SKELETAL MUSCLE STUDY QUESTIONS - WEEK 3

PART A - ANATOMY REVIEW

1) Which types of muscle are voluntary and involuntary.  How would you morphologically differentiate between skeletal, cardiac and smooth muscle?

2) What are the 3 major layers of connective tissue found in skeletal muscle and which structure is surrounded by each of these connective tissue layers?

3) What are the 2 major roles of the extensive connective tissue in skeletal muscle?

4) What is the proper name for a skeletal muscle cell; why this name?

5) A little kid walks up to you on the street and asks you what makes a skeletal muscle cell morphologically unique relative to other cells in the body; what do you tell her?

6) Differentiate between red and white muscle cells...

7) When we exercise regularly, which unit of muscle tissue increases in number?

8) When muscles atrophy, which unit of muscle tissue decreases in number?

9) What is the transmitter at the NMJ?

10) Why is it necessary to electrically insulate individual muscle cells?

11) What do we call the transmitter containing vesicles found in the axon terminal?

12) What do we call the area of the muscle cell membrane located in the region of the NMJ?

13) What is the name of the system of membrane tubes which carry action potentials (ap's) deep into the muscle cells?

14) What do we call the specialized region of the SR which releases Ca²⁺ to initiate muscle contractions?

PART B - THE NEUROMUSCULAR JUNCTION

1) When a membrane is depolarized, does the membrane become more positive or more negative?  Does depolarization represent stimulation or inhibition of activity?

2) In order for transmitter to be released from the axon terminals, what ion must enter the axon terminal and how does it get into the axon terminal?

3) Following a muscle cell contraction, what type of mechanism is used to get the Ca2+ back into the SR?  How would you classify this mechanism?

4) How do transmitter molecules get across the synaptic cleft?

5) The ACh receptor mechanism opens a "chemically gated" ion channel which lets a lot of ____ diffuse inward and a small amount of ____ diffuse outward - the net effect is _____________ of the motor end plate!

6) What is the name of the enzyme which breaks down ACh in order to halt the activation of the motor end plate and allow muscle contraction to cease?

7) What would happen if a drug blocked acetylcholinesterase activity?

8) What would happen if a drug blocked acetylcholine from binding to the ACh receptor?

PART C - THE SLIDING FILAMENT THEORY

1) What proteins make up the thick and thin filaments?

2) Are myosin and actin contractile proteins or regulatory proteins?

3) The myosin head (cross-bridge) has 2 receptors - what do these receptors bind?

4) Which filament, thick or thin, has ATPase activity?

5) What are the 3 major uses of ATP energy in the sliding filament theory?

6) What are the 2 regulatory proteins and which filament are they associated with?

7) Why are the 2 proteins in #6, above, known as the regulatory proteins?

8) Which molecule of the sliding filament theory binds Ca²⁺ at the start of the contraction process?

9) What is the name of the chemical process that breaks down ATP to release energy?

10) Each thin filament interacts with ___ thick filaments; each thick filament interacts with ___ thin filaments.