female reproductive system

the lining of the uterus that is thickened monthly to allow implantation of an embryo, and is shed in menstruation if fertilization does not occur

endometrial lining

-The lining of the uterus is called the endometrium. -it is richly supplied with blood vessels to provide nutrients for the fetus. -The zygote implants itself in the endometrium, and development of the embryo begins. -If the egg is not fertilized, it does not implant in the endometrium. The endometrium disintegrates, and its tissues and blood flow out the vagina in a process known as menstruation.

endometrium

XX

female chromosome

the process of creating gametes from somatic cells; includes meiosis

gametogenesis

cells in the first meiotic division of oogenesis

primary oocytes

the external female genital organs

vulva

the larger sex chromosome with many more genes than Y

X chromosome

the tightly constricted opening from the vagina into the uterus

cervix

After about 10 days of hormone secretion, the corpus luteum breaks down and is no longer able to secrete progesterone and estrogen. It becomes a small, white body called the corpus albicans

corpus albicans

the structure that develops from a matured follicle that has released its egg. The corpus luteum produces progesterone and some estrogen. If pregnancy does not occur, the corpus luteum degenerates.

corpus luteum

severe menstrual cramps

dysmenorrhea

-A typical human egg cell is just over 0.1 mm in diameter. -At birth, there are thousands of egg cells in each ovary. -Each egg cell is surrounded by a thin layer of supporting cells. At this stage, the egg cell, along with its surrounding support cells, is called a primordial follicle. Primordial follicles can remain dormant in an ovary for as long as 50 years.

egg cells

the offspring in the period of development from the cleavage of the zygote to the ninth week, when the embryo becomes a fetus

embryo

finger-like projections called fimbriae continually sweep over the ovary.

fimbriae

-specialized cells that surround and nurture the developing ova in the ovary and that secrete estrogen and progesterone. -Starting at puberty, follicles take turns developing. -Under the influence of hormones and other factors, primordial follicles change and become primary follicles. -As levels of follicle-stimulating hormone increase, primary follicles change again and become secondary follicles. -Continued stimulation by hormones results in the accumulation of fluid around the egg. As a result, the structure grows and becomes a mature follicle. -The follicular cells, which are left behind in the ovary after the egg is released, collapse. -As they wrinkle up, they form a structure called a corpus luteum, which means yellow body in Latin. -The cells of the corpus luteum are still alive and secrete the hormones progesterone and estrogen. -Progesterone causes the inner lining of the uterus to thicken in preparation for the arrival of a fertilized egg, and estrogen is responsible for maintaining female secondary sexual characteristics.

follicles

the period of pregnancy

gestation

-The two female gonads, or ovaries, produce only a limited number of gametes. -The female gametes are called eggs, or ova -The other female sexual organs are adapted to provide a safe environment for fertilization, for supporting and nourishing a developing fetus, and for allowing the birth of a baby.

gonads (ovaries)

Meiosis is a specialized form of cell division that produces reproductive cells, such as plant and fungal spores, sperm and egg cells.

meiosis

a female's first menstrual cycle

menarche

the monthly shedding of the endometrial lining

menstruation

cells that are undergoing meiosis in the ovary

oocytes

the process of egg production in females

oogenesis

diploid cells in the ovary that will undergo meiosis

oogonia

-The two ovaries are suspended by ligaments within the abdominal cavity, just above the uterus. -The ovaries are the site of oogenesis— the production of an ovum. -Ova are also called oocytes. -ovaries usually alternate so that only one produces an egg each month. -The ovary contains specialized cell structures called follicles. -ovaries are responsible for producing egg cells and the hormones estrogen and progesterone.

ovaries

-the cilia-lined tube of smooth muscle that carries the ovulated egg from each ovary to the uterus. -If a living egg encounters sperm in the oviduct, fertilization may take place. -Around the fourteenth day of the menstrual cycle, luteinizing hormone is released from the pituitary gland. This hormone causes ovulation. When ovulation occurs, one of the mature follicles bursts, releasing its egg into the Fallopian tube.

oviduct (Fallopian tube)

the release of the mature ovum from the follicle of the ovary into the oviduct

ovulation

-the female gamete that contributes half of the chromosomes to the zygote in sexual reproduction -A mature ovum is a non-motile, sphere-shaped cell approximately 0.1 mm in diameter (that is, over 20 times larger than the head of a sperm cell). - The ovum contains a large quantity of cytoplasm, which contains nutrients for the first days of development after fertilization. -The ovum is encased in a thick membrane which must be penetrated by a sperm cell before fertilization can take place. -The ovum survives in the oviduct for up to 24 hours after ovulation.

ovum

-A single ovum develops within each follicle. Each month, a single follicle matures and then ruptures, releasing the ovum into the oviduct. -Thread-like projections called fimbriae continually sweep over the ovary. -When an ovum is released, it is swept by the fimbriae into a cilia-lined tube about 10 cm long called an oviduct. -The oviduct carries the ovum from the ovary to the uterus. Within the oviduct, the beating cilia create a current that moves the ovum toward the uterus.

process of ovulation

-The uterus is a muscular organ that holds and nourishes a developing fetus. -The uterus is normally about the size and shape of a pear, but it expands to many times its size as the fetus develops. -the uterus connects to the oviducts. At its base, the uterus forms a narrow opening called the cervix.

uterus

-the muscular tube that leads from the uterus to the external environment. - The cervix connects to the vagina. -The vagina is an entrance for the penis to deposit sperm. -The vagina is also an exit for the fetus during childbirth. -the glans clitoris becomes erect during sexual arousal.

vagina

-a single cell produced by the fusion of the egg and sperm. -The fertilized egg, now called a zygote, continues to move through the oviduct for several days before reaching the uterus. During this time, the endometrium thickens as it prepares to receive the zygote.

zygote (fertilized egg)