Chapter 12: Muscle Physiology

15 Questions | By Iheartwaffles | Last updated: Mar 21, 2022 | Total Attempts: 4170

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Today we’ll be taking a look under the hood of our bodies and focusing on the muscular system and our physiology, with reference to the biological systems within humans which produce movement. What can you tell us about the subject? Let’s take a look at the questions below and find out!

Questions and Answers

1.

When a muscle cell is relaxed and intracellular ATP levels are normal, a crossbridge will remain in which of the following states?
- A.
  
  Bound to actin and in the low-energy form
- B.
  
  Bound to actin and in the high-energy form
- C.
  
  In the high-energy form, with ADP and Pi bound to it
- D.
  
  In the high-energy form, with ATP bound to it
- E.
  
  In the low-energy form with nothing bound to it
2.

Which of the following would tend to reduce the concentration of lactic acid that accumulates in a muscle cell as a result of contractile activity?
- A.
  
  Increasing the concentration of glycolytic enzymes
- B.
  
  Decreasing the oxygen supply to the cell
- C.
  
  Increasing the diameter of the cell
- D.
  
  Increasing the number of mitochondria in the cell
- E.
  
  All of the above
3.

Which of the following statements is a valid generalization regarding properties of smooth muscle?
- A.
  
  Neurotransmitters can either excite or inhibit smooth muscle contraction, but any given neurotransmitter is always excitatory or inhibitory, regardless of where the muscle is located
- B.
  
  A given smooth muscle cell can respond to more than one type of neurotransmitter
- C.
  
  Smooth muscle cells are generally unresponsive to neurotransmitters of all types
- D.
  
  Smooth muscle cells can respond to neural input from the somatic or autonomic nervous systems
- E.
  
  None of the above
4.

In an isotonic contraction,
- A.
  
  Muscle length shortens
- B.
  
  Muscle tension exceeds the force of the load
- C.
  
  The load is moved
- D.
  
  A & c
- E.
  
  All of the above
5.

Which of the following is true for the excitation-contraction coupling of all muscle types (skeletal, cardiac, and smooth)?
- A.
  
  An action potential causes calcium levels in the cytosol to increase
- B.
  
  Calcium binds to troponin
- C.
  
  Thick and thin filaments slide past each other
- D.
  
  A & c
- E.
  
  All of the above
6.

Which of the following statements concerning the characteristics of different types of muscle fibers is false?
- A.
  
  The higher the myosin ATPase activity, the faster the speed of contraction
- B.
  
  Muscles that have high glycolytic capacity and large glycogen stores are more resistant to fatigue
- C.
  
  Oxidative types of muscle fibers contain myoglobin
- D.
  
  Oxidative fibers have a richer blood supply
- E.
  
  Larger diameter fibers can produce greater tension
7.

Which of the following muscle types contain gap junctions?
- A.
  
  Skeletal muscle
- B.
  
  Smooth muscle
- C.
  
  Cardiac muscle
- D.
  
  A & b
- E.
  
  B & c
8.

In skeletal muscle, when calcium is released from the sarcoplasmic reticulum it binds to (troponin/ tropomyosin) to initiate the crossbridge cycle.
9.

Glycolytic fibers generate more force than oxidative fibers because they are larger in diameter (true/ false)
10.

(glycolytic/ oxidative) fibers contain high concentrations of the oxygen-binding protein myoglobin
11.

The plasma membrane of a muscle cell is aka the _________________.
12.

During muscle contraction, ATP hydrolysis is catalyzed by (myosin head groups/ actin monomers).
13.

During an (isometric/ isotonic) muscle contraction, a muscle develops contractile force but does not change in length.
14.

A reduction in the number of active crossbridges is responsible for a decrease in force-generating capacity of a muscle fiber that is significantly (longer/ shorter) than its optimum length
15.

(oxidative/ glycolytic) muscle fibers are more resistant to fatigue