Which of the following muscles is not a derivative of mesoderm?
Ans. d. Dilators of pupil (Ref: Parson 20/e p5, Grays inatomy 40/e p702; Longman's Medical Embryology 11/e p337)Smooth muscles of iris (constrictorQ and dilator pupillaeQ) are derivative of neural ectoderm.Smooth muscles of iris (constrictorQ and dilator pupillaeQ)The sphincter and dilator pupillae muscles of the iris are derived from the ectoderm.The region between the optic cup and the overlying surface epithelium is filled with loose mesenchyme. The sphincter and dilator pupillae muscles form in this tissue.These muscles develop from the underlying ectoderm of the optic cupDerivatives of MesodermAll connective tissue i.e. superficial and deep fasciaQ, ligaments, tendons, aponeurosis, dermis of skinQ, adipose tissue, reticular tissue, cartilage and boneQAll cardiovascular system i.e. heart, blood vessels, lymphatic and blood cellsQAll Musculoskeletal system i.e. bone, cartilage, tendon, ligaments and muscles (smooth, striated and cardiac) except musculature of iris (sphincter and dilator pupillae) which are ectodermalQAll Reproductive system i.e. ovary; uterine tubes, uterus and upper vagina in females; testis, epididymis, ductus deferens, prostate (inner glandular zone) seminal vesicle and ejaculatory duct in males.Except epithelium of greater part of vagina, vestibule and inner surface of labia minora in female and greater part of prostate (except inner glandular zone) is endodermalOuter surface of labia minora and whole labia majora are ectodermalAll urinary system i.e. kidney, ureters, trigone of bladder, posterior part of female urethra, posterior part of prostatic urethra (upper half) of males and inner glandular zone of prostateEpithelium of urinary bladder (except trigone), female urethra (except posterior wall), male urethra (except prostatic part which is mesodermal and penile urethra which is ectodermal) and most of prostate (except inner glandular zone) are endodermalMesothelial lining of - pleural, pericardial, and peritoneal cavitiesQ and of tunica vaginalis, bursae and jointsDentine of teethQ: (enamel is ectodermalQ)Duramater and MicrogliaQExcept these all other nervous system i.e. neurons, neuroglia and schwann cells are ectodermalEye i.e. substance of comea, sclera, choroid, ciliary body and irisExcept anterior epithelium of comea. epithelium of conjunctiva, epithelium of ciliary, and iris; iris muscles and lensQ are ectodermal
Skeletal muscles
Smooth muscles
Cardiac myocyte
Dilators of pupil
Fertilization and Development of Embryo