Exam 1

Question 1

________are the functional units of the brain.

Answer 1

Neurons

Question 2

______ play a supportive role in the brain.

Answer 2

Glial cells.

Question 3

What are the two major cell types that make up the brain?

Answer 3

1. Neurons
2. Glial Cells

Question 4

Cajal formulated the Neuron Theory which says_________

Answer 4

The cells forming the brain are not continuous with each other. Instead they are individual units

Question 5

The neuron theory was proposed in opposition to the Reticular theory proposed by Golgi which postulates_______

Answer 5

That the brain is one big reticulum (not composed of individual cells) and thus the cytoplasm is a giant syncytium (a single cell or cytoplasmic mass containing several nuclei)

Question 6

The reticular theory and the neuron theory both were supported using the _________ method

Answer 6

Golgi staining method. (Black reaction)

Cajal used a modified version of this method which allowed him to only color parts of the network (these parts were neurons)

Question 7

What underlies the flow of information in neurons?

Answer 7

Polarity

Question 8

How many types Neurons exist?

Answer 8

The number is unknown. It depends on how you classify them.

Question 9

What are some different ways of classifying neurons?

Answer 9

Morphology
Transcription profile
Origin
Function

Question 10

How many major types of glial cells are recognized?

Answer 10

6

Question 11

Do Neurons undergo cellular division?

Answer 11

No. They are in a post-mitotic state

Question 12

The major parts of a neuron are:

Answer 12

Cell body
Axon
Dendrites
Presynaptic sites

Make sure you can identify these on a diagram

Question 13

Neurons are both _______ and ______ excitable

Answer 13

Chemically and electrically

This allows neurons to transform stimuli into electrical signals that can be transmitted over long distances

Question 14

How do neurons communicate with each other?

Answer 14

Synapses

Question 15

A neuron has both ______ and ________ sites.

Answer 15

Presynaptic and post synaptic sites

Question 16

If neurons differentiated by the number of processes that originate from the cell body, how many types of neurons are there and what are they.

Answer 16

4 types:

1) unipolar neurons
2) bipolar neurons
3) pseudo-unipolar neurons
4) multipolar neurons

Question 17

What are unipolar neurons?

Answer 17

They have only one process that bifurcates into a dendritic end and an axon an axonal end.

Most neurons in invertebrates are unipolar

Question 18

What is a bipolar neuron?

Answer 18

The neurons have two processes that originate from the cell body:
One dendritic structure
One axonal structure

Many sensory neurons in vertebrates are bipolar

Question 19

What are pseudo-unipolar neurons?

Answer 19

These neurons initially develop as bipolar cells, but the two cell processes fuse into a single continuous structure that emerges from a single point in the cell body

This type of neuron is found I. The somatosensory system.

Question 20

What is a multipolar neuron?

Answer 20

These neurons usually have a single axon and multiple dendritic structures. They vary greatly in shape, especially in the extent, dimensions and intricacy of their branchings.

Most neurons in our brain are multipolar

Question 21

If neurons are categorized by their function, how many types of neurons are there and what are they?

Answer 21

3 types:

1) sensory neurons
2) motor neurons
3) interneurons

Question 22

What is a sensory neuron?

Answer 22

These neurons detect physical features of the outside world (e.g. a wavelength) and transform these features into electrical signals. They are mostly found in the peripheral nervous system

Question 23

What are motor neurons?

Answer 23

These neurons transform electrical signals into behaviors- by regulating muscle tone.

Question 24

What is an interneuron?

Answer 24

These neurons connect sensory neurons to motor neurons and integrate/process an electrical signal into a command signal.

Most of the brain is interneurons.

Question 25

The many different ways that neurons can be classified highlights what?

Answer 25

The cellular diversity of the brain

Question 26

True/false: neurons are much like other cells in that they have a nucleus, cytoplasm, organelles and a vacuolar apparatus (ER, Golgi, lysosomes)

Answer 26

True

Question 27

What determines the shape of a neuron?

Answer 27

It’s cytoskeleton

Question 28

What are the three types of cytoskeletal filaments that compose the neuron?

Answer 28

1) neurofilaments
2) microtubules
3) microfilaments

Question 29

What are neurofilaments?

Answer 29

They are the most abundant and most stable cytoskeletal elements in neurons.

They are highly stable polymers (~10 nm in diameter)

Polymers are made from 3 different subunits:
1) neurofilament L
2) neurofilament M
3) neurofilament H

(MLH)

Because of their stability, neurofilaments provide strong architectural support.