211 Components Of Fetal Circulation
As the placenta acts as the intermediary organ of transfer between the mother and fetus, fetal circulation differs from that required for extrauterine existence. The fetus receives oxygen through the placenta because the lungs do not function as organs of respiration in the uterus. To meet this situation, the fetal circulation contains certain special vessels that shunt the blood around the lungs, with only a small amount circulating through them for nutrition. See figure 2-9. The following...
212 Changes Continue In Circulation After Birth
Figure 2-10. Fetal circulation after birth. Figure 2-10. Fetal circulation after birth. a. The umbilical vein is obliterated and becomes the round ligament of the liver. b. The umbilical arteries are obliterated and ultimately become ligaments. c. The ductus venosus is obliterated and becomes a ligament. Anatomic closure is completed at the end of 2 months. The ductus venosus is superficially embedded in the wall of the liver. d. The ductus arteriosus is obliterated and becomes a ligament....
27 Fetal Membranes
Two closely applied but separate membranes line the uterine cavity and surround the developing embryo-fetus. Both membranes, the amnion inner membrane and the chorion outer membrane , arise from the zygote. As the chorion develops, it blends with the fetal portion of the placenta the amnion blends with the fetal umbilical cord. These deceptively strong, translucent membranes contain not only the fetus but also the amniotic fluid, and they are continuous with the margins of the placenta. See...
19 General
a. The male reproductive tract consists of external genitals and internal organs. These organs are located in the pelvic cavity see figure 1-8 . The male's reproductive system begins to develop in response to testosterone during early fetal life. Essentially no testosterone is produced during childhood. Resumption of testosterone production at the onset of puberty stimulates growth and maturation of the male's reproductive structures and secondary sex characteristics. Testosterone is the male...
22 Principles Of Fertilization Conception
a. Fertilization refers to the joining together of the ovum egg and sperm cells. The ovum originates in the graafian follicle within the ovary. The sperm cell originates in the testes. The microscopic union of sperm and ovum increase in size more than 20 billion times from conception to birth. See figure 2-2 for union of sperm and ovum. b. During sexual intercourse, 2 to 5 ml of semen, usually containing more than 300 million sperm, is ejaculated into the female's vagina. By flagellar wiggly...
26 Functions Of The Placenta
Being knowledgeable of the placenta functions gives insight into prenatal life and is helpful in providing nursing care to the unborn and the newborn. The placenta functions as a transport mechanism between the embryo and the mother see figure 2-6 . The placenta has many tasks it transports oxygen, nutrients, and antibodies to the fetus by means of the umbilical vein removes carbon dioxide and metabolic wastes from the fetus by the two umbilical arteries serves as a protective barrier against...
24 Sex Determination
Chromosomes are small, threadlike structures within each cell that contain genes, which carry genetic instructions. These genes control the physical and chemical traits inherited by children from their parents. The inherited traits are color of the eyes, sex, height, and skin color. a. The female has 23 pairs of chromosomes. The pair of chromosomes that determined her sex are named XX. The ovum carries one chromosome from each of the female's pairs 23 chromosomes . The ovum can only carry an X...
23 Process Of Implantation
a. The morula floats in the uterus for 3 to 4 days, gaining in size and weight. At this time, the hollow fluid-filled morula, now called blastocyst burrows into the uterine lining. b. The outer surface of the blastocyst becomes covered with finger-like projections called chorionic villi. Chorionic villi aid in the process of implantation into the endometrium decidua . Villi also manufacture human chorionic gonadotropin HCG which signal the corpus luteum within the ovaries to continue production...
c Fallopian Tubes Two
1 Location. Each tube is about 4 inches long and extends medially from each ovary to empty into the superior region of the uterus. 2 Function. The fallopian tubes transport ovum from the ovaries to the uterus. There is no contact of fallopian tubes with the ovaries. 3 Description. The distal end of each fallopian tube is expanded and has finger-like projections called fimbriae, which partially surround each ovary. When an oocyte is expelled from the ovary, fimbriae create fluid currents that...
16 Facts About The Menstrual Cycle
Menstruation is the periodic discharge of blood, mucus, and epithelial cells from the uterus. It usually occurs at monthly intervals throughout the reproductive period, except during pregnancy and lactation, when it is usually suppressed. a. The menstrual cycle is controlled by the cyclic activity of follicle stimulating hormone FSH and LH from the anterior pituitary and progesterone and estrogen from the ovaries. In other words, FSH acts upon the ovary to stimulate the maturation of a...
14 External Female Genitalia
The external organs of the female reproductive system include the mons pubis, labia majora, labia minora, vestibule, perineum, and the Bartholin's glands. As a group, these structures that surround the openings of the urethra and vagina compose the vulva, from the Latin word meaning covering. See Figure 1-6. Figure 1-6. External female genitalia. Figure 1-6. External female genitalia. a. Mons Pubis. This is the fatty rounded area overlying the symphysis pubis and covered with thick coarse hair....
12 Terms And Definitions
These are only a few terms and definitions that will be used in this lesson. Other terms and definitions will be dispersed throughout the lesson. a. Broad Ligaments. Two wing-like structures that extend from the lateral margins of the uterus to the pelvic walls and divide the pelvic cavity into an anterior and a posterior compartment. b. Corpus Luteum. The yellow mass found in the graafian follicle after the ovum has been expelled. c. Estrogen. The generic term for the female sex hormones. It...
Subcourse Md0921 Obstetric And Newborn Care I Introduction
Obstetrics is the branch of medicine concerned with the management of childbirth. The ultimate goal of all workers in the field of obstetrics is to assist a mother to produce a healthy baby, with a minimum of danger and discomfort to both. Pregnancy is defined as the condition of being with child. To understand pregnancy, we must know how it begins, how the fetus grows in the uterus, and how it affects the mother. Today, more than ever before nurses play a central role in the planning for and...