![]() ![]() Some receptors are activated by changes in the transmembrane potential (the difference in electric potential. The primary function of a receptor is to recognise and respond to a specific ligand, such as a neurotransmitter or hormone. The same is true for cell organelle membranes. The anatomy of the fine, varicose 'free' nerve endings of the Rohon-Beard cell neurites is discussed in relation to their function in detecting transient, touch stimuli to the skin and their role in evoking swimming of the embryo. Rapidly-adapting nerve receptors deliver information on changes that occur at the skin, such as occurs as you move your finger over a gritty surface. A portion of the receptor protrudes from the cell membrane. ![]() This showed that there were enough Rohon-Beard cells to innervate the skin from 1.5 to 2.5 times. Receptive fields (mean area 0.16 mm 2) were mapped and related to the total number of Rohon-Beard cells and the area of skin to be innervated. These discharges adapted rapidly and quickly fatigued when stimulated repeatedly. Impulses were evoked by light touch or stroking of the skin with fine hairs. The Pacinian corpuscle, lamellar corpuscle or Vater-Pacini corpuscle is one of the four major types of mechanoreceptors (specialized nerve ending with adventitious tissue for mechanical sensation) found in mammalian skin. Study with Quizlet and memorize flashcards containing terms like describe the function of sensory receptors, name the general sensory receptors that belong to each structural class a) free nerve endings b) encapsulated nerve endings, receives input from third order neurons sensory information is consciously perceived and more. The functions of these peptides are largely unknown but they presumably mediate slow, modulatory synaptic actions in the dorsal horn neurons. Figure 6.9 Conduction of noxious information via A delta and C fibers. (unencapsulated) Merkel- tonic receptors for light touch, sensing textures, edges and shapes. The free nerve endings arise from both A delta fibers and the unmyelinated C fibers, which are scattered together (Figure 6.9). Answer and Explanation: Become a member to unlock this answer Create. Responses of Rohon-Beard cells to skin stimulation can be recorded extracellularly using a suction electrode. (unencapsulated) bare dendrites that have no special association with specific accessory cells or tissues. Many of the free nerve endings are nociceptors, also known as pain receptors. The neurites are periodically varicose and, between the superficial skin cells, these bulges are invaginated into the skin cell membranes where some terminate. They supply either 'warm spots' or 'cold spots' scattered over the skin. In the electron microscope narrower neurites from this network are found running into the skin between the cells. Functions Some sensory units with free nerve endings are thermoreceptors. These Rohon-Beard cells have naked peripheral neurites, usually under 1 μ m in diameter, which form a loose network under the skin. The skin of the body and tail in embryonic and young larval Xenopus is innervated by sensory neurones with cell bodies lying along the dorsal midline of the spinal cord. ![]()
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