Fetus

About: Fetus is a research topic. Over the lifetime, 21567 publications have been published within this topic receiving 646380 citations. The topic is also known as: foetus & fœtus.

Before We Are Born: Essentials of Embryology and Birth Defects

Abstract: 1 - Introduction to Human Development Importance of and Advances in Embryology Descriptive Terms Clinically Oriented Questions 2 - Human Reproduction Reproductive Organs Female Reproductive Organs Male Reproductive Organs Gametogenesis Meiosis Spermatogenesis Oogenesis Comparison of Male and Female Gametes Female Reproductive Cycles Ovarian Cycle Menstrual Cycle Transportation of Gametes Oocyte Transport Sperm Transport Maturation of Sperms Viability of Oocytes and Sperms Clinically Oriented Questions 3 - First Week of Human Development Fertilization Phases of Fertilization Results of Fertilization Cleavage of Zygote Formation of Blastocyst Clinically Oriented Questions 4 - Second Week of Human Development Formation of Amniotic Cavity, Embryonic Disc, and Umbilical Vesicle Development of Chorionic Sac Implantation Sites of Blastocytes Clinically Oriented Questions 5 - Third Week of Human Development Gastrulation: Formation of Germ Layers Primitive Streak Notochordal Process and Notochord Neurulation: Formation of the Neural Tube Neural Plate and Neural Tube Neural Crest Formation Development of Somites Development of Intraembryonic Coelom Early Development of Cardiovascular System Vasculogenesis and Angiogenesis Development of Chorionic Villi Clinically Oriented Questions 6 - Fourth to Eighth Weeks of Human Development Folding of Embryo Head and Tail Folds Lateral Folds Germ Layer Derivatives Control of Embryonic Development Estimation of Embryonic Age Highlights of the Fourth to Eighth Weeks Fourth Week Fifth Week Sixth Week Seventh Week Eighth Week Clinically Oriented Questions 7 - Fetal Period: The Ninth Week to Birth Highlights of Fetal Period Nine to Twelve Weeks Thirteen to Sixteen Weeks Seventeen to Twenty Weeks Twenty-One to Twenty-Five Weeks Twenty-Six to Twenty-Nine Weeks Thirty to Thirty-Eight Weeks Expected Date of Delivery Factors Influencing Fetal Growth Procedures for Assessing Fetal Status Ultrasonography Diagnostic Amniocentesis Chorionic Villus Sampling Cell Cultures Percutaneous Umbilical Cord Blood Sampling Magnetic Resonance Imaging Fetal Monitoring Alpha-Fetoprotein Assay Noninvasive Prenatal Diagnosis Neonatal Period Clinically Oriented Questions 8 - Placenta and Fetal Membranes Placenta Decidua Development of Placenta Fetomaternal Junction Intervillous Space Amniochorionic Membrane Placental Circulation Parturition Stages of Labor Placenta and Fetal membranes after Birth Umbilical Cord Amnion and Amniotic Fluid Significance of Amniotic Fluid Umbilical Vesicle Significance of Umbilical Vesicle Allantois Multiple Pregnancies Twins and Fetal Membranes Other Types of Multiple Births Clinically Oriented Questions 9 - Body Cavities, Mesenteries, and Diaphragm Embryonic Body Cavity Mesenteries Division of Embryonic Body Cavity Development of Diaphragm Septum Transversum Pleuroperitoneal Membranes Dorsal Mesentery of Esophagus Muscular Ingrowth from Lateral Body Walls Positional Changes and Innervation of the Diaphragm Clinically Oriented Questions 10 - Pharyngeal Apparatus, Face, and Neck Pharyngeal Arches Pharyngeal Arch Components Pharyngeal Pouches Derivatives of Pharyngeal Pouches Pharyngeal Grooves Pharyngeal Membranes Development of Thyroid Gland Development of Tongue Lingual Papillae and Taste Buds Nerve Supply of Tongue Development of Salivary Glands Development of Face Development of Nasal Cavities Paranasal Sinuses Development of Palate Primary Palate Secondary Palate Clinically Oriented Questions 11 - Respiratory System Development of Larynx Development of Trachea Development of Bronchi and Lungs Maturation of Lungs Clinically Oriented Questions 12 - Alimentary System Foregut Development of Esophagus Development of Stomach Development of Duodenum Development of Liver and Biliary Apparatus Development of Pancreas Development of Spleen Midgut Rotation of Midgut Loop Cecum and Appendix Hindgut Cloaca Anal Canal Clinically Oriented Questions 13 - Urogenital System Development of Urinary System Development of Kidneys and Ureters Positional Changes of Kidneys Changes in Blood Supply of Kidneys Development of Urinary Bladder Development of Urethra Development of Suprarenal Glands Development of Genital System Development of Gonads Development of Genital Ducts Development of External Genitalia Development of Inguinal Canals Relocation of Testes and Ovaries Descent of Testes Descent of Ovaries Clinically Oriented Questions 14 - Cardiovascular System Early Development of Heart and Blood Vessels Development of Veins Associated with Embryonic Heart Pharyngeal Arch Arteries and Other Branches of the Dorsal Aorta Fate of Vitelline and Umbilical Arteries Later Development of Heart Circulation through Primordial Heart Partitioning of Primordial Heart Changes in Sinus Venosus Primordial Pulmonary Vein and Formation of Left Atrium Partitioning of Primordial Ventricle Partitioning of Bulbus Cordis and Truncus Arteriosus Development of Cardiac Valves Conducting System of Heart Birth Defects of Heart and Great Vessels Derivatives of Pharyngeal Arch Arteries Derivatives of First Pair of Pharyngeal Arch Arteries Derivatives of Second Pair of Pharyngeal Arch Arteries Derivatives of Third Pair of Pharyngeal Arch Arteries Derivatives of Fourth Pair of Pharyngeal Arch Arteries Fate of Fifth Pair of Pharyngeal Arch Arteries Derivatives of Sixth Pair of Pharyngeal Arch Arteries Pharyngeal Arch Arterial Birth Defects Fetal and Neonatal Circulation Fetal Circulation Transitional Neonatal Circulation Derivatives of Fetal Vessels and Structures Development of the Lymphatic System Development of Lymph Nodes Development of Spleen and Tonsils Clinically Oriented Questions 15 - Musculoskeletal System Skeletal System Development of Cartilage and Bone Histogenesis of Cartilage Histogenesis of Bone Development of Joints Fibrous Joints Cartilaginous Joints Synovial Joints Development of Axial Skeleton Development of Vertebral Column Cartilaginous Stage of Vertebral Development Bony Stage of Vertebral Development Development of Ribs Development of Sternum Development of Cranium Development of Appendicular Skeleton Muscular System Development of Skeletal Muscle Development of Smooth Muscle Development of Cardiac Muscle Development of Limbs Early Stages of Limb Development Final Stages of Limb Development Cutaneous Innervation of Limbs Blood Supply of Limbs Clinically Oriented Questions 16 - Nervous System Development of Nervous System Development of Spinal Cord Development of Spinal Ganglia Development of Spinal Meninges Positional Changes of Spinal Cord Myelination of Nerve Fibers Birth Defects of Spinal Cord Development of Brain Brain Flexures Hindbrain Myelencephalon Metencephalon Choroid Plexuses and Cerebrospinal Fluid Midbrain Forebrain Congenital Anomalies of Brain Development of Peripheral Nervous System Spinal Nerves Cranial Nerves Development of Autonomic Nervous System Sympathetic Nervous System Parasympathetic Nervous System Clinically Oriented Questions 17 - Development of Eyes and Ears Development of Eyes and Related Structures Development of Retina Development of Choroid and Sclera Development of Ciliary Body Development of Iris Development of Lens Development of Aqueous Chambers Development of Cornea Development of Eyelids Development of Lacrimal Glands Development of Ears Development of Internal Ears Development of Middle Ears Development of External Ears Clinically Oriented Questions 18 - Integumentary System Development of Skin and Appendages Epidermis Dermis Development of Glands Development of Hairs Development of Nails Development of Mammary Glands Development of Teeth Bud Stage of Tooth Development Cap Stage of Tooth Development Bell Stage of Tooth Development Tooth Eruption Clinically Oriented Questions 19 - Human Birth Defects Teratology: Study of Abnormal Development Birth Defects Caused by Genetic Factors Numerical Chromosomal Abnormalities Structural Chromosomal Abnormalities Birth Defects Caused by Mutant Genes Birth Defects Caused by Environmental Factors Principles of Teratogenesis Human Teratogens Environmental Chemicals as Teratogens Infectious Agents as Teratogens Radiation as a Teratogen Maternal Factors as Teratogens Mechanical Factors as Teratogens Birth Defects Caused by Multifactorial Inheritance Clinically Oriented Questions 20 - The Cellular and Molecular Basis of Development Intercellular Communication Gap Junctions Cell Adhesion Molecules Morphogens Retinoic Acid Transforming Growth Factor-ss/Bone Morphogenetic Protein Sonic Hedgehog Wnt/ss-Catenin Pathway Receptor Tyrosine Kinases Common Features Regulation of Angiogenesis by Receptor Tyrosine Kinases Notch-Delta Pathway Transcription Factors Hox/Homeobox Proteins Pax Genes Basic Helix-Loop-Helix Transcription Factors Epigenetics DNA Methylation Histone Modifications Stem Cells: Differentiation versus Pluripotency Summary of Common Signaling Pathways Used during Development Bibliography and Suggested Reading Answers to Clinically Oriented Questions Index

Changes of serum melatonin level and its relationship to feto-placental unit during pregnancy.

Abstract: Serum melatonin concentrations were studied in normal pregnant women and in women with several types of pathologic pregnancies, e.g., twins, preeclampsia or intrauterine growth retardation (IUGR). Blood samples were collected from the maternal antecubital vein at 14:00 hr (daytime) and 02:00 hr (nighttime) during pregnancy, and also from the umbilical vein and artery immediately after delivery. Serum melatonin concentrations were measured by radioimmunoassay. Daytime serum melatonin levels in normal (single fetus; singleton) pregnancies were low. While the levels showed an increasing tendency toward the end of pregnancy, no statistically significant changes occurred. On the other hand, the nighttime serum melatonin levels increased after 24 weeks of gestation, with significantly (P < 0.01) high levels after 32 weeks; these values decreased to non-pregnant levels on the 2nd day of puerperium. Nighttime serum melatonin levels were significantly (P < 0.05) higher in twin pregnancies after 28 weeks of gestation than in singleton pregnancies, whereas the patients with severe preeclampsia showed significantly (P < 0.05) lower serum melatonin levels than the mild preeclampsia or the normal pregnant women after 32 weeks of gestation. Melatonin concentrations in umbilical vessels showed a higher tendency in neonates who were born during at night compared with the other neonates; moreover, those in the umbilical artery were generally higher than those in the umbilical vein. The present results indicate that in humans, the maternal serum melatonin levels show a diurnal rhythm, which increases until the end of pregnancy, reflecting some pathologic states of the feto-placental unit. Fetuses may produce melatonin with a circadian rhythm.

Intestinal glycosidase activities in the human embryo, fetus, and newborn.

Abstract: 1. In 32 human embryos, fetuses, newborns, and infants α-glycosidase activities (maltase, sucrase, isomaltase, palatinase, trehalase, dextranase, and amylase) and β-glycosidase activities (lactase and cellobiase) of the small intestine were determined. 2. The enzyme activities are distributed uniformly throughout the small intestine except in duodenum and terminal ileum. Lower values were found in these areas except for trehalase which remained high in the terminal ileum. 3. All glycosidases are present by the third month of intrauterine life. Most of the α-glycosidase activities reach maximal values by the 6th to 8th fetal month. Levels of activity are independent of the period lapsed since birth and independent of previous food intake. Only amylase and maltase 1 activities are low at birth in the full-term newborn. 4.β-glycosidase activities reach maximum values only at the end of normal gestation. After premature birth development of β-glycosidase activity occurs rapidly. 5. The observed development of the intestinal disaccharidases in the human is apparently different from that known in animals (calves, rabbits, pigs, and rats), where the α-disaccharidases develop only after birth and where lactase activity develops earlier in fetal life and drops after birth.