Chapter 5

Question 1

How do neurons communicate and adapt

Answer 1

• A chemical message
• Varieties of neurotransmitter and receptors
• Neurotransmitter systems and behavior
• Adaptive role of synapses in learning and memory

Question 2

A chemical message

Answer 2

Chemicals relay excitatory messages to speed up and inhibitory messages to slow down

Question 3

Otto Loewi

Answer 3

Performed frog heart experiment and found Epinephrine and norepinephrine

Question 4

Acetylcholine

Answer 4

The first neurotransmitter discovered in the PNS and CNS- activates skeletal muscles in the somatic nervous system and may excite or inhibit internal organs in the autonomic nervous system

Question 5

Neurotransmitter

Answer 5

Chemical released by a neuron onto a target with an excitatory or inhibitory effect. Outside of the CNS these can be hormones

Question 6

Electron microscope

Answer 6

Project a beam of electrons through a very thin slice of tissue, making an image

Question 7

Chemical syanapse

Answer 7

Where messenger neurons are sent from one neuron to another, causing an excitation or an inhibition

Question 8

Exocytosis

Answer 8

Expelling a neurotrasmitter

Question 9

Presynaptic membrane

Answer 9

Where the action potential terminates to release the chemical message

Question 10

Postsynaptic membrane

Answer 10

The receiving side of the chemical message, where EPSPs or IPSPs are generated

Question 11

Synaptic cleft

Answer 11

Small gap where chemical travels from pre to postsynaptic

Question 12

Tripartite synapse

Answer 12

Functional integration and physical proximity of the presynaptic membrane, postsynaptic membrane, and their intimate association with surrounding astrocytes

Question 13

Synaptic vesicle (presyn)

Answer 13

Small membrane bound spheres that contain neutransmitters

Question 14

Storage granule (postsyn)

Answer 14

Membranous compartment that holds several vesicles with neurtransmitters

Question 15

Postsynaptic receptor

Answer 15

Site to which neurotransmitter molecule binds

Question 16

Anterograde synaptic transmission

Answer 16

Process that occurs when a neurotransmitter released from a presynaptic neuron and minds to the receptor of the postsynaptic

Question 17

Transporter

Answer 17

Protein molecule that pumps substance across membrane

Question 18

5 Steps of Anterograde Synaptic transmission

Answer 18

1. The neurotransmitter is synthesized somewhere in the neuron
2. It is packaged and stores within vesicles at the axon terminal
3. It is transported to the presynaptic membrane and released into the cleft in response to and action potential
4. It binds to and activates receptors on the postsynaptic membrane
5. It is degraded or removed, so it will not continue to interact with a receptor and work indefinitely

Question 19

Two ways neurotransmitters are derived

Answer 19

1. Synthesized in the axon terminal

2. Created in the cell body

Question 20

Neurotransmitter release process

Answer 20

At the axon terminal, the action potential opens sensitive Calcium Ca2+ channels. Ca2+ enters the protein and binds to calmodulin. The complex causes some vesicles to empty their contents into the synapse and other to get ready to empty their contents

Question 21

What do neurotransmitters do on the postsynaptic side

Answer 21

1. Depolarize the postsynaptic membrane, causing excitatory action on the postsynaptic neuron (EPSP)
2. Hyperpolarize the postsynaptic membrane, signalling a IPSP
3. Initiate other chemical reactions that modulate the excitatory or inhibitory effect or influence other functions

Question 22

Autoreceptor

Answer 22

Self-receptor on the presynaptic membrane that responds to the transmitter that the neuron releases

Question 23

Neurotransmitter inactivation

Answer 23

1. Diffusion of neurotransmitters
2. Degradation: enzymes in the synaptic cleft break down neurotransmitters
3. Reuptake: Transmitter is brought back into the axon terminal and recycled
4. Astrocyte uptake: Nearby astrocytes take up the neurotransmitter

Question 24

Dendrodendritic synapse

Answer 24

Dendrites send synapse to other dendrites

Question 25

Axondendritic synapse

Answer 25

Axon sends to dendrite

Question 26

Axoextracellular synapse

Answer 26

Axon sends to no specific target (extracellular fluid)

Question 27

Axosomatic synapse

Answer 27

Axon sends into cell body

Question 28

Axosynaptic synapse

Answer 28

Axon terminal ends on another axon terminal

Question 29

Axoaxonic synapse

Answer 29

Axon terminal ends on another axon

Question 30

Axosecretory synapse

Answer 30

Axon ends at a blood vessel and sends into blodstream

Question 31

Gap junction

Answer 31

Fused presynaptic and postsynaptic membrane that allows an action potential to pass directly from one neuron to the next. Electrical synapses are faster than chemical synapses but less flexible

Question 32

Chemical transmission origin

Answer 32

Feeding behaviour of single-celled creatures. | -Digestive juices are secreted onto pray and causes exocytosis. This process may have evolved for other needs.

Question 33

4 criteria for identifying a neurotransmitter

Answer 33

1. Transmitter must be synthesized in the neuron or must otherwise be present in it 2. When the neuron is active, the chemical must be released and produce a response 3. The same response must be obtained when the transmitter is experimentally placed on the target 4. A mechanism must exist for removing the transmitter from its action after its work is done

Question 34

Neurotransmitter may also...

Answer 34

1. Carry a message from on neuron to another to another by influencing the voltage of the postsynaptic membrane 2. Change the structure of the synapse 3. Communicate by sending messages in the opposite direction

Question 35

4 classes of neurotransmitters

Answer 35

1. Small-molecule transmitters 2. Peptide transmitters 3. Lipid transmitters 4. Gaseous transmitters

Question 36

Small molecule transmitter

Answer 36

Class of quick acting neurotransmitters that are synthesized from dietary nutrients and packaged ready for use in axon terminals (eg. acetylcholine)

Question 37

Subunits of acetylcholine synthesis

Answer 37

Choline | Acetate

Question 38

Breakdown of acetylcholine causes by

Answer 38

Enzyme: Acetylcholinesterase

Question 39

Amino acid transmitters

Answer 39

Glutamate:Main excitatory transmitter GABA: main inhibitory transmitter GABA is formed by simple modification of glutamate

Question 40

Peptide transmitters

Answer 40

Synthesized through translation of mRNA from instructions in the neuron's DNA. Most are assembled by ribosomes, act slowly and are not replaced quickly. Act as hormones that respond to stress, enable bonding, activate metapatrophic receptors and help with learning