Components: Acrosome, plasma membrane, mitochondria, nucleus, axial filament, centriole, tail, end piece.
Spermatogenesis:
Starts at puberty.
Continuous process with three phases:
Mitotic Division: Maintains spermatogonia stem cell population and provides cells destined to become sperm.
Meiotic Division: Reduces chromosome number to produce haploid spermatids.
Spermiogenesis: Transformation of spermatids into mature spermatozoa (loss of cytoplasm, development of flagella).
Components: Corona radiata, nucleus, cortical granules, zona pellucida, mitochondria.
Ova Development: Occurs within ovarian follicles, involving primary oocytes maturing into secondary oocytes (meiosis resumes at ovulation).
28-day cycle from puberty to menopause divided into:
Follicular Phase (Days 1-13): Development of ovarian follicles; one becomes dominant.
Ovulation (Day 14): Release of secondary oocyte from dominant follicle.
Luteal Phase (Days 15-28): Formation of corpus luteum from ruptured follicle.
Fusion of male and female gametes; occurs in the ampullary region of the uterine tubes.
Phases of Fertilization:
Penetration of the Corona Radiata: Coating surrounding the egg.
Penetration of the Zona Pellucida: Glycoprotein shell around the egg, induces acrosome reaction (release of enzymes).
Fusion of Oocyte and Sperm Cell Membranes: Adhesion mediated by integrins and subsequent fusion of membranes.
Post-fertilization, the zygote undergoes cleavage:
Series of mitotic divisions producing smaller cells called blastomeres.
At 16-cell morula stage, cells form inner cell mass (future embryo) and outer cell mass (trophoblast).
Blastulation leads to formation of the blastocyst, characterized by a cavity (blastocele).
Trophoblasts from the blastocyst penetrate the uterine epithelium around day 6.
Three phases of implantation:
Apposition: Initial contact with the endometrium.
Adhesion/Attachment: Strong attachment.
Invasion/Penetration: Trophoblastic cells invade the uterine tissue.
28-day menstrual cycle:
Menstrual Phase (Days 1-7): Shedding of the endometrium.
Proliferative Phase (Days 7-14): Repair and growth of the endometrium stimulated by estradiol.
Secretory Phase (Days 14-28): Endometrium becomes secretory under progesterone influence.
Human Growth & Development: Prenatal Development
Components: Acrosome, plasma membrane, mitochondria, nucleus, axial filament, centriole, tail, end piece.
Spermatogenesis:
Starts at puberty.
Continuous process with three phases:
Mitotic Division: Maintains spermatogonia stem cell population and provides cells destined to become sperm.
Meiotic Division: Reduces chromosome number to produce haploid spermatids.
Spermiogenesis: Transformation of spermatids into mature spermatozoa (loss of cytoplasm, development of flagella).
Components: Corona radiata, nucleus, cortical granules, zona pellucida, mitochondria.
Ova Development: Occurs within ovarian follicles, involving primary oocytes maturing into secondary oocytes (meiosis resumes at ovulation).
28-day cycle from puberty to menopause divided into:
Follicular Phase (Days 1-13): Development of ovarian follicles; one becomes dominant.
Ovulation (Day 14): Release of secondary oocyte from dominant follicle.
Luteal Phase (Days 15-28): Formation of corpus luteum from ruptured follicle.
Fusion of male and female gametes; occurs in the ampullary region of the uterine tubes.
Phases of Fertilization:
Penetration of the Corona Radiata: Coating surrounding the egg.
Penetration of the Zona Pellucida: Glycoprotein shell around the egg, induces acrosome reaction (release of enzymes).
Fusion of Oocyte and Sperm Cell Membranes: Adhesion mediated by integrins and subsequent fusion of membranes.
Post-fertilization, the zygote undergoes cleavage:
Series of mitotic divisions producing smaller cells called blastomeres.
At 16-cell morula stage, cells form inner cell mass (future embryo) and outer cell mass (trophoblast).
Blastulation leads to formation of the blastocyst, characterized by a cavity (blastocele).
Trophoblasts from the blastocyst penetrate the uterine epithelium around day 6.
Three phases of implantation:
Apposition: Initial contact with the endometrium.
Adhesion/Attachment: Strong attachment.
Invasion/Penetration: Trophoblastic cells invade the uterine tissue.
28-day menstrual cycle:
Menstrual Phase (Days 1-7): Shedding of the endometrium.
Proliferative Phase (Days 7-14): Repair and growth of the endometrium stimulated by estradiol.
Secretory Phase (Days 14-28): Endometrium becomes secretory under progesterone influence.