Rotunda midwifery for nurses and midwives / by G.T. Wrench.

  • Guy T. Wrench
Date:
1908
Catalogue details

Licence: In copyright

Credit: Rotunda midwifery for nurses and midwives / by G.T. Wrench. Source: Wellcome Collection.

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    GROWTH OF THE OVUM The ovum is now fertilized; it is capable of growing under favourable conditions from the size of a pin’s point to form the full-term baby arid the afterbirth. The Length of Pregnancy.—From conception to child- birth is on average 280 days or forty weeks or ten lunar- months. Nourishment and Excretion of the Ovum.—We next have to consider the way the ovum receives food during its growth, and the way in which it gets rid of the waste products of its life. The Decidua.—The uterus is hned with a membrane called a mucous membrane, which is hke the membrane that lines the mouth, nose and other cavities. This membrane becomes thicker and more spongy when the woman is pregnant. It is then called the decidua. The ovum, when fertilized, becomes buried in the decidua as is shown at 5 in the diagram on p. 6. It is actually buried in the decidua and covered over by it, as a seed is buried in the soil. The decidua are so called from the Latin deciduus, meaning falling, not lasting through the year. The Chorion (Greek cliorein, to contain).—The next question to answer is how is the ovum to get food from the decidua and get rid of waste products 1 This it does by means of the chorion. The fertihzed egg grows rapidly and divides into many different cells. Two membranes are formed which sur- round the foetus {fcetus—Latin fruit) and enclose the waters. The outer one is called the chorion, the inner the amnion. The chorion then being the outer layer lies next to the spongy decidua. From it grow little soft branching filaments, the chorionic villi {villus—Latin for a shaggy hair), which burrow into the decidua like little roots. In each villus are blood-vessels, and the blood-vessels of the villus come into close contact with the blood that makes the decidua spongy. Some of you may know what water culture of plants is. You take a young plant and let its rootlets dip into
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