| egg coat | A layer of glycoproteins and other stuff which surrounds an egg (ovum), just outside of the egg's cell membrane. The coat protects the egg, and for organisms which practice external fertilization (fertilization outside of the parents' bodies) it can help prevent the sperm of other species from entering the egg. For the eggs of mammals, the egg coat is called the zona pellucida and for sea urchins (a popular study organism for developmental biologists) it is called the vitelline layer. (09 Oct 1997) |
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| longitudinal layer of muscular coat | The outer, longitudinal layer of the smooth muscle of the muscular coat. Nomina Anatomica lists longitudinal layers of muscular coats (stratum longitudinale tunicae muscularis...) of the following: 1) colon (... Coli ); 2) rectum (... Recti ); 3) small intestine (... Intestini tenuis ); 4) stomach (... Gastrici ). Synonym: stratum longitudinale tunicae muscularis gastricae, stratum longitudinale tunicae muscularis. (05 Mar 2000) |