18/12/2015 10:02 GMT | Updated 17/12/2016 05:12 GMT

Studying Biology the Bite­Sized Way: The Nervous System


Bite­sized learning divides a subject into its most important pieces of information, then presents the divided content in a logically organized way, from basic concepts to more advanced ones. With each nugget of content, the student feeds his or her brain with knowledge about the subject.

Go through the method for yourself below. Study the human nervous system by reading the following bite­sized Q&As. (This set of Q&As is from Biology Q&As, a bite­sized resource to learn Biology.)

1. What physiological systems are known as integrative systems? What is the reason for this designation?

Both nervous system and the endocrine system are considered integrative systems. This designation stems from the fact that both systems control and regulate biological functions and act at distance, receiving information from organs and tissues and sending effector commands (nervous impulses or hormones) to organs and tissues, thus integrating the body.

2. Which structures make up the nervous system?

The structures that form the nervous system can be divided into the central nervous system (CNS) and the peripheral nervous system (PNS).

The organs of the CNS are the brain (cerebrum, brainstem and cerebellum) and spinal cord. The PNS is made of nerves and neural ganglia. In addition to these organs, the meninges (dura­mater, arachnoid and pia­mater) are also a part of the nervous system, since they cover and protect the encephalon and the spinal cord.

3. What are the main cells of the nervous system?

The main cells of the nervous system are neurons. In addition to neurons, the nervous system is also made up of glial cells.

4. What are the functional differences between neurons and glial cells?

Glial cells and neurons are the cells that form the nervous system. Neurons are cells that have the function of receiving and transmitting neural impulses whereas glial cells (astrocytes, microgliacytes, ependymal cells and oligodendrocytes) are the cells that support, feed and insulate (electrically) the neurons. The Schwann cells that produce the myelin sheath of the peripheral nervous system can also be considered glial cells.

5. What are the three main parts into which a neuron can be divided? What are their respective functions?

The three mains parts into which a neuron can be divided are: dendrites, the cell body and the axon.

Dendrites are projections of the plasma membrane that receive the neural impulse from other neurons. The cell body is where the nucleus and the main cellular organelles are located. The axon is the long membrane projection that transmits the neural impulse at a distance to other neurons, to muscle cells and to other effector cells.

6. What is the name of the terminal portion of the axon?

The terminal portion of the axon is called the presynaptic membrane. Through this membrane, neurotransmitters are released into the synaptic junction.

7. What are synapses?

Synapses are the structures that transmit a neural impulse between two neurons.

When the electric impulse arrives, the presynaptic membrane of the axon releases neurotransmitters that bind to the postsynaptic receptors of the dendrites of the next cell. The activated state of these receptors alters the permeability of the dendritic membrane and the electric depolarization moves along the plasma membrane of the neuron to its axon.

This subject contains more 50 bite­sized Q&As, such as "What are nerves?", "What is the function of the myelin sheath?" and "What is the spinal cord?".

The full set of Q&As on the nervous system can be found here.