Embryology 1 - 2.1 PDF

**[Embryology 1 - 2.1]** Human somatic cell - 46 (2 sex, 44 autosomes and 22 homologous sets) Words:\ Spermatozoa = male sex cell Ova = female sex cell (has ZP3 receptors zona pellucida receptor) Diploid = 2 sets of chromosomes Haploid = 1 set of chromosomes Meiosis = forms 4 non identical hap...

**[Embryology 1 - 2.1]** Human somatic cell - 46 (2 sex, 44 autosomes and 22 homologous sets) Words:\ Spermatozoa = male sex cell Ova = female sex cell (has ZP3 receptors zona pellucida receptor) Diploid = 2 sets of chromosomes Haploid = 1 set of chromosomes Meiosis = forms 4 non identical haploid sex cells Mitosis = forms 2 identical diploid body cells Synthetic (S) phase -  Prenatal development **Stage 1 (0-4 weeks)** **Stage 2** **Stage 3** ------------------------- -------------------------------- ----------------------- Cellular proliferation morphogenesis Growth and maturation Cellular migration Intricate embryology processes **Induction, competence and differentiation** - - - - **Week 1** = fertilisation to formation of blastocyst - - - - - -  **Week 2** = Implantation of blastocyst - - - - - - - Endoderm - form organs eg colon, stomach, intestines, liver, lungs, pancreas Ectoderm - forms outer linings eg skin, oral mucosa, NS, enamel NCC - form rest of tooth  **Week 3** = Gastrulation Bilaminar → trilaminar 1. - - - 2. 3. 4. Head = prochordal region or prechordal plate (cranial end) Tail = cecal plate (caudal end) This forms 3 primary germ layers: Ectoderm - - - - - - Endoderm - - - - Mesoderm Paraxial mesoderm - - - - Intermediate mesoderm - - Lateral plate mesoderm (somatic and splanchnic layer) - - - - - - - - - - - - **M**yeloid sc **E**rythroid sc **S**pleen **O** gonads **D**ermin **E**ntire trunk **R**enal system **M**eninges **A**drenal cortex **L**ymphoid sc **C**irculatory system **E**ndothelium of bv **L**ining of body cav - viscer and parietal **L**imbs **S**mooth muscle of GIT - - - - - - -   **[Defects in embryonic development]** Abnormal no of chromo causes congenital anomalies 10% of malfunctions caused by alteration in single gene Autosomal dominant inheritance: - - - - Autosomal recessive inheritance: - - - **Downs syndrome - Trisomy 21** Cause: - Features: - - - - **Turners syndrome - XO** Common chromosomal disorders in females Causes: - Features: - - - - **Klinefelter syndrome - XXY** Causes: - Features: - - - - -