1.1 (Neurons and action potential) Flashcards
What are some components of micro neuroscience
neurons, synapses, dendrites and
axons
What are some components of macroneuroscience
the hippocampus, the basal ganglia, the cerebellum
What are glial cells
Glial cells, or glia, are non-neuronal cells in the nervous system that support, protect, and maintain neurons. They provide structural support, regulate the extracellular environment, supply nutrients, and play roles in immune defense and neural signaling. Glial cells include astrocytes, microglia, oligodendrocytes (in the CNS), and Schwann cells (in the PNS).
What are neurons
Neurons are specialized cells in the nervous system that transmit information through electrical and chemical signals. They consist of a cell body, dendrites (which receive signals), and an axon (which sends signals). Neurons communicate with each other via synapses, forming networks essential for brain function, movement, sensation, and cognition.
Draw a neuron and label the key parts
What is the soma responsible for within a neuron
In the center there is the soma,
the neuron is a cell and the soma is the cell body; here many of the metabolic
processes, the life-supporting, functions of the neuron occur, it contains, for
example, the nucleus where the genetic material is found and which con-
trols the synthesis of proteins.
Are dendrites and axons tubes or wires
tubes
What is the axon
The axon is a long, slender projection of a neuron that conducts electrical impulses away from the cell body to other neurons, muscles, or glands. It plays a key role in transmitting signals over distances within the nervous system.
What are dendrites
Dendrites are branch-like extensions of a neuron that receive signals from other neurons and transmit them to the cell body, enabling communication within neural networks.
What is the difference between the fluid inside and outside the neuron
Both inside and outside the neuron there is fluid, basically water with dissolved salts, but the fluid inside and out have different concentrations of the ions that make up the salts. There can be a potential difference, that is a voltage difference, across the membrane and, as we will discuss, the signals we are will be talking about are changes in voltage.
How do dendrites and axons connect
The axon of other neurons will transmit signals to this neuron’s dendrites at points where they, the other neuron’s axon and this neuron’s dendrite, nearly touch: the nearly-touching place is called a synapses and synapses contains complicated bio-mechanical machinery to allow the sig- nals to be communicated from axon to dendrite.
What is a Purkinje cell and how many connections can it recieve. (Also how diverse are neurons)
There is a huge diversity of different neurons, they differ in their shape, in their size, in how connected they are and in their voltage dynamics. As an extreme example, the Purkinje cell (see Fig. 3) has a huge number of dendrites and receives connections from as many as 100_000 other neurons, however, many of those other neurons are cerebellum granule cells, very small neurons that receive inputs from only three or four other neurons.
What does the drawing of a Purkinje cell look like. And where in the brain are they found
What is the potential difference of the fluid inside and outside of a neuron. And which side is negative.
There is a potential difference between the inside and outside of a neuron. For convenience we usually regard the fluid in the brain as being at a zero voltage; Relative to that the fluid inside a neuron has a negative voltage; -70 mV at rest would be a typical value.
Why doesn’t current flow between the inside and outside of a neuron at rest
- Cell membrane is an insulator
- Difference in concentration of ions (excess of sodium outside, excess of potassium inside)
- There are pumps, which pump ions in and out to maintain the voltage difference
What are action potentials
Action potentials are rapid electrical impulses that travel along a neuron’s axon, enabling the transmission of signals over long distances. They occur when a neuron’s membrane potential quickly depolarizes and then repolarizes, allowing communication between neurons and other cells.
What is the magnitude and duration of an action potential
During a spike the voltage shoots up by about 80 mV and then falls back to near the resting value, **all during 1–2 ms. **The dynamics that allow this to happen come from ions trav- elling through the membrane, in a sense the energy for the spike has been stored up by the all ion pumping that has created the concentration differ- ences across the membrane. The spike will travel along the axon. The axon will usually have many branches and when this happens a spike will travel down each branch: the spike doesn’t split in the sense that the spike travel- ling down each branch will be the same size as the original spike.
Does an action potential change amplitude or shape as is propagates along the axon?
No. Broadly speaking, the spike does not change amplitude or shape as it prop- agates along the axon. A useful analogy here is a train of dominoes falling over; the energy in that case comes from the energy stored in the domino when it was set upright, the collision from the other domino hitting it is what causes it to fall over, but isn’t the source of most of the energy involved in its own fall. When a train of dominoes splits, the wave of falling-over is just as fast along each branch
Draw an action potential
