Question

1. True or False: The striations in skeletal muscle are formed by the arrangement of thick and thin filaments.                 

2.

2. True or False: In skeletal muscle cells, the sarcoplasmic reticulum is continuous with the sarcolemma.                 

3.

3. The interval between two Z lines is called a ­________________.

4.

At a neuromuscular junction, the space between the plasma membrane of the synaptic terminal and the motor end plate is the __________________.

5.

5. An action potential (electric impulse) is transferred from a motor neuron to a muscle cell at a ___________________.

6.

6. True or False: Like most other cells in the body, skeletal muscle cells have only one nucleus.                 

7.

7. True or False: The influx of sodium ions generates an action potential at the motor end plate.                 

8.

8. A _________________________ consists of a motor nerve fiber and all the muscle fibers it stimulates at neuromuscular junctions.

9.

9. What is ACh? Explain what it is and it’s function during the sequence of events at the neuromuscular junction.

11.

10.

True or False: When a muscle contracts to cause an action at a joint, the origin is the moving attachment of the muscle, and the insertion is the stationary attachment.                 

11. True or False: When a muscle contracts to cause an action at a joint, the insertion is the moving attachment of the muscle, and the origin is the stationary attachment.

12.

12. True or False: The rectus abdominis is the primary respiratory muscle.                                 

13.

13. True or False: Muscle length will shorten during an isometric contraction.                 

14.

14. True or False: It takes a longer period of time for a muscle to exceed the load of a heavier object than a lighter object.                 

15.

15. The minimum stimulus required to initiate a muscle contraction is called the                 .

16.

16. When muscle fatigue occurs, what metabolic waste product accumulates in muscle cells?                 

17.

17. True or False: The levator scapulae and rhomboids connect the scapula to the vertebral column.                 

18.

18. The extensor digitorum longus muscle is located in the ________________ compartment of the leg.

19.

19. The suprahyoid muscles connect the hyoid bone to the ___________________ .

20.

20. The ________________________ muscles perform voluntary eye movements.

Answer 1

1). True , striations are seen in skeletal muscles due to arrangement of thick myosin filament and thin actin filament in the myofibril.

2). False , T tubules are continuous with sarcolemma not sarcoplasmic reticulum.

3). Sarcomere , region between 2 z line which is called the structural and functional unit of muscle fibre .

4).space between motor end plate and plasma membrane of synaptic terminal is called synaptic cleft. It is the space where neurotransmitter is released, from where it attaches to receptors in motor end plate . Enzymes that degrade neurotransmitters are also present in synaptic cleft.

6). False , skeletal muscle is multinucleated .

7). True , resting membrane potential is negative at motor end plate , when impulse travels down, sodium channels open causing sodium influx , causing depolarization.  

9). Ach is acetylcholine , it is the neurotransmitter mostly found in motor end plate and neurotransmitter of parasympathetic nervous system. It has 2 receptors nicotinic receptors and muscarnuc receptors where it binds and brings about its functions. At nmj it binds with nicotinic receptor, which causes depolarization of muscle fibres , which causes release of calcium from sarcoplasmic reticulum causing binding of myosin head to actin causing muscle contraction.  

12). False, the primary respiratory muscle is diaphgram and intercostal muscles. Rectus abdominus is an acessory muscle of respiration.

13). False , it is in isotonic contraction where muscle length shortens and tension remains same . In isometric muscle length remains same and tension changes .

15). Threshold potential, it is the minimum stimulus required to produce contraction in a muscle . It is the potential which makes the resting membrane less negative causing depolarization by opening sodium channels.

16 ). Lactic acid, during muscle contraction glucose will be utilized for energy production, that is atp , if muscle contraction takes place for long time then anaerobic respiration takes place inside muscle cell , where glycolysis produces lactic acid as its end product. Which cause muscle fatigue ness.