control of muscle

• What is the role of mitochondria in a neuromuscular junction?

  To provide energy for the process of neurotransmission

  
• What are synaptic vesicles?

  Small sacs that store and release neurotransmitters at the synapse

  
• What is the synaptic cleft?

  The gap between the motor neuron and the muscle fiber

  
• What is the folded sarcolemma?

  The folded membrane of the muscle fiber at the neuromuscular junction

  
• What are the components of a motor end plate?

  • Mitochondria
  • Synaptic vesicles
  • Synaptic cleft
  • Folded sarcolemma

  
• What does the motor end plate facilitate?

  Neurotransmission at the neuromuscular junction

  
• What are the functions of a motor neuron fiber in the neuromuscular junction?

  • Conducts nerve impulses to the muscle fiber
  • Branches to innervate multiple muscle fibers

  
• What are nerve fiber branches in a neuromuscular junction?

  The extensions of the motor neuron fiber that interact with individual muscle fibers

  
• What is the muscle fiber nucleus?

  The control center of a muscle fiber

  
• How do mitochondria support the function of the motor end plate?

  Mitochondria provide energy to the motor end plate by producing ATP. This energy is necessary for the release and uptake of neurotransmitters, maintaining membrane potential, and overall synaptic function.

  
• What is the function of myofibrils in muscle fibers?

  They are the contractile units of the muscle fiber

  
• How would damage to the motor end plate affect muscle function?

  Damage to the motor end plate would disrupt neurotransmission, leading to muscle weakness or paralysis since nerve impulses could not be effectively transmitted to the muscle fibers.

  
• What is the importance of the synaptic cleft in the neuromuscular junction?

  It provides space for neurotransmitters to diffuse and bind to receptors on the muscle fiber, ensuring efficient neurotransmission

  
• What are the main structural features of a motor end plate?

  • Synaptic vesicles
  • Synaptic cleft
  • Folded sarcolemma
  • Mitochondria

  
• What are the main components of the neuromuscular junction?

  • Axon terminal of motor neuron
  • Synaptic cleft
  • Motor end plate of muscle fiber

  
• What neurotransmitter is stored in vesicles at the axon terminal of the neuromuscular junction?

  Acetylcholine

  
• What type of channel opens when an action potential reaches the axon terminal of a motor neuron?

  Voltage-gated calcium channel

  
• What is the term used to describe the spreading of a muscle action potential?

  Propagation

  
• What does SR stand for in the context of muscle physiology?

  Sarcoplasmic reticulum

  
• What are the key structural components of the sarcomere?

  • Z lines
  • I bands
  • A bands
  • H zone
  • M line

  
• What is the function of voltage sensors in T-tubules?

  They detect changes in membrane potential and initiate the opening of $SR \, Ca^{2+} \, channels.$

  
• What occurs when the T-tubule membrane is depolarized?

  The voltage sensors open $SR \, Ca^{2+} \, channels,$ leading to calcium release into the sarcoplasm.

  
• What role do $SR \, Ca^{2+} \, channels$ play in muscle excitation?


  They mediate the release of calcium ions from the sarcoplasmic reticulum into the sarcoplasm.

  
• What are the three main parts of a neuron?

  Dendrites, cell body, and axon.

  
• What is the role of each part of a neuron?

  • Dendrites: Receive signals from other neurons
  • Cell body: Contains the neuron's nucleus and organelles
  • Axon: Transmits signals to other neurons

  
• What is the function of myelin in a neuron?

  • Increases the speed of signal transmission

  
• What is the synapse?

  It is the gap between two neurons where communication occurs.

  
• How does communication occur at the synapse?

  1. Action potential reaches the axon terminal
  2. Neurotransmitters are released into the synaptic cleft
  3. Neurotransmitters bind to receptors on the receiving neuron
  4. Signal is transmitted to the next neuron

  
• What are the two main subsections of the nervous system?

  • Central Nervous System (CNS)
  • Peripheral Nervous System (PNS)
• What components make up the Central Nervous System (CNS) of the nervous system?

  • Brain
  • Spinal Cord
• What are the two types of efferent (motor) nerves in the Peripheral Nervous System (PNS)?

  • Somatic (Skeletal muscle)
  • Autonomic (Cardiac/smooth muscle, exocrine glands)
• What are the two types of afferent (sensory) nerves in the Peripheral Nervous System (PNS)?

  • Somatic
  • Visceral
• How is each skeletal muscle fibre innervated?

  Each skeletal muscle fibre is innervated by a motor neuron.
• Are motor neurons excitatory or inhibitory?

  Excitatory
• How many muscle fibres can a single motor neuron innervate?

  Each neuron can innervate a few or many muscle fibres.
• Can skeletal muscle contract without innervation from motor neurons?

  No
• What determines the pattern of muscle contraction such as strength, duration, and speed?

  The pattern of muscle contraction is determined by the pattern of activity in motor neurons.
• What is a motor unit?

  One motor neuron and all the muscle fibres that it innervates.
• How does the ratio of nerve to muscle fibres vary in different muscles?

  The ratio varies depending on the function of the muscle:

  • Strength (e.g. limb) – many fibres by one nerve
  • Control (e.g. eye) – few fibres by one nerve
• How can the nervous system control muscle force?

  The nervous system can control muscle force by:

  • Recruiting more/fewer motor units
  • Controlling force within a motor unit