Chapter 2: Neurons and Gila

Question 1

What are the two main types of cells in nervous system?

Answer 1

Neurons and gila

Question 2

How many neurons are there in human brain?

Answer 2

86 billion

Question 3

How many gila are there in human brain?

Answer 3

85 billion

Question 4

What do neurons do?

Answer 4

They sense changes in environment, communicate changes to other neurons and command our body’s responses

Question 5

What do gila do?

Answer 5

They insulate, support and nourish neighbouring neurons

Question 6

What is the consistency of brain tissue like?

Answer 6

Jello-O, not firm enough to make thin slices

Question 7

How do scientist harden brain tissue?

Answer 7

Immersing them in formaldehyde

Question 8

What does a microtome do?

Answer 8

Make very thin slices

Question 9

What is Nissl stain?

Answer 9

Basic dyes that stain the nuclei of all cells as well as Nissl bodies

Question 10

What is Nissl bodies?

Answer 10

Clumps of material surrounding nuclei of neurons

Question 11

Why is Nissl stain useful?

Answer 11

1. Distinguishes between neurons and gila

2. Enable the study of cytoarchitecture (arrangement) of neurons in different parts of brain

Question 12

What is golgi stain?

Answer 12

Soaking brain tissue in silver chromate solution

Question 13

What do golgi stain show?

Answer 13

Neurons have two parts:

1. Central region that contains cell nucleus called cell body, soma and perikaryon
2. Numerous thin tubes that radiate from central region called neurites and have two types: axons and dendrites

Question 14

How many axons does a cell body give rise to?

Answer 14

1

Question 15

What are axons like?

Answer 15

Uniform diameter throughout its length, any branches from it generally extend at right angles

Question 16

What are dendrites like?

Answer 16

Rarely longer than 2mm, dendrites extend from cell body and taper at fine point

Question 17

What is neuron doctrine?

Answer 17

Neurites of different neurons are not continuous with each other and communicate by contact, not continuity

Question 18

What is cell body/soma like?

Answer 18

• 20μm (micrometer) in diameter
• has watery fluid inside cell called cytosol
• cytosol is separated from outside by neuronal membrane
• contain same organelles found in all animal cells

Question 19

What is cytosol?

Answer 19

Salty, potassium rich solution

Question 20

What are the organelles found in all animal cell?

Answer 20

Nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, mitochondria

Question 21

What is cytoplasm?

Answer 21

Everything inside cell membrane, including organelles but excluding nucleus

Question 22

What is the size of nucleus?

Answer 22

5-10 μm (micrometer)

Question 23

What is nucleus like?

Answer 23

• contained with nuclear envelope

- inside nucleus are chromosomes which contain DNA

Question 24

What is nuclear envelope?

Answer 24

• double membrane containing nucleus

- perforated by pores about 0.1 μm across

Question 25

What distinguishes a neuron from other cells?

Answer 25

Specific parts of DNA used to assemble cell called genes

Question 26

What are the size of genes?

Answer 26

0.1 to several micrometers in length

Question 27

What is gene expression?

Answer 27

Reading of DNA

Question 28

What is the final product of gene expression?

Answer 28

Proteins

Question 29

What is protein synthesis?

Answer 29

Assembly of protein molecules

Question 30

Where do protein synthesis occur?

Answer 30

In the cytoplasm

Question 31

How does protein synthesis work?

Answer 31

DNA never leaves the nucleus, hence an intermediary (mRNA) carries the genetic message to sites of protein synthesis in the cytoplasm

Question 32

What does mRNA work?

Answer 32

Four different nuclei acids strung together in various sequences to form a chain, the different sequences represent the information in the gene

Question 33

What is transcription?

Answer 33

Process of assembling a piece of mRNA that contains information of a gene

Question 34

What is the name of resulting mRNA after transcription?

Answer 34

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