BIOL 2003 Lecture Notes - Lecture 7: Water Vascular System, Tube Feet, Deuterostome
31 Aug 2016
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Document Summary
Deuterostome embryogenesis: radial cleavage - the division of cells in the early embryo. Cleavage ends with the formation of the blastula. In radial cleavage the spindle axes are parallel or at right angles to the polar axis of the oocyte: regulative (indeterminate) If cell is split apart following second cleavage division = generate complete embryo: fate of blastopore (mouth second) = anus, enterocoelous development outpocketing of mesoderm = coelom formatiom. Mesodermal endoskeleton: ossicles (calcareous plates) connected by collagen. Stereom = part of a unique coelom. Hydraulic system = canals and tube feet. Functions = respiration, excretion, locomotion and feeding. Open on one end, and fluid moves throughout a series of canals from the. Outside all the way to thousands of coordinated tube feet, through muscular and neural control. Working together, each tube feet can provide enough force to open a mussel shell, climb a vertical surface, etc.
