and approximates to the placental type.
- Characterized by the woolly scaleleaves and carpels; the latter terminate in a thick laminar expansion of triangular form, bearing two placental cushions, on which the ovules are situated.
These projections and ridges may be homologous with the seminiferous scale of the pines, firs, cedars, &c. The simplest interpretation of the cone of the Abietineae is that which regards it as a flower consisting of an axis bearing several open carpels, which in the adult cone may be very small or large and prominent, the scale bearing the ovules being regarded as a placental outgrowth from the flat and open carpel.
With the exception of the Cetacea, most of the Edentata, and the Sirenia, in which the teeth, when present, have been specialized in a retrograde or aberrant manner, the placental mammals as a whole have a dentition conforming more or less closely to the foregoing type.
That is to say, he believes that, with the exception of the duckbill and the echidna, the mammalian class as a whole can lay claim to descent from small arboreal forms. This view is, of course, almost entirely based upon palaeontological considerations; and these, in the author's opinion, admit of the conclusion that all modern placental and marsupial mammals are descended from a common ancestral stock, of which the members were small in bodily size.
The Insectivora are certainly the lowest group of existing placental mammals, and exhibit many signs of affinity with marsupials; they may even be a more generalized group than the latter.
The marsupials also attain their maximum development in Australia (" Notogaea " of the distributionists), extending, however, as far west as Celebes and the Moluccas, although in these islands they form an insignificant minority among an extensive placental fauna, being represented only by the cuscuses (Phalanger), a group unknown in either Papua or Australia.
Carla had her first baby at 19 years old and suffered a placental abruption.
The sexy singer reportedly suffered from placental abruption, which can kill a fetus in just two hours.
Fetal: Maternal catecholamines secreted as a result of labor pain may cause fetal acidosis due to low placental blood flow 8.
catecholamines secreted as a result of labor pain may cause fetal acidosis due to low placental blood flow 8.
The imprinting phenotypes generally involve early embryonic, fetal or neonatal lethality, and alterations in fetal and placental growth (reviewed in Ref.
Barbiturates readily cross the placental barrier and are distributed throughout fetal tissues with highest concentrations in placenta, fetal liver and brain.
The placental mammals are a very diverse group with an enormous range of body forms and complex social interactions.
Marsupials and placental mammals marsupials and placental mammals Marsupials and placental mammals give birth to live young.
These data show that placental Igf2 regulates the development of the diffusional exchange characteristics of the mouse placenta.
This interface, consisting of the maternal decidua and the invading placental trophoblast, is exposed to profound changes in oxygen tension during pregnancy.
trophoblast inclusions by performing microscopic examinations of placental tissues.
villusmaternal blood circulating around the placental villi is shown in red.
3, thus bringing it in accord, so far as these teeth are concerned, with the placental formula, and making the single pair of replacing teeth the third premolars.
It may be added that the formula given above shows that the marsupial dentition may comprise more teeth than the 44 which form the normal full placental complement.
A placental perfusion map for a patient with intrauterine growth restriction 3-d rendering of a fetal liver.
Kliman and the team identified trophoblast inclusions by performing microscopic examinations of placental tissues.
The maternal blood circulating around the placental villi is shown in red.
If you're pregnant or nursing, avoid goldenseal, since it is unknown whether it crosses the placental barrier or is excreted in breast milk.
Women who smoke are much more likely to face serious pregnancy complications such as placenta previa and placental abruption.
Amniotic fluid-The liquid in the amniotic sac that cushions the fetus and regulates temperature in the placental environment.
Placental abruption: The placenta separates from the uterine wall before the baby is born.
The risk of placental abruption is higher in multiple births and in women with high blood pressure.
Placental abruption-An abnormal separation of the placenta from the uterus before the birth of the baby, with subsequent heavy uterine bleeding.
Structural abnormalities of the placenta, premature detachment of the placenta from the uterine wall (abruption), and placental infections (chorioamnionitis) are thought to pose some risk for CP.
Following detailed ultrasound, a thin fetoscope is inserted through the mother's abdominal and uterine walls and into the amniotic cavity of the recipient twin to examine the surface placental vessels.
Biochemical tests on hormone levels of estriol and human placental lactogen provide minimal information.
Placental infarction-An area of dead tissue in the placenta that is due to an obstruction of circulation in the area.
If the uterus is not relaxing or if the resting tone is rising, this can be an indication of a placental abruption (the tearing away of the placenta from the wall of the uterus).
Because CMV can cross the placental barrier, initial infection in a pregnant woman can lead to infection of the developing baby.
In other cases, transmission may occur during pregnancy, if the infectious agent can cross the placental barrier, and it may occur during breastfeeding, if the infectious agent can be found in breast milk.
There are potential complications from an amniocentesis, i.e., preterm labor, spontaneous rupture of membranes, fetal or placental injury; and the clinician performing the procedure should explain what these are prior to the procedure.
These antibodies cross the placental barrier, but not all types are transmitted equally.
After 42 weeks, the risk of placental malfunction increases dramatically.
Reasons for during pregnancy spotting include implantation bleeding, miscarriage, an ectopic pregnancy, various infections, sexual intercourse, placental problems, preterm labor, and actual labor.
During pregnancy spotting may be also be sign of a placental problem such as placenta previa (when the placenta covers the cervix) or a placental abruption (when the placenta disenganges prematurely).
When the babies are sharing the same placental membrane, there may be increased risk of the cords wrapping around one or the other infant.
Placental abruption is more likely in triplet pregnancies than in single gestations.
According to one theory, these rudimentary teeth, together with the one pair of functional teeth in each jaw that has vertical successors, represent the milk-teeth of placental mammals.
The comparatively few indigenous placental mammals, besides the dingo or wild dog - which, however, may have come from the islands north of this continent - are of the bat tribe and of the rodent or rat tribe.
UNGULATA, the name of an order of placental mammals in which the terminal joints of the toes are usually encased in solid hoofs or covered with broad hoof-like nails, while the molar (and not unfrequently some or all of the premolar) teeth have broad tuberculated crowns adapted for crushing vegetable substances.
Thus Huxley, with true prophetic instinct, found that the sum of primitive characters of all the higher placental mammals points to a stem form of a generalized insectivore type, a prophecy which has been fully confirmed by the latest research.
Successive discoveries have revealed certain grand centres, such as (1) the marsupial radiation of Australia, (2) the littleknown Cretaceous radiation of placental mammals in the northern hemisphere, which was probably connected in part with the peopling of South America, (3) the Tertiary placental radiation in the northern hemisphere, partly connected with Africa, (4) the main Tertiary radiation in South America.
RODENTIA, or Glires, an order of placental mammals characterized by the peculiar form and structure of their front or incisor teeth, which are reduced to a single functional chisellike pair in each jaw, specially adapted for gnawing, and growing throughout the entire life of their owners.
Rodents may be characterized as terrestrial, or in some cases arboreal or aquatic, placental mammals of small or medium size, with a milk and a permanent series of teeth, plantigrade or partially plantigrade, and generally five-toed, clawed (rarely nailed or semi hoofed) feet, clavicles or collar-bones (occasionally imperfect or rudimentary), no canine teeth, and a single pair of lower incisors, opposed by only one similar and functional pair in the upper jaw.
The main point of interest connected with the dingo relates to its origin; that is to say, whether it is a member of the indigenous Australian fauna (among which it is the only large placental mammal), or whether it has been introduced into the country by man.
It is urged that the imperfect placenta of the bandicoots instead of being vestigial, may be an instance of parallelism, and that in marsupials generally the allantois failed to form a placental connexion.
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