Lecture XVI - Nervous System 1

Question 1

What is a Nerve net?

Answer 1

-a diffuse network of neurons
-may include ganglia
-ganglion: a cluster of neurons

Question 2

Central nervous system includes?

Answer 2

-Brain: anteriormost cluster or neurons
-Nerve cord: prominent longitudinally extending condensed part of CNS
-Nerve cord may include ganglia

Question 3

Peripheral nervous system includes?

Answer 3

-Nerves and ganglia outside the CNS
-Connects muscles, organs, and sensory cells to the CNS

Question 4

The origin of nervous systems

Answer 4

1. The ancestor of animals did not have a nervous system
2. Nerve nets evolved first after sponges
3. CNS evolved from nerve nets
4. CNS evolved between 1 and 9 times
5. All animals with a CNS also have a PNS

Question 5

Neuron

Answer 5

Three parts
1. Dendrites
2. Cell body
3. Axon

Question 6

Dendrites

Answer 6

-Highly branched group of relatively short projections
-Receive signals from other axons of other neurons
-Send signals to cell body

Question 7

Cell body

Answer 7

-Houses nucleus
-Receives signals from dendrites or axons from other neurons
-Sends a response signal to the axon

Question 8

Axon

Answer 8

-One or more long projections
-Receives signals form cell body
-Sends signals to the dendrites and cell bodies of other neurons

Question 9

Synapse

Answer 9

-Where axons from one neuron meet dendrites or a cell body of a different neuron
-Where signaling between neurons takes place

Question 10

Which of these choices is a possible direction of information flow within a neuron?

Answer 10

dendrite → cell body → axon

Question 11

Types of neurons

Answer 11

1. Sensory neuron
2. Motor neuron
3. Interneuron

Question 12

Sensory neuron

Answer 12

-Part of the PNS
-Carry sensory information to the CNS
-Bundled together into Nerves

Question 13

Interneuron

Answer 13

-Part of the CNS
-Receive signal from sensory neuron
-Send signal to motor neuron

Question 14

Motor neuron

Answer 14

-Part of the PNS
-Receive signal from interneuron
-Send signal to muscle cell
-Bundled together into nerves

Question 15

Real life Frankenstein

Answer 15

Giovanni Aldini (Italiian scientist; 19th century):
studied galvanism - bioelectricity
experimented on animal corpses
Thought to have influenced Mary Shelley

Question 16

Conclusion

Answer 16

-The neuron is the specialized cell of the nervous system
-A neuron includes an axon, dendrite, and cell body
-There are sensory, inter, and motor neurons
-Neurons produce bioelectrical signals