Lecture 8 Lateral Line and Electrical Senses

Question 1

Lateral Line (3)

Answer 1

-Allows detection of water movements around fish “distant touch” through hydraulic medium
-used for navigation, prey detection
-sensing of low frequency sounds associated with water movement

Question 1

Lateral Line (3)

Answer 1

-Allows detection of water movements around fish “distant touch” through hydraulic medium
-used for navigation, prey detection
-sensing of low frequency sounds associated with water movement

Question 2

Specializations of lateral line (3)

Answer 2

-lateral lines may be displaced when fin movements influence water flow around canal or the direction of focus (up/down) is influenced by behavior
-less active, slow moving fish tend to have more free neuromasts
-canal diameter may “tune” for response to specific frequencies

Question 3

Electroreception (2)

Answer 3

-Common in fishes EXCEPT TELEOSTS
-can be passive or active

Question 4

passive electroreception (2)

Answer 4

-sensing electrical currents already present in the environment such as muscle activities of prey
-elasmobranchs classic example, can detect gradients of 5x10-4 millivolts / cm (generated by anything swimming in geomagnetic field)

Question 5

active electroreception (3)

Answer 5

-sensing generated currents and their distortions
-for electrolocation (navigation & predation) & signaling
-teleosts fit this category: such as electric catfish and elephant fish

Question 6

Organs of Electroreception (2)

Answer 6

-Ampullary of Lorenzini
-Tuberous

Question 6

Ampullary of Lorenzini (3)

Answer 6

-conductive gel fills canal open to water
-sensory cells surround canal
-kinocilium (elasmobranchs) or microvilli (teleosts) extend into lumen of canal

Question 7

tuberous (3)

Answer 7

-no opening to exterior
-if present, canal filled with loose epithelial cells
-more sensitive to high frequency signals

Question 8

Electrical Communication in Elephant Fishes

Answer 8

-caudal electrical organ
-males signal to females from their mating territories with a “rasp” discharge in response to female’s EOD (electrical organ discharge)
-can discriminate signals based upon duration of pulse and waveform