Block 1 Mini1 Pt 2 Neuroembryology
Questions and Answers
- 1.
The embryonic location of the nucleus of the fourth cranial nerve, an exclusively motor nerve which exits from the dorsum of the brainstem and innervates a muscle that moves the eyeball, is
- A.
Alar plate of the metencephalon
- B.
Alar plate of the myelencephalon
- C.
Basal plate of the mesencephalon
- D.
Basal plate of the diencephalon
- E.
Intermediolateral position near the sulcus limitans of the rhombencephalon
Correct Answer
C. Basal plate of the mesencephalonExplanation
The correct answer is basal plate of the mesencephalon because the fourth cranial nerve, also known as the trochlear nerve, is an exclusively motor nerve that innervates the superior oblique muscle of the eye. The basal plate of the mesencephalon is responsible for the development of motor neurons, making it the embryonic location of the nucleus of the fourth cranial nerve.Rate this question:
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- 2.
Which of the following is a derivative of the epaxial musculature?
- A.
Rectus femoris
- B.
Biceps brachii
- C.
Trapezius
- D.
Innermost intercostal
- E.
Rectus capitis posterior minor
Correct Answer
E. Rectus capitis posterior minorExplanation
The rectus capitis posterior minor is a derivative of the epaxial musculature. The term "epaxial" refers to the muscles that lie dorsal to the transverse processes of the vertebrae, and the rectus capitis posterior minor is one of these muscles. It is a small muscle located in the back of the neck, and it helps to extend and rotate the head. The other options listed are not derivatives of the epaxial musculature.Rate this question:
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- 3.
Nerve tracts running through the caudal medulla develop ventral to the sulcus limitans and eventually form the pyramids. Based on the position of their embryological development, the functional association of the pyramids is
- A.
Somatic sensory
- B.
Visceral sensory
- C.
Special sensory
- D.
Motor
- E.
Sympathetic
Correct Answer
D. MotorExplanation
The pyramids develop ventral to the sulcus limitans in the caudal medulla, indicating their embryological position. This suggests that the functional association of the pyramids is motor, as they are responsible for carrying motor information from the brain to the spinal cord and ultimately to the muscles.Rate this question:
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- 4.
Which of the following is a derivative of the epaxial musculature?
- A.
Rectus abdominis
- B.
Pectoralis major
- C.
Sternocleidomastoid
- D.
Inner intercostal
- E.
Rectus capitis posterior minor
Correct Answer
E. Rectus capitis posterior minorExplanation
The rectus capitis posterior minor is a derivative of the epaxial musculature. This muscle is located at the back of the neck and is involved in the movement and stabilization of the head. It is derived from the epaxial muscles, which are the muscles that develop along the back of the body during embryonic development. The other options listed, such as the rectus abdominis, pectoralis major, sternocleidomastoid, and inner intercostal muscles, are not derivatives of the epaxial musculature.Rate this question:
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- 5.
DiGeorge Syndrome is a suite of congenital craniofacial malformations associated with immunological defects due to failure of the thymus gland to differentiate and calcium metabolic defects related to failed parathyroid gland development. A primary embryological cause is
- A.
Failure of development of Rathke’s pouch
- B.
Lack of migration of ectoderm through the primitive streak
- C.
Lack of normal development and migration of neural crest cells
- D.
Failure of descent of the thyroid gland primordium
- E.
Lack of normal closure of the cervical sinus
Correct Answer
C. Lack of normal development and migration of neural crest cellsExplanation
The correct answer is lack of normal development and migration of neural crest cells. DiGeorge Syndrome is a congenital disorder that is caused by the abnormal development of neural crest cells, which are a group of cells that play a crucial role in the formation of various tissues and organs in the body. These cells are responsible for the development of the thymus gland, parathyroid gland, and other structures in the craniofacial region. When there is a lack of normal development and migration of neural crest cells, it can result in the malformations and defects seen in DiGeorge Syndrome, including craniofacial malformations, immunological defects, and calcium metabolic defects.Rate this question:
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- 6.
Failure of closure of the cranial neuropore causes this serious congenital malformation.
- A.
Meroanencephaly
- B.
Rachischisis
- C.
Myelocele
- D.
Spina bifida occulta
- E.
Spina bifida cystica
Correct Answer
A. MeroanencephalyExplanation
Meroanencephaly is a serious congenital malformation that occurs when the cranial neuropore fails to close properly. This results in incomplete development of the brain and skull. The condition is characterized by a lack of cerebral hemispheres and a thin layer of brain tissue covering the base of the skull. Meroanencephaly is a severe form of neural tube defect and is typically incompatible with life.Rate this question:
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