HW 3

Neuron Parts

• Match the part of the neuron identified with its description:
  

1. _B_Axon A. Contains the nucleus, which controls the function of the entire cell

2. _D_ Axon terminals B. Carry signals to other nerve cells

3. _A_ Cell body (soma) C. Receive signals from other nerve cells

4. _C_ Dendrites D. Contain small sacs called synaptic vesicles that play an important
role in transmitting signals from one cell to the next

5. Dendrites ______detect__________

6. Axons _______announce__(send)________

7. What does it mean to say that an axon’s membrane is “selectively permeable”?

Answer: That means that some molecules can pass easily through the membrane, while others can only pass through special channels controlled by gates.

8. Given what you know about synaptic transmission, how do you think a message jumps across the synaptic gap and is passed to the next neuron?
Answer: The process of synaptic transmission involves the release of neurotransmitter molecules that float across the synaptic gap and stimulate receptors in the next neuron. When the neural impulse reaches the axon terminal, the vesicles open up and release their neurotransmitter molecules into the synaptic cleft.

The neurotransmitter molecules float across the gap, and find their way to special receptors on the surface of the other neuron’s membrane. Each neurotransmitter molecule is like a piece of a jigsaw puzzle.

Each receptor (binding site) will accept only a certain type of neurotransmitter molecule.