Neurons and synaptic transmission

Question 1

Where is the nucleus of a neuron?

Answer 1

in the soma or cell body

Question 2

What are dendrites?

Answer 2

branching extensions of the cell body

-input sites that receive input from other neurons

Question 3

What is the axon?

Answer 3

The long part of the neuron that the signal travels down.

-ends at axon terminal

Question 4

Where are the synaptic vesicles and what are they?

Answer 4

• in the axon terminal

- contain neurotransmitters

Question 5

How is the signal transmitted from one neuron to another?

Answer 5

• action potential from electrical impulse moves rapidly down axon to axon terminal
• triggers the release of neurotransmitters from the synaptic vesicles into the synaptic cleft
• neurotransmitters bind to receptors on dendrites of another neuron
• triggers an action potential
• electrical impulse is transferred

Question 6

What are receptors?

Answer 6

proteins on the cell surface

• complimentary to different neurotransmitters
• lock and key mechanism

Question 7

What is the purpose of a sensory neuron?

Answer 7

• carry nerve impulses from sensory receptors to spinal cord towards brain
• translate sensory information into neural impulses
• translated into sensations e.g. taste when they reach the brain

Question 8

What is a quick reflex action?

Answer 8

• when sensory input doesn’t reach the brain and neuron terminates at the spinal cord
• allows for a faster reaction without delay of sensing information to brain

Question 9

What is a relay neuron?

Answer 9

• allows sensory and motor neurons to communicate

- only within the brain and spinal cord

Question 10

What is a motor neuron?

Answer 10

• lie in the CNS but project axons outside CNS
• form synapses with muscles to control their contractions
• releases neurotransmitters that bind to receptors on the muscle to trigger a muscle contraction
• muscle relaxation is caused by inhibition of motor neuron