Changes

== Reproductive Endocrinology ==

== Reproductive Endocrinology ==

In fish, as with all higher animals, [[Endocrine_System_-_Hormones_-_Anatomy_%26_Physiology|hormones]] play a critical role in the reproductive process. [[Endocrine_System_-_Hormones_-_Anatomy_%26_Physiology|Hormones]] are chemical messengers released into the blood by specific tissues, such as the [[Endocrine_System_-_Pituitary_Gland_-_Anatomy_%26_Physiology|pituitary gland]]. The [[Endocrine_System_-_Hormones_-_Anatomy_%26_Physiology|hormones]] travel through the bloodstream to other tissues, which respond in a variety of ways. One response is to release another [[Endocrine_System_-_Hormones_-_Anatomy_%26_Physiology|hormone]], which elicits a response in yet another tissue. The primary tissues involved in this hormonal cascade are the [[Endocrine_System_-_Hypothalamus_-_Anatomy_%26_Physiology|hypothalamus]],[[Endocrine_System_-_Pituitary_Gland_-_Anatomy_%26_Physiology|pituitary gland]], and gonads.

In fish, as with all higher animals, [[Hormones_-_Anatomy_%26_Physiology|hormones]] play a critical role in the reproductive process. [[Hormones_-_Anatomy_%26_Physiology|Hormones]] are chemical messengers released into the blood by specific tissues, such as the [[Pituitary_Gland_-_Anatomy_%26_Physiology|pituitary gland]]. The [[Hormones_-_Anatomy_%26_Physiology|hormones]] travel through the bloodstream to other tissues, which respond in a variety of ways. One response is to release another [[Hormones_-_Anatomy_%26_Physiology|hormone]], which elicits a response in yet another tissue. The primary tissues involved in this hormonal cascade are the [[Hypothalamus_-_Anatomy_%26_Physiology|hypothalamus]],[[Pituitary_Gland_-_Anatomy_%26_Physiology|pituitary gland]], and gonads.

* Reproduction occurs under environmental conditions that are favorable to the survival of the young.  

* Reproduction occurs under environmental conditions that are favorable to the survival of the young.  

*** Food availability.

*** Food availability.

* A variety of sensory receptors detect these cues, including the [[Special_Senses_-_Visual_-_Anatomy_%26_Physiology#Structure|eye]], [[Endocrine_System_-_Pineal_Gland_-_Anatomy_%26_Physiology|pineal gland]] (an organ in the dorsal part of the [[Forebrain_-_Anatomy_%26_Physiology|forebrain]] that is sensitive to light), [[Special_Senses_-_Olfactory_-_Anatomy_%26_Physiology|olfactory organs]], [[Oral_Cavity_-_Tongue_-_Anatomy_%26_Physiology#Taste_Buds|taste buds]], and thermoreceptors.

* A variety of sensory receptors detect these cues, including the [[Special_Senses_-_Visual_-_Anatomy_%26_Physiology#Structure|eye]], [[Endocrine_System_-_Pineal_Gland_-_Anatomy_%26_Physiology|pineal gland]] (an organ in the dorsal part of the [[Forebrain_-_Anatomy_%26_Physiology|forebrain]] that is sensitive to light), [[Special_Senses_-_Olfactory_-_Anatomy_%26_Physiology|olfactory organs]], [[Oral_Cavity_-_Tongue_-_Anatomy_%26_Physiology#Taste_Buds|taste buds]], and thermoreceptors.

* The [[Endocrine_System_-_Hypothalamus_-_Anatomy_%26_Physiology|hypothalamus]], located at the base of the brain, is sensitive to signals from sensory receptors and releases [[Endocrine_System_-_Hypothalamus_-_Anatomy_%26_Physiology#Outputs|gonadotropin releasing hormones (GnRH)]] in response to environmental cues.

* The [[Endocrine_System_-_Hypothalamus_-_Anatomy_%26_Physiology|hypothalamus]], located at the base of the brain, is sensitive to signals from sensory receptors and releases [[Hypothalamus_-_Anatomy_%26_Physiology#Outputs|gonadotropin releasing hormones (GnRH)]] in response to environmental cues.

* GnRH travels from the [[Endocrine_System_-_Hypothalamus_-_Anatomy_%26_Physiology|hypothalamus]] to the [[Endocrine_System_-_Pituitary_Gland_-_Anatomy_%26_Physiology|pituitary gland]].  

* GnRH travels from the [[Hypothalamus_-_Anatomy_%26_Physiology|hypothalamus]] to the [[Endocrine_System_-_Pituitary_Gland_-_Anatomy_%26_Physiology|pituitary gland]].  

* Gonadotroph cells of the [[Endocrine_System_-_Pituitary_Gland_-_Anatomy_%26_Physiology|pituitary]] receive [[Endocrine_System_-_Hypothalamus_-_Anatomy_%26_Physiology#Outputs|GnRH]] and release gonadotropic hormones into the bloodstream.

* Gonadotroph cells of the [[Pituitary_Gland_-_Anatomy_%26_Physiology|pituitary]] receive [[Hypothalamus_-_Anatomy_%26_Physiology#Outputs|GnRH]] and release gonadotropic hormones into the bloodstream.

** '''GTH-I''' has FSH-like activity.

** '''GTH-I''' has FSH-like activity.

** '''GTH-II''' has LH-like activity.

** '''GTH-II''' has LH-like activity.