2.1 The Cells of the Nervous System

Question 0

Neurons

Answer 0

Receive information and transmit it to other cells

Question 1

Nervous system consists of which kind of cells?

Answer 1

Two: neurons and glia

Question 2

Estimated numbers of neurons in humans

Answer 2

100 billion

Question 4

Membrane (or plasma menbrane)

Answer 4

The surface of a cell. It’s structure separates the inside of the cell from the outside enviroment.

Question 5

Nucleus

Answer 5

The structure that contains the chromosomes (DNA; hereditary controll)

Question 6

Mitochondrion (mitochondria)

Answer 6

The structure that preformes metabolic activities, providing the energy that the cell requires for all other activities

Question 7

Ribosomes

Answer 7

The sites at which the cell synthesize new protein molecules that provide building materials for the cell

Question 8

Endoplasmic reticulum

Answer 8

A network of thin tubes that transport newly synthesized proteins and other substances to other locations

Question 9

Motor neuron

Answer 9

Has its cell body (soma) in the spinal cord. It recives excitation (arousal, sensation) from other neurons throught its dendrites and conduts impulses along its axon to a muscle.

Question 10

Sensory neuron

Answer 10

Neuron that is highly sensetive to a particular type of stimulation, such as light, sound or touch

Question 11

Dendritic spines

Answer 11

The short outgrowths that receive incoming information. That information apparently plays a key role in learning and memory

Question 12

Soma ( or cell body)

Answer 12

Contains the nucleus, ribosomes, and mitochondria. Most metabolic work of the neuron occurs here

Question 13

Axon

Answer 13

Is the neuron’s information sender, conveying an impulse toward other neurons or an organ or muscle

Question 14

Myelin sheath

Answer 14

An insulating material that covers vertebrate axons

Question 15

Nodes of Ranvier

Answer 15

Also known as myelin sheath gaps, are the gaps formed between the myelin sheaths and can generate electrical activity

Question 16

Presynaptic terminal (or end bulb or bouton/button)

Answer 16

Axons many branches each of which swells at its tip. This is the point from which the axon releases chemicals from one neuron and the next

Question 17

Afferent axon (afferent starts with “a” as in admit)

Answer 17

Brings information into a structure

Every sensory neuron is this to the rest of the nervous system

Question 18

Efferent axon (efferent starts with “e” as in exit)

Answer 18

Carries information away from a structure

Every motor neuron is this from the nervous system

Question 19

Interneuron or intrinsic neuron

Answer 19

A nerve cell found within the CNS that acts as a link between sensory neurons and motor neurons

Question 20

Glia

Answer 20

Type of cell in the nervous system that, in contrast to neurons, does not conduct impulses over long distances.
The brain has several types with different functions

E.g. Astrocytes, microglia and radial glia

Question 21

Astrocytes

Answer 21

Is star-shaped glia and wrap around the presynaptic terminals (button) of a group of functionally related axons. It

• sends messages
• remove waste material created when neurons die
• controll the amount of blood flow to each brain area
• dilate the bloodvessels to bring more nutrients into the area of heightend activity in some brain areas

Question 22

Microglia

Answer 22

Cells that remove waste materials such as viruses, fungi, and other microorganisms.

They function like part of the immune system

Question 23

Oligodendrocytes (OL-i-go-DEN-dro-cytes)

Answer 23

In the brain and spinal cord
Specialized type of glia that build the myelin sheaths that surround and insulate certain vertebrate axons (same as the Schwann cells)

Question 24

Schwann cells

Answer 24

In the periphery of the body
Specialized type of glia that build the myelin sheaths that surround and insulate certain vertebrate axons (like the oligodendrocyte)

Question 25

Radial glia

Answer 25

Guide the migration of neurons and their axons and dendrites during embryonic development. When embryological development finishes most radial glia differentiate into neurons

Question 26

Blood-brain barrier

Answer 26

The vertebrate brain does not replace damaged neurons (unlike skin cells and blood cells), so to minimize the risk of irreparable brain damage, the body builds a wall along the sides of the brain’s blood vessels. This wall keeps out most viruses, bacteria, and harmful chemicals

Question 27

Active transport

Answer 27

The brain uses a protein-mediated process that expends energy to pump chemicals from the blood into the brain. These chemicals include things like

• glucose (the brain’s mail fuel)
• amino acids (the building blocks of proteins)
• purines
• choline
• few vitamins
• iron
• certain hormones

Question 28

Glucose

Answer 28

A sugar

Vertebrate neurons depend almost entirely on this

Question 29

Thiamine

Answer 29

Vitamin B1 that the body needs to use glucose

Question 30

Dendrites

Answer 30

Branching fibers that get narrower near their ends. It receives information from other neurons