Exam 4 (CH. 5)

Question 1

What are the 2 big categories of synapse? What are the important parts of them?

Answer 1

• Electrical & Chemical
• Electrical (Gap Junctions): channel between presynaptic & postsynaptic neuron & Chemical (presynaptic neuron [axon terminal], synaptic cleft, & postsynaptic neuron (dendritic spine)

Question 2

What type of synapse works fastest?

Answer 2

Electrical

Question 3

Compare and contrast g-protein coupled receptors to ligand-gated ion channels

Answer 3

Ligand gated ion channels (ionotropic) : a ligand binds and ions go through the channel. Fast, less selectivity
g-protein coupled receptor (metabotropic): Slower, broad ranges of outcomes. NT binds to receptor embedded in the postsynaptic membrane. The receptor protein activates small proteins called G-protein which are free to move along the intracellular face of the postsynaptic membrane. The activated G-proteins activate “effector” proteins.

Question 4

What are common synaptic arrangements?

Answer 4

-axosomatic: axon terminal ends on cell body
-axosynaptic: axon terminal ends on another axon.
- axodendritic: axon terminal of one neuron synapses on dendritic spine of another.

Question 5

How might you tell if a synapse is excitatory or inhibitory? What NT are commonly found at each type? What sort of ion channel is likely to be affiliated with them?

Answer 5

• the voltage of the action potential. asymmetric membrane w/ circular vesicles are excitatory. symmetrical membrane w/ oval vesicles are inhibitory.
• GABA (inhibitory), Glutamate (excitatory), Glycine (inhibitory), 5-HT (inhibitory or excitatory), dopamine (inhibitory or excitatory)
• Inhibitory (K+ leaving cell OR Cl- entering cell)
  Excitatory (Na+ channels opening)

Question 6

What is the neural code?

Answer 6

Frequency

Question 7

How can a neuron process incoming signals (e.g., how are multiple inputs counted?)

Answer 7

• temporal: one input but frequency is amped up. Involved in timing.
• spatial: timing and location- multiple inputs at different locations at the same time

Question 8

What’s the difference between an IPSP & EPSP?

Answer 8

• Inhibitory post synaptic potential: brief GRADED potential that decreases the chance a neuron will fire (K+ leaves cell (efflux) OR Cl- (Enters cells (influx))
• Excitatory post synaptic potential: brief GRADED potential that increased the chance of a neuron will fire (Depolarizes neuron: Na+ channels open).

Question 9

What are agonists and antagonists? What are some examples?

Answer 9

-receptor anatgonists bind to the receptor & block the normal action of the NT (e.g. curare, which is a narrow tip poison which paralyzes prey)
-receptor agnoists: bind to receptors and mimic the actions of the naturally reoccurring NT (e.g. nicotine)

Question 10

What are the NT types?

Answer 10

• Amino acids: GABA (inhibitory, CNS), glutamate (excitatory, CNS) , & glycine (inhibitory: brainstem, spinal cord)
• Amines: Ach, DA, Epi, Histamine, NE, 5-HT
• Peptides: CCK, Dynorphin, Enk, NAAG, & NPY

Question 11

What makes the neuromuscular junction such a special synapse?

Answer 11

• easy to look at because of size, fast & reliable. It’s also the site for many diseases & a site of action for many pharmological drugs
• an essential synapse for muscle contraction and movement

Question 12

What is the role of myelin in the nervous system?

Answer 12

• Myelin is an insulating layer that forms around nerves. It allows electrical impulses to transmit quickly and efficiently along the nerve cells.