Signalling 2

• What is the primary function of cell signaling?

  Cells sense, integrate, and respond to signals from their environment
• Why is correct signaling important for multicellular organisms?

  It allows normal function and coordination among cells, tissues, and organs
• What are the three stages of signaling?

  (Bio)Chemical signaling, transduction/amplification, and responders
• What types of receptors are involved in cell signaling?

  Intracellular receptors, GPCRs, RTKs, and ion-channel-linked receptors
• What role do second messengers play in signaling?

  They are involved in transduction and amplification of signals
• What is the definition of a 'signal' in the context of cell signaling?

  Movement of electrical charge, such as ion movement
• How fast can nerve impulses travel in neurons?

  Up to approximately 120 m/s
• What is the term for the wave of altered charge that travels along the axon?

  Action potential
• What maintains the resting membrane potential of a neuron?

  Ion pumps in the plasma membrane
• What happens when a nerve cell is stimulated?

  Action potential is generated and Na⁺ channels open
• What occurs during depolarization of a neuron?

  Na⁺ ions flow into the cell, causing a positive charge
• What is the role of K⁺ channels during action potential?

  K⁺ channels open to allow K⁺ ions to flow out, leading to repolarization
• What is the refractory period in nerve signaling?

  It is the time after an action potential when a new action potential cannot be initiated
• What is spatial summation in nerve signaling?

  Summation of inputs from different areas of the cell
• What is temporal summation in nerve signaling?

  Input occurring multiple times from the same area or dendrite
• How is signal intensity encoded in action potentials?

  By the frequency of action potentials
• What happens when an action potential reaches the end of a neuron?

  It must cross the synapse to set up an action potential in the next neuron
• What are neurotransmitters?

  Chemical signals that transmit signals across synapses
• What is the role of acetylcholine at the neuromuscular junction?

  It binds to receptors to allow Na⁺ entry and initiates muscle contraction
• What is the effect of acetylcholinesterase at the neuromuscular junction?

  It removes acetylcholine to switch off the signal
• What is myasthenia gravis?

  An autoimmune condition where antibodies attack acetylcholine receptors
• What is the function of connexin proteins in gap junctions?

  They form connections that allow ion movement between cells
• How does electrical signaling occur in cardiac myocytes?

  Electrical impulses travel across heart tissue to cause contraction
• What are the intended learning outcomes of the session on signaling?

  • Outline how information is transmitted electrically in cells and tissues
  • Understand signal transmission between nerve cells and across the neuromuscular junction
  • Provide examples of pharmacology that exploit signal transduction
• Why is understanding cell signaling important for physiology and medicine?

  • Required for understanding normal physiology
  • Many diseases involve aberrant signaling
  • Many drugs target signaling pathways
• What is the complexity of cell signaling?

  • Involves multiple types of signals
  • Achieves specificity through various mechanisms
  • Essential for multicellular organism function