When the cholinergic vagal fibers to nodal tissue are stimulated, the membrane becomes hyperpolarized and the slope of the prepotentials is decreased

TLS Online TPP Program

#Id: 121

#Unit 5. Developmental Biology

The development of the vertebrate eye is a classic example used to describe the modus operandi of tissue organization via intercellular interactions.

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#Id: 122

#Unit 5. Developmental Biology

In the initiation of the vertebrate eyes, paired regions of the brain bulges (optic vesicles, act as inducer) out and approach the surface ectoderm (act as responder) of the head.

TLS Online TPP Program

#Id: 123

#Unit 5. Developmental Biology

The head ectoderm is competent to respond to the paracrine factors made by the optic vesicles & induced to form the lens of the eye.

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#Id: 124

#Unit 5. Developmental Biology

The optic vesicle is able to induce lens formation in the anterior ectoderm but not in the presumptive trunk and abdomen.

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#Id: 125

#Unit 5. Developmental Biology

If the optic vesicle is removed, the surface ectoderm forms either an abnormal lens or no lens at all.

TLS Online TPP Program

#Id: 126

#Unit 5. Developmental Biology

The prospective lens cells secrete paracrine factors that instruct the optic vesicle to form the retina.