Ovaries contain follicles that nurture eggs and produce sex hormones. Oviducts convey eggs to the uterus where embryos develop. The uterus opens into the vagina through the cervix. THe vagina receives the penis during sexual intercourse and forms the birth canal.
WHAT IS A REPRODUCTIVE ANATOMY OF THE HUMAN MALE?
Testes produce sperm and male hormones. Epididymis stores sperm as they develop further and several glands contribute to semen, such as seminal vesicles, prostate, and bulbourethral. During ejaculation, sperm is expelled from the epididymis, and the seminal vesicles, prostate, and bulbourethral glands secrete into the urethra, then semen is formed and expelled from the penis. Sperm production is regulated by a negative feedback system of hormones, and it involves the hypothalamus, pituitary, and testes.
WHAT IS SPERMATOGENESIS?
The formation of sperm and egg requires meiosis. Spermatogenesis occurs in seminiferous tubules. IT has primary and secondary, and primary spermatocytes are formed by mitosis and they divide by meiosis I to produce secondary spermatocytes. Secondary spermatocytes divide by meiosis II to produce spermatids. Round spermatids differentiate into elongate sperm and mature sperm released into seminiferous tubule.
SUMMARY:
Some organisms can reproduce asexually and sexually. Some animals exhibit hermaphroditism. It is easier to find a mate for animals less mobile or solitary. Sperm may be transferred to the female by external fertilization or internal fertilization. Bot sexes in humans have a set of gonads where gametes are produced, ducts for gamete transport, and structures of copulation. Oogenesis begins before birth. Each month, about one primary oocyte resumes meiosis. A secondary oocyte arrested at metaphase of meiosis II is ovulated. Meiosis of the ovum is completed after fertilization. Ovarian and menstrual cycles occur about every 28 days. Hypothalamus signals the anterior pituitary to secrete FSH and LH. After ovulation, ovarian follicle becomes corpus luteum. Corpus luteum secretes estrogen and progesterone, which stimulate the endometrium to thicken, and prepare the uterus for implantation of the embryo. If egg is fertilized, embryo releases hormones that maintain the uterine lining, and menstruation does not occur. If egg is not fertilized, drop in LH shuts down corpus luteum and its hormones, menstruation is triggered, and hypothalamus and pituitary stimulate development of a new follicle. Sexual activity can transmit disease. Viral diseases can only be controlled, however bacterial diseases can often be cured. Embryonic development begins with fertilization. The union of sperm and egg to form a diploid zygote. Sperm are adapted to reach and fertilize an egg. Streamlined shape moves more easily through fluids. Many mitochondria provide ATP for tail movements. Cleavage is a rapid serious of cell divisions. It produces a ball of cells from the zygote. Gastrulation is when cells migrate. the basic body plan of three layers is established, ectoderm, endoderm, and mesoderm. Multiple processes give form to the developing animal. Tissues and organs develop by changes in cell shape, or cell migration, or programmed cell death. Induction is adjacent cells and cell layers, and also influence each other's differentiation via chemical signals. Human fertilization occurs in the oviduct. Cleavage produces a blastocyst. Placenta is close association of embryonic chorion, and mother's blood vessels. It is also a site of gas exchange, nutrient exchange, and waste exchange.
KEY TERMS:
- Asexual reproduction: one parent produces genetically identical offspring
- Sexual reproduction: fusion of gametes from two parents
- Hermaphroditism: one individual with male and female reproductive systems
- External fertilization: eggs and sperm are discharged near each other
- Internal fertilization: sperm is deposited in or near the female reproductive tract
- Ovaries: female reproductive organ
- Follicles: nurture eggs and produce sex hormones
- Spermatogenesis: occurs in seminiferous tubules
- Chiamydia: most common bacterial STD
- Contraception: the deliberate prevention of pregnancy
This diagram shows the structure of sperm. All the structures it has are made to be easy to get to the egg. The fastest and the best one usually gets to the egg to fertilize so that they can make a good offspring.
Streamlined shape moves easily through fluids. Many mitochondria provide ATP for tail movements. Head contains a haploid nucleus, and tipped with an acrosome containing penetrating enzymes.
http://www.youtube.com/watch?v=9MnQxiSJZ4Q
This video shows sperm fertilization.
5 FACTS:
1) Sexual reproduction results in the generation of genetically unique offspring.
2) The formation of sperm and egg requires meiosis.
3) Sexual activity can transmit diseases.
4) Contraception can prevent unwanted pregnancy.
5) Fertilization results in a zygote and triggers embryonic development.
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