The Central Nervous System Part 1- Structural Organization and the Cerebrum

Question 1

What embryonic tissue will eventually form the epidermis of the skin as well as the nervous system?

Answer 1

Ectoderm

Question 2

As development continues early in the embryo a groove appears in the ectoderm along the dorsal midline of the embryo’s body. This groove deepens and becomes what? And at what day of development?

Answer 2

Neural Tube- 20 days after conception

Question 3

What is located between the neural tube and the surface of the ectoderm?

Answer 3

The neural crest.

Question 4

What eventually becomes the CNS?

Answer 4

The Neural Tube

Question 5

The Neural crest eventually becomes what?

Answer 5

Will become the ganglia of the peripheral nervous system, among other structures.

Question 6

By the end of the 4th week after conception three distinct swellings can be seen on the anterior end of the neural tube, which will form the brain. What are the names of the three swellings?

Answer 6

The Forebrain (Prosencephalon)
The Midbrain (Mesencephalon)
The Hindbrain (Rhombencephalon)

Question 7

Another name for the midbrain (at week 4)?

Answer 7

Mesencephalon

Question 8

Another name for the hindbrain (at week 4)?

Answer 8

Rhombencephalon

Question 9

Another name for the Forebrain (at week 4)?

Answer 9

Prosencephalon

Question 10

During the 5th week of embryonic development the forebrain, midbrain, and hindbrain, modify to form five regions. What are the new regions?

Answer 10

Forebrain splits into
-Telencephalon
-Diencephalon
The Midbrain stays the same as the  mesencephalon.
Hindbrain splits into the
-Metencephalon
-Myelencephalon

Question 11

What does the Telencephalon form into in a mature brain?

Answer 11

Telencephalon grows disproportionately in humans and forms the two cerebral hemispheres (of the cerebrum), covers the diencephalon, midbrain, and a portion of the hindbrain.
Telencephalon=Cerebrum

Question 12

What are the hollow spaces of the brain called? What about the hollow space of the spinal cord? and what fluid eventually fills it once they are formed?

Answer 12

Ventricles, become filled with cerebrospinal fluid. The Central Canal of the spinal cord, and it also becomes filled with CSF.

Question 13

What is the Diencephalon in a mature brain?

Answer 13

It stays the same- the Diencephalon (consists of Thalamus and Hypothalamus)

Question 14

What is the Mesencephalon in a mature brain?

Answer 14

It stays the same- The mesencephalon (midbrain)

Question 15

Rhombencephalon—forms Metencephalon which eventually becomes what?

Answer 15

Cerebellum and Pons

Question 16

Rhombencephalon–forms Myelencephalon which eventually becomes what?

Answer 16

Medulla Oblongata

Question 17

What are choroid plexuses?

Answer 17

Structures found in the lateral ventricles that produce cerebrospinal fluid. It is a highly vascular structure consisting of epithelial cells around a core of blood vessels and connective tissue.

Question 18

In choroid plexuses what prevents paracellular transport of molecules into the CNS?

Answer 18

Tight Junctions, which prevent leakage between the gap of one cell to the next. This contributes to the blood brain barrier.

Question 19

Describe the movement of CSF, where it is made and starts to where it exits the CNS.

Answer 19

1- CSF is produced in the lateral ventricles, known as the first and second ventricles.
2- From there it flows through the interventricular foramina to the third ventricle.
3- From the third ventricle through the cerebral aqueduct to the fourth ventricle
4-from the fourth ventricle to the central canal of the spinal cord.
5-The central canal of the spinal cord is a dead end within the terminal portion of the spinal cord.
6- CSF exits through openings in the Pia mater covering the brain to the subarachnoid space (between pia and arachnoid)
7-From the subarachnoid space the CSF is secreted by microscopic arachnoid villi and larger arachnoid granulations into the sinuses of the outermost dura mater.
8-From there CSF is reabsorbed by blood and lymphatic capillaries.

Question 20

Gray matter containing neuron cell bodies and dendrites is found where?

Answer 20

The cerebral cortex (surface layer of the brain) and deeper in the brain in aggregations known as nuclei.

Question 21

White matter consists of myelinated axons, found where?

Answer 21

The cerebral medulla, below the cortex, and surround the nuclei.

Question 22

Neurogenesis- the formation of new neurons from neural stem cells in adult mammals, including humans.
What two locations does neurogenesis happen in?

Answer 22

1. Subventricular Zone–thin layer of cells adjacent to the ependymal cells that line the lateral ventricles.
   (animals-these new cells migrate to olfactory bulbs, in humans, the new interneurons migrate to the striatum)
2. Subgranular Zone of the hippocampus– results in interneurons that function within the hippocampus, perhaps to aid learning and memory.

Question 23

What is the Striatum area of the brain involved in?

Answer 23

Regulation of motor control and cognitive functions.

Question 24

Voluntary Motor Control of Skeletal Muscles, personality, higher intellectual processes, verbal communication.
What lobe(s) is responsible for these?

Answer 24

Frontal Lobe

Question 25

Parietal Lobes

Answer 25

Somatesthetic interpretation (cutaneous and muscular sensations) Understanding speech and formulating words to express thoughts and emotions, interpretation of textures and shapes.

Question 26

Interpretation of auditory sensations, memory storage of auditory and visual experiences 
Which Lobe(s)?

Answer 26

Temporal Lobes

Question 27

Integration of movements in focusing the eye, correlation of visual images with previous visual experiences and other sensory stimuli, conscious perception of vision.
Which Lobe(s)?

Answer 27

Occipital Lobe

Question 28

Memory, Sensory (principally pain) and visceral integration.
Which Lobe(s)?

Answer 28

Insula

Question 29

Just anterior to the central sulcus, in the frontal lobe, is the precentral gyrus. What does it do?

Answer 29

Motor Area–association neurons located in the precentral gyrus are called upper motor neurons because they help control the motor neurons of the spinal cord.
MOTOR CORTEX

Question 30

Posterior to the central sulcus, in the parietal lobe, is the postcentral gyrus. What does it do?

Answer 30

SOMATOSENSORY CORTEX
this is the primary area of the cerebral cortex responsible for somatesthetic sensations, sensations arising from skin, muscles, tendons, and joints.

Question 31

Alpha Waves

Answer 31

Best recorded from the parietal and occipital regions while a person is awake and relaxed.

Question 32

Beta waves

Answer 32

Strongest from the frontal lobes and are produced by visual stimuli and mental activity.

Question 33

Theta Waves

Answer 33

Emitted from the temporal and occipital lobes and are common in newborn infants and sleeping adults.
If these show in an awake adult it indicates severe emotional stress, impending nervous breakdown.

Question 34

Delta Waves

Answer 34

Come from the cerebral cortex and are common during sleep and in an awake infant.
Presence in an awake adult indicates brain damage.

Question 35

Two categories of sleep?

Answer 35

REM Sleep-Rapid Eye Movement

Non-REM Sleep

Question 36

What neurotransmitters promote sleep?

Answer 36

GABA and adenosine.

Question 37

What does GABA stand for? What type of channel does it use?

Answer 37

Gamma-aminobutyric acid. Ligand Gated ion channels.

Question 38

When GABA and glycine bind to their respective receptors, what channels do they open? And what is the result?

Answer 38

They open Cl- channels hyperpolarize the postsynaptic membrane and produce an Inhibitory postsynaptic potential. IPSP.

Question 39

What EEG patterns show during Rem Sleep?
Non-Rem?
EEG= electroencephalogram

Answer 39

Theta Waves

Non-Rem-divided into four stages based on EEG patterns, stages 3 and 4 are “slow wave sleep”