Development of the Brain

Question 1

When do the vesicles form ?

Answer 1

fourth week

Question 2

When does brain formation begin?

Answer 2

Brain formation begins on day 28.

Question 3

What are the three primary brain vesicles formed after the neural folds fuse?

Answer 3

Forebrain (Prosencephalon)

Midbrain (Mesencephalon)

Hindbrain (Rhombencephalon).

Question 4

What does the Forebrain (Prosencephalon) develop into?

Answer 4

Cerebral hemispheres and diencephalon.

Question 5

What does the Midbrain (Mesencephalon) develop into?

Answer 5

The adult midbrain.

Question 6

What does the Hindbrain (Rhombencephalon) develop into?

Answer 6

The pons, medulla, and cerebellum.

Question 7

What occurs by the fifth week of development?

Answer 7

The Five Vesicle Stage is reached.

Question 8

What are the five vesicles in the five vesicle stage?

Answer 8

telencephalon

diencephalon

midbrain

metencephalon

mylecephalon

Question 9

What does the Forebrain divide into during the Five Vesicle Stage?

Answer 9

Telencephalon and Diencephalon.

Question 10

What does the Hindbrain divide into during the Five Vesicle Stage?

Answer 10

Metencephalon and Myelencephalon.

Question 11

What does the Telencephalon form?

Answer 11

The cerebral hemisphere and basal ganglia.

Question 12

What does the Diencephalon form?

Answer 12

The thalamus, hypothalamus, epithalamus, and subthalamus.

Question 13

What does the neural canal become?

Answer 13

The lateral ventricles, third ventricle, fourth ventricle, and cerebral aqueduct.

Question 14

What structures make up the Tectum?

Answer 14

Superior Colliculus and Inferior Colliculus.

This would be visible in a posterior view of the brainstem

Question 15

What does the Metencephalon become?

Answer 15

The pons and cerebellum.

Question 16

What does the Myelencephalon become?

Answer 16

The medulla.

Question 17

What is the result of rapid cell proliferation in the growing brain?

Answer 17

An increase in both length and diameter of the neural tube.

Question 18

What happens to the surface of the cerebral hemispheres as growth proceeds?

Answer 18

Grooves (sulci) and elevations (gyri) appear.

Question 19

What are the two developmental processes at the cellular level?

Answer 19

Pathfinding and Pruning.

Question 20

Insula

Answer 20

will be covered by growth of neighboring areas of cortex in the frontal, parietal, and temporal lobes

Question 21

What is Pruning in neuronal development?

Answer 21

The process involving axon retraction and neuron death.

Question 22

What is essential for neuronal development?

Answer 22

The correct number of synaptic connections to the correct target cell which is why neurons are “pruned”

Question 23

When does myelination of axons begin?

Answer 23

During the fetal period (4 months in utero) and continues after birth.

Question 24

When are most myelin sheaths usually completed?

Answer 24

by the 3rd yr of life

Question 25

What are critical periods in neuronal development?

Answer 25

Times when axons compete for synaptic sites to optimize neural connections. - Appropriate neural activity during critical periods is necessary for normal development - Interruption of development during a critical period may explain some differences in outcome between perinatal and adult brain injury

Question 26

What is 'growing into deficit'?

Answer 26

Nervous system damage occurring early in development that is not evident until the damaged system normally becomes functional. - Not all neuronal systems or pathways are functional at birth (e.g. motor control of walking) - An error in neuronal development may have occurred, but will not be noticeable until the system should be operational

Question 27

When is the CNS most susceptible to major malformations?

Answer 27

Between day 14 and week 20. Growth and remodeling continue, but later insults can cause functional disturbances and/or minor malformations

Question 28

What is Anencephaly?

Answer 28

Formation of a rudimentary brainstem without cerebral and cerebellar hemispheres. Occurs when the cranial end of the tube (cranial neuropore) remains open and the forebrain does not develop; the skull does not form over the incomplete brain, leaving the malformed brainstem and meninges exposed.

Question 29

What is Arnold-Chiari malformation?

Answer 29

A developmental deformity of the hindbrain.(cranial end of the neural tube)

Question 30

What are the two types of Arnold-Chiari malformation?

Answer 30

Type I (often asymptomatic) Type II (causes progressive hydrocephalus, paralysis of the sternocleidomastoid muscles, deafness, bilateral weakness of lateral eye movements, and facial weakness. )

Question 31

What is Spina Bifida?

Answer 31

A neural tube defect that results when the inferior neuropore does not close.

Question 32

What are the three types of spina bifida cystica?

Answer 32

Meningocele, Myelomeningocele, Myeloschisis.

Question 33

What can in utero exposure to alcohol result in?

Answer 33

Fetal alcohol syndrome or alcohol-related birth defects.

Question 34

What are the symptoms when a utero is exposed to alcohol?

Answer 34

- – Abnormally small head, indistinct philtrum, a thin upper lip, short vertical space between the open eyelids - – Cognitive, movement, and behavioral problems; impaired intelligence, memory, language, attention, reaction time, visuospatial abilities, decision- making skills, goal-oriented behavior, fine- and gross-motor skills, social and adaptive functioning

Question 35

What are the effects of in utero exposure to cocaine?

Answer 35

Difficulties with attention and impulse control. Disturbance of neuronal proliferation is the most frequent consequence; interference with other neurodevelopment processes also occurs.

Question 36

what is the abnormal gyri in the cerebral cortex due to?

Answer 36

an abnormal number of cells in the cortex.

Question 37

What is heterotopia in the context of abnormal cell location?

Answer 37

Abnormal areas of gray matter located deep in the cerebrum. Seizures are often associated with heterotopia.

Question 38

What is Cerebral Palsy?

Answer 38

A movement and postural disorder caused by permanent, nonprogressive damage of the developing brain. Effects include cognitive, somatosensory, visual, auditory, and speech deficits; growing into a deficit is common.

Question 39

How is Cerebral Palsy classified?

Answer 39

According to the type of motor dysfunction: Spastic-Damage to axons adjacent to lateral ventricles Dyskinetic-neuronal damage in the basal gangle Ataxic- damage to the cerebellum Hypotonic-site of damage unknown Mixed-when more than one type of abnormal movement is present

Question 40

What is the common belief about the cause of Cerebral Palsy?

Answer 40

It is traditionally believed to result from difficulties during the birth process.

Question 41

What do epidemiologic studies indicate about the causes of Cerebral Palsy?

Answer 41

80% of cases result from events occurring before the onset of labor. hypoxia is rarely a cause of CP

Question 42

Defect Chart

Answer 42