exam 2 fill in the blanks and essay questions

1. enable movement

2. provide stability

list 2 functions of joints

greater, range, motion, weaker

the ___ the ___ of ____ at the joint the ___ it becomes

tension

list 1 factor that will limit the range of motion, stabilize the joint, and reduce the chance of injury

muscular, substantial heat

____activity generates ____

1. support soft tissues

2. guard entrances and exits

list 2 functions of skeletal muscle

transfer energy from one place to another

list the primary function of ATP

1. conductivity: cells ability to conduct electrical changes across the plasma membrane

2. elasticity: cells ability to return to its original length after it has been stretched

list and define 2 characteristics of muscle cells

2 structures:

1. multinucleated

2. striated

2 functions:

1. Supports soft tissues

2. maintain body temperature

list 2 structures and 2 functions of skeletal muscle

2 structures:

1. striated

2. contains intercalated discs

2 functions:

1. inability to undergo tetanic contractions

2. contracts to pumps blood throughout the body

list 2 structures and 2 functions of cardiac muscle

2 structures:

1. non-striated

2. single nuclei

2 functions:

1. calcium ions trigger contraction (excitation-contraction coupling)

2. propels food through the intestines

list 2 structures and 2 functions of smooth muscle

1. inefficient, it only produces 2 ATP

list 1 drawback to anaerobic energy production (glycolysis)

1. ability of the muscle to tolerate lactic acid

list 1 thing that limits anaerobic endurance

1. the types of muscle fibers

list 1 factor that affects skeletal muscle performance

1. normal blood oxygen concentration

list 1 thing required for normal muscle function

1. arrival of an action potential

2. release of ACh into the synaptic cleft

3. ACh binding at ACh’s receptors on the motor end plate; this increases the sarcolemma’s permeability to sodium ions; sodium ions rush into the sarcoplasm; this step continues until AChE removes ACh from the ACh receptors

4. Appearnce of an action potential in the sarcolemma results from the rush of sodium ions into the sarcoplasm; the action potential travels across the entire membrane surface and each transverse tubule

5. Return to the inital state ; ACh is broken down by AChE

steps involved in stimulating a muscle fiber

1. active-site exposure :Ca2+ ions bind to troponin, which changes position and moves tropomyosin away from the active sites of actin

2. cross-bridge attachment: cross-bridges of myosin heads then bind to actin

3. pivoting: each myosin head pivots at its base, pulling the actin filament toward the center of the sarcomere; ADP and phosphate group are released

4. cross-bridge detachment: ATP binds to the myosin head to break the binding to actin; active site is exposed again

5. myosin reactivation: free myosin head splits ATP into ADP and phosphate group

steps in the contraction cycle