EMBRYOLOGY NOTES. I. Summary of First Three Weeks a. Definitions b. Germ layers. Central Nervous System. III. Gastrointestinal System

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1 EMBRYOLOGY NOTES I. Summary of First Three Weeks a. Definitions b. Germ layers II. Central Nervous System III. Gastrointestinal System IV. Urogenital System and Homologues V. Cardiovascular System and Changes in Circulation VI. Brachial Arches and Pharyngeal Pouches

4 EMBRYOLOGY Germ layer derivatives ectoderm Surface ectoderm Neuroectoderm Epidermis Hair Nails Cutaneous structures Neural tube Inner ear Central nervous system Neural Crest Enamel of teeth Retina Adrenal Medulla Lens of eye Pineal gland Ganglia Anterior pituitary Posterior pituitary Sensory Cranial Autonomic Pigment cells Schwann cells Satellite cells Meninges Pia and arachnoid Branchial arch cartilage Mesoderm Smooth Cardiac Skeletal Connective tissue All serous membranes Bone and cartilage Blood, lymph, cardiovascular organs Adrenal cortex Gonads and internal reproductive organs Spleen Kidney Dura mater Endoderm Forms Epithelial parts of: Tonsils Thymus Pharynx Larynx Trachea Bronchi Lungs Urinary bladder Urethra Tympanic cavity Auditory tube GI tract Forms parenchyma of: Liver Parathyroid gland Pancreas Glands of the GI Thyroid gland tract

7 GI Tract Derivatives Foregut Midgut Hindgut Celiac Artery Superior Mesenteric Artery Inferior mesenteric Artery Esophagus Duodenum (parts 2, 3, & 4) Transverse colon Stomach Jejunum Descending colon Duodenum (first part) Ileum Sigmoid colon Liver and pancreas Cecum Rectum Biliary apparatus Appendix Anal canal (Superior part) Gall bladder Ascending colon Epithelium of urinary bladder and most of the urethra NOTE: the celiac artery supplies the spleen although it is not a foregut derivative. Transverse colon (right half)

12 EMBRYOLOGY Urogenital System Adult derivatives of embryonic urogenital structures. MALE EMBRYONIC STRUCTURES FEMALE Testis Seminiferous tubules Rete testis Indifferent gonad Cortex Medulla Ovary Ovarian follicles Medulla Rete ovarii Gubernaculum testis Gubernaculum Ovarian ligament Round ligament of uterus Efferent ductile Mesonephric tubules Epoöphoron Epididymis Mesonephric duct Gartner s duct Vas deferens Ureter, pelvis, calyces and collecting tubules Ureter, pelvis, calyces and collecting tubules Ejaculatory duct and seminal vesicles Appendix of testis Paramesonephric duct Uterine tube Uterus Urinary bladder Urethra Urogenital sinus Urinary bladder Urethra Prostatic utricle Prostate gland Bulbourethral glands Penis Phallus Clitoris Glans penis Corpora cavernosa Corpus spongiosum Vagina Urethral and paraurethral glands Greater vestibular glands Gland clitoris Corpora cavernosa Vestibular bulb Ventral aspect of penis Urogenital folds Labia minora Scrotum Labioscrotal swellings Labia majora

15 Common cardiovascular anomalies Interventricular septal defects: Interatrial Septal defects: Transposition of great vessels: Coarctation of the aorta: Patent ductus arteriosus usually in the membranous portion persistent of patent foramen ovale usually accompanied by a interventricular septal defect commonly in the area of the ductus arteriosus Tetralogy of Fallot (four defects) Pulmonary stenosis Ventricular septal defect Overriding aorta Hypertrophy of the right ventricle

17 Embryology Cardiovascular System Vitelline veins Left degenerates Right hepatic veins Umbilical veins Right and part of left between liver and sinus venosus degenerates Left umbilical vein (ligament venosus in adult) Cardinal veins Right anterior and common cardinal veins superior vena cava Left anterior left brachiocephalic vein Posterior cardinal veins Root of the azygos vein Common iliac veins Left common cardinal vein of the left atrium DEVELOPMENT OF THE HEART Atria primitive atrium forms roughened part of each atria Smooth portions Right sinus venosus Left pulmonary veins Ventricles (right and left) primitive ventricle Interatrial septum Septum primum valve of the foramen ovale Septum secundum interatrial septum Septum secundum, and primum fuse after birth to form the complete interatrial septum Foramen primum disappears Foramen secundum foramen ovale Interventricular septum Muscular part primitive intermuscular septum Membranous part right and left bulbar ridges and fused endocardial cushions Truncus arteriosus Pulmonary trunk Ascending aorta

18 Bulbus cordis Left aortic vestibule Right conus arteriosus Sinus venous Right horn smooth part of right atrium Left horn coronary sinus DERIVATIVES OF THE AORTIC ARCHES First contribute to the maxillary arteries Second stapedial arteries Third Proximal common carotid arteries Distal join with dorsal aortae to form the internal carotid arteries Fourth Left arch of the aorta Right Proximal part of right subclavian artery (Distal portion from right dorsal aorta) NOTE: left subclavian artery formed from the left seventh intersegemtal artery. Fifth degenerate Sixth Left proximal part left pulmonary artery Left distal part ductus arteriosus (ligamentum arteriosus in adult) Right proximal - right pulmonary artery Right distal - degenerates

20 First (Mandibular) Second (Hyoid) BRANCHIAL ARCH DERIVATIVES INNERVATION Arch Cranial Nerves Muscles Skeletal Trigeminal (V) Muscles of mastication Malleus Mylohyoid Incus Digastric (ant. Belly) Tensor tympani Tensor veli palatini Facial (VII) Muscles of facial expression Stylohyoid Digastric (post. Belly) Stapedius Stapes Styloid process Hyoid Lesser cornu Upper body Third Glossopharyngeal (IX) Hyoid Greater cornu Lower body Fourth and Sixth Vagus (X) Stylopharyngeus Thyroid cartilage Accessory (XI) Cricothyroid Levator veli palatini Constrictors of the pharynx Intrinsic muscles of the larynx Cricoid cartilage Arytenoid, corniculate, and cuneiform cartilages Muscles of the head region derived from somites Preotic somites Levator palpebrae superioris Extraocular muscles Recti: superior, inferior, medial and lateral Oblique: superior and inferior Innervation: (SO 4 LR 6 ) 3 Occipital somites Tongue musculature Innervation: hyoglossal nerve (XII)

04 Development of the Face and Neck. Development of the Face Development of the neck

04 Development of the Face and Neck Development of the Face Development of the neck Development of the face Overview of facial development The fourth week ~ the twelfth week of prenatal development Between