Topic 5 - Development Of The Central Nervous System

Question 1

Development of the specific tissues and organs of the body.

Answer 1

Organogenesis

Question 2

Composed of the brain and spinal cord.

Answer 2

Central nervous system (CNS)

Question 3

Basic functional units of the CNS.

Answer 3

Neurons (nerve cells)

Question 4

It is a cell specialized to receive
stimuli from the environment and transmit impulses to the spinal cord and brain where
these impulses are interpreted; and then to the effector organs (e.g. muscle, stomach,
etc.) for response.

Answer 4

neurons (nerve cells)

Question 5

The connective tissue cells of the CNS

Answer 5

gliocytes
(oligodendrocytes, astrocytes, microgliocytes and ependymal cells).

Question 6

which contains cytoplasm and nucleus;

Answer 6

nerve cell body

Question 7

conducts impulses away from the cell body.

Answer 7

axon

Question 8

The axon presents at its end many tiny branches called

Answer 8

telodendria

Question 9

Several axons may be grouped/ bundled together to form

Answer 9

nerve tracts

Question 10

Number of axon in all neurons

Answer 10

constant and is always one.

Question 11

which receive stimuli from the environment and convert these stimuli into impulses.

Answer 11

dendrites

Question 12

neuron w/ only one process (axon only)

Answer 12

Unipolar neuron

Question 13

neuron w/ two processes (axon & dendrite)

Answer 13

Bipolar neuron

Question 14

neuron w/ many processes (one axon & many dendrites)

Answer 14

Multipolar neuron

Question 15

Enlarged cranial portion of the neural tube becomes the

Answer 15

brain

Question 16

The slender middle and caudal portions become the

Answer 16

spinal cord

Question 17

Neural canal becomes the

Answer 17

ventricles of the brain and the central canal of the spinal cord.

Question 18

Layers of the Neural Tube Wall

Answer 18

1. Germinal layer or ventricular zone
2. Mantle layer or intermediate zone
3. Marginal layer

Question 19

inner layer; composed of neuroepithelial cells that remain lining the central canal and designated as ependymal cells

Answer 19

Germinal layer or ventricular zone

Question 20

middle layer; zone of high cell density, formed by accumulation of neuroblasts and glioblasts; becomes the gray matter of the CNS w/c contains cell bodies of neurons & several gliocytes.

Answer 20

Mantle layer or intermediate zone

Question 21

the outer layer surrounding the mantle layer; cell-sparse zone
where axons of neurons & some gliocytes are present; becomes the white matter of the CNS which contains mainly myelinated axons of neurons.

Answer 21

Marginal layer

Question 22

The lateral wall of the neural tube is divided into 2 plates:

Answer 22

Alar or dorsal plate and
basal or ventral plate

Question 23

a bilateral indentation in the neural cavity that serves as a landmark to divide the wall.

Answer 23

sulcus limitans

Question 24

contains cell bodies of efferent or motor neurons that send axons into the PNS.

Answer 24

basal plate

Question 25

contains neurons that receive afferent or sensory input from the PNS.

Answer 25

Alar plate

Question 26

Midline region of the wall dorsal to the neural canal constitutes the

Answer 26

roof plate

Question 27

counterpart wall ventral to the neural canal is the

Answer 27

floor plate.

Question 28

occupies the rostral part of the head.

Answer 28

Prosencephalon (forebrain)

Question 29

Prosencephalon neural canal is

Answer 29

prosocoele

Question 30

Mesencephalon neural canal is

Answer 30

mesocoele

Question 30

Rhombencephalon neural canal is

Answer 30

rhombocoele

Question 31

By about 29 – 30 hours of incubation, the lateral walls of prosencephalon evaginate to form two

Answer 31

primary optic vesicles

Question 32

occurs at the level of the midbrain; concave ventrally.

Answer 32

Midbrain flexure

Question 33

occurs between the midbrain and the hindbrain; concave dorsally.

Answer 33

Pontine flexure

Question 34

appears at the junction of the hindbrain and spinal cord; persists slightly in domestic animals; concave ventrally.

Answer 34

Cervical flexure

Question 35

By 72 hours of incubation, the telencephalon presents a median portion called; and 2 lateral evagination called

Answer 35

median telencephalon; lateral telencephalic vesicles.

Question 36

Malformations of the Brain

Answer 36

1. Cerebellar hypoplasia and atrophy 2. Cerebellar abiotrophy 3. Hydrocephalus 4. Hydranencephaly

Question 37

failure of cerebellum to develop due to destruction of cerebellar cortex.

Answer 37

Cerebellar hypoplasia and atrophy

Question 38

premature degeneration of Purkinje cell layer of cerebellar cortex.

Answer 38

Cerebellar abiotrophy

Question 39

accumulation of excessive amount of cerebrospinal fluid in the cranial cavity.

Answer 39

Hydrocephalus

Question 39

accumulation of excessive amount of cerebrospinal fluid in the cranial cavity.

Answer 39

Hydrocephalus

Question 40

thin walled and greatly enlarged lateral ventricle filled with CSF.

Answer 40

Hydranencephaly

Question 41

Malformations of the Spinal Cord

Answer 41

1. Myelodysplasia 2. Myeloschisis 3. Meningocoele 4. Meningomyelocoele

Question 42

general term for a malformation of the spinal cord. Originates during neurula.

Answer 42

Myelodysplasia

Question 43

reduced or absence of development of one or more segments of spinal cord.

Answer 43

Hypoplasia (aplasia)

Question 44

dilation of central canal due to excess accumulation of CSF.

Answer 44

Hydromyelia

Question 45

abnormal cavitation of the spinal cord.

Answer 45

Syrinomyelia

Question 46

2 spinal cords develop beside each other usually in one set or meninges and in one vertebral canal.

Answer 46

Diplomyelia

Question 47

2 spinal cords develop w/ a partition between them. Usually in separate vertebral canals and have separate meninges.

Answer 47

Diastematomyelia

Question 48

cleft in the neural tube brought about by the failure of this part to close during neurulation.

Answer 48

Myeloschisis

Question 49

protrusion of the meninges through an opening in the vertebral arches to form a cyst beneath the skin.

Answer 49

Meningocoele

Question 50

similar to meningocoele except that both meninges and spinal cord protrudes.

Answer 50

Meningomyelocoele

Question 51

the failure of vertebral arches to close dorsal to spinal cord.

Answer 51

Spina bifida