Lecture 20 October 22 2008 Semicircular canals otoliths

Lecture 20. October 22, 2008 - Semi-circular canals, otoliths, & Lateral Line 1. 2. 3. 4. 5. Reminder about haircell biology Function & Purpose of Semi-circular canals Function & Purpose of Utricle Function & Purpose of Lagena & Sacculus Lateral line, neuromasts, and external detectors

Video on Fish Sound • http: //videos. howstuffworks. com/sciencechannel/5080 -discoveries-fish-mating-calls -video. htm

hair cells from saccule of squirrelfish hair cells from giant zebra danio (Cyprinidae)

Three Semi-Circular Canals and Three Otoliths Semi-Circular Canals - provide info on acceleration/balance/orientation in space – yaw, pitch, roll & acceleration/deceleration. Utriculus (an otolith chamber) - provide info on GRAVITY (i. e. up versus down) Sacculus & Lagena (2 more otolith chambers) - provide info on SOUND Chamber Utriculus Sacculus Lagena >> >> >> Otolith Lapillus Sagitta Asteriscus

Otolith OL = back calculation 1 y 4 y TL

Weberian Apparatus >> Otophysi HO#55

Weberian Apparatus HO#55

Lateral Line System

Review Questions: 1) Be able to draw the ampulla in the semi-circular canal and label the following parts: endolymph, hair cells, sensory hairs, cupula. How do fish detect their own movement in water via the ampulla? 2) Be able to draw the otoliths and how they connect to the hair cells via the sensory hairs. 2 b) Why do fish need otoliths to detect sound? How do hair cells detect sound? 3) How do the Webberian apparatus and the extended swimbladder increase the sensitivity of fish to sound? How do they stimulate the otoliths? Which fish have a Webberian apparatus? Which fish have an extended swimbladder? 4) Draw out a neuromast and label the following parts: hair cells, cupula, sensory hairs. How do neuromasts provide information on the direction of water flow? Where on the fish can neuromasts be located? Which fish have neuromasts in pores as opposed to on the body surface? 5) Why do fish orient their lateral lines so that they “are out of the way” of their pectoral fins?