Principles of Anatomy and Physiology Thirteenth Edition Chapter 29 Development and Inheritance Copyright © 2012 by John Wiley & Sons, Inc. Gerard J. Tortora Bryan H. Derrickson

Sperm cell First polar body PATH OF SPERM CELL: Corona radiata Zona pellucida Plasma membrane of secondary oocyte Cytoplasm of secondary oocyte (a) Sperm cell penetrating secondary oocyte

1100x SEM Head of sperm cell Secondary oocyte (b) Sperm cell in contact with secondary oocyte

Pronuclei 250x LM (c) Male and female pronuclei

Polar bodies Blastomeres Zona pellucida Nucleus Cytoplasm (a) Cleavage of zygote, two- cell stage (day 1) (b) Cleavage, four-cell stage (day 2) (c) Morula (day 4) (d) Blastocyst, external view (day 5) (e) Blastocyst, internal view (day 5) Embryoblast (inner cell mass) Blastocyst cavity Trophoblast

Opening of endometrial gland Endometrium of uterus Blastocyst Uterine cavity (a) External view of blastocyst, about 6 days after fertilization

Frontal plane Frontal section through uterus Uterine cavity

Endometrial gland Opening of endometrial gland Trophoblast Embryoblast (inner cell mass) Blastocyst cavity Endometrium of uterus Blood vessels (b) Frontal section through endometrium of uterus and blastocyst, about 6 days after fertilization

Decidua capsularis Decidua parietalis Frontal section of uterusDetails of decidua Decidua basalis

Frontal plane 1. Fertilization (occurs within uterine tube 12–24 hours after ovulation) 2. Cleavage (first cleavage completed about 30 hours after fertilization) 3. Morula (3–4 days after fertilization) 4. Blastocyst (4 1 / 2 –5 days after fertilization) Uterine cavity 5. Implantation (occurs about 6 days after fertilization) Uterus Endometrium Myometrium Ovulation Ovary Frontal section through uterus, uterine tube, and ovary

Cytotrophoblast (a) Frontal section through endometrium of uterus showing blastocyst, about 8 days after fertilization Syncytiotrophoblast Amnion Amniotic cavity Blood vessel Endometrium of uterus Endometrial gland Formation of exocoelomic membrane Bilaminar embryonic disc: Hypoblast Epiblast Blastocyst cavity Uterine cavity

(b) Frontal section through endometrium of uterus showing blastocyst, about 9 days after fertilization Exocoelomic membrane Yolk sac Hypoblast Epiblast Bilaminar embryonic disc: Amniotic cavity Lacunae Blood vessels Syncytiotrophoblast Cytotrophoblast Endometrium of uterus Uterine cavity

(c) Frontal section through endometrium of uterus showing blastocyst, about 12 days after fertilization Maternal sinusoids Chorion: Extraembryonic mesoderm Syncytiotrophoblast Cytotrophoblast Amnion Amniotic cavity Bilaminar embryonic disc: Lacunae Yolk sac Lacunar network Uterine cavity Epiblast Endometrium of uterus Hypoblast Endometrial gland (right) and sinusoid (left) emptying into lacunar network

Uterine cavity Cytotrophoblast Bilaminar embryonic disc: Yolk sac Connecting stalk Epiblast Hypoblast Extraembryonic mesoderm Amnion Amniotic cavity

Dorsal surface of bilaminar embryonic disc Oropharyngeal membrane (future site of mouth) Yolk sac HEAD END Primitive node Amnion Primitive streak Connecting stalk Bilaminar embryonic disc: Epiblast Hypoblast Transverse plane (a) Dorsal and partial sectional views of embryonic disc, about 15 days after fertilization TAIL END

Primitive streak (b) Transverse section of trilaminar embryonic disc, about 16 days after fertilization Oropharyngeal membrane Trilaminar embryonic disc: Ectoderm Mesoderm Endoderm Yolk sac

(a) Dorsal and partial sectional views of trilaminar embryonic disc, about 16 days after fertilization Yolk sac Trilaminar embryonic disc Cloacal membrane Connecting stalk TAIL END Primitive streakPrimitive node Neural plate Notochordal process (outlined beneath ectoderm) HEAD END Oropharyngeal membrane

(b) Sagittal section of trilaminar embryonic disc, about 16 days after fertilization Allantois Connecting stalk Cloacal membrane Mesoderm Notochordal process TAIL END HEAD END Oropharyngeal membrane Neural plate Yolk sac Amniotic cavity

Neural plate TAIL END HEAD END Transverse plane Cut edge of amnion Primitive streak Amnion Mesoderm Endoderm Ectoderm Neural plate Amniotic cavity Yolk sac Notochord (a) 17 days Dorsal viewTransverse section

Neural plate Primitive streak (b) 19 days Primitive node Neural fold Neural groove Paraxial mesoderm Neural fold Lateral plate mesoderm Intermediate mesoderm Neural groove Dorsal viewTransverse section

Neural plate Primitive streak Neural fold Neural groove Neural fold Neural groove (c) 20 days Somite Endoderm Amnion Somite Dorsal viewTransverse section

Neural fold (d) 22 days Somite Neural crest cells Neural tube Lateral plate mesoderm: Somatic mesoderm Splanchnic mesoderm Endoderm Dermatome Myotome Sclerotome Intermediate mesoderm Intraembryonic coelom Extraembryonic coelom Somite Dorsal viewTransverse section

(a) Frontal section through uterus showing blastocyst, about 13 days after fertilization Lacunae Extraembryonic mesoderm Chorion: Syncytiotrophoblast Cytotrophoblast Chorionic villi Connecting stalk Amniotic cavity Maternal sinusoid Yolk sac Extraembryonic coelom

(b) Details of two chorionic villi, about 21 days after fertilization Maternal sinusoid Chorion: Cytotrophoblast Syncytiotrophoblast Connecting stalk Extraembryonic mesoderm Blood capillary Intervillous space

(c) Frontal section through uterus showing embryo and vascular supply, about 21 days after fertilization Maternal sinusoid Extraembryonic mesoderm Umbilical vein Umbilical arteries Intervillous space Connecting stalk Chorionic villus Maternal sinusoid Amniotic cavity Embryo Yolk sac

Chorionic villiYolk sac Amniotic fluid in amniotic cavity Allantois Umbilical cord Amnion Chorion

(a) Details of placenta and umbilical cord Amnion Mucous connective tissue Umbilical vein Umbilical arteries Umbilical cord: Intervillous space containing maternal blood Maternal endometrial arteriole Fetal blood vessels Chorionic villi Maternal endometrial venule Decidua basalis of uterus (maternal portion of placenta) Chorionic villi of chorion (fetal portion of placenta)

(b) Fetal surface of placenta Umbilical cord Amnion covering fetal surface of placenta Umbilical arteries Umbilical veins

(a) 22 days Neural tube Notochord Intraembryonic coelom Amniotic cavity Yolk sac Amniotic cavity Yolk sac Notochord Connecting stalk Cloacal membrane TAIL END Neural tube HEAD END Oropharyngeal membrane Sagittal sectionTransverse section

(b) 24 days Lateral folds Heart Primitive gut Yolk sac Sagittal sectionTransverse section

(c) 26 days Midgut Intraembryonic coelom Lateral folds Yolk sac Hindgut Proctodeum Tail fold Foregut Stomodeum Head fold Midgut Yolk sac Sagittal sectionTransverse section

(d) 28 days Aorta Dorsal mesentery Midgut Ventral mesentery Abdominal wall Amniotic cavity Cloacal membrane Proctodeum Future pharynx Oropharyngeal membrane Stomodeum Future umbilical cord Sagittal sectionTransverse section

Otic placode Somite Pharyngeal clefts Pharyngeal (branchial) arches Lens placode Heart prominence 4 4 (a) External view, about 28-day embryo

Pharyngeal (branchial) pouches Esophagus Lung bud Pharyngeal (branchial) arches Brain Thyroid diverticulum Hypophyseal (Rathke’s) pouch Stomodeum Heart (b) Sagittal section, about 28-day embryo

Cartilages (c) Transverse section of the pharynx, about 28-day embryo Nerve Muscle 1st pharyngeal arch 2nd pharyngeal arch 2nd pharyngeal pouch 3rd pharyngeal arch artery 3rd pharyngeal pouch

(weeks)

Neural plate (a) 20-day embryo Neural groove Cut edge of amnion Somite Yolk sac Primitive streak

Developing brain (b) 24-day embryo Heart prominence Developing spinal cord Somite

Pharyngeal arches (c) 32-day embryo Lens placode Heart prominence Upper limb bud Tail Lower limb bud

Otic placode (d) 44-day embryo Developing nose Upper limb Lower limb Umbilical cord

Ear (e) 52-day embryo Eye Nose Upper limb Umbilical cord Lower limb

Ear (f) 10-week fetus Eye Nose Upper limb Yolk sac Rib Umbilical cord Placenta Lower limb

(g) 13-week fetus Ear Eye Nose Upper limb Mouth Umbilical cord Lower limb

(h) 26-week fetus Ear Eye Nose Upper limb Mouth Lower limb

Needle Ultrasound transducer Amnion Amniotic fluid Uterus Fetus (14–16 weeks) Placenta (a) Amniocentesis

Ultrasound transducer Needle Catheter Urinary bladder Vagina Fetus (8–10 weeks) Amniotic fluid Uterine cavity Chorionic villi (b) Chorionic villi sampling (CVS)

Human chorionic gonadotropin (hCG) Relaxin Human chorionic somatomammotropin (hCS) Corticotropin-releasing hormone Rescues corpus luteum from degeneration until the 3rd or 4th month of pregnancy Corpus luteum (in ovary) Progesterone Estrogens 1.Maintain endometrium of uterus during pregnancy 2.Help prepare mammary glands for lactation 3.Prepare mother’s body for birth of baby 1.Increases flexibility of pubic symphysis 2.Helps dilate uterine cervix during labor 1.Helps prepare mammary glands for lactation 2.Enhances growth by increasing protein synthesis 3.Decreases glucose use and increases fatty acid use for ATP production 1.Establishes the timing of birth 2.Increases secretion of cortisol Placenta (a) Sources and functions of hormones

Human chorionic gonadotropin (hCG) Estrogens Progesterone Age of embryo/fetus (weeks) FertilizationBirth (b) Blood levels of hormones during pregnancy Blood levels

Left lung Heart Left breast Stomach Small intestine Left ovary Left uterine (fallopian) tube Head of fetus Inguinal ligament Urinary bladder Pubic symphysis Umbilical cord Right ovary Right uterine (fallopian) tube Maternal umbilicus Ascending colon Uterine wall Small intestine Greater omentum Liver Gallbladder Right breast Right lung Round ligament of uterus Descending colon Anterior view of position of organs at end of full-term pregnancy

Stage of dilation Urinary bladder Vagina Ruptured amniotic sac Rectum 1

Stage of expulsion Placenta 2

Placental stage Placenta Uterus Umbilical cord 3

Suckling of baby on nipple causes Touch sensations Receptors Touch-sensitive sensory neurons in nipple Control center Hypothalamus and posterior pituitary Effectors Contraction of myoepithelial cells in mammary glands Milk ejection Interruption of cycle: Baby ceases to suckle, thus breaking the positive feedback cycle Positive feedback: milk availability encourages continued suckling, so touch sensations on nipple and oxytocin release continue Increasing Nerve impulses Increased oxytocin in blood Output Input

Homologous chromosomes of heterozygous father Homologous chromosomes of heterozygous mother PpPp PP P P pp p p PP Pp pp Meiosis Possible ova types Possible sperm types Possible genotypes of zygotes (in boxes) Punnett square 1PP2Pp1pp Homozygous dominant Heterozygous dominant Homozygous recessive Possible genotypes of offspring Possible phenotypes of offspring 1PP2Pp1pp Do not have PKUHas PKU

Possible genotypes of zygotes (in boxes) Meiosis Possible ova types Possible sperm types Hb A Punnett square Hb A Hb S Hb S Hb A Hb S Hb A Hb S Hb A Hb S Hb A Hb S Hb A Hb A Hb A = normal Hb A Hb S = carrier of sickle-cell disease Hb S Hb S = has sickle-cell disease

A A BA ABA OB B ABB OAB AB OO Parents Offspring A, OA, B, AB, OA, B, ABA, OB, O A, B, ABB, OA, B, ABA, BO

P generation F 1 generation offspring Possible ova Possible sperm Possible F 2 generation offspring AABBCC (very dark) aabbcc (very light) AaBbCc (intermediate) AaBbCc (intermediate)

XY

Possible sex chromosomes of zygotes (in boxes) Meiosis Possible ova types Possible sperm types Punnett square XX Sex chromosomes of mother XY Sex chromosomes of father X XX Y Y X XX XX XY 2 XX2 XYPossible gender of offspring FemalesMales

Possible genotypes of zygotes (in boxes) Meiosis Possible ova types Possible sperm types Punnett square X C X c Normal female who carries recessive gene X C Y Normal male XCXC Y Y XCXC XCXC XcXc XCXCXCXC XCXcXCXc XCYXCYXcYXcY Possible phenotypes of offspring Normal female XCXC XcXc XCXCXCXC XCXcXCXc XCYXCYXcYXcY Normal female (carrier) Normal male Color-blind male