| Human Anatomy, 6/e Kent Van De Graaff,
Weber State University
Female Reproductive System
Chapter SummaryInternal Affairs (113.0K) Introduction to the Female
Reproductive System - The reproductive period
of a female is the period between puberty (about age 12) and menopause (about
age 50). In the course of this age span, cyclic ovulation and menstruation
patterns occur in nonpregnant females.
- The functions of the
female reproductive system are to produce ova; secrete sex hormones; receive
sperm from the male; provide sites for fertilization, implantation, and development
of the embryo and fetus; facilitate parturition; and secrete milk from the
mammary glands.
- The female reproductive
system consists of (a) primary sex organs-the ovaries; (b) secondary sex organs-those
that are essential for sexual reproduction, characterized by latent development;
and (c) secondary sex characteristics-features that are sexual attractants,
expressed after puberty.
Structure and Function
of the Ovaries - The ovaries are supported
by the mesovarium, which extends from the broad ligament, and by the ovarian
and suspensory ligaments.
- The ovarian follicles
within the ovarian cortex undergo cyclic changes.
- Primary oocytes,
arrested at prophase I of meiosis, are contained within primordial follicles.
- Upon stimulation
by gonadotropic hormones, some of the primordial follicles enlarge to
become primary follicles.
- When a follicle develops
a fluid-filled antrum, it is called a secondary follicle.
- Generally only one
follicle continues to grow to become a vesicular ovarian follicle.
- The vesicular ovarian
follicle contains a secondary oocyte, arrested at metaphase II of meiosis.
- In the process of
ovulation, the vesicular ovarian follicle ruptures and releases its secondary
oocyte, which becomes a zygote upon fertilization.
- After ovulation,
the empty follicle becomes a corpus luteum.
Secondary Sex Organs
- The uterine tube, which
conveys ova from the ovary to the uterus, provides a site for fertilization.
- The open-ended portion
of each uterine tube is expanded; its margin bears fimbriae that extend
over the lateral surface of the ovary.
- Movement of an ovum
is aided by ciliated cells that line the lumen and by peristaltic contractions
in the wall of the uterine tube.
- The uterus is supported
by the broad ligaments, uterosacral ligaments, cardinal ligaments, and round
ligaments. The regions of the uterus are the fundus, body, and cervix. The cervical
canal opens into the vagina at the uterine ostium.
- The endometrium consists
of a stratum basale and a stratum functionale; the superficial stratum
functionale is shed during menstruation.
- The myometrium produces
the muscular contractions needed for labor and parturition.
- The vagina serves to
receive the erect penis, to convey menses to the outside, and to transport
the fetus during parturition.
- The vaginal wall
is composed of an inner mucosa, a middle muscularis, and an outer fibrous
layer.
- The vaginal orifice
may be partially covered by a thin membranous hymen.
- The external genitalia,
or vulva, include the mons pubis, labia majora and minora, clitoris, vaginal
vestibule, vestibular bulbs, and vestibular glands.
- Impulses through parasympathetic
nerves stimulate erectile tissues in the clitoris and vestibular bulbs; in
orgasm, muscular contraction occurs in the perineum, uterus, and uterine tubes.
Mammary Glands - Mammary glands, located
within the breasts, are modified sweat glands.
- Each mammary gland
is composed of 15 to 20 lobes; the lobes are subdivided into lobules that
contain mammary alveoli.
- During lactation,
the mammary alveoli secrete milk. The milk passes through mammary ducts,
lactiferous ducts, and lactiferous sinuses and is discharged through the
nipple.
- The nipple is a cylindrical
projection near the center of the breast, surrounded by the circular pigmented
areola.
Ovulation and Menstruation
- Ovulation and menstruation
are reproductive cyclic events that are regulated by hormones secreted by
the hypothalamus, the anterior pituitary, and the ovaries.
- The menstrual cycle is
divided into menstrual, proliferative, and secretory phases.
- The principal hormones
that regulate ovulation and menstruation are estrogen, progesterone, follicle-stimulating
hormone (FSH), and luteinizing hormone (LH).
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