Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Embryology 1 Timetable of Human Prenatal Development Ovum 2 1 2 3 • • • • • Chromosome • • • • • 4 5 7 carries genetic material picture of chromosome - karotype 23 pairs, 22 autosomes and 1 sex chromosome sex pair determines sex study of chromosomes =cytogenetics Karotype Fertilization • • • • • • 6 single large cell, .14mm zona pellucida -surrounding membrane surrounded by corona radiata full complement at birth meiosis-cell preparation: reduction of genetic material sperm enters ovum “day one” of prenatal development restores full complement of genetic material determines sex of organism initiate cleavage perpetuates species variation Cleavage Week One • fertilized ovum = zygote • primarily cell duplication • rapid succession of mitotic divisions 8 Morula • Day 4 • grape like cluster • cell growth in number, not size 9 Blastocyst/blastula • Result of cell differentiation • inner cell mass • outer trophoblast 10 Implantation - day 6 • blastocyst sinks into lining of uterus 1 • nutritional connection established • maternal and fetal circulatory systems Formation of Germ Layers 11 • from one cell comes a human • process of cell differentiation • “germ” layers are premordia for all tissues of organism Day 8 12 • • • • • 8-17th Day 13 • • • • • development of third germ layer mesoderm cells migrate/differentiate between endoderm and ectoderm process called gastrulation day 17, embryo is trilaminar Gastrulation 14 • • • • cells move along midline on craniocaudal plane = primitive streak meet and fuse at cephalic end = prochordal plate prochordal plate marks site of mouth meet and fuse at caudal end = posterior opening (HAH) Ectoderm 15 1 2 16 day 8-two types of cells: endoderm and ectoderm bilaminar disk = embryo represents embryonic period of development embryonic period extends to 7th week 7th week - beginning of all major structures present • • • • • • • • • • • • CNS, PNS epidermis hair nails subcutaneous glands pituitary gland tooth enamel epithelial lining lining of the oral and nasal cavities and pharynx inner ear lens mammary glands Endoderm 2 1 2 • • • • • Epithelial lining of most of respiratory tract and larynx lining of esophagus, stomach and small intestine epithelial parts of tympanic cavity Epithelium of G.I. Tract Liver, pancreas, bladder Mesoderm 17 1 2 • • • • • • • • • • Cardiovascular system connective tissue cartilage bone-skeleton joints skeletal muscles Blood and lymph systems kidneys gonads spleen Other 2nd-3rd week events 18 • Flexion in embryo at cephalic end • primitive forebrain -proencephalon • neural fold along primitive streak = spinal cord Somite Period 19 • • • • characterized by paired blocks of mesoderm craniocaudal sequence of growth 42-44 pairs basic features for face and neck Branchial Arches 20 • Basic features for face and neck • 4 arches separated by ectodermal grooves: 5th not visible • within each arch, derivatives for: – – – – artery nerve cartilage muscle Arch 1 - Mandibular 21 1 2 • • • • • • • • Cartilage - mandiular process, malleus and incus nerve-mandibular branch trigeminal muscle - mastication Abnormalities: micro/macrosomia deformed ear ossicles microagnathia Syndromes: treacher Collins, Robin Sequence Arch 2 - Hyoid 22 1 • Cartilage - Reicherts - hyoid, styloid process, stapes 3 2 • • • • • • nerve- 7th cranial muscle - facial expression; stapedius Abnormalities: rare: defect of hyoid and styloid bones Arch 3 23 1 2 • • • • • Cartilage - hyoid bone nerve- 9th cranial muscle - stylopharnygeus, middle constrictor of pharynx Abnormalities: extremely rare Arch 4 24 1 2 • • • • • Cartilage - Thyroid nerve- superior branch, 10th cranial muscle - cricothyroid Abnormalities: extremely rare; clinically insignificant Arch 5 25 1 2 • • • • • Cartilage - cricoid, arytenoids, cuniform, corniculate nerve- recurrent branch, 10th cranial muscle - laryngeal muscles Abnormalities: extremely rare; clinically insignificant • Endodermal derivative: glottis 26 Adult Landmarks • • • • palatoglossal fold -anterior fauces - 2nd arch palatopharyngeal fold - posterior pillar - 3rd arch pharyngo-epiglottic fold - 4th arch aryepiglottic fold - 5th arch 4