stabilizing body positions
- Regulating organ volumes
- Movement of substances
- Heat production
What are the properties of muscle tissue?
- Excitability
- Conductivity
- Contractibility
- Extensibility
- Elasticity
What is a sarcomere?
The functional unit of muscle contraction.
What are the types of protein filaments in myofibrils?
- Thick filaments (myosin)
- Thin filaments (actin)
What is the role of myosin heads during muscle contraction?
They bind to actin, forming cross-bridges.
What happens when the calcium ion concentration in the cytosol rises?
Binding sites on thin filaments become exposed.
What is the epimysium?
Layer of connective tissue beneath the fascia covering the muscle.
What is the perimysium?
Connective tissue that groups muscle cells into fascicles.
