chapter23 - pregnancy and development

Copyright © 2012 F.A. Davis Company

Understanding Anatomy & PhysiologyUnderstanding Anatomy & PhysiologyA Visual, Interactive ApproachA Visual, Interactive Approach

Chapter 23

Pregnancy and Pregnancy and Human DevelopmentHuman Development



FertilizationFertilization



How long can sperm remain viable within the female reproductive tract?A. As long as 72 hoursB. As long as 6 daysC. 24 hoursD. 14 hours



Correct answer: B

Rationale:The egg is viable for 24 hours, and it takes 72 hours for the egg to reach the uterus.



GestationGestation Ranges from conception until birth

(266 days) Divided into trimesters:

First trimesterFirst trimester: First 12 weeks Second trimesterSecond trimester: Weeks 13 through 24 Third trimesterThird trimester: Week 25 until birth



Prenatal developmentPrenatal development Preembryonic stagePreembryonic stage: First 16 days Embryonic stageEmbryonic stage: Third until eighth

week Fetal stageFetal stage: Eighth week until birth



Preembryonic stagePreembryonic stage

View animation on fertilization and implantation



ImplantationImplantation



The product of conception is at which stage when it implants in the uterus?A. EmbryoB. ZygoteC. MorulaD. Blastocyst



Correct answer: D

Rationale:The product of conception is known as an embryo from the third until the eighth week, a zygote at the time of fertilization, and a morula when it first enters the uterine cavity.



Embryonic stageEmbryonic stage

Yolk sac

Allantois

Amnion

Chorion



Placenta and umbilical cordPlacenta and umbilical cordLacunae



Function of the placentaFunction of the placenta

Fetal waste

Oxygen, nutrients, & antibodies



Fetal Fetal circulationcirculation

View animation on fetal circulation



What is the function of the foramen ovale?A. Divert blood from the right to the left atrium B. Divert blood from the umbilical vein to the inferior vena cavaC. Divert blood from the pulmonary artery to the descending aorta D. Shunt blood from the umbilical artery to the umbilical vein



Correct answer: A.

Rationale:The ductus venosus diverts blood from the umbilical vein to the inferior vena cava to bypass the liver. The ductus arteriosus diverts blood from the pulmonary artery to the descending aorta to bypass the lungs. There is no shunt from the umbilical artery to the umbilical vein.



Fetal developmentFetal development

4 weeks



8 weeks



12 weeks



20 weeks



36 weeks



When is the fetus capable of gas exchange?

A.16 weeks gestationB.36 weeks gestationC.28 weeks gestationD.22 weeks gestation



Correct answer: C

Rationale:Although the respiratory system is immature at this stage, it is capable of gas exchange.



Physical changes with Physical changes with pregnancypregnancy

Nausea and vomiting Constipation Heartburn ↑ basal metabolic rate

Digestive Digestive systemsystem




↑ maternal blood volume ↑ cardiac output Hemorrhoids, varicose veins, foot

swelling

Circulatory Circulatory systemsystem




↑ ventilation Shortness of breath

Respiratory Respiratory systemsystem




Salt and water retention ↑ urine output Frequent urination (later in

pregnancy)

Urinary systemUrinary system




Skin stretches over abdomen and breasts

Uterus enlarges dramatically

Integumentary system & uterusIntegumentary system & uterus



Why does maternal cardiac output increase by 30% to 40% by the 27th week?

A.Because the fetus needs bloodB.Because of the demands of the uterusC.Because of the demands of the placentaD.Because the fetus needs more oxygen



Correct answer: B

Rationale:As the uterus expands, it demands a greater blood supply.



ChildbirthChildbirth Probable triggers:

Decline in progesterone Release of oxytocin Uterine stretching



Stage 1: Dilation of cervixStage 1: Dilation of cervix



Stage 2: Expulsion of babyStage 2: Expulsion of baby



Stage 3: Delivery of Stage 3: Delivery of placentaplacenta



LactationLactation

Progesterone stimulates development of acini

Estrogen stimulates growth of ducts



Anterior pituitary →Prolactin→ Milk production

Posterior pituitary→ Oxytocin →Milk secretion



Which hormone is responsible for the production of milk in the mammary glands?A. EstrogenB. OxytocinC. ProlactinD. Progesterone



Correct answer: C

Rationale:Estrogen stimulates the growth of ducts throughout the mammary glands. Progesterone stimulates the development of acini at the ends of the ducts. Oxytocin is responsible for the secretion of milk.

chapter23 - pregnancy and development

Health & Medicine

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