Neurons

Question 1

Neurons

Answer 1

-There are 100 billion nerve cells (neurons) in the human nervous system, 80% of which are located in the brain.
-By transmitting signals electricity and chemically, these provide the nervous system with its primary means of communication

Question 2

Three Types Neurons

Answer 2

-Sensory neurons carry messages from the PNS to the CNS. They have long dendrites and short axons. Located in the PNS in clusters called ganglias.
-Relay neurons connect the sensory neurons to motor or other relay neurons. They have short dendrites and short axons. Of all neurons, 97% are relay neurons and mos are in the brain and visual systems.

Question 3

Cell Body

Answer 3

Includes a nucleus which contains the genetic material of the cell

Question 4

Dendrites

Answer 4

Branchlike structures that protrude from the cell body. These carry nerve impulses from neighbouring neurons towards the cell body.

Question 5

Axon

Answer 5

Carries the electrical impulse impulse away from the cell body down the length of the neurone
-Covered in a fatty layer of myelin sheath that protects the axon
-Gaps in the axon called nodes of Ranvier speed up the transmission of the impulse.

Question 6

Terminal Button

Answer 6

At the end of the axon communicate with the next neuron in the chain across a gap called the synapse.

Question 7

Electrical Transmission

Answer 7

-When a neuron is in a resting state the inside of the cell is negatively charged compared to the outside.
-When a neuron is activated, the inside of the cell becomes positively charged for a split second causing an action potential to occur.
-This creates an electrical impulse that travels down the axon towards the end of the neuron.