ANAT 2130 Lecture Notes - Lecture 4: Mitosis, Inner Cell Mass, Reproductive System
16 Oct 2016
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Distal and proximal are relativistic anatomical terms: proximal. Distant from site of attachment: example: Uterine tubes: convey fertilized ova to uterus. Vagina: site for sperm entry and delivery of fetus. Releases secondary oocyte, zona pellucida, corona radiata, and a mass of mucus. Entrapped in ciliated epithelium of uterine tubes and swept into lumber of female reproductive tract. Remnants of mature follicle become corpus luteum. Supports changed in lining of uterus favorable to implantation. Within about 24 hours of ovulation, spermatozoa meet ovum complex. Fertilization probably occurs in the expanded, distal (ampullary) portion of uterine tubes. One spermatozoon locks to the door for other spermatozoa in block to polyspermy. Triggers meiosis ii in secondary oocyte > ovum and 2nd polar body. Haploid female pronucleus and haploid male pronucleus share ovum cytoplasm. They fuse (syngamy) to produce a single diploid zygote nucleus. In about 24 hours, mitosis occurs > two diploid blastomeres.
