Lecture 6

Question 1

What does the olfactory system do?

Answer 1

Sends info from the olfactory bulb to the pyriform cortex-humans have a small olfactory system in comparison to other animals.

Question 2

What are the 2 divisions of the autonomic nervous system?

Answer 2

1) Sympathetic-arousal, “fight or flight” response. Stress hormones, increased heart rate etc.
2) Parasympathetic- calm, “rest and digest.” System of excitation and inhibition.

Question 3

What is the Enteric Nervous System (ENS)?

Answer 3

Largely independent of ANS-talks to CNS through ANS. 200-500 million neurons. Controls digestion, bowel, motility, blood flow etc. ENS Sends info to brain, influences mental state (stress, anxiety). Serotonin plays a key roll!

Question 4

What are the 2 opposing views on what neurons are and who came up with them?

Answer 4

Camillo Golgi- Nervous system is composed of a network of interconnected fibers: “nerve hat”.
Santiago Ramon Cajal-Nervous system is made of discrete cells- Neuron theory: Neurons are unit of brain function.

Question 5

What was the Golgi Technique?

Answer 5

Used a staining technique to look at neurons

Question 6

What was a consequence of Golgi coming up with his technique?

Answer 6

Figured his hypothesis was right from what he saw, but Cajal used this technique on chick embryos and found that Golgi was not right.

Question 7

What are the 3 main parts of a neuron?

Answer 7

1) Dendrites-Gathers info from other neurons
2) Cell body/soma-Integration of information
3) Axon- carries information to be passed on to other cells.

Question 8

What are a few things to keep in mind about neurons?

Answer 8

1) Most behaviours are produced by hundreds or thousands of neurons
2) Neurons are plastic, changing with experience
3) Most of your neurons are with you for life and are never replaced (there are discrete regions in the brain that have continuous turnover of new neurons-neurogenesis).

Question 9

What parts of the brain demonstrate neurogenesis?

Answer 9

Hippocampus and lateral ventricles.

Question 10

What are dendrite spines?

Answer 10

Protrustions from a dendrite-usual point of contact with axons of other cells. Increases the surface area, and is a good house for proteins to chill. Very plastic!

Question 11

What is the axon hillock?

Answer 11

Juncture of soma and axon where the action potential begins.

Question 12

What is the axon collaterals?

Answer 12

Branch of axon-have ends called teleodendria

Question 13

What are the terminal buttons?

Answer 13

AKA endfeet-knob at the tip of the axon, conveys information to other neurons.

Question 14

What are the synapses?

Answer 14

Juntion between 1 neuron and the next-site of info transfer.

Question 15

What are the 3 basic neurons?

Answer 15

1) Sensory (bring info into CNS) 2) Interneurons (associate sensory/motor activity) 3) Motor neurons (send signals to muscles)

Question 16

What are some examples of sensory neurons?

Answer 16

Structurally very simple. ex) Bipolar neuron: Retina, conduct afferent info to visual centres of the brain. Somatosensroy neuron- afferent info to spinal cord.

Question 17

What are some examples of interneurons?

Answer 17

Much more complex. Pyrimidal Cell-Long axon, 2 sets of dendrites. Purkinje Cell-Extremely branched dendrites, info from cerebellum to the rest of brain.

Question 18

What is a motor neuron?

Answer 18

Complex dendrites, long axons that connect to muscles. Located in lower brainstem and spinal cord.

Question 19

How do neurons talk to each other?

Answer 19

Sum up the thousands of excitatory/inhibitory signals they receive.
Mostly excitatory input? Neuron is active
Mostly inhibitory? Inactive neuron.

Question 20

What are the incoming and outcoming signals of neurons like?

Answer 20

Incoming-Analog: graded signal (summation of input)

Outgoing- Digital: On or Off (binary)

Question 21

How does a simple yes-no language of neurons support more complex behaviour?

Answer 21

Complexity can arise from simplicity-blind -watchmaker argument-computer program, put in some lines, code a few simple commands. Watch it do it’s thing. Incredibly complex things form out of simple commands.

Question 22

What is Barbara Webb’s Robot Cricket?

Answer 22

Robot that seeks a chirping male cricket using only 2 rules 1) Microphone detects song, sends excitatory message to opposite wheels motor. 2) Message sent shoud be proportional to intensity of sound. Robot orients itself towards cricket using only two excitatory inputs. When we add an inhibitory input the behaviour becomes more complex, robot only orients itself towards the male if it is SAFE.

Question 23

What are the glia?

Answer 23

Support cells within the nervous system.
1) Act as nerve glue, holds neurons in place
2) Supplies nutrients to neurons
3) Acts as insulation around axons
4) Removes pathogens and dead neurons
There are 5 types…

Question 24

What are the ependymal cells (glial)

Answer 24

Small, ovoid cells found in the walls of the ventricles. Make and secrete CSF (if CSF cannot leave the brain, hydrocephalus may result).

Question 25

What is hydrocephalus?

Answer 25

The resulting buildup of pressure and swelling of the head-left untreated can result in retardation and death.

Question 26

What are astrocytes (glial)

Answer 26

Star shaped cells, relatively symmetrical. Responsible for providing structural support for neurons. Transport substances between neurons and capillaries. Scar tissue formation. Dilate blood vessels to provide more blood (and thus nutrients etc) for active brain regions.