Development of the Nervous System

Question 1

Two functional divisions of the nervous system

Answer 1

Somatic/Visceral (Autonomic)

Question 2

What does the somatic nervous system innervate?

Answer 2

Skin and most skeletal muscles (sensory and motor)

Question 3

What does the visceral (autonomic) nervous system innervate?

Answer 3

Viscera (organs of the body) and smooth muscle and glands in the peripheral part of the body

Question 4

Neurons in the mantle layer of the spinal cord organize into what?

Answer 4

Four plates/columns that run the length of the cord; a pair of dorsal/alar plates, and a pair of ventral/basal plates.

Question 5

Cells of what region become the somatic motor neurons of the spinal cord? Where are these neurons located?

Answer 5

Cells of the basal columns. Located in the ventral horn.

Question 6

Cells of the alar columns develop into what kinds of neurons? Where are they located?

Answer 6

Association neurons - located in dorsal horns.

Question 7

Association neurons receive synapses from what types of fibers? These fibers come from sensory neurons located where?

Answer 7

Afferent fibers from sensory neurons located in dorsal root ganglia.

Question 8

What are two destinations for the axon of an association neuron?

Answer 8

May synapse with ipsilateral or contralateral motor neurons OR ascend to the brain.

Question 9

What is formed by the synapse of association neurons and motor neurons?

Answer 9

Reflex arc

Question 10

Which spinal levels contain intermediolateral cell columns?

Answer 10

T1-T12. L1-L2. S2-S4.

Question 11

The thoracic and lumbar intermediolateral cell columns contain what?

Answer 11

Visceral motor neurons that constitute the autonomic motor neurons of the sympathetic division.

Question 12

The sacral intermediolateral cell columns contain what?

Answer 12

Visceral motor neurons that constitute the autonomic motor neurons of the parasympathetic division.

Question 13

Three primary brain swellings that form forebrain, midbrain and hindbrain?

Answer 13

Prosencephalon, mesencephalon and rhombencephalon respectively

Question 14

What secondary brain swelling becomes the cerebral hemispheres?

Answer 14

Telencephalon

Question 15

What secondary brain swelling becomes the thalamus and hypothalamus?

Answer 15

Diencephalon

Question 16

What does the mesencephalon give rise to?

Answer 16

Midbrain

Question 17

What does the metencephalon give rise to?

Answer 17

Pons and cerebellum

Question 18

What does the myelencephalon give rise to?

Answer 18

Medulla

Question 19

What secondary swellings are contained within the brain stem?

Answer 19

Myelencephalon, metencephalon (pons only) and mesencephalon.

Question 20

The lumen of the neural tube enlarges in the brain to form what?

Answer 20

Ventricles (CSF production)

Question 21

Prosencephalon gives rise to what secondary brain swelling(s)

Answer 21

Telencephalon, diencephalon

Question 22

Mesencephalon gives rise to what secondary brain swelling(s)?

Answer 22

Mesencephalon

Question 23

Rhombencephalon gives rise to what secondary brain swelling(s)?

Answer 23

Metencephalon, myelencephalon

Question 24

Where in the brainstem and spinal cord are basal and alar plates visible?

Answer 24

Throughout

Question 25

What is the trend of basal and alar plates in the cerebral and cerebellar regions?

Answer 25

more alar, less basal

Question 26

Which cranial nerves innervate extrinsic ocular mm. and mm. of the tongue? Which brainstem column is this associated with?

Answer 26

III, IV, VI, XII. Somatic efferent

Question 27

Which nerves innervate striated mm. derived from pharyngeal arches as well as trapezius and sternocleidomastoid mm.? Which brainstem column is this associated with?

Answer 27

V, VII, IX, X, XI. Special visceral efferent.

Question 28

Which brainstem columns are associated with the basal plates?

Answer 28

Somatic efferent, special visceral efferent, general visceral efferent

Question 29

Which brainstem columns are associated with the alar plates?

Answer 29

General visceral afferent, special visceral afferent, somatic afferent

Question 30

What cranial nerves and function are associated with the general visceral efferent column of the brainstem?

Answer 30

CN III, IX and X - serve parasympathetic pathways

Question 31

What cranial nerve and function is associated with the general visceral afferent column of the brainstem?

Answer 31

CN X - Receive impulses from sensory receptors in the walls of thoracic, abdominal and pelvic viscera

Question 32

Cranial nerves VII, IX and VIII are associated with what function and brainstem column?

Answer 32

Special senses. Special visceral afferent.

Question 33

Cranial nerves V, VII, and IX are associated with what function and brainstem column?

Answer 33

General sensation. Somatic afferent

Question 34

What two structures is the cerebellum derived from?

Answer 34

Alar plates of the metencephalon and adjacent rhombic lips.

Question 35

Describe the formation of cerebellar plates. When does this happen, and what happens subsequently?

Answer 35

Cerebellar plates are formed when rhombic lips are compressed together. In month 2, plates meet and form primordium that covers the fourth ventricle.

Question 36

The basal plates within the mesencephalon will form what two columns? What are the functions of these columns?

Answer 36

1) Somatic efferent (motor output to extraocular muscles, CN III and IV) 2) General visceral efferent (motor output to ciliary ganglion of eye, CN III)

Question 37

From what does the crus cerebri form? What is its function?

Answer 37

Forms from the marginal layer around the basal plates of the mesencephalon. Acts as a pathway for fibers between the cerebral cortex, pons, and spinal cord.

Question 38

The basal plates of the mesencephalon organize themselves to form what two structures?

Answer 38

Red nucleus and substantia nigra

Question 39

The alar plates of the mesencephalon form what two structures? What are their functions?

Answer 39

(1) Superior (anterior) colliculus – visual relay. | (2) Inferior (posterior) colliculus – auditory relay

Question 40

What plates are contained within the diencephalon?

Answer 40

Alar plates and a roof plate

Question 41

The roof plate of the diencephalon gives rise to what?

Answer 41

Choroid plexus of the 3rd ventricle and pineal body (epiphysis)