animal reproduction

Vocabulary flashcards about animal reproduction based on lecture notes.

Androgen

A male sex hormone, such as testosterone, that promotes the development and maintenance of male sex characteristics.

Artificial Insemination (AI)

When semen is placed into the cervix.

Conceptus

The product of conception, being the embryo/fetus together with the surrounding membranes.

Corpus Luteum

Produces progesterone that in turn allows and maintains pregnancy.

Estrous

An adjective describing the estrous cycle (in U.S. English).

Estrus

A noun denoting the time of heat.

Gonads Function

To produce gametes and sex hormones.

Gonad

The ovary in females and testis in males; the primary reproductive organ.

Libido

The desire to mate.

Monoestrous

Where there is a single estrus followed by an absence of ovarian activity.

Polyestrous

Where an animal will show repeated estrus separated by 16–23 days depending on the species.

Reflex Ovulators

Show estrus but require mating to ovulate.

Pregnancy Recognition

When the conceptus signals its presence to the mother to allow pregnancy to continue.

Primordial Germ Cell

Migrates to the site destined to be the gonad; becomes gonocytes in the developing gonad and ultimately become gametes.

Progesterone

The hormone that is essential to the maintenance of pregnancy.

Sertoli Cells

Are in the seminiferous tubules of the testis and function as “nurse cells” for developing spermatozoa.

Testis

The primary male reproductive organ because it produces spermatozoa, and the male reproductive hormone testosterone.

Vas Deferens

Connects the epididymis with the urethra, providing an environment suitable for survival of spermatozoa and the additions of secretions resulting in semen.

Testes

Primary reproductive organs of the male, with spermatozoa produced in very large numbers in the seminiferous tubules.

Leydig Cells

Cells in the interstitium between the seminiferous tubules that produce the hormone testosterone (TST).

Scrotum

The bag-like structure located outside the body that houses the testes.

Cremaster Muscles

Muscles connecting the testes to the abdominal cavity that contract in cold weather to bring the testes close to the body.

Tunica Dartos Muscles

Muscles in the scrotal wall that contract in cold weather to bring the testes close to the body.

Seminiferous Tubules

Hollow structures in which the germ cells differentiate to spermatozoa.

Epididymis

A coiled structure also in the scrotum that stores quiescent but live spermatozoa before ejaculation, and matures spermatozoa.

Male Accessory Sex Glands

Situated along the pelvic portion of the urethra, comprising of vesicular gland, prostate gland, and bulbourethral glands; it varies depending on species.

Ampullary Gland

Surrounds the terminal part of the ductus deferens.

Seminal Vesicles

Produce secretions that are added to the spermatozoa, containing proteins to stimulate capacitation and gelling or clotting of the semen.

Prostaglandins (in seminal vesicles)

Stimulates contraction of the female reproductive tract.

Prostate gland

Produces secretions that are added to the spermatozoa and are slightly alkaline to neutralize the lactic acid present in the epididymis.

Bulbourethral Gland

Found in all domestic animals except in dog; situated into the dorsal aspect of the pelvic urethra close to the pelvic exit.

Vas Deferens

A duct through which spermatozoa passes along during ejaculation.

Urethra

Connects the bladder and the vas deferens with the tip of the penis; urine from the bladder also passes through it.

Cowper's Gland

The secretion from it acts to clean the urethra.

Corpus Cavernosum (corpora cavernosa)

A spongy tissue surrounding the urethra in the penis.

Sigmoid Flexure

Extends the penis from the sheath in bulls, rams, and boars.

Retractor Muscle

Extends the penis from the sheath in bulls, rams, and boars.

Os Penis (baculum)

A bone in the penis that facilitates erection, found in dogs, cats, and most primates.

Fibroelastic Penis

Has small blood spaces divided by a substantial amount of tough fibroelastic tissue enclosed by thick tunica albuginea surrounding both the corpus cavernosum and corpus spongiosum.

Musculocavernous Penis

Blood spaces are larger and the tunic and intervening septum is much more delicate and muscular.

Prepuce

Cutaneous sheath around the free part of the penis in a quiescent state.

Seminiferous Tubules

Coiled tubes located within the testicles, and are the specific location of meiosis, and the subsequent creation of male gametes, namely spermatozoa.

Pudendal Nerve

Sensory input is delivered to the spinal cord via branches of this nerve.

Nitric Oxide

Activates relaxation of corporal cavernosal smooth muscle tissue resulting in increased blood flow into the penis resulting in an erection.

Spinothalamic Nerves

Involved with integrating this complex signaling.

Vas Deferens (Avian)

Sperm travels through it to the cloaca in avian male reproduction.

Papillae (Avian)

Small bumps on the back wall of the cloaca that serve as the mating organs in avian male reproduction.

Caponization

Castration in roosters.

Ovaries

Principal function is to produce ova; the ova develop in follicles associated with other cells and a developing fluid-filled lumen.

Graafian Follicle

The fully mature follicle that produces estradiol.

Zona Pellucida

A thin membrane surrounding ova that is ovulated.

Corpus Hemorrhagicum

The remnants of a follicle after ovulation, appearing as a bloody or red body.

Corpus Luteum (CL)

Forms after ovulation, producing progesterone.

Luteolysis

The process by which the CL breaks down.

Corpus Albicans

A white body that forms after the CL breaks down.

Oviduct

Connects the ovary to the uterus and is lined with ciliated cells to push the released ovum down it, fertilization occurs here.

Uterus

Muscular bag with a soft lining where the fertilized egg (zygote) will be implanted to develop into a foetus.

Cervix

Ring of muscle at the lower end of the uterus to keep the developing foetus in place during pregnancy.

Vagina

Muscular tube that leads to the inside of the woman's body, where the male's penis will enter during sexual intercourse and sperm are deposited.

Vulva

A collection of structures (including the pubic mound, labia, clitoris and hymen), one function of which is to protect the more internal parts of the female reproductive system.

Zygote

The ovum after fertilization.

Endometrium

Glandular layer of the uterus.

Myometrium

Layer of smooth muscles of the uterus.

Bicornuate Uterus

Has two large uterine horns, a uterine body and a single cervix.

Pyometra

A life-threatening, inflammatory bacterial infection of the uterus of mature intact female canines.

Cervix Function

A barrier between the uterus and vagina, normally constricted because of connective tissue and muscles with a mucus plug to prevent foreign materials from entering the uterus.

Vulva

he external opening consisting of labia majora, labia minora, and clitoris.

Infundibulum (Hen)

Functions by engulfing the ovulated ovum, where fertilization occurs.

Magnum (Hen)

Functions by adding concentrated egg white proteins and membranes to the egg.

Isthmus (Hen)

Functions by adding fluid to egg white.

Uterus (Hen)

Functions by adding calcium carbonate shell to the egg with calcium from the blood.

Vagina (Hen)

Functions by expelling the egg due to muscular contractions and is the site for insemination.

Germ Cells

Cells that give rise to gametes, playing a key role in sexual differentiation by affecting gonad development.

Sex-Determination System

A biological system that determines the development of sexual characteristics in an organism.

Sry Gene

The principal gene controlling the sex of a mammal, located on the Y chromosome.

Gonadotropin Releasing Hormone (GnRH)

A modified peptide with 10 amino acid residues; has been also called LH-releasing hormone.

Gonadotropin Inhibiting Hormone (GnIH)

Inhibits the release of both gonadotropins, LH and FSH, in both mammals and birds.

Luteinizing Hormone (LH)

A glycoprotein hormone that is produced by the anterior pituitary gland.

Follicle-Stimulating Hormone (FSH)

A glycoprotein hormone that is produced by the anterior pituitary gland.

Testosterone

The male sex hormone, a steroid synthesized from cholesterol.

Estrogens

Female sex hormones, such as estradiol, estrone, and estriol; steroids produced by the follicle before ovulation.

Progesterone

Its major role is maintaining pregnancy.

Oxytocin

A peptide hormone produced by the posterior pituitary gland; causes uterine contractions during the birthing process and milk to be let down.

Gametogenesis

A biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes.

Spermatogenesis

Occurs throughout the life of the male animal, except in the seasonal breeders, when it is restricted to the breeding season.

Meiosis

A type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes (the sex cells, or egg and sperm).

Oogenesis

Begins when the 2n oogonium undergoes mitosis, producing a primary oocyte.

Acrosome

Assists in the binding and penetration into the egg.

Flagellum

Provides motility for the sperm to travel in the vaginal canal.

Primary Follicle

The oocyte is surrounded by a single layer of (cuboidal) cells and a basement membrane.

Granulosa Cells

The cells around the oocyte which destined to become these.

Secondary Follicle

Located near the surface of the ovary; the oocyte is usually about 120 μm in diameter and has several layers of small darkly staining granulosa cells.

Pre-ovulatory (Graafian) Follicle

Bulging from the surface of the ovary before ovulation, containing the ovum surrounded by fluid and cells producing estrogen.

Estrous Cycles

Named for the cyclic appearance of behavioral sexual activity (estrus) that occurs in all mammals except for higher primates.

Menstrual Cycles

Occur only in primates and are named for the regular appearance of menses due to the shedding of the endometrial lining of the uterus.

Monestrous

Species such as canids and bears have only one breeding season per year.

Proestrus

The period between the regression of the corpus luteum of the previous cycle and estrus.

Estrus

When high amount of estrogen is presents in the blood. Also called “in heat”.

Metestrus

The corpus luteum develops under the influence of LH and starts to produce increasing amounts of progesterone.

Diestrus

The period between metestrus and the beginning of the regression of the corpus luteum.