Embryology (Subject) / Part 2 (Lesson)
There are 11 cards in this lesson
Part 2
This lesson was created by smilesmile.
This lesson is not released for learning.
- neural tube closure defects anencephalie: no closure of the anterior neuropore (lethal) spina bifida: no closure of the posterior neuropore (on the 27 day) craniorachischisis: no closure over the entire length
- cerebral convolutions the reason your cerebral cortex has so many folds like a wrinkled up walnut, is that there is a limited amount of spare inside your skull; by wrinkling up, the cortex creates more space to fit in more neurons -> more brain power
- mesoderm begins to differentiate lateral to notochord, week 3 extends cranially and caudally (from head to tail of crown to rump)
- division of mesoderm into three regions somites: 40 pairs of body segments (repeating units, like building blocks) intermediate mesoderm: just lateral to somites lateral plate: splits to form coelom ("cavity")
- the lateral plate mesoderm in the head is equivalent to the cardiogenic mesoderm the somatic layer forms part of the lining of the pericardial cavity the splanchnic layer forms the heart wall
- derivatives of the mesoderm praxial mesoderm (somites): sclerotome (skeleton) dermatome myotome (muscles) intermediate mesoderm: kidneys and gonads lateral plate mesoderm: somatic mesoderm (body wall) dermis of skin bones ligaments splanchnic mesoderm (viscera) musculature, connective tissues, and serosa of the digestive and respiratory structures heart and most blood vessels branchial arch mesoderm facial muscles
- folding of embryo laterally and at the head and tail embryonic disc bulges, growing faster than yolk sac "tadpole shape" by day 24 after conception primitive gut- encloses tubular part of the yolk sac, site of future digestive tube and respiratory structures
- blood islands structures in the developing embryo which lead to many different parts of the circulatorty system; they primarily derive from plexus formed from angioblasts
- derivatives of the endoderm induces the formation of several endodermic structures constructs the linings of two tubes: - digestive tube (including liver, gallblader and pancreatic buds) - respiratory tube (as an outgrowth of the digestive tube)
- pharynx region of the digestive tube anterior to the point where the respiratory tube branches
- by week 4 (1 month) of development (olfactory placodes appear (ectoderm) > invaginate to form olfactory pits) laryngotracheal bud > forms trachea, bronchi and bronchi subdivisions ⇒ reaches functional maturity late in development