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[[Image:Mare Uterus.jpg|thumb|right|150px|The Mare Uterus- Courtesy of A.Crook, Copyright RVC 2008]]

[[Image:Mare Uterus.jpg|thumb|right|150px|The Mare Uterus- Courtesy of A.Crook, Copyright RVC 2008]]

== Puberty ==

== Puberty ==

[[Puberty - Defining Puberty - Anatomy & Physiology|Puberty]] is the process of aquiring reproductive capability, and age at onset of puberty varies from between [[Puberty- Overview of Puberty - Anatomy & Physiology|species]]. There are several factors involved in triggering the [[Puberty - Factors Influencing the Onset of Puberty - Anatomy & Physiology|onset]] of puberty, including body size, nutritional factors, day length, genetic factors and environmental and social factors. The onset depends on the ability of specific hypothalamic neurons to produce [[Puberty - Endocrine Events of Puberty - Anatomy & Physiology|gonadotropin-releasing hormone (GnRH)]] in sufficient quantities to both promote and support gametogenesis. The hypothalamus itself is influenced by hormonal factors that are [[Puberty - Differences in the Male and Female Hypothalamus- Anatomy & Physiology|male or female specific]].

[[Puberty Defining - Anatomy & Physiology|Puberty]] is the process of aquiring reproductive capability, and age at onset of puberty varies from between [[Puberty Overview - Anatomy & Physiology|species]]. There are several factors involved in triggering the [[Puberty Onset Influencing Factors - Anatomy & Physiology|onset]] of puberty, including body size, nutritional factors, day length, genetic factors and environmental and social factors. The onset depends on the ability of specific hypothalamic neurons to produce [[Puberty Endocrine Events - Anatomy & Physiology|gonadotropin-releasing hormone (GnRH)]] in sufficient quantities to both promote and support gametogenesis. The hypothalamus itself is influenced by hormonal factors that are [[Hypothalamus Differences in the Male and Female - Anatomy & Physiology|male or female specific]].

== Female Reproductive Tract and Reproductive Behaviour==

== Female Reproductive Tract and Reproductive Behaviour==

== Fertilisation, Implantation and Early Embryonic Development ==

== Fertilisation, Implantation and Early Embryonic Development ==

After mating has occured, sperm must [[Copulation -Sperm in the Female Tract - Anatomy & Physiology|travel]] along the female reproductive tract towards the uterus in order to [[Fertilisation, Implantation and Early Embryonic Development -Fertilisation- Anatomy & Physiology|fertilise]] the oocyte. A single spermatazoon penetrates the oocyte and the male and female pronuclei fuse to form an ootid which divides repeatedly to form the [[Blastocyst Embryonic Development - Anatomy & Physiology|blastocyst]]. At this stage the genetic sex of the offspring is determined as male gametes are [[Fertilisation, Implantation and Early Embryonic Development -Sexual Differentiation- Anatomy & Physiology|heterogametic]]. The blastocyst continues to divide and grow until the outer layer, the zona pellucida ruptures and the blastocyst 'hatches' and becomes free floating within the uterus. The blastocyt continues to grow and develop until it becomes an embryo with placental and embryonic membranes such as the amniotic sac; the placental membranes then attach to the uterine endometrium in a process known as [[Fertilisation, Implantation and Early Embryonic Development -Implantation- Anatomy & Physiology|implantation]]. During embryonic development the process of [[Internal and External Genitalia Development - Anatomy & Physiology|sexual differentiation]] begins.

After mating has occured, sperm must [[Sperm in the Female Tract - Anatomy & Physiology|travel]] along the female reproductive tract towards the uterus in order to [[Fertilisation - Anatomy & Physiology|fertilise]] the oocyte. A single spermatazoon penetrates the oocyte and the male and female pronuclei fuse to form an ootid which divides repeatedly to form the [[Blastocyst Embryonic Development - Anatomy & Physiology|blastocyst]]. At this stage the genetic sex of the offspring is determined as male gametes are [[Sexual Differentiation - Anatomy & Physiology|heterogametic]]. The blastocyst continues to divide and grow until the outer layer, the zona pellucida ruptures and the blastocyst 'hatches' and becomes free floating within the uterus. The blastocyt continues to grow and develop until it becomes an embryo with placental and embryonic membranes such as the amniotic sac; the placental membranes then attach to the uterine endometrium in a process known as [[Implantation - Anatomy & Physiology|implantation]]. During embryonic development the process of [[Internal and External Genitalia Development - Anatomy & Physiology|sexual differentiation]] begins.

== Pregnancy and Parturition ==

== Pregnancy and Parturition ==

In most domestic species, pregnancy is maintained by hormonal feedback from the corpus luteum and, in many species, the placenta. The corpus luteum is maintained in early pregnancy and progesterone levels remain elevated as a result. This maintains negative feedback to the hypothalamus and anterior pituitary gland which inhibits further follicular development and ovulation. In polyoestrous species, it prevents the return to oestrus. In many species the [[Placenta Endocrine Function_- Anatomy & Physiology|placenta]] will take over or supplement the corpus luteum as the source of progesterone during pregnancy; the placenta is a source of many of the hormones that  regulate changes during preganancy, stimulating mammary growth, the growth of the myometrium, preparation for parturition, and secreting chorionic gonadotrophin in species where this is required for the [[Gestation -Maternal Recognition of Pregnancy - Anatomy & Physiology|maternal recognition of pregnancy]]. [[Gestation -Litter Sizes - Anatomy & Physiology|Litter sizes]] vary between species, as do methods of [[Gestation -Diagnosis of Pregnancy - Anatomy & Physiology|pregnancy diagnosis]].  

In most domestic species, pregnancy is maintained by hormonal feedback from the corpus luteum and, in many species, the placenta. The corpus luteum is maintained in early pregnancy and progesterone levels remain elevated as a result. This maintains negative feedback to the hypothalamus and anterior pituitary gland which inhibits further follicular development and ovulation. In polyoestrous species, it prevents the return to oestrus. In many species the [[Placenta Endocrine Function_- Anatomy & Physiology|placenta]] will take over or supplement the corpus luteum as the source of progesterone during pregnancy; the placenta is a source of many of the hormones that  regulate changes during preganancy, stimulating mammary growth, the growth of the myometrium, preparation for parturition, and secreting chorionic gonadotrophin in species where this is required for the [[Maternal Recognition of Pregnancy - Anatomy & Physiology|maternal recognition of pregnancy]]. [[Litter Sizes - Anatomy & Physiology|Litter sizes]] vary between species, as do methods of pregnancy diagnosis.  

* [[Gestation -Reference Table of Gestation Lengths in Various Species - Anatomy & Physiology|Summary of Gestation Lengths in Various Species]]

* [[Gestation Lengths in Various Species - Anatomy & Physiology|Summary of Gestation Lengths in Various Species]]

The process of giving birth, or [[Parturition - Normal Parturition - Anatomy & Physiology|parturition ]] is conventionally divided into [[Parturition - Normal Parturition - Anatomy & Physiology|three stages]]; stage one includes the movement of the foetus into the birthing position and preparation of the reproductive tract for birth, which is followed by stage two - contractions and the birth itself. Finally, stage three involves the expulsion of the foetal membranes. The timings of each stage vary from species to species, and a good knowledge of the normal progression of parturition is essential to detect when things are not proceeding normally. There are several [[Parturition - Risks in Parturition - Anatomy & Physiology|conditions]] that can occur to disturb the normal progress of parturition, including dystocia, uterine inertia, ring womb, prolapses, retained placenta, endometritis and foetal abnormalities. Like pregnancy, parturition is under complex [[Parturition - Endocrine Control of Parturition - Anatomy & Physiology|hormonal control]], and this can be manipulated [[Parturition - Pharmacological Manipulation of Parturition - Anatomy & Physiology|pharmacalogically]] to alter the timing of parturition.

The process of giving birth, or [[Normal Parturition - Anatomy & Physiology|parturition ]] is conventionally divided into [[Normal Parturition - Anatomy & Physiology|three stages]]; stage one includes the movement of the foetus into the birthing position and preparation of the reproductive tract for birth, which is followed by stage two - contractions and the birth itself. Finally, stage three involves the expulsion of the foetal membranes. The timings of each stage vary from species to species, and a good knowledge of the normal progression of parturition is essential to detect when things are not proceeding normally. There are several [[:Category:Reproductive Disorders|conditions]] that can occur to disturb the normal progress of parturition, including dystocia, uterine inertia, ring womb, prolapses, retained placenta, endometritis and foetal abnormalities. Like pregnancy, parturition is under complex [[Parturition Endocrine Control - Anatomy & Physiology|hormonal control]], and this can be manipulated [[Parturition Pharmacological Manipulation - Anatomy & Physiology|pharmacalogically]] to alter the timing of parturition.

== The Puerperium ==

== The Puerperium ==

[[The Puerperium - Overview of the Puerperium - Anatomy & Physiology|Puerperium]] describes the period of time immediately following parturition, when the female enters a period of reproductive repair and begins lactation. For a period of time these two processes overlap. During this time the female experiences regular [[The Puerperium - Myometrial Contraction and Expulsion of Lochia - Anatomy & Physiology|myometrial contractions]] which expel the remaining fluid and tissues present following birth, allowing the uterus to begin [[The Puerperium - Endometrial Repair- Anatomy & Physiology|involution and repair]] so that the reproductive cycle can begin once more. The discharge appears at the vulva and is known as [[The_Puerperium_-_Myometrial_Contraction_and_Expulsion_of_Lochia_- Anatomy & Physiology#Lochia|lochia]]. The process of birth can predispose the reproductive tract to heavy bacterial contamination, but physiological and hormonal changes encourage the [[The Puerperium - Elimination of Bacterial Contamination of the Reproductive Tract- Anatomy & Physiology|removal of bacteria]] before infection can become established. There are many [[The Puerperium - Factors Influencing the Puerperium- Anatomy & Physiology|environmental and management]] influences that will affect the length of time that puerperium lasts, as well as differences between [[The Puerperium - Species Differences in the Puerperium- Anatomy & Physiology| species]].

[[Puerperium - Anatomy & Physiology|Puerperium]] describes the period of time immediately following parturition, when the female enters a period of reproductive repair and begins lactation. For a period of time these two processes overlap. During this time the female experiences regular myometrial contractions which expel the remaining fluid and tissues present following birth, allowing the uterus to begin involution and repair so that the reproductive cycle can begin once more. The discharge appears at the vulva and is known as lochia. The process of birth can predispose the reproductive tract to heavy bacterial contamination, but physiological and hormonal changes encourage the removal of bacteria before infection can become established. There are many environmental and management influences that will affect the length of time that puerperium lasts, as well as differences between species.

== Lactation ==

== Lactation ==

The secretion of milk from the mammary glands is known as [[Lactation - Overview of Lactation - Anatomy & Physiology|lactation]] - the milk provides [[Lactation - Milk Composition and Biosynthesis- Anatomy & Physiology|nourishment]] for the neonate in addition to immunoprotection in the form of anitibodies which are contained in the initial mammary secretions, or [[Lactation_-_Milk_Composition_and_Biosynthesis- Anatomy & Physiology#Colostrum|colostrum]]. Mammary development and milk production and ejection are induced by [[Lactation - Endocrine Control - Anatomy & Physiology|hormonal signals]]. Lactation continues until the neonate is weaned; after weaning the [[Lactation - The Mammary Gland - Anatomy & Physiology|mammary glands]] undergo [[Lactation - Involution - Anatomy & Physiology|involution]] and return to a non-secretory state.  

The secretion of milk from the mammary glands is known as [[Lactation - Anatomy & Physiology|lactation]] - the milk provides [Milk Composition and Biosynthesis- Anatomy & Physiology|nourishment]] for the neonate in addition to immunoprotection in the form of anitibodies which are contained in the initial mammary secretions, or [[Milk_Composition_and_Biosynthesis- Anatomy & Physiology#Colostrum|colostrum]]. Mammary development and milk production and ejection are induced by [[Lactation - Endocrine Control - Anatomy & Physiology|hormonal signals]]. Lactation continues until the neonate is weaned; after weaning the [[Mammary Gland - Anatomy & Physiology|mammary glands]] undergo [[Lactation - Anatomy & Physiology#Involution|involution]] and return to a non-secretory state.  

Various pathological states that affect mammary tissues include [[Neoplasia - Pathology#Examples of Tumour Types|mammary neoplasia]] and [[Healing and Repair - Pathology#Female|mastitis]]. Metabolic disturbances can also occur during lactation, the most common being [[General Pathology - Vascular Fluid Balance - Pathology#Calcium|hypocalcaemia]] or 'milk fever'.

Various pathological states that affect mammary tissues include [[Neoplasia - Pathology#Examples of Tumour Types|mammary neoplasia]] and [[Healing and Repair - Pathology#Female|mastitis]]. Metabolic disturbances can also occur during lactation, the most common being hypocalcaemia or 'milk fever'.

== Reproductive Technologies ==

== Reproductive Technologies ==

Technologies such as [[Artificial Insemination - Anatomy & Physiology|artificial insemination]] (AI) have been in use for some time and in cattle, for example have become standard practice for reproduction purposes; the technique requires collection of [[Reproductive Technologies -Semen Collection - Anatomy & Physiology|semen]] from the male, which is preserved, transported and introduced into the female reporoductive tract in synchrony with her ovulation cycle. Recently other techniques have been developed which permit development of the embryo from a donor animal in a recepient female who will carry the pregnancey to term and nurse the resulting offspring - a technique called [[Embryo Transfer - Anatomy & Physiology|embryo transfer]]. This technique has some unique advantages and is becoming popular, for example in some equine studs where successful mares can continue their competative careers and still become part of a breeding programme. Other more specialised techniques used in breeding include:

Technologies such as [[Artificial Insemination - Anatomy & Physiology|artificial insemination]] (AI) have been in use for some time and in cattle, for example have become standard practice for reproduction purposes; the technique requires [[Semen Collection - Anatomy & Physiology|collection of semen]] from the male, which is preserved, transported and introduced into the female reporoductive tract in synchrony with her ovulation cycle. Recently other techniques have been developed which permit development of the embryo from a donor animal in a recepient female who will carry the pregnancey to term and nurse the resulting offspring - a technique called [[Embryo Transfer - Anatomy & Physiology|embryo transfer]]. This technique has some unique advantages and is becoming popular, for example in some equine studs where successful mares can continue their competative careers and still become part of a breeding programme. Other more specialised techniques used in breeding include:

* [[In Vitro Fertilization - Anatomy & Physiology|In Vitro Fertilization]]

* [[In Vitro Fertilization - Anatomy & Physiology|In Vitro Fertilization]]

* [[Embryo Sexing - Anatomy & Physiology|Embryo Sexing]]

* [[Embryo Sexing - Anatomy & Physiology|Embryo Sexing]]

* [[Reproductive Technologies -Semen Sexing- Anatomy & Physiology|Semen Sexing]]

* [[Semen Sexing - Anatomy & Physiology|Semen Sexing]]

* [[Embryo Splitting - Anatomy & Physiology|Embryo Splitting]]

* [[Embryo Splitting - Anatomy & Physiology|Embryo Splitting]]

* [[Nuclear Transplantation/Cloning - Anatomy & Physiology|Nuclear Transplantation/Cloning]]

* [[Nuclear Transplantation/Cloning - Anatomy & Physiology|Nuclear Transplantation/Cloning]]

* [[Reproductive Technologies -Transgenic Animals- Anatomy & Physiology|Transgenic Animals]]

* [[Transgenic Animals - Anatomy & Physiology|Transgenic Animals]]

== Camelids (LLamas & Alpacas) ==

== Camelids (LLamas & Alpacas) ==

* [[Fish Reproduction - Anatomy & Physiology|Fish Reproductive Anatomy and Physiology ]]

* [[Fish Reproduction - Anatomy & Physiology|Fish Reproductive Anatomy and Physiology ]]

==Test yourself - Reproduction System flashcards==

*'''[[Reproductive System Flashcards - Anatomy & Physiology|Reproductive System Flashcards]]'''

|flashcards = [[Reproductive System Flashcards - Anatomy & Physiology|Reproductive System Flashcards]]

== References ==

== References ==

* B.Young, J.W Heath: Wheater's Functional Histology, A Text and Colour Atlas

* B.Young, J.W Heath: Wheater's Functional Histology, A Text and Colour Atlas

[[Category:Reproductive System]]

[[Category:Reproductive System - Anatomy & Physiology]]