1.3 The Neuron and Neural Firing

• The soma houses the nucleus and vital organelles for cell maintenance.


  True
• Match the neuron component with its function:

  Axon ↔️ Transmits signals away from the soma

  Terminal Buttons ↔️ Release neurotransmitters

  Myelin Sheath ↔️ Speeds up signal transmission
• What is the primary function of the myelin sheath?

  Insulate the axon
• What is contained within the soma of a neuron?

  Nucleus and organelles
• The soma of a neuron contains the nucleus
• Arrange the following neuron components in the order signals travel through them:

  1️⃣ Dendrites

  2️⃣ Soma

  3️⃣ Axon

  4️⃣ Myelin Sheath

  5️⃣ Axon Terminals
• Input signals received by dendrites are converted into electrical impulses
• The myelin sheath speeds up signal transmission by insulating the axon.


  True
• An action potential is initiated if the combined potential at the axon hillock reaches the threshold
• What is the resting potential of a neuron in millivolts (mV)?

  -70 mV
• During depolarization, voltage-gated sodium channels open
• The action potential is a rapid, self-propagating change in the membrane potential
• The soma, or cell body, contains the nucleus
• The myelin sheath is present on all neurons in the nervous system.

  False
• A neuron transmits information throughout the body via electrical and chemical signals
• What is the function of the myelin sheath?

  Speeds up signal transmission
• What type of signals do dendrites convert input signals into?

  Electrical impulses
• An action potential is initiated if the combined potential at the axon hillock reaches the threshold
• What is the resting potential of a neuron in millivolts?

  -70 mV
• What is the function of the myelin sheath?

  Speeds signal transmission
• What do terminal buttons release to communicate with other neurons?

  Neurotransmitters
• Which part of the neuron houses the nucleus and essential organelles?

  Cell body (Soma)
• What is the primary function of dendrites in a neuron?

  Receive signals
• Axon terminals release neurotransmitters to communicate with other neurons
• What type of signals do dendrites receive from other neurons?

  Input signals
• What is another name for a nerve cell?

  Neuron
• What is the process called by which the soma integrates signals from dendrites?

  Summation
• The gaps in the myelin sheath are called Nodes of Ranvier
• What is the resting potential of a neuron?

  -70 mV
• Match the stage of neural firing with its description

  Resting Potential ↔️ Negative charge (-70 mV) maintained across membrane

  Depolarization ↔️ Reduction of negative charge, reaching threshold

  Repolarization ↔️ Restoring negative charge by K+ efflux

  Hyperpolarization ↔️ Membrane potential briefly exceeds resting potential
• What is the role of the myelin sheath in signal transmission?

  Speeds it up
• The axon transmits signals away from the soma
• What are the five main parts of a neuron?

  Dendrites, soma, axon, myelin sheath, axon terminals
• The axon transmits signals away from the soma
• What do inhibitory postsynaptic potentials (IPSPs) do to the likelihood of an action potential?

  Decrease it
• The gaps in the myelin sheath are called Nodes of Ranvier
• What happens to the membrane potential during the depolarization stage of an action potential?

  It increases
• What happens to the membrane potential during the action potential when it reaches the threshold?

  It increases rapidly
• Match the step in neurotransmitter release with its description:

  Arrival of Action Potential ↔️ Action potential reaches the axon terminal

  Opening of Calcium Channels ↔️ Ca2+ enters the cell

  Neurotransmitter Vesicle Fusion ↔️ Vesicles fuse with the presynaptic membrane

  Release of Neurotransmitters ↔️ Neurotransmitters are released into the synaptic cleft
• Stages of neurotransmitter release at a synapse

  1️⃣ Action potential reaches the axon terminal

  2️⃣ Calcium channels open

  3️⃣ Neurotransmitter vesicles fuse

  4️⃣ Neurotransmitters are released