Turner Syndrome And Developmental Anomalies

Turner Syndrome And Developmental Anomalies

Question 1. Turner’s syndrome.
Answer:

Turner’s syndrome. Causes: Monosomy of sex chromosome.

Turner’s syndrome. Effects:

• Agenesis of ovaries
• Mental retardation
• Skeletal abnormalities
• Webbed neck.
• Short stature
• Lymphedema of the extremities
• Broad chest with widely space.

Question 2. Development of pituitary gland/Hypophysis cerebri.
Answer:

• Pituitary gland develops from the two separate sources.
  1. The anterior and intermediate parts develop from an ectodermal diverticulum (rathke’s pouch) that grows upwards from the roof of the stomadeum.
     • The anterior wall of Rathke’s pouch proliferates to form the pars anterior of the hypophysis.
     • The posterior wall remains thin and forms the pars intermedia.
  2. The pars nervosa and stalk of the hypophysis cereberi develop from a down growth from the floor of the third ventricle in the region of the infundibulum.
     • A small extension of this lobe, the pars tuberalis, grows along the stalk of the infundibulum and eventually surrounds it.
     • The posterior lobe of the hypophysis is composed from the hypothalamic area.

Question 3. Development of parathyroid gland.
Answer:

• In the fifth week embryo parathyroid gland develops.
• The inferior parathyroid gland [Parathyroid III] develops from endoderm of the third pharyngeal pouch.
• The superior parathyroid gland [Parathyroid IV] develops from endoderm of the fourth pharyngeal pouch.
• When the thymus descend toward the thorax, parathyroid III is carried along with it.
• But parathyroid IV is prevented from descending as it is closely related to thyroid gland.
• Thus parathyroid III becomes caudal to parathyroid IV.