Structure of the Nervous System

Question 1

What is the neuraxis?

Answer 1

An imaginary line drawn through the center of the length of the central nervous system, from the bottom of the spinal cord to the front of the forebrain.

Question 2

What is the anterior?

Answer 2

With respect to the central nervous system, located near or toward the head.

Question 3

What is the posterior?

Answer 3

With respect to the central nervous system, located near or toward the tail.

Question 4

What is the rosteral?

Answer 4

‘toward the back’ - with respect to the central nervous system, in direction along the neuraxis toward the front of the face.

Question 5

What is the caudal?

Answer 5

‘toward the tail’ - with respect to the cns, in a direction perpendicular (meets at a right angle) to the neuraxis toward the top of the head or the back.

Question 6

What is the dorsal?

Answer 6

‘Toward the back’ - with respect to the cns, in a direction perpendicular (meets at a right angle) to the neuraxis toward the bottom of the skull or the front surface of the body.

Question 7

What is the lateral?

Answer 7

Toward the side of the body, away from the middle

Question 8

What is the medial?

Answer 8

Toward the middle of the body, away from the side.

Question 9

What is the ipsilateral?

Answer 9

Located on the same side of the body

Question 10

What is the contralateral?

Answer 10

Located on the opposite side of the body

Question 11

What is the cross section?

Answer 11

With respect to the cns; a slice taken at right angles to the neuraxis

Question 12

What is the frontal section?

Answer 12

A slice through the brain parallel to the forehead

Question 13

What is the horizontal section?

Answer 13

A slice through the brain parallel to the ground

Question 14

What is the midsagittal plane?

Answer 14

The plane through the neuraxis perpendicular to the ground; divides the brain into two symmetrical halves.

Question 15

What does the nervous system do?

Answer 15

Receive, integrate and transmit information

Question 16

What is the central nervous system made up of?

Answer 16

Brain and spinal cord

Question 17

What is the peripheral nervous system made up of?

Answer 17

Somatic and Autonomic

Question 18

The human brain is made up of…

Answer 18

2 ceberal hemispheres, cerebral cortex, gyri, sulci, lateral fissure and longitudinal fissure

Question 19

What are the four lobes of the brain?

Answer 19

Precentral gyrus, central fissure, postcentral gyrus, lateral fissue, superior temporal gyrus, cerebellum

Question 20

What is the neuron?

Answer 20

The basic unit of structure and function in the nervous system

Question 21

Where are neurons located?

Answer 21

in the CNS and PNS

Question 22

What are the 3 types of neurons?

Answer 22

Sensory = respond to external stimuli and transmit sensory information to the cns. These neurons are afferent, meaning they detect information from the environment.

Motor neurons = carry messengers from the CNS to muscles and glands. These neurons are efferent.

Interneurons = transmit messenges to other neurons.

Question 23

What do Oligodendrocytes do?

Answer 23

Make up the mylein sheath in the cns

Question 24

What do Schwann cells do?

Answer 24

Make up the mylein sheath in the pns

Question 25

What do microglia do?

Answer 25

Protect the brain from invading organisms and clean up dead tissue by causing an inflammatory effect in the brain.

Question 26

If a neuron doesn’t have a mylein sheath, what happens?

Answer 26

Information transmission is slowed down. If the MS breaks down there is no recovery, this is seen in Parkinson’s disease.

Question 27

What are Glial Cells?

Answer 27

Other cells in nervous system

Question 28

What are Astrocytes?

Answer 28

They wrap around blood vessels in the CNS, which allow some chemcials from the blood into the brain and some chemicals from the brain into the blood. They provide neurons with physical support, nutrients and clear waste. They also module neuronal activity, communicate with other neurons and glial cells.

Question 29

What are the two methods of signalling in neurons?

Answer 29

Within the neuron - electrical
From the cell body - down the axon - to nerve terminals

Between neurons - chemical
From nerve terminals - across the synapse - to receptors on adjacent target cell

Question 30

What is chemical signalling in neurons?

Answer 30

Chemical signalling occurs in synaptic junction between neurons.

Question 31

What is the role of the nerve membrane?

Answer 31

The nerve membrane defines the cell, creating the intracellular and extracellular fluid components.

Question 32

What is the resting membrane potential?

Answer 32

An electrical difference that exists across the nerve membrane of inactive neurons

Question 33

The inside of the neuron is..

Answer 33

Electronegative (-70 millivolts) relative to the outside

Question 34

An inactive neuron is said to be..

Answer 34

Polarised

Question 35

What does intracellular and extracellular fluid contain?

Answer 35

Positively and negatively charged particles called ions.

Question 36

What are the most important ions?

Answer 36

Anions & Cations

Question 37

What are anions?

Answer 37

Organic and chloride

Question 38

What are cations?

Answer 38

Sodium and potassium

Question 39

What causes resting membrane potential?

Answer 39

Ions are unequally distributed across the nerve membrane.

Question 40

Electrical Transmission - Read only flash card

Answer 40

Strength of sodium transporter is proportional to membrane potential and is maximal at resting potential (-70mV) i.e. is voltage-dependent

Sodium transporter breaks down if membrane potential becomes and little less negative and this is what happens when the neuron is stimulated.

Normally excluded sodium (Na+) ions rush into the cell and briefly reverse the normal polarity.

The inside of the cell briefly becomes positive with relation to the outside of the cell

The active neuron is said to be depolarized