Changes

== 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_%26_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 [[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]].  

== 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_%26_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]].

[[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]].

== 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_%26_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 - 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.  

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 [[General Pathology - Vascular Fluid Balance - Pathology#Calcium|hypocalcaemia]] or 'milk fever'.