Embryology 415 bio

1. بسم الله الرحمن الرحيم Embryology415 bio 4credit (3 lec+1 lab=2hr.)

2. مقدمة ومحتويات ومتطلبات المقرر ولمحة تاريخية عن علم الاجنة Introduction, Course content and Requirements and Historical review http://fac.ksu.edu.sa/ahimaidiموقع المحاضرات أ.د احمد راشد الحميدي

3. أهداف مقرر علم الاجنة ((Embryology • يهدف هذا المقرر الى تزويد الطالب بالمعلومات عن المراحل الاساسية التي يمر بها التكوين الجنيني من الاخصاب الى الولادة او الفقس. • يركز هذا المقرر على التغيرات الشكلية او المورفولوجية والتي تحصل اثناء نمو الجنيني مع توضيح بعض الاليات الجزيئية التي لها علاقة بالتشوهات الخلقية اثناء تكون الجنيني بشكل عام.

4. محتويات مقرر علم الاجنة حيا 415 النظريEmbryology (Bio415)

5. تابع محتويات المقرر حيا 415 النظري

6. مراجع مقرر علم الاجنة (415 حيا) (BIO 415)Embryologyشرائح المحاضرات ا.د. احمد راشد الحميدي http://fac.ksu.edu.sa/ahimaidi • 1.Theory Lecture References: • 1- Developmental Biology "by Scott F. Gilbert 2014 10thed .Sinauer Association Inc. Sunderland Massachusetts’s. • 2- Experimental Embryology :by Ahmad Rashed Al Himaidi and Saleh Abdulaziz Karim / King Saud University Press,2008. • . 2. Lab Reference book Title :Embryonic Technologies/ by Ahmed Al Himaidi/ King Saud University Press/2012/1433H.

7. Embryology (BIO 415):Introduction and historical review قال تعالى { فَلْيَنظُرِ الْإِنسَانُ مِمَّ خُلِقَ{5} خُلِقَ مِن مَّاء دَافِقٍ{6} يَخْرُجُ مِن بَيْنِ الصُّلْبِ وَالتَّرَائِبِ{7} سورة الطارق • The embryology science reported by some verses of the Quran in particular with regard to human creation "so let man see, create, creation of water flush from between back bone and ribs,(altraeb).... • Yes it is God sinah in this life.

8. Embryo development • All multicellular organisms arose from the mating between male and female gametes (by fertilization) • The embryo in different developmental stages inter cleavage stage (from Zygote to blastula stage) by somatic cell division (mitosis).

9. Embryo development • Then Gastrulation stage start, by the formation of the three different embryonic layers, ectoderm, mesoderm and endoderm(gastrula). • Later the organogenesis stage: from these 3 embryonic layers were all the organs of the embryo will form. • Finally the grow and increase in size until the exit of the embryo for life (hatching or birth).

10. Introduction The development of multicellular organisms from a single cell) the fertilized egg(. During embryonic development, the egg divides to give rise to many millions of cells ,which form structures as complex and varied as eyes,arms, and brain.

11. Cont. • This amazing achievement raises many questions: • How do the cells arise from division of the fertilized egg become different from each other? • How do they become organized into structures such as limbs and brains? • What controls the behavior of individual cells so that such highly organized patterns emerge? • How are the organizing principles of development embedded within the egg, and in particular within the genetic material, DNA?

12. Cont. • Deferent factor can affect embryo development such as: • Gene and genetic control. • cellular differentiation. • The development of an embryo from the fertilized egg is known as embryogenesis.

13. فروع علم الاجنة Branches of Embryology Embryology has many sub-branches in it. They are:- 1- Descriptive Embryology It is applied to the method of study concerned with the direct observation and description of embryological development. 2- Comparative embryology • It is the embryological development of different animals(sea urchin, frog, chick and mammals) studied and compared. • Comparative embryology throws much light on the understanding of evolution and phylogenetic significance. • It also give some ideas on the developmental stages of certain animals.

14. 3- Experimental Embryology • it is experiments are used for studying the developmental stages. It helps to understand the fundamental developmental mechanisms. • In experimental embryology the various parts of developing embryo are removed, transplanted, parts exchanged or the environmental conditions altered. This helps to understand induction, gradient system, etc. • Experimental embryology is also called casual embryology of analytical embryology. Wilhelm Roux (1850 – 1924) is the pioneer in the field of experimental embryology.

15. 4- Chemical Embryology The developmental stages are studied by biochemical and physiological techniques. It is also called physiological or biochemical embryology. Needham (1931) is the pioneer in this field. 5- Teratology It is a branch of embryology concerned with the study of malformations or abnormal development of embryo, caused by several factors, drugs, genetic or ecological factors. 6- Developmental Biology: It includes not only embryonic development but also postnatal processes such as normal and neoplastic growth, metamorphosis, regeneration and tissue repair in both animal and plant .

16. Historical and background of Embryology Aristotle (384 – 322 B.C ): • Embryology as a branch of biology was initiated by the famous Greek philosopher Aristotle (384 – 322 B.C.). • He was the first embryologist to describe the development and reproduction of many kinds of organisms in his book entitled "Degeneration Animalium". هذا الجزء للقراءة والإطلاع

17. Cont .Historical and background of Embryology 2-Wilhelm Roux (1888)and Hans Driesch1892 Both In separate experiments, Wilhelm Roux (1888) and Hans Driesch (1892) set out to determine whether epigenesisالتكوين التراكمي or preformation التكوين المسبقwas correct. Preformation التكوين التراكمي: Sagest that the embryo is already formed in the sperm or the egg and it grows like the seeds of plant (By Malpegy and Hart Sukar). Epigenesisالتكوين التراكمي: Sagest that the embryo is formed step by step and is not preformed in egg. Wilhelm Roux (1888) and Hans Driesch (1892) Both allowed a fertilized egg to divide to the two-cell stage. Roux, using amphibian embryos (frogs, toads, salamanders), killed one of the two cells with a hot needle. Driesch, using echinoderm embryos (sea stars, sea urchins, sea cucumbers), completely separated the divided cells.

18. Cont .Historical and background of Embryology Cont. Wilhelm Roux (1888)and Hans Driesch (1892) An entire animal developing from a single cell would support epigenesis. A portion of the animal developing would favor preformation. What was the result? Interestingly, Roux described the formation of a half embryo that he called a “hemiembryo” (figure a), and Driesch found that each cell retained the potential to develop into an entire organism (figure b).

19. 3-August Weismann 1880s Propose that the germ plasma theory: The egg and sperm contribute chromosomes equally to the zygote (fertilized egg). The chromosomes are carriers of the hereditary potentials, and the germ cells (gametes) of the embryo are the only ones to carry the complete set of hereditary potentials (nuclear determinants), whereas each somatic (body) cell type contains only part of these potentials required for the specific cell type.

20. 4-Oscar Hertwig (1872) • He repeat the Wilhelm's experiments, but he separate the 2 cell frog embryo from them and improved that each cell had a potential to grow, but the embryo result is half size than normal embryo. This experiment is considered the one of explanations of twins formation result from one egg. • 5-Theodor Boveri (1902) • He studied the effect of nucleus and cytoplasm on the development of the sea urchin fertilized ovum by study of centriole and filaments formation during different division stages. Also, he tries to insemination of specific species ovum with another species sperm, and he found that the chromosomes are different in quantity and numerically.

21. 6- Thomas Hunt Morgan (1866 – 1945) • He is the first scientist that suggested that the embryonic development is controlled by expressions of different genes, and he awarded Nobel prize for discovered the mutations in Drosophila and their role in understand the role of genes in heredity. • 7- Otto Warburg (1908 – 1910) • He studied the respiratory mechanism in sea urchin embryo cells, and he considers the first scientist who definition oxygen consumes in respiratory of ovum and embryonic cells. Their study resulted in know that the fertilization make to increase the cellular reparatory rate of fertilized ovum. So, he discovered the cytochrome Oxidase and he awarded the Nobel prize on this discovery at 1931.

22. 8- Ernest E. Just (1883 – 1941) • He descried the changes occurred around the oocytes during the fertilization in sea urchin and he studied the parthenogenesis to understand the relationship between penetrate of sperm and the first division of Nematoda oocytes. • 9-Viktor Hamburger (1954) • The discovery of chick embryo's neural sector. Hamburger proposed an ant apoptotic action of the hypothetical target-derived trophic signals, identified as nerve growth-stimulating factor, later named nerve growth factor (NGF). • 10-Ross Granville Harrison (1870 – 1975) • He successfully cultured frog neuroblasts in a lymph medium and thereby took the first step toward current research on precursor and stem cells. He was considered for a Nobel prize for his work on nerve-cell outgrowth, which helped form the modern functional understanding of the nervous system, and he contributed to surgical tissue transplant technique.

23. 11-Hans Spemann and Mangold (1924) • Hilde Mangold’s experiment involved taking a piece of the lip of the blastopore of the gastrula stage of the amphibian embryo and grafting it to the wall (flank) of another gastrula at a site distant from the host blastopore, and thereby induced a secondary axis of polarity in the host that eventually developed into a secondary embryo. • In 1935 Spemann received the Nobel Prize for Medicine or Physiology as the first embryologist.

24. 12- Jean Brachet (1988 – 1909) • In 1933 Brachet was able to show that DNA was found in chromosomes and that RNA was present in the cytoplasm of all cells. His work showed that RNA plays an active role in protein synthesis. Brachet also carried out pioneering work in the field of cell differentiation. Brachet later demonstrated papers that differentiation is preceded by the formation of new ribosomes and accompanied by the release from the nucleus of a wave of new messenger RNA. • 13-Robert Briggs (1983 – 1911)and Thomas Joseph King • He was a scientist who in 1952, together with Thomas Joseph King, cloned a frog by nuclear transfer of embryonic cells. • The same technique, using somatic cells, was later used to create Dolly the Sheep by Willmut and Kith Kemble 1997 . Their experiment was the first successful nuclear transplantation performed in metazoans.