Biopsych: Neurons

Question 1

What is the structure of a neuron?

Answer 1

There are 100 billion of these in our bodies and 80% of them are in the brain.
Allow the brain to send electrical impulses and chemical messages around the body

Question 2

What is a synapse?

Answer 2

Gaps between the terminal button that transmitters pass across

Question 3

What is a Myelin Sheath?

Answer 3

Fatty substance around the cells that speeds up the rate of transmission of impulses

Question 4

What is a soma?

Answer 4

The cell body

Question 5

What is an axon?

Answer 5

The extension from the soma

Question 6

What is the nucleus?

Answer 6

The brain of the cell

Question 7

What are dendrites?

Answer 7

Branches of the cell that receive signals from other cells

Question 8

What are Nodes of Ranvier?

Answer 8

The gap in the myelin sheath which speeds up the transmission of electric impulses

Question 9

What are terminal bulbs (or buttons)?

Answer 9

Ends of the cell that link to other cells dendrites

Question 10

How do neurons communicate?

Answer 10

• neurons receive messages from sensory organs or other neurons. Messages pass between two neurons by neurotransmitters diffusing across the synaptic cleft (a gap between neurons)
• messages run through neurons by becoming electrical impulses triggered by neurotransmitters reaching post synaptic receptor sites

Question 11

What is a sensory neuron?

Answer 11

• long dendrites and short axons
• are found in receptors such as the eyes, ears, tongue and skin and carry nerve impulses to the spinal cord and brain
• when these nerve impulses reach the brain, they are translated into ‘sensations’, such as vision, hearing, taste and touch.
• however, not all sensory neurons reach the brain, as some neurons stop at the spinal cord, allowing for quick reflex action.

Question 12

What are relay neurons?

Answer 12

• short dendrites and short axons
• connect the sensory and motor neurons (or other relay neurons)
• found in the brain and the spinal cord and allow sensory and motor neurons to communicate
• allow fast reflex responses to take place by bypassing the brain.

Question 13

What are motor neurons?

Answer 13

• short dendrites and long axons
• connect the CNS to effectors (muscles or glands)
• found in the CNS and control muscle movement
• when motor neurons are stimulated, they release neurotransmitters that bind to the receptors on muscles to trigger a response, which leads to a movement.

Question 14

how can the transmission of messages through the neuron be electric?

Answer 14

When a neuron is in resting state, it is negatively charged. When it is activated by a stimulus, the inside of the cell becomes positively charged for a split second. An action potential will pass through the neuron when it is positively charged. This allows an electrical impulse to move through the neuron.