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1) The human body\'s arterial blood pH is tightly maintained around 7.4 by buffe

ID: 50568 • Letter: 1

Question

1) The human body's arterial blood pH is tightly maintained around 7.4 by buffering agents that bind hydrogen ions to stop any change in pH. If an acid-base imbalance overcomes the buffer system, the body changes the ventilation rate, or the rate at which gas enters or leaves the lungs. Changing the ventilation rate changes the concentration of CO2 in the blood, which alters the pH of the blood. In this case, the muscles that control the ventilation rate are acting as the:

homeostatic challenge

sensor

effector

integrator

2) For cells to maintain an appropriate solute concentration, _____ will occur; for cells to maintain an appropriate water concentration, _____ will occur.

diffusion, osmosis

osmosis, diffusion

diffusion, facilitated diffusion

diffusion, active transport

3) A marine fish with a cold body temperature that matches its cold surroundings is an example of

negative feedback

regulating

conforming

homeostasis

4) Fiddler crabs are small crabs that inhabit intertidal areas. When the tide comes in, the salinity rises to 35ppt and when the tide leaves, the salinity falls to 5ppt. Fiddler crabs can maintain their internal salinity at 32ppt when the external environment ranges from 20-40ppt, but cannot regulate at levels higher or lower than this. The range of 20-40ppt is the ____________________ for these animals.

zone of conforming

zone of stability

osmoregulatory conforming capacity

positive feedback effector range

homeostatic challenge

sensor

effector

integrator

Explanation / Answer

1. Answer - C Effector. Since Co2acts as effector based on which the muscle cells controls the ventilation.

2. Answer - A (Diffusion, Osmosis). Because

Diffusion is passive movement of solute molecules from a region of high concentration to a region of low concentration.

Osmosis is the passive movement of water molecules, across a partially permeable membrane, from a region of lower solute concentration to a region of higher solute concentration.

3. Answer - C (Conforming) Since it is a mechanism to act in accordance with the situation.

4. Answer - C Osmoregulatory conforming capacity - Since osmoregulation is the process involved with the maintance of salt concentration by a given organism.