BIOL 111 Lecture 7: Lecture 7 Animals

• School: McGill University
• Department: Biology
• Course: BIOL 111
• Professor: Andrew Hendry

Document Summary

Proteoglycan complex: jelly structure , proteins heavily glycosylated, unique types of junctions. Tight junctions abundant in epithelial tissue: seal cells, desmosomes connect the cytoskeleton of the cell, abundant in epithelial tissue, gap found in nerve/ muscles for communication. Fertilization of 2 haploids, fusion to diploid zygote. Zygote is first cell of next generation. Young animal in protective structure (egg, uterus) 2 major processes during embryonic development: cleavage. Many cells produced, embryo is not yet growing: gastrulation. Inner skin, becomes lining of digestive and respiratory systems. Middle skin, becomes internal organs, muscles, skeletal system, heart. Midsagittal plane divides body into mirrored halves. Endoskeleton made of spicules and elastic fibers, 2mm to 2m. Need a strong water current in order to filter feed. Flagella of choanocytes (cells in sponge) are used to create the current. Choanocytes are very similar to the protist choanoflagellates, close relative.