ch4 1

Bony fishes are neutrally ______ (i.e., have the same density as water).

In countercurrent exchange, blood cells are separated from oxygen-rich water only by the thin ______ cells of the capillary wall.

Countercurrent flow maintains a ______ in oxygen concentration between blood and water for the full length of the lamella.

If water and blood flowed in the same direction, the ______ in oxygen concentration and the diffusion gradient would be high initially.

In figure 4-2, the direction of ______ flow across the gill opposes the flow of blood through the secondary lamellae.

Blood leaving the gill has a high ______ concentration due to countercurrent exchange.

These fishes do not have to swim to maintain their vertical position in the ______ column.

The only movement they make when at rest is backpedaling of the ______ fins to counteract the forward thrust.

Fishes capable of hovering in the water like this usually have well-developed ______ bladders.

The ______ bladder is located between the peritoneal cavity and the vertebral column.

The swim bladder wall, which has smooth walls composed of interwoven ______ fibers without blood vessels, is virtually impermeable to gas.

Neutral buoyancy produced by a swim bladder works as long as a fish remains at one ______, but if a fish swims vertically up or down, the hydrostatic pressure that the surrounding water exerts on the bladder changes.

The rete mirabile is a structure that moves gas, especially ______, from the blood to the gas bladder.

The gas gland secretes oxygen by releasing ______ acid and carbon dioxide.

Acidification causes ______ to release oxygen into solution.

The gas gland is located ______ the gas gland.

The rete mirabile is a structure that is known as a ______ net.

Gas secretion occurs in many deep-sea fishes despite the hundreds of ______ of gas pressure within the bladder.

Fishes that migrate over large vertical distances depend more on lipids such as ______ esters than on gas for buoyancy.

Air-Breathing Divers Air in the lungs of air-breathing aquatic vertebrates reduces their ______.

Deep-diving animals, such as elephant seals and some whales and porpoises, face a different problem, however. These animals dive to depths of ______ meters or more.

Under those conditions, nitrogen would be forced from the air in the lungs into solution in the ______ and carried to the tissues at high pressure.

Specialized diving mammals avoid the problem by allowing the ______ cavity to collapse as external pressure rises.

Air is forced out of the lungs as they collapse, reducing the amount of nitrogen that ______ into the blood.

Aquatic mammals such as whales and porpoises have spherical lenses like those of ______

Fishes have taste-bud organs in the mouth and around the head and anterior ______

Sharks and salmon can detect odors at concentrations of less than 1 part per ______

Homeward-migrating salmon are directed to their stream of origin from astonishing distances by a chemical signature from the home stream that was permanently imprinted when they were ______

Mechanical receptors detect ______, sound, pressure, and motion

Fishes also have ______ detectors at the base of the semicircular canals that allow them to distinguish up from down

What property of seawater makes it possible for sharks to detect the electrical activity of their prey?

Where are the ampullae of Lorenzini located in sharks and rays?

What is the function of the canal in the ampullae of Lorenzini?

What is the threshold of detection for electroreceptors in sharks?

What type of activity generates electrical potential in animals?

What is the function of electroreceptors in sharks?

What is the purpose of the cupula in the lateral line system of fishes?

How does the deflection of the kinocilium in one direction versus the opposite direction affect the hair cell receptor potential?

What is the effect of cupula displacement on the afferent nerve discharge rates in a lateral line organ?

How do the paired hair cells in a neuromast organ respond to cupula displacement?

What is the role of the neuromast organ in the lateral line system of fish?

How do the lateral line organs in fish contribute to their spatial awareness and navigation?

What do sharks use for navigation and locating prey?

What do sharks detect in their surroundings using electroreception?

What is the role of the electromagnetic field at Earth's surface in shark navigation?

What is the function of the experiment shown in Figure 4-8?

What is the relationship between electrical signals and olfactory cues in shark prey detection?

What is the significance of the agar shield in the experiment shown in Figure 4-8?

What is the purpose of the dual system in sharks, and how does it enable them to find food items?

How do weakly electric teleost fishes produce their electric discharge, and what is the range of pulse rates observed in these fishes?

How do electric fishes detect the presence, position, and movement of objects in their environment?

What is the role of rocks and other objects in the environment of electric fishes, and how do they affect the fish's electric field?

What is the advantage of having a pulsating electric discharge, and how does it relate to the energy costs of maintaining an electric field?

How do the electric fields of weakly electric fishes interact with their environment, and what is the significance of the electric field's range?

What is the primary function of electroreceptors in weakly electric fishes?

How do conductive objects affect the electric field of a weakly electric fish?

What happens when two weakly electric fishes swim close to each other?

What is the likely origin of electroreception in vertebrates?

What type of cells have a prominent kinocilium and fire when the environment around the kinocilium is negative relative to the cell?

What is the location of the electroreceptor cells in the brain?