Embryology /organogenesis/ Development and teratology of nervous system. Development of endocrine glands (pp. 35-44) 2 http://classconnection.s3.amazonaws.com/391/flashcards/578391/png/untitled1308508383511.png NOTOCHORD DEVELOPMENT NOTOCHORD - induces neural plate development in neuroectoderm Neuroectoderm Neural plate 3 1 Neural plate – thickened area of ectoderm ð neuroectoderm Pharyngeal membrane Primitive streak and node Cloacal membrane Notochord pseudostratif. columnar ep. columnar cells proliferate 4 https://people.creighton.edu/~idc24708/Genes/Behavioral%20Genetics/3-step%20neurulation.png NEURULATION – invagination of neural plate (day 16 - 24) -neural folds (a) -neural groove (b) - - - - - - - -neural tube -neural crest notochord a a b 5 Nervový systém - 42 Day 20 Neural folds 6 Nervový systém - 44 Neuroporus anterior Neuroporus posterior Day 22, 23 closes on D 25 closes on D 27 7 Nervový systém - 43 NEURAL CREST 8 neuralcrest.jpg image by musuq Odontoblasts Leptomeningeal cells What originate from neural crest 9 http://www.biog1105-1106.org/demos/106/unit03/media/neuralcrest.jpg EKTOMESENCHYME 10 SC-XSect Histogenesis of neural tube The wall of neural tube: (simple → pseudostratified neural epithelium) Cell proliferation ð 3 zones: Ependymal Intermediate Marginal zone Ependyma Gray matter White matter (in medulla spinalis) 11 HISTOGENESIS of NEURAL TUBE Nervový systém - 48 Marginal zone (white matter) Intermediate zone (gray matter) (mantle zone) Ependymal zone (germinal) 12 Early development of the neural tube Three zones line neural tube (the spinal cord and brain stem). Marginal zone (white matter) – without neurons, but with axons of neurons and glial cells Mantle zone (gray matter) – neuroblasts + spongioblasts give rise to bodies of neurons and glial cells Ependymal zone (germinal) – lining of central canal ependyme gray matter white matter In spinal cord and brain stem 13 Early development of the neural tube ependyme white matter gray matter In brain and cerebellum In brain and cerbellum: mantle zone cells migrate through marginal layer and the gray matter coveres white matter. Some neurons stay in white matter ð nuclei. 14 DrwNeurtube Spinal cord development Dorsal horns Ventral horns motor zone sensory zone future white matter future gray matter 15 Nervový systém - 49 SPINAL CORD: 1.Ependymal layer (germinal) 2.Mantle layer (gray matter) 3.Marginal layer (white matter) 16 Nervový systém - 52 Positional changes of spinal cord Vertebrate canal grows more rapidly than spinal cord and caudal end of spinal cord doesn‘t extend the entire length of canal in adult; it terminates at L2 in adults # . the end fo the 2nd month the 5th month new-born child # Cauda equina Brain development •Brain develops from cranial part of neural tube •Week 4 – three primary brain vesicles: • - prosencephalon (forebrain) • - mesencephalon (midbrain) • - rhombencephalon (hindbrain) 17 18 3-1-2-5 week 5 3 primary → 5 secondary vesicles: Lamina terminalis Prosencephalon Mesencephalon Rhombencephalon Telencephalon Diencephalon Metencephalon Myelencephalon 1 2 4 1 – ventriculi lat., 2 – ventriculus tertius, 3 – aqueductus cerebri, 4 – ventriculus quartus 3 Optic vesicle Neurohypophysis Epiphysis Cerebellum Pons week 4 19 Nervový systém - 46 Midbrain flexure Cervical flexure 20 http://www.startsateight.com/wp-content/uploads/2011/05/48_23BrainDevelopment.jpg 21 Myelination of nerve fibers Nervová tkáň - 16 Obaly nervových výběžků Myelinani from the 4th prenatal month to the end of 2nd postnatal year animated picture 22 CNS malformations •failure neurulation (absence of notochord inductive influence or teratogen influence on neuroectodermal cells) •defects of spinal cord •defects of brain •difficult malformations of CNS are usually connected with skull or spinal column (vertebral) defects. • •Etiology: usually multifactorial (fever, drugs during gravidity, hypervit. A etc.) or hereditary disposition. •Folic acid use influence normal development of CNS. •Sonography detects anomalies. 23 Spinal cord malformations •Defects (clefts) of vertebral •arches •Menigocele •Menigomyelocele •Menigohydromyelocele • •Myeloschisis – complete cleft of spinal column in the whole length http://www.primehealthchannel.com/wp-content/uploads/2012/06/Neural-tube-defect-Image.jpg spina bifida cystica http://skeletalsystemdev.weebly.com/uploads/7/0/4/3/7043675/7236642_orig.jpg 24 http://media.tumblr.com/tumblr_m4ynmmYZdJ1r261r3.jpg 19087 25 Nervový systém - 53 26 Urodynamics FIG01 Examples of external signs of spina bifida: 1) hairy patch 2) hemangioma 3) skin appendage 4) lipomatous mass 27 Brain malformations •Anencephalia (†) (with myeloschisis) zarte%20seele%201 28 http://escuela.med.puc.cl/paginas/cursos/tercero/patologia/fotos242-248/244.jpg Anencephalia 29 Brain malformations • • • • • tcge010 MICROCEPHALIA ANENCEPHALIA Final_Microcephaly2 30 Hydrocephalus -accumulation of abundant cerebrospinal fluid in brain ventricular system, -etiology: stenosis or obliteration of aqueductus cerebri between the 3rd and 4th ventricles fluid is accumulated in lateral ventricles pushes on the brain tissue (is thinned); internal pressure complicates drenage of fluid insubarachnoid space; -until skull suture don‘t ossify – skull can grows extremely . Roční dívenka z Indie umírá, trpí strašnou chorobou 31 VPS_Shunt HYDROCEPHALUS fig84_1 ventriculoperitoneal shunt 32 Nervový systém - 58 Brain and meninges hernia(tion) 33 http://neuropathology-web.org/chapter11/images11/11-4l.jpg http://neuropathology-web.org/chapter11/images11/11-2al.jpg Brain and meninges hernia(tion) 34 end Endocrine glands development Hypophysis Pineal gl. Thyroid gl. Parathyr. gll. Langerhans islets Adrenal gll. adenohypo – ectoderm (roof of stomodeum) neurohypo – neuroectoderm (floor of diencephalon) – neuroectoderm (floor of diencephalon) – endoderm (tongue) – endoderm (pharyngeal pouches) – endoderm Cortex – mesoderm Medulla – neuroectoderm Výsledek obrázku pro hypophysis development Výsledek obrázku pro hypophysis development Neurohypophyseal diverticle of diencephalon floor + Rathke‘s pouch of stomodeum roof Výsledek obrázku pro congenital anomalies of hypophysis Pineal gland (epiphysis) – diverticulum of the roof of diencephalon Související obrázek Thyroid gland Výsledek obrázku pro development of thyroid gland Descensus of thyroid gland Ductus thyroglossus Ultimobranchial body – the 4th endodermal pouch – parafollicular cells Výsledek obrázku pro development of thyroid gland Související obrázek CORTEX -mesoderm (coelomic epithelium) MEDULLA -neuroectoderm (neural crest) Související obrázek 45 end 46 Terms repetition •Neuron – perikaryon – axon (= neurite) – dendrite(s) •Nissl bodies = rough ER •Axon hillock •Myeline sheath •Schwann sheath •Mesaxon •Internodium •Node of Ranvier •Neuron – classification •Synapse (presynaptic membrane, synaptic cleft, postsynaptic memrane) •Neurotransmitters • 47 Terms repetition •Neuroglia - classification •Oligodendroglia •Astrocytes •Microglia (of Horteg) •Ependyma - tanycytes •Schwann cells •Satelite cells • • • in CNS in PNS 48 Terms •Brain cortex – 6 layers (lamina) •Cajal cells, Martinotti cells, granular and pyramidal cells •Membrana limitans gliae superficialis and perivascularis) •Brain barrier •Cerebellum – 3 layers of cortex (stratum) •Purkinje cells, basket cells, granular cells •Glomeruli cerebellares •Mossy and climbing fibers 49 Terms •Dura mater – arachnoidea – pia mater •Endoneurium – perineurium – epineurium •Plexus chorioideus 50 end (following pictures are not included in the lecture, but can help students) 51 Braincase3 Development of the skull base 52 Fig. 1 (a) A myelinated axon in the peripheral nervous system and (b) its development. Each Schwann cell myelinates a single axon, to which it is directly apposed. During development (anticlockwise) Schwann cells loosely ensheath axons and the myelin sheath grows around the axon to form concentric layers, which become tightly apposed Fig. 1 (a) A myelinated axon in the peripheral nervous system and (b) its development. Each Schwann cell myelinates a single axon, to which it is directly apposed. During development (anticlockwise) Schwann cells loosely ensheath axons and the myelin sheath grows around the axon to form concentric layers, which become tightly apposed 53 Fig. 3 Myelination in the central nervous system. A single oligodendrocyte myelinates numerous axons (a) and, in section, concentric layers of myelin are seen to spiral around the axon (b). Myelin sheaths are arranged along axons in segments 1 mm long separated by short nodes, and would appear as large sheets if they were unwrapped from around the axon Fig. 3 Myelination in the central nervous system. A single oligodendrocyte myelinates numerous axons (a) and, in section, concentric layers of myelin are seen to spiral around the axon (b). Myelin sheaths are arranged along axons in segments 1 mm long separated by short nodes, and would appear as large sheets if they were unwrapped from around the axon 54 Nervový systém - 51 55 Nervový systém - 39 Vztah míchy k rostoucí páteři 56 http://oxfordmedicine.com/doc/10.1093/med/9780195378580.001.0001/graphic005015-inline.gif 57 HumHPD6L 58 Nervový systém - 54