Three types of pregnancies are found in mammals, which correspond embryo or fetus grows within the uterus of the mother.
When rians, eutherians, and metathe cally are included, it is considered to begin not at fertilization but when they are pregnant.
The embryo is in the uterus.
The platypus is the only mammal that can lay fertilized days of fertilization in animals that have short lifespans.
The young are born in large animals and take weeks to mature.
Maternal length varies widely and is related to her pouch, where they attach to a nipple to suckle and obtain nour to the size of adults in a particular species.
There are small animals within the pouch.
Humans and other eutherian mammals have a longer period of time in the uterus and can give birth to more than one child at a time.
The embryo and the mother are more developed at birth.
Maternal and fetal tissues make up the placenta in mammals.
The relationship between fetal and maternal structures can be seen in theEnlarged view of the placenta.
Fetal and maternal blood does not mix in humans.
The direction of blood flow is indicated by the black and white arrows.
The blue and red colors of the arteries signify that they carry deoxygenated blood, and the vein is red to signify that it carries oxygenated blood.
Normally, arteries and veins carry oxygenated blood, but they don't carry deoxygenated blood in the pulmonary circulation.
There is a maternal portion and a fetal portion.
The mother's blood vessels are rich in blood vessels from the fetus.
The maternal and fetal vessels are close together.
A lower P indicates a higher affinity of hemoglobin for oxygen.
The values are for humans.
From the maternal blood comes suites that diffuse into fetal capillaries and then into the fetal vein.
Carbon genes are only expressed during certain stages of embryonic dioxide and other waste products from the fetus are carried through development.
The oxygen er's circulation is important in mammals because they excrete it in the placenta.
Fetal and maternal blood do not mix because of the different demands of the embryo and fetus.
The differential expression of hemoglobin genes during the third and fourth trimesters of fetal development in humans lasts about 3 months.
The major subunits in hemoglobin are found in the second trimester.
When the fetus makes the transition to breathing air, the e-globin and Z-globin genes are turned on.
The higher affinities of embryonic and fetal hemo globins allow the embryo and fetus to remove oxygen from the bloodstream and use it to create gene families.
Families with genes have had their own demands.
The evolution of different important in the evolution of complex traits because the vari globin genes each of which is expressed at particular stages of members of a gene family enable the expression of complex, of development enables placental mammals to develop in the specialized forms and functions.
The uterus is not breathing on its own or being exposed to the globin gene family in animals.
Oxygen is delivered to all of the body's cells by Hemoglobin, which is present in erythrocytes.
Hor tend to have specialized functions at the end of pregnancies.
Estradiol enters the maternal circulation when certain globin mones from the fetus are stimulated.
The mother's hypothalamus sends stimulatory signals to the stretch sensitive sensory neurons that the fetus' head pushes against.
The sensory nerves are stimulated by the hypothalamus.
Stronger uterus contractions can be stimulated by the drug roxtocin.
Prostaglandins are produced by the uterus.
Sensory input to the hypothalamus continues to be enhanced by stronger contractions.
Neural signals from the uterus and maternal hormones are used in birth.
In response to the push of the fetus on the cervix, the maternal posterior pituitary releases oxytocin into the blood, which stimulates uterine smooth muscle contraction.
The uterus makes prostaglandins that increase the strength of the contractions.
A positive feedback loop is formed when the uterus senses the more powerful contractions and signals the mother's pituitary to produce more oxytocin.
There are at least two major effects on the uterus.
The smooth muscle cells in the cervix allow coordinated uterine contractions.
Estradiol increases uterine sensitivity to the hormone oxytocin.
In Chapter 50 there is a reference to the stimulation of the contraction of the uterus.
The uterus is more sensitive to oxytocin when estradiol is high in the mother's blood near the end of pregnancy.
The cervix is umbilical.
The stretch is detected by the cells in the struc delivered.
The release of oxytocin into the blood is triggered by signals from the stretch-sensitive neurons.
There is a positive feedback loop until the baby is born.
Female mammals eat the placenta after it passes out of the uterus.