Which of the following are derived from mesoderm?
Ans. c (Microglia). (Ref. Human Embryology by IB Singh, 6th ed., 352).CNS/PNS cells:AstrocytesPhysical support, repair, K+ metabolism; help maintain blood-brain barrier. Astrocyte marker--GFAP.MicrogliaCNS phagocytes. Mesodermal origin. Not readily discernible in Nissl stains. Have small irregular nuclei and relatively little cytoplasm.OligodendrogliaCentral myelin production. Each oligodendrocyte myelinates multiple CNS axons, up to 30 each.In Nissl stains, they appear as small nuclei with dark chromatin and little cytoplasm.Predominant type of glial cell in white matter.Schwann cellsPeripheral myelin production. Each Schwann cell myelinates only 1 PNS axon. Also promote axonal regeneration. Derived from neural crest.Ependymal cellsInner lining of ventricles; make CSF.Microglia, like Macrophages, originate from Mesoderm. All other CNS/PNS supportive cells originate from ectoderm.DerivativesEctodermSkin, hair, enamel, Lens of eye, mucous membrane lower anal canal, terminal male urethra, labia majora, outer surface of minora, epithelium of cornea, conjunctiva, ciliary body & iris, outer layer of tympanic membrane, exocrine salivary gland & sweat gland, endocrine hypophysial cells, adrenal medulla, CNS Including all neurons, neuroglia & schwanncells except microgliaEndodermEpithelial lining of mouth, palate, tongue, tonsils pharynx, oesophagus, stomach, intestine, upper anal canal, middle ear, respiratory system, gall bladder, urinary bladder except trigone, vagina, thyroid, parathyroid, thymus, Islet cell of pancreas, prostrate except inner zoneMesodermAll connective tissue dermis, dentine small striated, cardiac muscle except iris muscle, heart, blood vessel, lymph, blood cell, kidney, ureter, trigone, inner zone of prostate, ovary, uterus, tubes, testis, epidydimis, seminal vesicles, ejaculatory duct. Pleural, pericardial & peritoneal cavity. Cornea, sclera, choroids, ciliary body, iris, dura, microglia.
Astrocytes
Oligodendrocytes
Microglial cells
Schwann cells
Fertilization and Development of Embryo