Spiral arteries are small arteries which temporarily supply blood to the
endometrium
The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The functional layer ...
of the
uterus
The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...
during the
luteal phase of the
menstrual cycle
The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that make pregnancy possible. The ovarian cycle controls the production and release of eggs ...
.
In
histology
Histology,
also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures v ...
, identifying the presence of these arteries is one of the most useful techniques in identifying the phase of the cycle.
The spiral arteries are converted for uteroplacental blood flow during pregnancy, involving:
* Loss of smooth muscle &
elastic lamina
The internal elastic lamina or internal elastic lamella is a layer of elastic tissue that forms the outermost part of the tunica intima of blood vessels. It separates tunica intima from tunica media.
Histology
It is readily visualized with light ...
from the vessel wall.
* 5-10 fold dilation at the mouth of the vessel.
Failure of the physiological conversion of the spiral arteries can cause a number of complications, including
intrauterine growth restriction
Intrauterine growth restriction (IUGR), or fetal growth restriction, refers to poor growth of a fetus while in the womb during pregnancy. IUGR is defined by clinical features of malnutrition and evidence of reduced growth regardless of an infant's ...
and
pre-eclampsia
Pre-eclampsia is a disorder of pregnancy characterized by the onset of high blood pressure and often a significant amount of protein in the urine. When it arises, the condition begins after 20 weeks of pregnancy. In severe cases of the disease ...
.
References
Arteries of the abdomen
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