The Structure of The Nervous System

Question 1

Anterior / rostral

Answer 1

Towards to nose.

from the Latin for “beak” (in Danish: “næb”)

Question 2

Posterior / caudal

Answer 2

Towards the tail.

from the Latin for “tail”

Question 3

Dorsal

Answer 3

The direction pointing up.

from the Latin for “back”

Question 4

Ventral

Answer 4

The direction pointing down

from the Latin for “belly”

Question 5

Bilateral symmetry

Answer 5

The nervous system is divided into two equal halves.
The right side of the brain and spinal cord is the mirror image of the left side.
With just a few exceptions, most structures within the nervous system come in pairs, one on the right side and the other on the left.

Question 6

Midline

Answer 6

The invisible line running down the middle of the nervous system.

Question 7

Medial

Answer 7

Structures closer to the midline.

E.g. the nose is medial to the eyes, and the eyes are medial to the ears

Question 8

Lateral

Answer 8

Structures farther away from the midline.

Question 9

Ipsilateral structures

Answer 9

Structures that are on the same side

E.g. the right ear is ipsilateral to the right eye.

Question 10

Contralateral structures

Answer 10

Structures that are on opposite sides of the midline.

E.g. the right ear is contralateral to the left ear.

Question 11

The three anatomical planes of section

Answer 11

1. The midsagittal plane
2. The horizontal plane
3. The coronal plane

Question 12

The midsagittal plane

Answer 12

Splitting the brain into equal right and left halves.

Question 13

The sagittal plane

Answer 13

Sections parallel to the midsagittal plane.

Question 14

The horizontal plane

Answer 14

The plane that is parallel to the ground

Could pass through both the eyes and the ears.

Question 15

The coronal place

Answer 15

Perpendicular to the ground and to the sagittal plane

Could pass through both eyes and both ears but not at the same time

Question 16

The two cerebral hemispheres are separated by …

Answer 16

the deep sagittal fissure

also called the longitudinal fissure

Question 17

Which side of the body is the left cerebal hemisphere concerned with?

Answer 17

the right side of the body

Question 18

Which side of the body is the right cerebral hemisphere concerned with?

Answer 18

the left side of the body

Question 19

Which side of the body is the left side of the cerebellum concerned with?

Answer 19

the left side of the body

Question 20

Which side of the body is the right side of the cerebellum concerned with?

Answer 20

the right side of the body

Question 21

What is the spinal cored encased in?

Answer 21

The bony vertebral column

Question 22

Spinal nerves

What? Exit the spinal cord? Attach the spinal cord? Dorsal and ventral?

Answer 22

• The spinal cord communicates with the body via the spinal nerves (part of PNS).
• They exit the spinal cord between each vertebra of the vertebal column.
• Each spinal nerve attaches the spinal cord through the dorsal and ventral root.
• The dorsal root contains axons bringing information into the spinal cord. The ventral root contains axons carrying information away from the spinal cord.

Question 23

The peripheral nervous system consists of …

Answer 23

The somatic PNS and the visceral PNS.

Question 24

The somatic PNS

Answer 24

• Consists of spinal nerves that innervate and collect information from the skin, muscles and joints.
• Voluntary nervous system
• Somatic motor axons: muscle contraction, derive from motor neurons in the ventral roots of the spinal cord.
• Somatic sensory axons, enter the spinal cord via the dorsal roots, cell bodies in dorsal root ganglia.

Question 25

What is the visceral PNS also called?

Answer 25

The involuntary, vegetative or autonomic nervous system.

Question 26

Visceral PNS

Answer 26

• Consists of neurons that innervate the internal organs, blood vessels and glands.
• Visceral sensory axons bring information about the organs to the CNS.
• Visceral motor axons command contraction and relaxation of muscles in organs
• Involuntarry system

Question 27

Afferent

Answer 27

From the latin (“carry to”).
Bringing information into the CNS.

Question 28

Efferent

Answer 28

From the Latin (“carry from”).
Emerging from the CNS to the internal organs.

Question 29

How many cranial nerves do we have? Where do they arise from?

Answer 29

12 cranial nerves that arise from the brain stem.

Question 30

The meninges

Answer 30

The collective name for the three membranes that protect the CNS in the skull and vertebral column.
The three membranes are the dura mater, the arachnoid membrane and the pia mater.

Question 31

The three membranes of the meninges and the subarachnoid space

Answer 31

The dura mater: The outermost covering. Leatherlike consistency. Tough, inelastic bag that surrounds the brain and spinal cord.
The arachnoid membrane: Appearance and consistency like a spider web.
The pia mater: A thin membrane close to the surface of the brain. Many blood vessels that dive into the underlying brain.
The subarachnoid space: Space between the pia mater and the arachnoid membrane that is filled with cerebrospinal fluid (CSP) , a salty clear liquid.

Question 32

The ventricular system

Answer 32

Consists of caverns and canals in the brain filled with cerebrospinal fluid.

Question 33

Where is cerebrospinal fluid produced? What happens to the produced CSP?

Answer 33

Where: In the choroid plexus tissue in the ventricles of the cerebral hemispheres.
How: CSF flows from the ventricles to some central cavities at the core of the brain stem. Exits the ventricular system and enters the subarachnoid space through small openings located where the cerebrum attaches to the brain stem. In the subarachnoid space, CSF is absorbed by the blood vessels at special structures called arachnoid villi.