Chapter 2 P1: Introduction to the Nervous System

Question 1

What is a neuron?

Answer 1

The basic unit of the nervous system, each composed of a cell body, receptive extension(s) (dendrites), and a transmitting extension (axon).

Question 2

What are glial cells?

Answer 2

Nonneuronal brain cells that provide structural, nutritional, and other types of support to the brain.

Question 3

What is an Oligodendroglia?

Answer 3

A specialized glial cell that has extensions that wrap around axons of some neurons in the Central Nervous System (CNS) to form many myelin sheaths.

Question 4

What glial cell wraps itself around a single neuron’s axon in the Peripheral Nervous System to form a single myelin sheath?

Answer 4

Schwann Cells

Question 5

What is an Astroglia?

Answer 5

The largest glial cells that have a variety of roles: the are only in the Central Nervous System.

Question 6

What glial cell is only in the Central Nervous System and responds to disease and injury?

Answer 6

Microglia: they multiply and then engulf cells that cause harm and then trigger an immune response. They also have other roles though!

Question 7

What is the connectome?

Answer 7

A map of neural connections in the brain - the goal being to map every neural connection.

Question 8

What does the Central Nervous System consist of?

Answer 8

The brain and spinal chord

Question 9

What does the Peripheral Nervous System consist of?

Answer 9

All nerves outside of the brain and spinal chord

Question 10

What does plastination of nerves do and what is it?

Answer 10

Plastination is the replacement of water and fat in nerve tissue with certain plastics to create specimens that can be touched, without decay of original appearance.

Question 11

Who created plastination?

Answer 11

Gunther van Haagen

Question 12

What are the 2 branches of the Peripheral nervous system?

Answer 12

the Somatic nervous system and the Autonomic nervous system

Question 13

What is the Somatic nervous system of the PNS for?

Answer 13

to interact with the external environment.

Question 14

what do the afferent (arrive to brain) nerves of the somatic nervous system do?

Answer 14

carry sensory signals from skin, muscles, etc. to central nervous system

Question 15

what do the efferent (exit from brain) nerves of the somatic nervous system do?

Answer 15

carry motor signals from central nervous system to muscles

Question 16

What is the Autonomic nervous system of the PNS for?

Answer 16

to interact with the internal environment

Question 17

what do the afferent (arrive to brain) nerves of the autonomic nervous system do?

Answer 17

carry signals from internal organs to central nervous system

Question 18

what do the efferent (exit from brain) nerves of the autonomic nervous system do?

Answer 18

carry motor signals from central nervous system to internal organs

Question 19

what efferent nerves in the autonomic nervous system use energy resources in life threatening situations?

Answer 19

sympathetic nervous system

Question 20

what efferent nerves in the autonomic nervous system conserves energy?

Answer 20

parasympathetic nervous system

Question 21

what is the enteric nervous system?

Answer 21

in the intestine, and is separate from the other nervous systems

Question 22

what is a neuron composed of?

Answer 22

dendrites, soma, axon, axon terminal buttons

Question 23

what part of the axon is very plastic (prone to change)?

Answer 23

dendritic spines

Question 24

label the synapse:

Answer 24

draw it out with these labels: axon of presynaptic neuron, axon terminal, mitochondrion, synaptic vesicles, synaptic cleft, neurotransmitter, receptor sites, post synaptic membrane

Question 25

name and identify the 3 types of neurons

Answer 25

bipolar: have a single dendrite at one end of the cell and a single axon at the other end. Common in sensory systems, such as vision.
unipolar: have a single extension (or process), usually thought of as an axon, that branches in two directions after leaving the cell body. One end is the input zone with branches like dendrites; the other, the output zone. Such cells transmit touch information from the body into the spinal cord.
and multipolar: have many dendrites and a single axon, and they are the most common type of neuron.

Question 26

Identify 5 functions of glia that are more than just supportive:

Answer 26

1) Astroglia control the creation and maintenance synapses between neurons
2) Astroglia are involved in the synchronous neuronal firing found in epilepsies
3) Glia are involved in circadian rhythms in some species
4) Glia communicate with neurons and other glial cells
5) Glia form glial circuits

Question 27

What does a Tract (in the CNS) mean?

Answer 27

A bundle of Axons (or Fibres)

Question 28

What does a Nerve (in the PNS) mean?

Answer 28

A bundle of Axons (or Fibres)

Question 29

What is a cluster of cell bodies called in the CNS and PNS respectively?

Answer 29

CNS: Nucleus
PNS: Ganglia

Question 30

What is the Neuron Doctrine?

Answer 30

Proposed

(1) that the cells of the brain are independent from one another structurally, metabolically, and functionally and
(2) that information is transmitted from one neuron to the next across tiny gaps (synapses).

Question 31

What is the function of the soma/cell body in a neuron?

Answer 31

Contains:
mitochondria that produce energy,
genes encoded in DNA,
ribosomes that translate genetic instructions from the cell nucleus into the proteins needed for the construction and operation of the neuron.

Question 32

Identify and describe the 4 functional zones of a neuron.

Answer 32

1) Input zone: where neurons collect and process information, either from the environment or from other cells. [includes dendrites and dendritic spines]
2) Integration zone: where the decision to produce a neural signal is made. [includes soma/cell body and axon hillock]
3) Conduction zone: where information can be electrically transmitted over great distances. [includes axon]
4) Output zone: where the neuron transfers information to other cells [includes axon terminals/synaptic boutons]

Question 33

What is an interneuron?

Answer 33

A neuron that is neither a sensory neuron nor a motor neuron; it receives input from and sends output to other neurons.

Question 34

What is arborization?

Answer 34

The elaborate branching of the dendrites of some neurons. (like a tree)

Question 35

What is neural plasticity/neuroplasticity?

Answer 35

The ability of the nervous system to change in response to experience or the environment.

Question 36

What part of the neuron functions as the integration zone?

Answer 36

the axon hillock

Question 37

What is are nodes of Ranvier?

Answer 37

Gaps between successive segments of the myelin sheath where the axon membrane is exposed.