Test Guide Unit 7 Reproduction Development | Arizona State University

University:
Arizona State University
Course:
BIO 181 | General Biology I
Academic year:

2022
Views:

417

Pages:

4
Author:

Nyasia Cardenas

Reproduction/Development Asexual Reproduction ❖ Genetically identical offspring ❖ Can quickly make many copies of itself ❖ Advantageous when in stable environment Sexual Reproduction ❖ Advantageous over asexual because of genetic variation in offspring ❖ Increases chances of survival in unstable environment Human Male Reproductive System ❖ Testes - where sperm is produced (male gonads) ❖ Vas deferens - carries sperm from epididymis to penis during ejaculation ❖ Prostate gland - secretes semen into urethra; is a large gland ❖ Scrotum - sac that holds testes ❖ Urethra - tube; carries sperm + urine Human Female Reproductive System ❖ Ovary - meiosis happens here; is also the place where the secondary oocyte forms before birth ❖ Oviduct or fallopian tube - fertilization happens here; egg moves from here to the uterus after ovulation ❖ Uterus - where the embryo implants/develops when fertilization happens ❖ Vagina - birth canal (baby passes through here during delivery) ❖ Cervix - lowest part of uterus ❖ Endometrium - uterine lining Menstrual Cycle Phases ❖ Follicular Phase - follicles in ovary respond to follicle-stimulating hormone (FSH) by growing and releasing more estrogen ❖ Ovulation - ~Day 14, luteinizing hormone (LH) levels surge, which makes the secondary oocyte rupture out of ovaries ❖ Luteal Phase - corpus luteum forms after ovulation and it releases estrogen and progesterone which thickens the uterine lining ❖ Menstruation - happens if embryo doesn’t implant to the uterus; uterine lining breaks down and is expelled through the vagina Spermatogenesis ❖ Sperm production begins during puberty; FSH + testosterone stimulate production of sperm by the testes ❖ Every diploid spermatogonium cell divides (mitosis) and creates 2 diploid primary spermatocytes. ➢ Each primary spermatocyte goes through meiosis I and produce 2 haploid secondary spermatocytes. ➢ Finally, each secondary spermatocyte goes through meiosis II which results in 4 genetically unique haploid sperm cells. Oogenesis ❖ Production of ova starts before birth; All of the eggs a female will have throughout her life will be present when she is born. ❖ In embryo, diploid oogonium cell divides (mitosis) to make 2 diploid primary oocytes. These are not activated until puberty. ➢ During puberty, meiosis I happens and haploid secondary oocytes are produced. These are released every time a female ovulates. ➢ Meiosis II only happens if a secondary oocyte is fertilized ➢ *During meiosis I and II, the cytoplasm divides unequally to create 1 active ovum + 2 small polar bodies Development of the Zygote ❖ The zygote goes through very quick mitotic division after fertilization (cleavage) and forms a blastula full of fluid. ❖ After this, the blastula continues to go through mitotic division (gastrulation) and forms a 3-layered embryo (gastrula) ➢ Three embryonic layers: ■ Ectoderm - becomes nervous system + skin ■ Endoderm - becomes the viscera (digestive organs, lungs, liver, etc.) ■ Mesoderm - becomes blood, bones, and muscle Extraembryonic Membranes (Bird Embryo) ❖ Chorion - located under the shell; facilitates diffusion of gases between atmosphere and inside of the egg ❖ Yolk sac - contains the yolk (food for embryo) ❖ Amnion - surrounds the embryo with amniotic fluid ❖ Allantois - similar to mammalian placenta (where embryo receives certain gases + gets rid of wastes