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- Its alkaline pH neutralizes the acidity of the male
urethra and female vagina.^
- It provides a transport medium for the swimming
sperm.^
- Semen contains enzymes that activate sperm after
ejaculation and an antibiotic called seminalplasmin to
control bacterial growth in the male and female
reproductive tract.
The Penis
- The penis delivers spermatozoa to the female repro-
ductive tract.^
- It consists of a shaft whose end is called the glans
penis or head covered with loose skin called the
prepuce or foreskin.^
- Internally, it is composed of three cylindrical
masses of spongy tissue containing blood sinuses.^
- Swelling of the blood sinuses during sexual stimula-
tion results in an erection.
The Female Reproductive System
- The primary sex organs of the female reproductive
system are the ovaries, or female gonads. They pro-
duce eggs and the female sex hormones.^
- Accessory organs of the system are the uterine or
fallopian tubes, uterus, vagina, and the external
genitalia.^
- Accessory glands produce mucus for lubrication
during sexual intercourse.
The Ovaries
- The ovaries are paired glands located in the up-per
pelvic cavity on each side of the uterus. They are
held in position by a series of suspensory
ligaments.^
- The surface of an ovary is covered with germinal
epithelium.^
- The capsule of an ovary consists of connective tis-sue
called the tunica albuginea, whose outer area is called
the cortex and contains ovarian follicles.^
- Ovarian follicles are eggs in various stages of
development.^
- Each follicle contains an immature egg or oocyte
and is called a primary follicle.^
- As the egg matures through meiosis, the follicle de-
velops a fluid-filled central area called the antrum
and is now called a secondary follicle.
Chapter 19- A mature follicle with a mature egg is called a graaf-
ian follicle, ready for ovulation.^ - When the egg ruptures from the graafian follicle in
ovulation, the follicle changes into the corpus lu-
teum or yellow body, which secretes estrogen and
progesterone.^ - The corpus luteum eventually degenerates, if fertil-
ization does not occur, into the corpus albicans, or
white body.^ - The ovaries produce and discharge eggs in ovula-
tion. They also secrete the female sex hormones
estrogen and progesterone.^ - Oogenesis, or formation of the female sex cells, be-
gins in the developing female fetus where female
stem cells called oogonia divide by mitosis to pro-
duce primary oocytes.^ - About 700,000 primary oocytes are produced at this
time and represent the total number of eggs a fe-male
will produce. They lie dormant until puberty.^ - At puberty, the ovarian cycle begins and approxi-
mately 450 of the 700,000 primary oocytes will
develop into eggs by meiosis during the female’s
reproductive years.^ - After the first meiotic division, a primary oocyte will
develop into two cells: the secondary oocyte is the
larger of the two with a smaller polar body cell.^ - After the second meiotic division, which occurs only
after fertilization, the secondary oocyte becomes an
ootid or mature egg with another nonfunctional polar
body. The polar body from the first meiotic division
divides into two nonfunctional polar bodies. Thus, one
mature^ egg and three polar bodies are produced.^ - The one mature egg cell has a large supply of stored
food to supply the developing embryo, if fertiliza-tion
occurs.
The Uterine or Fallopian Tubes- The two uterine or fallopian tubes transport the ova
from the ovaries to the uterus.^ - The funnel-shaped open end is called the infun-
dibulum and is surrounded by a fringe of finger-like
projections called the fimbriae.^ - Cilia on the epithelium of the infundibulum and the
waving fimbriae sweep an ovum into the uterine tube
after ovulation.^ - The egg is moved by peristalsis and the action of
cilia toward the uterus. Fertilization usually occurs in
the upper one-third of the tube within 24 hours after
ovulation.