Chapter 12.6 synapses

Question 1

What is presynaptic neuron

Answer 1

sends the message

Question 2

what is the postsynaptic neuron

Answer 2

receives message

Question 3

What are the types of synapses

Answer 3

• Electrical synapses
• Direct physical contact between cells
• Chemical synapses
• Signal transmitted across a gap by neurotransmitters

Question 4

Describe the electrical synapses

Answer 4

Electrical synapses
* Presynaptic and postsynaptic membranes are locked
together at gap junctions
* Ions pass between cells through pores
* Local current affects both cells
* Action potentials are propagated quickly
* Found in some areas of brain, the eye, and ciliary ganglia

Question 5

Describe the chemical synapses

Answer 5

Only type of synapse between neurons and other cells
* Cells are separated by synaptic cleft

Question 6

What are the types of chemical synapses

Answer 6

• Neuromuscular junction
• Synapse between neuron and skeletal muscle cell
• Neuroglandular junction
• Synapse between neuron and gland cell

Question 7

Describe a neurotransmitters’

Answer 7

• Chemical messengers contained within synaptic vesicles in
  axon terminal of presynaptic cell
• Released into synaptic cleft
• Affect receptors of postsynaptic membrane
• Broken down by enzymes
• Reabsorbed and reassembled by axon terminal

Question 8

What is synaptic fatigue

Answer 8

• Occurs when neurotransmitter cannot be recycled fast
  enough to meet demands of intense stimuli
• Response of synapse weakens until ACh is replenished