Avian Reproductive Physiology Vocabulary Flashcards

A complete set of 50 vocabulary flashcards covering female and male avian reproductive anatomy, neuroendocrine regulation, egg development stages, and mating physiology based on the lecture transcript.

Precocial birds

Birds that are well developed when they hatch and quickly able to stand and walk on their own.

Altricial birds

Birds that are less developed when they hatch and require a greater amount of post-hatch parental care.

Clutch

A group of eggs laid by a hen on consecutive days.

Ovulation

The release of a mature ovum from the ovary into the oviduct.

Ovary

A cluster of developing ova located midway between the neck and the tail of the bird and attached at the back.

Pullet chick

A young female chicken that hatches with tens of thousands of ova, representing all the potential eggs it can ever lay.

Xanthophylls

Fat-soluble pigments contained in a hen's diet that provide color to the egg yolk.

Stigma

The suture line on the sac enclosing an ovum that ruptures during ovulation.

Oviduct

A twisted tube that is $25$ to $27\text{ inches}$ long when fully developed where egg formation occurs.

Infundibulum

The first section of the oviduct, $3$ to $4\text{ inches}$ long, which engulfs the released ovum and serves as the site of fertilization.

Magnum

The largest section of the oviduct, $13\text{ inches}$ long, where thick albumen forms over $3\text{ hours}$.

Isthmus

The $4\text{-inch}$ long section of the oviduct where inner and outer shell membranes form over $75\text{ minutes}$.

Shell gland

The $4$ to $5\text{ inch}$ long section of the oviduct (uterus) where the calcium carbonate eggshell forms over $20$ or more hours.

Vagina

The muscular $4$ to $5\text{ inch}$ long final section of the oviduct that helps push the egg out of the hen's body.

Bloom

The protective cuticle that forms on the egg in the vagina prior to oviposition.

Oviposition

The laying of a fully formed egg.

Sperm host glands

Deep glands located near the junction of the shell gland and vagina that store sperm for $10\text{ days}$ to $2\text{ weeks}$.

Testes

Paired, elliptical, light yellow organs located along the male chicken's back near the top of the kidneys that produce sperm.

Vas deferens

The duct through which sperm are transported from the testes to the cloaca and the primary area of sperm storage in male birds.

Milking the rooster

The process of applying external pressure to the vas deferens area to collect sperm for artificial insemination.

Papilla

A small bump on the back wall of the cloaca where each vas deferens opens, serving as a mating organ.

Rudimentary copulatory organ

A structure located on the middle and front portion of the cloaca used by breeders to classify the sex of baby chicks.

Hypothalamus-pituitary-gonadal axis

The neuroendocrine axis regulating avian reproductive systems via hypothalamic GnRH, pituitary LH and FSH, and gonadal steroids.

Gonadotropin-releasing hormone

A hormone (GnRH) produced by the hypothalamus that stimulates pituitary gland production of LH and FSH.

cGnRH-I

The primary chemical form of avian GnRH concentrated in the hypothalamus that stimulates synthesis and release of LH and FSH.

cGnRH-II

A phylogenetically old chemical form of avian GnRH distributed throughout the brain that plays a role in regulating courtship and mating behavior.

Refractory birds

Birds that have become unresponsive to stimulatory photoperiods.

Catecholamines

Neurochemicals located in brain areas that regulate and modulate the GnRH system during various life cycle stages.

Opioid peptides

Peptides, including metenkephalin and B-endorphin, that exert a dose-dependent inhibitory effect on cGnRH-I release.

Adrenergic systems

Receptor systems (alpha and beta) through which norepinephrine and epinephrine act to stimulate cGnRH-I release.

Vasoactive intestinal peptide

A neuropeptide in turkey hens important in the regulation of prolactin.

Prolactin

A hormone regulated by vasoactive intestinal peptide that is associated with broody behavior in birds.

Testosterone

The major androgen secreted from the testes, required for avian male sexual behavior and spermatogenesis.

Estradiol

The biologically active metabolite formed by the aromatization of testosterone in target areas in the central nervous system.

Inhibin

A gonadal hormone produced in the ovary and Sertoli cells that acts to inhibit pituitary gonadotropin.

Luteinizing hormone

A pituitary gonadotropin (LH) regulated by GnRH that is composed of an alpha and beta subunit.

Follicle-stimulating hormone

A pituitary gonadotropin (FSH) that regulates ovarian function and acts on Sertoli cells in the testes.

Seminiferous tubules

Tubules within the testes containing Sertoli and germ cells where spermatogenesis takes place.

Sertoli cells

Cells located in the seminiferous tubules that respond primarily to FSH and produce inhibin.

Leydig cells

Androgen-producing cells dispersed between the seminiferous tubules in the testes.

5-alpha dihydrotestosterone

The active metabolite to which secreted testosterone is enzymatically reduced.

Transparent fluid

A lymphlike fluid mixed with semen during ejaculation in Galliformes to compensate for the absence of accessory sex glands.

Semen extender

A cell culture medium specifically designed for sperm used to dilute semen and sustain viability for artificial insemination.

Albumen

The egg white, which forms around the yolk primarily within the magnum.

Calcium carbonate

The primary chemical compound that forms the eggshell in the shell gland.

Preoptic and septal areas

Regions of the central nervous system where cell bodies containing cGnRH-I-reactive material are primarily located.

Median eminence

The region in the central nervous system where most axonal projections of cGnRH-I neurons terminate.

Metenkephalin

An opioid peptide that depresses baseline and norepinephrine-stimulated cGnRH-I release.

Epinephrine

A neurochemical present in highly measurable concentrations in avian hypothalamic areas that stimulates cGnRH-I release.

Norepinephrine

A catecholamine known to stimulate the release of cGnRH-I in birds via alpha and beta adrenergic receptor systems.