The Lateral Line System and Inner Ear: Sense Organs in Aquatic Organisms, Quizzes of Equine Science and Management

Download The Lateral Line System and Inner Ear: Sense Organs in Aquatic Organisms and more Quizzes Equine Science and Management in PDF only on Docsity! TERM 1 lateral line system DEFINITION 1 The lateral line is a sense organ in aquatic organisms (chiefly fish), used to detect movement and vibration in the surrounding water. Isolated sensory organs called pit organs and grooves that are lined with arrays of sensory organs. Detect water displacement and currents. lost in adult amphibians, entirely absent in amniotes. TERM 2 Origin of receptor cells DEFINITION 2 In the lateral line system develop from nuerogenic placodes called lateral line placodes TERM 3 Inner Ear DEFINITION 3 Sense of hearing Sense of balance develops from nuerogenic placode called otic placode TERM 4 What do the lateral line system and the inner ear have in common? DEFINITION 4 1) Receptor cells associated with lateral line system, hearing and equilibrium are called hair cells. 2)Hair cells are mechano-electric transducers that convert a mechanical force into an electric signal that is sent to the brain. * The receptor in the lateral line sytem are cluster of sensory cells ( hair cells) called nueromasts TERM 5 Individual Hair Cell DEFINITION 5 apical end or the hear of the hair cell is covered with cilias (single kinocilium and a series of sterocilia that are of decreasing length away from the kinocilium) Basal end of the hair cell synapses with neurons that take info from and to the central nervous system Hair cells are often arranged in pairs TERM 6 Stereocilia DEFINITION 6 Stereocilia are apical modifications of the cell, which are distinct from microvilli and cilia. are actin filaments covered by plasma membrane, they lack microtubules and are not true true cilia. TERM 7 kinocilium DEFINITION 7 A kinocilium is a special structure on the apex of hair cells located in the sensory epithelium. is a true cilium with a central axoneme that has 9+2 arrangement of microtubules. TERM 8 Occurrence of nueromasts DEFINITION 8 Some nueromasts are free standing and occur as isolated structures in shallow pits in the skin. these nueromasts are known as pit organs. pits may be arranged in rows. TERM 9 Role of Hair Cells in Detecting Water Currents DEFINITION 9 When water currents move the cupula, this causes the cilia to bend and can excite or inhibit the hair cell. hair cell is excited (depolarization) if the stereocilia bend along the axis of symertry toward the kinocilium ion channels open--> influx of K+ into apical end of cell -->calcium ions admitted near base of cell --> release of neurotransmitters -->firing rate increases Hair cell is inhibited if displacement of stereocilia is along the axis of symmetry but away from the kinocilium (firing rate decre TERM 10 Role of Hair Cells in Detecting Water Currents DEFINITION 10 Movement of cilia that is prependicular to the axis of symmetry will have no effect on exciting or inhibiting the hair cell. Morphological polarization of paired hair cells allows for currents in opposite direction.