A & P II TAKE-HOME REVIEW NAME_________________________

TO UNDERSTAND CARDIAC MUSCLE CONTRACTION, WE MUST REVIEW SOME MATERIAL FROM CHAPTER 10 RELATED TO SKELETAL MUSCLE. LOOK IN THAT CHAPTER OR YOUR A & P I NOTES TO ANSWER THESE QUESTIONS.

1. WRITE A DEFINITION OF:

MUSCLE FIBER

SARCOLEMMA

SARCOPLASM

SARCOPLASMIC RETICULUM (SR)

2. WHAT IS A MYOFIBRIL?

3. THE CROSSWISE COMPARTMENTS OF MYOFIBRILS ARE CALLED ________________.

4. DRAW ONE SARCOMERE BELOW, INCLUDING AND LABELING:

Z LINES

M LINES

THICK (MYO)FILAMENTS

THIN (MYO)FILAMENTS

MYOSIN HEADS

5. WHAT IS ACTIN?

6. WHAT IS MYOSIN? SKETCH ONE MYOSIN MOLECULE.

7. WHAT ARE CROSSBRIDGES AND WHAT IS THEIR ROLE IN MUSCLE CONTRACTION?

8. EXPLAIN WHAT MYOSIN BINDING SITES ARE & TELL WHERE THEY ARE LOCATED.

9. A. IN A RELAXED MUSCLE CELL, WHAT IS THE LEVEL OF CALCIUM IN THE SARCOPLASM? (GENERAL ANSWER, NO NUMBERS REQUIRED)

B. WHERE IS THE SKELETAL MUSCLE CELL’S CALCIUM LOCATED DURING RELAXATION?

FILL IN THE BLANKS IN THE STEPS LEADING TO SKELETAL MUSCLE CONTRACTION:

I. NERVE IMPULSE REACHES THE NEUROMUSCULAR JUNCTION AND CAUSES THE RELEASE OF

____________________________ FROM SYNAPTIC VESICLES.

II. THIS SUBSTANCE BINDS TO RECEPTORSAND CAUSES THE SARCOLEMMA TO BRIEFLY BECOME

HIGHLY PERMEABLE TO ___________ IONS.

III. THE NET CHARGE INSIDE THE CELL CHANGES FROM ______________ TO ________________. (THIS IS REFERRED TO AS GENERATION OF AN ACTION POTENTIAL)

IV. AS A RESULT OF THE ACTION POTENTIAL, _________________ ARE RELEASED FROM THE SR INTO THE CYTOSOL.

V. THE RISING LEVEL OF ANSWER #IV CAUSES THE REGULATORY PROTEIN _______________________ TO

CHANGE SHAPE AND PULL THE OTHER REGULATORY PROTEIN, ___________________________, OFF THE MYSOIN BINDING SITES.

VI. AT THIS POINT, ENERGY FROM _________ IS REQUIRED.

VII. _____________________ GRASP THE THIN MYOFILAMENTS AND PRODUCE THE _____________ STROKE,

WHICH PULLS THE THIN MYOFILAMENTS TOWARD THE ___________ LINE AND SHORTENS THE SARCOMERE.