reproduction & the hormones causing it 2

Reproduction & Hormones:

Reproduction & Hormones What are the steps of reproduction & How do certain hormones cause those steps?

Overview: Types of Reproduction:

Overview: Types of Reproduction Asexual reproduction is the creation of new individuals from one parent. Many invertebrates reproduce asexually by fission. Another common ways invertebrates reproduce is budding and fragmentation. Sexual reproduction is the creation of offspring by the fusion of male (sperm) and female (egg) gametes to form a zygote Some animals can reproduce both asexual and sexual Another way is parthenogenesis Hermaphroditism is when an animal is both male and female An animal may also be able to change between male and female through out their lifetime.

Steroid Hormone enter target cells and bind to intracellular receptors:

Steroid Hormone enter target cells and bind to intracellular receptors Gonadotropic Hormones: Follicle-stimulating hormone (FSH). Stimulates production of sperm and ova. Secretion regulated by hypothalamic hormones. Luteinizing hormone (LH). Stimulates ovaries and testes. Secretion regulated by hypothalamic hormones.

The Hormone: Androgen :

The Hormone: Androgen Androgen (testosterone) ~ Supports sperm formation and promotes development Maintenance of the male secondary sex characteristics. (in males this would be facial hair in humans or antlers in most species of deer) Testes secretion regulated by FSH and LH.

Androgen secretion and sperm production:

Androgen secretion and sperm production

The Journey of Sperm: Spermatogenesis:

Spermatogenesis is the production of mature sperm cells from spermatogonia . A continuous and prolific process in the adult male. Each ejaculation contains 100- 650 million sperm. Occurs in seminiferous tubules. As spermatogenesis progresses the developing sperm cells move from the wall to the lumen of a seminiferous tubule. The Journey of Sperm: Spermatogenesis

Sperm Structure :

Sperm Structure Sperm structure: Haploid nucleus. Tipped with an acrosome . Contains enzymes that help the sperm penetrate to the egg. A large number of mitochondria provide ATP to power the flagellum

The Journey of the Egg: Oogenesis:

The Journey of the Egg: Oogenesis Oogenesis is the production of ova from oogonia . Differs from spermatogenesis in three major ways: At birth an ovary contains all of the primary oocytes it will ever have. Beginning at puberty, the hormone FSH periodically stimulates a small group of follicles to resume growth and development. Unequal cytokinesis during meiosis results in the formation of a single large secondary oocyte and three small polar bodies. The polar bodies degenerate. Oogenesis has long “ resting ” periods.

The Hormones: Estrogen and Progestins:

The Hormones: Estrogen and Progestins Estrogens ( estradiol ) ~ stimulates uterine lining growth. Promotes development and maintenance of female sex characteristics. Ovary secertion is regulated by FSH and LH. Progestins (progesterone)~ Promotes uterine lining growth. Ovary secretion is regulated by FSH and LH.

The Reproductive Cycles of Females :

The Reproductive Cycles of Females The Ovarian Cycle Hormones stimulate follicle growth, which results in ovulation Following ovulation the follicular tissue left behind transforms into the corpus luteum . The Uterine (Menstrual Cycle) Cycle after cycle the maturation and release of egg cells from the ovary are integrated with changes in the uterus If an embryo has not implanted in the endometrium by the end of the secretory phase A new menstrual flow commences

Conception :

Conception Did you know that you were once the fastest swimmer? Yes it’s true, because during human copulation about 2-5 mL of semen is transferred. In about each mL there is about 70-103 million sperm. Some how you made it. The Alkalinity of the semen helps neutralize the acidic enviroment of the vagina. When the sperm reaches the cerviz it then liquefys and then it begins speming through the uterus and oviducts. When the sperm fuses with the egg( mature oocyte) in the oviduct. After 24 hours it results in a zygote and begins dividing which is called cleavage.

Fertilization of an egg by a sperm Conception:

Fertilization of an egg by a sperm Conception