Transcript cells
Basic morphogenetic processes 138 Course 5: Cells and tissues development Course 5: Development • • • • • • • • • • • • • 137 Case report: Thalidomide 138 Basic morphogenetic processes 139 Regeneration and reparation 140 Female reproductive system 142 Gametogenesis and fertilization 144 Genetic determination of the sex 145 Signalization in development 146 Blastogenesis, notogenesis 149 Embryonic period.. 151 Histogenesis 152 Human reproductive genetics 153 Developmental toxicology 154 Ageing Aim • mechanisms, participating during ontogenesis, creating multicellular organism from one cell, zygote Oocyt + sperm = zygote Oocyt Oocyte and sperms Basic morphogenetic processes: mechanisms participating during ontogenesis, creating multicellular organism from one cell Zygote Multicellular organism • terminology, theoretical background • normal development example • abnormal development example Ontogenesis – development of individual being • begins by fertilisation (oocyte and sperm) - zygote culminates by maturity : physical, structural, functional, sexual, mental, emotional – terminates by death • time of birth - divides ontogenesis prenatal and postnatal • prenatal period: 40 weeks blastogenesis - embryonal - fetal - perinatal 0-2 weeks 3.-8.w 9.-.38.w around 40w 1. trimester 2.a 3. trimester blastogenesis embryonic period fetal period Ontogenesis - prenatal - zygote development toward multicellular organism • • • • mechanisms operate…at different levels cells - differentiation cell populations - morphogenesis - structure development cell populations set - morphogenetic system – realizes structure and function programme in organ or part of the body – basic morphogenetic processes Cell level • differentiaton - process that cause cell specialisation • different cell types develop from totipotent zygote, by specific and different proteins synthesis, underlying specific morphology (structure) and function of particular cell Zygote Oocyt + sperm Oocyt Oocyte and sperms Goblet cells and cilliated cells Blood cells Chondrocytes Different cell types – different proteins • • • • Cilliated cell - tubulin a dynein Neuron - neurotransmitter, tubulin a kinesin B- cell of pankreas Red blood cell - hemoglobin Differentiation • differentiation is dependent on signals from cell environment (regulatory differentiation) – in case of higher species (e.c.-human) Differentiation and determination • • • gene - RNA - DNA - protein = differentiation regulatory genes control the expression of one or more other genes they are activated by the signal from environment a cell can become specified for a particular fate – it becomes determined – the cell fate determination • determination is followed by differentiation mesenchymal cell chondroblast cartilage lipoblast fat fibroblast osteoblast myoblast bone muscle hemocytoblast endothelium blood cells connective tissue, ligaments, tendons Diferentiation of neuroepithelium Cell populations level • development of structures/ organs - morphogenesis • 1. induction – one cell population induces the change of the fate in another cell population • epithelial-mesenchymal interactions examples: limbs, lens, nephrons, teeth cross-talk • 2. cell-signalling, signalising cell x target cell (must be sensitive to this signal) paracrine interactions, contact interactions • neuroectoderm induction / target is surface ectoderm – lens placode Morphogenetic systems level = group of cell populations developmental programme • basic morphogenetic processes - 4 processes play out at the cell population level to essentially create the final organism • proliferation • migration • asociation • programmed cell death - apoptosis Proliferation (mitotic activity) • characteristic feature of development – the embryo grows + cavity formation a extracellular material increase (interstitial growth in cartilage) + cell increase • considerable in embryonic period 3.-8. week , 3mm – 30 mm • in adult tissues proliferation in regeneration process (hematopoeisis, epithelial tissues..) • programmed structure growth (limb is preformed as miniature in 4th week of development, followed by its growth) • growth/proliferation is regulated – growth factor – insulin, insulin-like-growth faktor, PDGF, VEGF… • mitotic activity is localised in the centres of proliferation Cell migration • cell movements from original site to the target site • passive – the cells are pushed from the proliferation centre • activní – movements thank to cell itself system of locomotion (philopodium, train) • Neural crest derived cells, germ layer cells, somites Neural crest cell derivates Cell association • association to the groups, for synchronisation of their function • CAM – cell adhesive molecules, cadherins, gap-junctions • syncytium in skeletal muscle, neurons, angiogenesis 2 multipolar neurons associated by synapse biomedicalengineering.yolasite.com Apoptosis • fysiological process • elimination of defect cells mutation or supranumeral elements (neurons) • creating of the shape interdigital spaces in hands and feets Limb development • Limb bud - mesenchyme, ectoderm • AED - apical ectodermal ridge - proliferation • ZPA – zone of polarisation activity- retinoid acid – morphogene – transcriptional factor- for axis pattern (SHH, BMP, WNT, HOX genes - postion) • differentiation – bones, connectives • migration – muscle cells from somites, melanocytes, Schwann cells from neural crest • growth of axons from spinal cord , angiogenesis association• apoptosis – interdigital spaces formation Affected limb development • critical period 4.-7.week • thalidomide - 20% risk of defects phokomelia, amelia • proximal part of limb is missing , stylopodium and zeugopodium • mechanism • block of growth factor for angiogenesis and integrins Neural tube differentiation in CNS development neuroepithelial cells - proliferation, neuroblast migration, neuron association to neuronal net. Solitary neurons die by apoptosis • basic morphogenetic processes - 4 processes play out at the cell population level to essentially create the final organism • proliferation • migration • asociation • programmed cell death - apoptosis Embryology • developmental processes during prenatal period of development • morfogenesis • organogenesis • teratogenesis