Ch 46: Animal Reproduction

Abortion

The termination of a pregnancy in progress

Parthenogenesis

A form of asexual reproduction in which females produce offspring from unfertilized eggs

Ectopic

Occurring in an abnormal location

Spermatogonium

(Plural, spermatogonia) a cell that divides mitotically to form spermatocytes

Primary Oocyte

An oocyte prior to completion of meiosis I

Menstruation

The shedding of portions of the endometrium during a uterine cycle

Ovulation

The release of an egg from an ovary. In humans, an ovarian follicle release an egg during uterine cycle

Vagina

Part of the female reproductive system between the uterus and the outside opening; the birth canal in mammals.

Placenta

A structure in the uterus of a pregnant eutherian mammal that nourishes the fetus with the mother’s blood supply; formed from the uterine lining and embryonic membranes

Uterus

A female organ where eggs are fertilized and/or development of the young occurs

Follicle-Stimulating Hormone (FSH)

A tropic hormone that is produced and secreted by the anterior pituitary and that stimulates the production of eggs by the ovaries and sperm by the testes

Menstrual Cycle

In humans and certain other primates, the periodic growth and shedding of the uterine lining that occurs in the absence of pregnancy

Testosterone

A steroid hormone required for development of the male reproductive system, spermatogenesis and male secondary sex characteristics; the major androgen in mammals

Semen

The fluid that is ejaculated by the male during orgasm; contains sperm and secretions from several glands of the male reproductive tract

Uterine Cycle

The cyclic changes in the uterine lining of mammals that occur in the absence of pregnancy. In certain primates, including humans, the uterine cycle is a menstrual cycle

Organogenesis

The process in which organ rudiments develop from the three germ layers after gastrulation

Ovary

(1) in flowers, the portion of a carpel in which the egg-containing ovules develop

(2) in animals, the structure that produces female gametes and reproductive hormones

Acrosome

A vessel in the tip of a sperm containing hydrolytic enzymes and other proteins that help the sperm reach the egg

Gonad

A male or female gamete-producing organ

Testis

(Plural, testes) the male reproductive organ, or gonad in which sperm and reproductive hormones are produced

Clitoris

An organ at the upper intersection of the labia minora that engorges with blood and becomes erect during sexual arousal

Seminiferous Tubule

A highly coiled tube in the testis in which sperm are produced

Oogenesis

The process in the ovary that results in the production of female gametes

Conception

The fertilization of an egg by a sperm in humans

Menopause

The cessation of ovulation and menstruation marking the end of a human female’s reproductive years

Epididymis

A coiled tubule located adjacent to the mammalian testis where sperm are stored

Gestation

Pregnancy; the condition of carrying one or more embryos in the uterus

Endometriosis

The condition resulting from the presence of endometrial tissue outside of the uterus

Ejaculation

The propulsion of sperm from the epididymis through the muscular vas deferens, ejaculatory duct and urethra

Gametogenesis

The process by which gametes are produced

Trophoblast

The outer epithelium of a mammalian blastocyst. It forms the fetal part of the placenta, supporting embryonic development but not forming part of the embryo proper

Contraception

The deliberate prevention of pregnancy

Fetus

A developing mammal that has all the major structures of an adult. In humans, the fetal stage lasts from the 9th well of gestation until birth

Ovarian Cycle

The cyclic recurrence of the follicular phase, ovulation and the luteal phase in the mammalian ovary, regulated by hormones

Sperm

The male gamete

Urethra

A tube that release urine from the mammalian body near the vagina in females and through the penis in males; also serves in males as the exit tube for the reproductive system

Scrotum

A pouch of skin outside the abdomen that house the testes; functions in maintaining the testes at the lower temperature required for spermatogenesis

Glans

In humans, the rounded head of the penis or of the clitoris; the glans is highly sensitive to stimulation

Endometrium

The inner lining of the uterus, which is richly supplied with blood vessels

Oviduct

A tube passing from the ovary to the vagina in invertebrates or the uterus in vertebrates

In Vitro Fertilization (IVF)

Fertilization of locates in laboratory containers followed by artificial implantation of the early embryo in the mother’s uterus

Vasectomy

The cutting and sealing of each vas deferens to prevent sperm from entering the urethra

Oogonium

(Plural, oogonia) a cell that divides mitotically to form oocytes

Hermaphroditism

A condition in which an individual has both female and male gonads and functions as both male and female in sexual reproduction by producing both sperm and eggs

Secondary Oocyte

An oocyte that has completed meiosis I

Labia Minora

A pair of slender skin folds that surround the openings of the vagina and urethra

Asexual Reproduction

The generation of offspring from a single parent that occurs without the fusion of gametes

Estrous Cycle

A reproductive cycle characteristic of female mammals except humans and certain other primates, in which the endometrium is reabsorbed in the absence of pregnancy and sexual response occurs only during a mid cycle point

Follicle

A microscopic structure in the ovary that contains the developing oocyte and secretes estrogens

Birth Control Pill

A hormonal contraceptive that inhibits ovulation, retards follicular development, or alters woman’s cervical mucus to prevent sperm from entering the uterus

Oocyte

A cell in the female reproductive system that differentiates to form an egg

Mammary gland

An exocrine gland that secretes milk for nourishing the young

Cloaca

A common opening for digestive, urinary, and reproductive tracts found in many non mammalian vertebrates but in few mammals

Luteinizing Hormone (LH)

A tropic hormone that is produced and secreted by the anterior pituitary and stimulates ovulation in females and androgen production in males

Blastocyst

The blastula stage of mammalian embryonic development, consisting of an inner cell mass, a cavity, and an outer layer, the trophoblast.

Sexual Reproduction

Reproduction arising from fusion of two gametes

Progesterone

A steroid hormone that contributes to the menstrual cycle and prepares the uterus for pregnancy

Spermatogenesis

The continuous and prolific production of mature sperm in the testis

Vulva

Collective term for the female external genitalia

Vas Deferens

In mammals, the tube in the male reproductive system in which sperm travel from the epididymis to the urethra

Prostate Gland

A gland in human males that secretes an acid-neutralizing component of semen

Seminal Vesicle

A gland in males that secretes a fluid component of semen that lubricates and nourishes sperm

Corpus Luteuum

A secreting tissue in the ovary that forms from the collapsed follicle after ovulation and produces progesterone

Penis

The copulatory structure of male mammals

Spermatheca

(Plural, spermathecae) in many insects, a sac in the female reproductive system where sperm are stored

Fertilization

(1) the union of haploid gametes to produce a diploid zygote

(2) the addition of mineral nutrients to the soil

Fission

The separation of an organism into two or more individuals of approximately equal size

Labia Majora

A pair of thick, fatty ridges that enclose and protect the rest of the vulva

Estradiol

A steroid hormone that stimulates the development and maintenance of the female reproductive system and secondary sex characteristics

Pregnancy

The condition of carrying one or more embryos in the uterus