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Pregnancy and Parturition - Horse Anatomy (view source)
Revision as of 17:30, 26 November 2012
, 17:30, 26 November 2012→Placenta
Oxygen and nutrient rich blood returns to the foetus via the '''umbilical vein'''. Maternal blood is supplied to the placenta via 80-100 '''spiral endometrial arteries''' which allow the blood to flow into intervillous spaces facilitating exchnage. The blood pressure within the spiral arteries is much higher than that found in the intervillous spaces resulting in more efficient nutrient exchange within the placenta.
Oxygen and nutrient rich blood returns to the foetus via the '''umbilical vein'''. Maternal blood is supplied to the placenta via 80-100 '''spiral endometrial arteries''' which allow the blood to flow into intervillous spaces facilitating exchnage. The blood pressure within the spiral arteries is much higher than that found in the intervillous spaces resulting in more efficient nutrient exchange within the placenta.
===Exchange===
The mare is not able to confer immunity via the placenta and instead relies on the passive transfer of antibodies via '''colostrum'''.
===Histotrophic Exchange===
This type of exhange facilitates nourishment of the embryo prior to implantation, i.e. where no placenta exists. In horses, this type of exchnage is very important as there is a long period prior to implantation (up to 35 days). Nutrition is supplied by uterine secretions/debris, often referred to as 'uterine milk'. Uterine milk secretions are usually maintained by '''progesterone'''. Pinocytosis (cellular drinking) is the main exchange mechanism.
==Parturition==
==Parturition==