Muscular System Study Guide

O 1. The six functions of the muscular system are to O 1 produce movement, O 2 maintain posture, O 3 stabilize joints, O 4 generate heat, O 5, store nutrients, O 6 protect body openings

What are three types of muscle tissue? O Cardiac, O Skeletal, O Smooth

3. Describe the characteristics of cardiac muscle. O Branching cells, uninucleate, striation, intercalcated disks, involuntary control, slow and rhythmic contractions, located in the heart.

4. Describe the characteristics of Skeletal muscle O Single, very long cylindrical cells, multinucleate, striation, voluntary and involuntary control, slow to fast variable speeds but not rhythmic contractions, located with bones and with the skin of the face.

5. Describe the characteristics of smooth muscle O Single, spindle shaped or fusiform, uninucleate cells with no striations, involuntary control by nervous system, hormones and chemicals sometimes rhythmic, located in the walls of hollow organs except the heart.

6. How is skeletal muscle different from cardiac muscle microscopically? Cardiac muscle is arranged spirally and is connected by intercalcated disks.

7. Label the sarcomere.

The protein found on thick filaments is O Myosin

9. The protein found in thin filaments is O actin

10From smallest to largest the following structures are O Myofilament O myofibrils O Sarcomere O Muscle fiber O fasicle

11. What part of skeletal muscle gives it the stripe d appearance? O sarcomere

actin molecules are pulled toward the center of the sarcomere 2. the distance between Z lines becomes less as each sarcomere shortens 3. The combined effect of shortened sarcomeres is the shortening of the muscle fiber 4.Contraction results from the attachments of the cross-bridges on the myosin molecules to the active sites on the actin molecules. Each cross-bridge attaches and detaches several times during one contraction. 5. Contraction requires the presence of calcium ions Troponin blocks the active sites on actin Calcium binds with and alters the shape of troponin the altered shape of troponin opens up the active sites on actin 6. When the active sites on actin are exposed the following four events occur a. a cross- bridge attaches to an actin active site b. the myosin head pivots into a bent shape that drags the actin toward the center of the sarcomere c. the cross-bridge de-ttaches d. the cross-bridge re-forms its straighter, "cocked" position

Table 7-1 Physiology of Skeletal Muscle Contraction Once an action potential (AP) is generated at the motor end plate it will spread like an electrical current along the sarcolemma of the muscle fiber Acetyl choline is released by the axon terminal of the motor neuron and the acetylcholine binds to the sarcolemma. This will cause Calcium (Ca +2 ) gates in the SR to open, allowing Ca +2 to diffuse into the sarcoplasm This depolarizes the cell membrane. The sarcomeres contract and acetylcholoinesterase takes up the acetylcholine so the muscle can relax.

14. O Acetylcholoine

15 O Tendon

16

Anatomy of a Muscle Cell

17 O sarcomere

18 O Myosin heads and actin binding sites

19 O Anaerobic Mechanism = O Glycolysis and lactic acid formation

20 O Oxidative phosphorylation

21 O Creatine phosphate gives an ATP to ADP providing power and releasing creatine.

22 O Glucose is broken down into carbon dioxide and water and energy. The energy is captured to bind molecules of ATP to provide energy.

23 O Glycogen is broken into glucose that is broken into ATP and pyruvic and lactic acids.

24 O Abducted – taken away from the midline O Lift your arm out ward O Adduction – closer to the midline O Put arm at your side O Flexion – bend toward the midline O Bend your elbow to eat O Extension- move away from the midline O put your arm behind your back O backhand your tennis racket

25 O Paralyzes the muscle