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| Frog Embryology |
Frog Embryology :
* Frog is an anuran amphibian.
* As the eggs of frog re larger in size.
* They are available in plenty they are extensively used in the study of embryogenesis.
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| Detailed view of sperm |
Sperm :
* The sperm is the male gamete, it is produced by the testis. It is haploid.
* The sperm is the of frog is microscopic and is about mm long.
* It is of the flagellate type.
* It has a head, a middle piece and a tail.
* The head is cylindrical and long.
* It is formed of acrosome and nucleus.
* The middle piece is short, it contain two centriole and the mitochondria.
* The tail is long, it contain an axial filament.
* The tail consist of two regions, namely main piece and end piece.
* Sperm :- Microscope about 0.03 mm, consist of head, middle piece and tail.
* Head :- Acrosome (derived from golgi apparatus) and nucleus (condensed DNA).
* Middle piece :- Centrioles and mitochondria in cytoplasmic sheath.
* Tail :- Contains axial filament and cytoplasm.
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| Egg |
Egg (Ovum) :
* The egg is the female gametes, it is also called ovum and it is haploid.
* It is produced by the ovary.
* It is a non-cleidoic egg as the shell is absent.
* It is a maglecithal egg as it contains large amounts of yolk.
* It is a telolecithal as the yolk is present on one side.
* The egg of frog spherical in shape. It is about 2 mm in diameter.
* It is surrounded by three egg membrane, namely an inner plasma membrane, a middle is vitelline membrane an an outer jelly coat.
* The egg cytoplasm is called as ooplasm.
*It has two regions namely, peripheral cortex and central endoplasm.
* The cortex contains two types of granules.
* They are dark brown pigment granules and cortical granules.
* Cortical granules are arranged in layer close to the plasma membrane.
* The endoplasm contains nucleus on one side an numerous white plate-like yolk platelets on the other side.
* The egg has two distinct colours.
* One side is black in colour, this side is called animals pole and nucleus situated at the side.
* The opposite side is yellow in colour. This side is called vegetal pole and it contain yolk.
* Telolecithal and mesolecithal.
* Released from ovary in primary occyte state.
* Enclosed by vitelline membrane.
* Coloured half called animal hemisphere contains nucleu.
* White half called vegetal hemisphere contains york.
* 60% protein and 40% fat.
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