1. Welcome to Week 5 SC 328: Histology and Embryology Seminar Sharon Marusiak Smarusiak@kaplan.edu

2. Q and A??? What questions can you think of for me, if any, this week?

3. Seminar Topics! **We will discuss the mechanisms of non- disjunction and polyploidy. 1.What is Haploid? 2.What is Diploid? 3.Let’s get your definitions: a. what is aneuploidy? b. what is non-disjunction? c. what is polyploidy?

4. Errors in chromosome numbers in humans Nondisjunction – during meiosis, chrmosomes do not separate properly and one egg or sperm ends up with an extra chromosome Most embryos with abnormal chromosome numbers abort spontaneously; but about half end up being born

5. Seminar Topics! **We will discuss chromosomal abnormalities and the syndromes they cause. 1.Define Nullisomy? 2.Define Monosomy? 3.Define Trisomy? 4.Define Tetrasomy?

6. Monosomy: Turner syndrome – XO; females but no menstruation, secondary sex characteristics, or mature eggs so are sterile Monosmy 21 Trisomy: Trisomy X – XXX; tall and below normal IQ; fertile Edwards Syndrome Patau Syndrome Klinefelter syndrome – XXY; men but are infertile Jacob syndrome – XYY; high testosterone levels; severe acne and tall Tetrasomy: Form of Klinefelter’s? XXXY?

7. medlibes.com

8. lucinafoundation.org Patau Syndrome

9. beltina.org Edwards Syndrome

10. Klinefelters Syndrome prattleonboyo.wordpress.com

11. XYY: Jacobs

12. Abnormal number of autosomal chromosomes Nondisjunction during meiosis but with autosomes NOT sex chromosomes Trisomy 21 (down syndrome) – child inherits extra copy of 21 st chromosome Weak muscle tone A small mouth held partially open Distinctively shaped eyelids Mental retardation Incidence increases with age

14. WHAT TO DO IN UNIT 5! 1.Read Chapter 1 and 2 in Developing Human Text 2.Post to the Discussion this week: discuss the causes of infertility and common contraceptive methods.. 3.Complete the comprehensive exam on the Histology portion of the course. It will cover the readings and topics covered in Units 1 through 4 of the course (100 points). 4.Finish and submit for grading your Histology Project! 5.Have a wonderful week!!!