Neurons
We'll start off with an exploration of neurons, the fundamental building blocks of the nervous system.
1) Start with this video:
2) Then, read this article: Know Your Brain - Neurons
3) Read these articles for some historical context:
History of Neuroscience - Camillo Golgi
History of Neuroscience - Santiago Ramon y Cajal
4) Watch this video for a quick refresher:
5) Finally, answer these questions to test your understanding:
1. Neurotransmitters are typically stored in and released from which part of a neuron?
- A. dendrites
- B. nucleus
- C. axons
- D. axon terminals (synaptic boutons)
Show Answer
Correct answer: D
Neurotransmitters are typically stored in and released from the axon terminals (synaptic boutons) of the neuron.
2. This part of a neuron contains the nucleus of the cell:
- A. soma (cell body)
- B. axon
- C. dendrites
- D. axon terminals (synaptic boutons)
Show Answer
Correct answer: A
The soma, also known as the cell body, is the central part of a neuron that contains the nucleus, along with other organelles like the endoplasmic reticulum and mitochondria. It plays a vital role in integrating incoming signals from the dendrites and generating outgoing signals to the axon. The nucleus inside the soma contains the cell's DNA and directs cellular activity.
3. A neuron receives most of its information (e.g., in the form of neurotransmitters) at its:
- A. dendrites
- B. soma (cell body)
- C. axon
- D. axon terminals (synaptic boutons)
Show Answer
Correct answer: A
Synapses can be formed between any two components of a neuron, but most of a neuron's synapses are found at its dendrites. This is where a neuron receives most of its incoming messages in the form of neurotransmitters and other signaling molecules.
4. This type of neuron has a single axon and many dendrites:
- A. bipolar
- B. unipolar
- C. multipolar
- D. pseudo-unipolar
Show Answer
Correct answer: C
Multipolar neurons are the most common type of neuron in the human nervous system and the nervous systems of other vertebrates. They usually have a single axon and many dendrites.
5. According to our best estimates, how many neurons are in an average brain?
- A. 500 million
- B. 24 billion
- C. 86 billion
- D. 100 trillion
Show Answer
Correct answer: C
Estimates have varied over time, but our current best estimate of the number of neurons in the brain is 86 billion (on average). Neurons are not distributed evenly throughout the brain, and some areas (e.g., cerebellum) have much more than others.
