BP: Neurons and synaptic transmission Flashcards
(67 cards)
Most of the brain is made up of cells called…
… glial cells and astrocytes.
What are neurons?
Specialised cells whose function is to move electrical impulses to and from the central nervous system (carry neural information throughout the body).
What gives the brain its impressive processing capabilities?
The highly complex neural networks within in.
What must neurons transmit?
Must transmit information both within the neuron and from one neuron to the next.
What do the dendrites of neurons receive?
Information from sensory receptors or other neurons.
What happens once the dendrites of neurons have received information from sensory receptors?
The information is passed down to the cell body and on to the axon.
It then travels down the length of the axon in the form of electrical signal known as an action potential.
What three types of neurons are there?
- Sensory neurons
- Relay neurons
- Motor neurons
What things do neurons typically consist of?
- A cell body
- Dendrites
- An axon
What are dendrites connected to?
The cell body, which is the control center of the neuron.
In a neuron, where does the impulse terminate?
The axon terminal.
In many nerves, what is there around the axon?
An insulating layer, known as a myelin sheath.
What is a myelin sheath?
An insulating layer that forms around the axon of a neuron.
Why is the myelin sheath important?
What happens when this is damaged?
It allows the nerve impulses to transmit more rapidly along the axon.
When damaged, the impulses slow down.
What is the length of a neuron?
It can vary from a few millimetres up to one metre.
What do sensory neurons do?
They carry nerve impulses from sensory receptors to the spinal cord and the brain.
What are sensory receptors?
Receptors for vision, taste, and touch etc.
All the senses.
Where are sensory receptors found?
They are found in various locations in the body.
For example in the eyes, ears tongue and skin.
What do sensory neurons convert?
They convert information from the sensory receptors into neural impulses, which can then travel to the brain.
What happens when impulses from the sensory neurons reach the brain?
They are translated into sensations of, for example, visual input, heat, pain etc. so that the organism can react appropriately.
If sensory information does not go to the brain, where does it go?
Why is it more beneficial for it to go there instead?
Some sensory neurons terminate at the spinal cord, and this allows reflex actions to occur quickly without the delay of sending the impulses to the brain.
What are relay neurons?
The most common type of neuron in the CNS.
They allow sensory and motor neurons to communicate with each other.
Where are relay neurons found?
They are only found in the brain or the spinal cord.
What does the term ‘motor neurons’ refer to?
To neurons located in the PNS that project their axons outside the PNS and directly or indirectly control muscles.
What do most motor neurons form?
Synapses with muscles to control their contractions