Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Memmler’s The Human Body in Health and Disease 11 th edition Chapter 24 Development and Birth
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins PregnancyPregnancy Gestation begins with fertilization and ends with delivery Approximately 38 weeks All fetal tissues differentiate from single fertilized egg
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Fertilization and the Start of Pregnancy Vagina receives semen Sperm dissolve egg cell coating, penetrate plasma membrane Sperm, egg combine in single cell (zygote) Zygote divides into cell cluster, moves to uterus Cluster becomes embryo
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The female reproductive system. Arrows show the pathway of the spermatozoa and ovum and also of the fertilization and implantation of the fertilized ovum. Zooming In: Where is the ovum fertilized?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-1: What structure is formed by the union of an ovum and a spermatozoon?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: What is the average length of human gestation? a. 28 weeks b. 38 weeks c. 42 weeks
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: b. 38 weeks
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Placenta Organ of nutrition, respiration, excretion for developing offspring Embryonic cluster forms villi (projections) Projections invade uterine wall, maternal blood channels (venous sinuses) Embryonic layer and uterine lining form placenta
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Umbilical Cord Connects embryo to placenta Carries blood to and from fetus Fetus has special circulatory features
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Fetal Circulation Circulatory adaptations to bypass non-functional lungs Umbilical vein from mother carries blood to liver Most blood added to deoxygenated blood in inferior vena cava via ductus venosus Foramen ovale in atrial septum bypasses rt ventricle and pulmonary circuit Ductus arteriosus connects pulmonary artery to descending aorta Two umbilical arteries return blood to placenta for oxygenation Adaptations close after birth of baby. Failure to close results in congenital defects
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Fetal circulation and section of placenta. Colors show relative oxygen content of blood. Zooming In: What is signified by the purple color in this illustration?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: In fetal circulation, a small hole in the fetal atrial septum allows blood to pass directly from the right atrium to the left, bypassing the right ventricle and pulmonary circuit. What is the name of that opening? a. foramen ovale b. ductus arteriosus c. ductus venosus
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: a. foramen ovale
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Placental Hormones Placenta is an endocrine organ Human chorionic gonadotropin (hCG) Progesterone Estrogen Human placental lactogen (hPL) or human chorionic somatomammotropin Relaxin
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-2: What organ nourishes the developing fetus? Checkpoint 24-3: What is the function of the umbilical cord? Checkpoint 24-4: Fetal circulation is adapted to bypass what organs?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Development of the Embryo Embryology is study of growth during first 8 weeks of life Nervous system begins to form Heart and blood vessels originate Limb buds form Human appearance
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-5: All body systems originate during the early development of the embryo. At what time in gestation does the heartbeat first appear?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Fetus Offspring from month 3 until birth Organs grow and mature Ovaries form Most rapid growth months four to six (second trimester) Can determine sex Amniotic sac Vernix caseosa
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-6: What is the name of the fluid-filled sac that holds the fetus?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: At what point does the embryo become a fetus? a. At the end of week 6 of life b. At the beginning of week 12 of life c. At the beginning of week 16 of life
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: b. At the beginning of week 12 of life
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Midsagittal section of a pregnant uterus with intact fetus. Zooming In: What structure connects the fetus to the placenta?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Mother Heart pumps more blood Lungs increase respiration Kidneys excrete waste from fetus and mother Digestive system supplies additional nutrients Nausea and vomiting common Urinary frequency and constipation common
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-7: What is the approximate duration of pregnancy in days?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Use of Ultrasound in Obstetrics Safe, painless, noninvasive method used to Diagnose pregnancy Judge fetal age Determine location of placenta Show presence of excess amniotic fluid and fetal abnormalities
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins ChildbirthChildbirth Factors that start labor Uterine muscle stretching stimulates prostaglandin production Pressure on cervix stimulates posterior pituitary to release oxytocin Placenta changes Fetal cortisol inhibits mother’s progesterone Increase of estrogen relative to progesterone
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Four Stages of Labor Parturition (labor and delivery) Onset of regular uterine contractions Cervix dilates, fetus passes to outside Afterbirth is expelled Bleeding is controlled
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-8: What is parturition?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: At what stage of labor is the fetus delivered from the mother? a. Second stage b. Third stage c. Fourth stage
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: a. Second stage
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Cesarean Section Incision made in abdominal wall and uterine wall for fetal delivery may be required for Placental abnormality Abnormal fetal position Disproportion between head of fetus and mother’s pelvis
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-9: What is a cesarean section?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Multiple Births Two types of twins Fraternal –Two different ova –Two placentas and surrounding sacs Identical –Single ovum –Embryonic cells separate into two units –Usually single placenta –Separate umbilical cords –Always same sex
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Termination of Pregnancy Live birth –Immature (premature) infant Abortion –Spontaneous (miscarriage) –Induced Fetal death Stillbirth
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Fetal Viability Fetus considered viable—able to live outside the uterus— at 20 weeks Apgar score –Used to assess newborns’ health, predict survival –5 features tested at 1 min and 5 min after delivery –Maximum score = 10
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-10: What does the term viable mean with reference to a fetus?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Mammary Glands and Lactation Mammary gland (breast) structure Lobes –Glandular tissue –Fat Lactiferous ducts Papilla (nipple) Lactation Placental lactogen (hPL) Prolactin (PRL) Colostrum Oxytocin Breast milk
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-11: What is lactation?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Disorders of Pregnancy, Childbirth and Lactation Ectopic pregnancy –Tubal ectopic pregnancy Placenta previa Abruptio placentae
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Pregnancy-Induced Hypertension Preeclampsia (toxemia of pregnancy) Caused by hormone imbalance May lead to eclampsia –Kidney failure –Convulsions –Coma
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-12: What is an ectopic pregnancy?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: What is the medical term for high blood pressure that arises in pregnancy? a. placenta previa b. hypoglycemia c. preeclampsia
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: c. preeclampsia (also known as pregnancy-induced hypertension [PIH] or toxemia of pregnancy)
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Postpartum Disorders Puerperal infections –Infections related to childbirth –Develops in about 6% of maternity patients Hydatidiform mole –Benign overgrowth of placental tissue –May invade wall of uterus, causing rupture Choriocarcinoma –Malignant tumor of placental tissue –Rare, spreads rapidly
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 24-13: What is puerperal infection?
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Lactation Disturbances Causes can vary Malnutrition or anemia Emotional disturbances Abnormalities in or injuries to mammary glands Mastitis (inflammation of breast) caused by infection
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins End of Presentation