Embryology Lecture 1 (Gametogenesis & Ovarian Cycle) PDF

Dr. Eman El Sawaf Anatomy & Embryology Department Faculty Of Medicine, Helwan University Basic Medical Science I Module Anatomy General Embryology General Embryology  Objectives By the end of this lecture student should be able to: Define the process of gametoge...

Dr. Eman El Sawaf Anatomy & Embryology Department Faculty Of Medicine, Helwan University Basic Medical Science I Module Anatomy General Embryology General Embryology  Objectives By the end of this lecture student should be able to: Define the process of gametogenesis and the ovarian cycle.  Contents -Introduction: (Definition of embryology-Reproductive system & Cell divisions). -Gametogenesis: (spermatogenesis & oogenesis). -Ovarian cycle & Ovulation. -Oocyte transport Embryology Embryology - It is the science of development (From a single cell to 9 months baby) Male & Female Reproductive Systems Female reproductive system Fallopian tube Uterus (Uterine tube) (Fundus) Uterus (body) Uterus Ovary (Cervix) Vagina  Female reproductive system Interstitial Fallopian Tube part Isthmus Uterus Ampullary part Ovary Fimbria Infundibulum Male reproductive system  Male reproductive system Urinary bladder Seminal vesicle Prostate Seminiferous Vas tubules deference Epididymis Testis Cell Divisions Mitotic division Cell divisions One cell (46 chromosomes) Divide by mitosis 2 Daughter cells each contains the diploid number of chromosomes (46) Meiotic division - The meiotic division occurs only in sex (germ) cells. Cell divisions - It generates male and female One cell gametes (sperms and ovum cells). (46 chromosomes) Divide by meiosis I 2 daughter cells each contains the haploid number of chromosomes (23) Divide by meiosis II 4 daughter cells each contains the haploid number of chromosomes (23) Gametogenesis - Conversion of germ cells into male Gametogenesis and female gametes (Sperm and Ovum). - It includes: Spermatogenesis & Germ cells Oogenesis Spermatogenesis Spermatogonia - It is the process by which spermatogonia are transformed into Mitotic D. spermatozoa (sperms). Meiotic D. I&II - It begins at puberty. - It occurs in the testes 74 days. (seminiferous tubules). Spermatozoa  Spermiogenesis Spermatid Spermatozoon - Approximately 300 million sperm cells Mature Sperm are produced daily. (Spermatozoon) Spermatogenesis - The Acrosome (Acrosomal cap) contains enzymes assist in penetration of the ovum and its surrounding layers during fertilization.  Oogenesis Oogonia - It is the process by which the oogonia differentiate into Mitotic D. mature oocytes. Meiotic D. I&II - It occurs in the ovary and it begins before birth. Mature oocyte  Definition Ovarian Cycle - It is a cyclic changes which occur in the ovary every month at the puberty. Hormonal control Ovarian Cycle Hypothalmus GnRH Pituitary gland Ovarian Cycle FSH - LH Ovary  Ovarian Cycle At puberty every month with each ovarian cycle 15 to 20 primordial follicles begin to mature under the effect of FSH Only one reaches full maturity Mature vesicular (Graafian) follicle The other follicls degenerate and become atretic (corpus atreticum)  Mature Graafian follicle Granulosa cells - Theca interna and granulosa cells secrete estrogen Follicular antrum hormone Zona pellucida Secondary oocyte  Ovulation Ovarian Cycle -Extrusion of the secondary oocyte from the ovary. -Mid cycle (LH surge causes follicular rupture and ovulation. Ovulation Ovarian Cycle The secondary oocyte Ovarian Cycle Corona radiata Zona Pellucida (cumulus oophorus Oocyte membrane  - Meiosis II is completed only if the secondary oocyte is fertilized; otherwise, the cell degenerates approximately 24 hours after ovulation.  Time Number At 5th month The total number of germ cells in the ovary prenatal reaches its maximum number (7 million) At birth 600,000 to 800,000 (primary oocyte) By the beginning 40,000 (primary oocytes) of puberty Oocyte transport  Oocyte transport In the uterine tube the oocyte is propelled by: -Peristaltic muscular contractions of the tube. -Cilia in the tubal mucosa. The oocyte is carried into the uterine tube by: Sweeping movements of the fimbriae.  Cilia in the tubal mucosa Oocyte transport Ovarian Cycle  Reference -Langman’s Medical Embryology 13th Edition, T.W. Sadler. Images: - Langman’s Medical Embryology - https://www.pinterest.com/pin/204350901824989137/ - http://people.upei.ca/bate/html/notesontesticularfunction.html - https://www.shutterstock.com/image-vector/sperm-cell-human-body-anatomical-diagram-607006469 - https://study.com/academy/lesson/gametes-definition-formation-fusion.html - https://theconversation.com/study-confirms-flushing-blocked-fallopian-tubes-can-improve-fertility-and- reduce-need-for-ivf-77627 - https://www.britannica.com/science/human-reproductive-system - https://extendfertility.com/your-fertility-3/egg-count/ - http://www.dzireivf.com/ovulation-induction/# - https://www.pinterest.com/pin/693554411344697779/ - https://www.evolvingsciences.com/Fertilisation%20and%20implantation%20.html - www.nucleusinc.com - https://makeagif.com/gif/ovulation-the-menstrual-cycle-narrated-3d-animation-youtube-a2K1Dp Thank You