Chapter 2 Flashcards
(32 cards)
What two forms of activity are common to all neurons?
Electrical and chemical activity.
How do neurons interact within the nervous system?
They cooperate and compete to regulate the overall state of the system.
What happens when chemical signals reach a neuron’s dendrite?
They’re transformed into electrical signals that are summed to decide whether the neuron will fire.
What are the three main parts of a neuron and their functions?
Dendrites (receive), Cell Body (integrate), Axon (transmit).
What is neuronal polarization?
The concept that information flows in one direction: dendrites → cell body → axon.
What structural component supports the neuron’s shape?
A cytoskeleton made of tubular and filamentous proteins.
What are dendritic spines?
Tiny protrusions on dendrites where incoming axons form synapses.
Where are most neuronal proteins made, and how do they reach other parts?
In the cell body; they are transported along the cytoskeleton.
What are growth factors and their function in neurons?
Molecules that influence gene expression and help neurons grow and adapt.
What powers neuronal activity?
Mitochondria that provide energy, and protein turnover to maintain structure.
What ensures communication between the axon’s end and the cell body?
Transport of information, nutrients, and messengers.
What is a synapse?
A junction between two neurons, separated by a tiny gap (~20 nm), where communication occurs.
Where do most synapses occur in cerebral cortex neurons?
On dendritic spines.
What is synaptic transmission?
The chemical process of communication across synapses.
What are excitatory and inhibitory inputs?
Excitatory inputs cause inward currents; inhibitory inputs cause outward currents.
When does a neuron fire an action potential?
When the summed electrical inputs reach a threshold value.
What is an action potential?
An electrical pulse that travels along the axon.
Which ion channels open first during an action potential?
Sodium (Na⁺) channels.
What is the voltage change during an action potential?
From ~-70 mV to +30 mV and back.
What causes the membrane to repolarize after depolarization?
Opening of potassium (K⁺) channels allowing K⁺ to leave the cell.
What maintains ion balance in the long term?
Ion pumps that expel excess Na⁺ and restore K⁺.
What is the refractory period?
A brief time after an action potential when the neuron cannot fire again.
What enables action potential conduction along the axon?
Voltage gradients between active and resting membrane regions.
What analogy helps explain action potential propagation?
A firework sparkler — local sparks create a spreading wave of activity.
