Lec 5 (physiology)

• What is the focus of Lecture 5 in the nervous system study material?

  The Neuromuscular Junction
• How do nerve cells communicate with muscle cells?

  Through the neuromuscular junction
• What are the three types of muscle mentioned?

  • Skeletal Muscle (Voluntary)
  • Cardiac Muscle (Involuntary)
  • Smooth Muscle (Involuntary)
• What is a characteristic of skeletal muscle cells?

  Skeletal muscle cells are multi-nucleate
• What do striations in skeletal muscle cells indicate?

  They indicate the presence of light and dark bands
• What is a motor unit?

  A single motorneuron plus all the muscle cells it controls
• What happens when an action potential occurs in muscle cells?

  All the muscle cells will contract simultaneously
• What are the differences between small and large motor units?

  • Small Motor Units: Contain small motor units, e.g., extraocular muscles
  • Large Motor Units: Contain large motor units, e.g., quadriceps muscles
• What is the neuromuscular junction?

  It is the site where nerve cells communicate with muscle cells
• What neurotransmitter is mentioned in relation to the neuromuscular junction?

  Acetylcholine (ACh)
• What is the end-plate potential?

  It is the electrical change in the muscle cell at the neuromuscular junction
• What role does acetylcholinesterase play at the neuromuscular junction?

  It detaches acetylcholine from the receptor sites
• What are neuromuscular blockers?

  • Drugs that inhibit communication at the neuromuscular junction
  • Example: Curare
• What is the effect of curare on the neuromuscular junction?

  It blocks the action of acetylcholine
• What are anticholinesterase drugs?

  • Drugs that inhibit the enzyme acetylcholinesterase
  • They prolong the action of acetylcholine at the neuromuscular junction
• What condition is associated with anticholinesterase drugs?

  Myasthenia Gravis
• What is the effect of pyridostigmine in the treatment of Myasthenia Gravis?

  It improves communication at the neuromuscular junction
• What is the difference in muscle function before and after treatment for Myasthenia Gravis?

  • Before Treatment: Poor communication at the neuromuscular junction
  • After Treatment: Improved communication and muscle function