Nervous System part 1 Flashcards
(35 cards)
Describe the structure of a neuron.
A neuron consists of a cell body, dendrites, an axon, a nucleus, a myelin sheath (Schwann cell), axon terminals, and nodes of Ranvier
Define the function of sensory neurons.
Sensory neurons are responsible for transmitting impulses from sensory organs to the central nervous system
How do motor neurons function in the
nervous system?
Motor neurons send impulses from the central nervous system to specific muscles or organs
Explain the role of interneurons.
Interneurons transmit impulses between sensory and motor neurons within the brain or spinal cord
Describe the resting potential of a neuron.
Resting potential occurs when the inside of the axon is more negatively charged compared to the outside, typically around -70mV
What is the role of the sodium-potassium
pump?
The sodium-potassium pump regulates the distribution of sodium (Na+) and the potassium (K+) ions, maintaining the resting potential of the neuron
How does an action potential begin?
An action potential begins when a stimulus causes some voltage-gated Na+ channels to open, allowing Na+ ions to diffuse inside the cell
Identify the main types of neurons and their
locations.
Sensory neurons are located in the peripheral
nervous system, motor neurons are also in
the peripheral nervous system, and
interneurons are found in the central nervous system.
Describe the steps involved in synaptic
transmission.
Synaptic transmission involves the release of
neurotransmitters from the axon terminal of
one neuron, which then bind to receptors on
the dendrites of another neuron, facilitating
communication between them.
Explain the significance of the nodes of
Ranvier
Nodes of Ranvier are gaps in the myelin
sheath that facilitate rapid conduction of
nerve impulses along the axon through
saltatory conduction.
Define the term ‘action potential’
An action potential is a rapid change in the
electrical charge of a neuron that occurs
when it is stimulated, leading to the
transmission of an impulse.
How do voltage-gated sodium channels
contribute to action potentials?
Voltage-gated sodium channels open in
response to a stimulus, allowing Na+ ions to
enter the neuron, which depolarizes the
membrane and initiates an action potential.
Describe the difference between resting
potential and action potential.
Resting potential is the state of a neuron
when it is not transmitting an impulse,
characterized by a negative charge inside,
while action potential is the rapid change in
charge that occurs during impulse
transmission.
What adaptations occur in neurons for
efficient signal transmission?
Neurons have adaptations such as
myelination, which increases the speed of
impulse transmission, and specialized
structures like dendrites and axon terminals
for communication.
Identify the associated cells of the nervous
system and their functions.
Associated cells include glial cells, which
support and protect neurons, and Schwann
cells, which form the myelin sheath around
peripheral nerves.
Describe the process that occurs when a
threshold is reached in a neuron.
An action potential is triggered, opening more Na+ channels and causing depolarization, where the inside of the cell becomes more positively charged than the outside.
How does depolarization affect the charge of
a neuron?
Depolarization causes the inside of the
neuron to become more positively charged
compared to the outside.
Define the role of Na+ and K+ ions during an
action potential.
Na+ ions enter the cell during depolarization,
while K+ ions exit the cell during
repolarization.
What happens at the peak voltage of an
action potential?
At the peak voltage around +40mV, Na+
channels close and voltage-gated K+
channels open, allowing K+ ions to diffuse
out.
Explain the process of repolarization in a
neuron.
Repolarization occurs when K+ ions diffuse
out of the cell after Na+ channels close,
returning the cell to a more negative internal
charge.
How does hyperpolarization occur in a
neuron?
Hyperpolarization occurs when more K+ ions
are outside the cell than Na+ ions inside,
making the inside of the neuron more
negative.
What is the function of the sodium-potassium
pump during the refractory period?
The sodium-potassium pump restores the
normal polarized state of the neuron by
moving K+ ions back inside and Na+ ions
outside.
Describe the significance of the refractory
period in neuronal activity.
The refractory period allows the neuron to
reset its ion concentrations, ensuring that
action potentials occur in a controlled
manner
Describe the process of saltatory conduction
in neurons.
Saltatory conduction is the process by which
action potentials jump across the gaps (nodes of Ranvier) in myelinated axons, allowing impulses to travel faster than in unmyelinated neurons
