Embryology

Question 1

What distinguishes primary oocytes? What stage are they in? What maintains that stage?

Answer 1

They are arrested in meiosis prophase 1 in the diplotene stage (resting stage) until puberty. They are surrounded by follicular cells that secrete oocyte maturation inhibitor (OMI) to prevent dev.

Question 2

What are examples of abnormal chromosome number?

Answer 2

• Klinefelter’s (XXY)
• Turner’s Syndrome (X,0)
• Trisomy 21

Question 3

Describe Klinefelter’s disease

Answer 3

An nondisjunction issue during meiosis ends in XXY. Leading to pt. who is often tall w/ long legs, small testes, aspermatogenesis and less intelligence than siblings

Question 4

Describe Turner’s Syndrome

Answer 4

A potential nondisjunction during meiosis leading to XO. Female patient who maybe short, webbed neck, lack sexual maturation, broad chest w/ wide nipples

Question 5

Describe Trisomy 21

Answer 5

Could be a translocation or a nondisjunction error leading to 3 copies of chromo 21. Patients can be male/female and often have cognitive deficiency, flat nasal bridge, protruding tongue, congenital heart defects, and GIT abnormalities