number 12

Choose the cells of erythropoiesis in sequence! Only one correct answer!

• Proerythroblast, basophil erythroblast, orthochromatophil erythroblast, oxyphil erythroblast or normoblast, reticulocyte, erythrocyte

• Basophil erythroblast, proerythroblast, orthochromatophil erythroblast, oxyphil erythroblast or normoblast, reticulocyte, erythrocyte.

• Basophil erythroblast, oxyphil erythroblast or normoblast, proerythroblast, orthochromatophil erythroblast, reticulocyte, erythrocyte

• Basophil erythroblast, orthochromatophil erythroblast, oxyphil erythroblast or normoblast, proerythroblast, reticulocyte, erythrocyte.

• Orthochromatophil erythroblast, basophil erythroblast, oxyphil erythroblast or normoblast, proerythroblast, reticulocyta, erythrocyte.

Choose the only correct statement!

• Progenitor stem cell of granulocytes (CFU-G) derives from the common granulocytemonocyte progenitor cell (CFU-GM).

• Progenitor stem cell of granulocytes (CFU-G) derives directly from the pluripotent hemopoietic stem cell (CFU-S).

• Progenitor stem cell of monocytes (CFU-Mo) derives directly from the pluripotent hemopoietic stem cell (CFU-S).

• All the progenitor stem cells of formed elements of the blood derive directly from the pluripotent hemopoietic stem cell (CFU-S).

• Progenitor stem cell of erythrocytes (CFU-E) derives directly from the pluripotent hemopoietic stem cell (CFU-S)

Choose the THREE correct statements!

• The bones of the limbs develop from the parietal plate of the lateral mesoderm.

• The muscles of the limbs are differentiated from the cells that migrate from the somites.

• Cartilage tissue in the limbs develops from mesenchyme originating from the parietal plate.

• The muscles of the limbs originate from the parietal plate of the lateral mesoderm.

• The bones of the limbs differentiate from mesenchymal cells that migrate to the limb buds from the sclerotome of the somites.

Choose the THREE correct statements!

• There is no bone ossifying membraneous way in the free limbs.

• The limb buds start to appear at the end of the fourth embryonic week.

• The upper limb buds appear earlier than the lower ones.

• The lower limb buds appear earlier in the embryo than the upper ones.

• The fingers separate from each other in the developing hand in the 5th embryonic week.

. Choose the THREE correct statements!

• The apical ectodermal ridge cells maintain the progression zone in the developing limb.

• Complete separation of the fingers occurs during the 8th embryonic week.

• AER cells are characterized by a high production of FGF4 and FGF8.

• The primary regulator of proximo-distal axis determination in developing limbs is Sonic Hedgehog, which is produced by AER cells

• The development of polydactyly is explained by the mis-sequencing of HOX genes.

Choose the TWO correct statements!

• The mesenchymal cells that give rise to the muscles of the limbs migrate from the dermamyotomes of the somite into the limb buds.

• MYOD is one of the master transcription factors controlling skeletal muscle differentiation.

• The mesenchyme that makes up the connective tissue of the skin of the limbs is derived from the dermatome of the lateral plate.

• Muscles of the limbs develop from the myotome of the lateral plate under the control of the transcription factor Myf-5.

• The primary ossification centers of the epiphyses appear in the long bones already in the fetal life.

Choose the TWO correct statements!

• Teratogens acting during the organogenesis can cause limb development abnormalities

• The connective tissue of the skin of the limbs is derived from the dermamyotome of the corresponding somites.

• Upper limb buds appear during the folding of the embryo.

• The bones of the limbs are derived from the ectomesenchyme.

• A malfunction of the zone of polarizing activity leads to amelia.

Choose the TWO correct statements!

• Teratogens acting during the organogenesis can cause limb development abnormalities.

• The connective tissue of the skin of the limbs is derived from the dermamyotome of the corresponding somites

• Upper limb buds appear during the folding of the embryo.

• The bones of the limbs are derived from the ectomesenchyme.

• A malfunction of the zone of polarizing activity leads to amelia

Choose the TWO correct statements

• The ossification of the long bones of the limbs occurs by enchondral ossification.

• At birth, the epiphyses of the long bones are still completely cartilaginous.

• Ossification of the limbs starts in the 8th embryonic week.

• The short bones in the limbs are ossified by the time of birth.

• On the hand and foot plates, fingers and toes are formed following apoptosis of the AER.

Choose the TWO correct statements!

• Higher doses of vitamin A can be highly teratogenic, including causing severe limb malformations.

• Teratogenic agents are particularly dangerous in the 4th-8th embryonic weeks because this is the primary time of organogenesis.

• In the dorso-ventral axis arrangements of the limbs, the effect of the zone of polarizing activity via retinol is of primary importance

• The counter-rotation of the limbs occuring during the tenth week of pregnancy determines the final orientation of the limbs, which causes the ventral location of the lower limb extensors

• The formation of the dorso-ventral limb axis requires WNT signalling from the ZPA.