The nervous system - neurons - ch 12 Flashcards
Describe neurons?
specialised nerve cells
What are neurons responsible for?
- commicating information in both chemical and electrical forms
Do neurons vary in size, shape and characteristics depending on their function and role?
yes
Name the three parts neurons have?
- cell bodies
- dendrite
- axon or nerve fibre
What do cell bodies contain?
nucleus
Describe dendrites and their role?
- hair-like structures that surround the cell body and which manage and direct incoming signals
What is the role of the axon and nerve fibre?
they guide the outgoing signals from the neuron.
What are axons covered in?
fatty sheath called myelin which acts to insulate the axon and facilitates the transmission of impulses.
How do neurons communicate?
by transmitting information both within the neuron and from one neuron to the next.
Where do neurons dendrites receive information from?
sensory receptors or other neurons
Where is the information from the the dendrites transferred to?
the cell body and then travels down the length of the axon in the form of an electrical signal known as an action potential. The point at which the message passes between two nerve cells is called a synapse.
Describe a synapse?
a small gap across which chemical neurotransmitters diffuse or electrical impulses connect to pass instructions to the dendrites of other neurons or to activate specialised sites called receptors on a target cell.
Is the target cell a specialised part of a muscle cell or a gland?
Yes
Can the electrical signal on occassion instantaneously connect across the space between the neurons and continue along its path?
Yes
What is the role of the chemical messenger (neurotransmitter)?
(neurotransmitter) diffuses across the synapse to reach the receptor sites of other neurons in a process that is slower than the electrical signal