When body temperature drops, sweat glands decrease their secretion to conserve heat.
Correct Answer
True
True. Sweating removes heat through evaporation, so sweat secretion falls when the body needs to conserve heat. Skin blood vessels also constrict and shivering produces heat.
Category: Temperature Regulation
Question 2
Nerve cells in the skin and brain can act as the receptors that sense changes in body temperature.
Correct Answer
True
True. These nerve cells detect a rise or fall in temperature and send the information to the temperature regulatory center in the brain, which directs the response.
Category: Feedback Loops
Question 3
A hypotonic solution causes water to move into cells, which can make them swell.
Correct Answer
True
True. A hypotonic solution has a lower tonicity than the cell's interior, so water enters the cell by osmosis. Too much swelling disrupts cell function.
Category: Osmolality and Tonicity
Question 4
Children are at higher risk of dehydration than adults partly because their kidneys conserve water less efficiently.
Correct Answer
True
True. Immature kidneys concentrate urine less effectively, and children also have a higher metabolic rate and a larger proportion of body water. These factors make fluid and electrolyte imbalances more likely.
Category: Special Populations
Question 5
Feedback loops work to correct deviations from a set point, the target value the body defends.
Correct Answer
True
True. A homeostatic control system compares the current value of a variable, such as body temperature, with its set point and triggers responses that return it toward that value.
Category: Feedback Loops
Question 6
Many medical conditions result from a breakdown in the body's homeostatic control systems.
Correct Answer
True
True. Disease can follow when the body fails to detect a change, fails to start a feedback loop, cannot return to the set point, or has a faulty set point. Treatment often aims to restore homeostasis before cells and organs are damaged.
Category: Homeostasis Basics
Question 7
Osmoreceptors in the hypothalamus trigger thirst when the osmolality of the blood rises.
Correct Answer
True
True. When blood becomes more concentrated, as in dehydration, osmoreceptors in the hypothalamus sense the change and stimulate thirst so the person drinks and dilutes body fluids. The hypothalamus also signals release of antidiuretic hormone, which helps the kidneys conserve water.
Category: Osmolality and Tonicity
Question 8
Oncotic pressure pulls fluid from the interstitial space back into the capillaries.
Correct Answer
True
True. Oncotic pressure, a form of osmotic pressure created by plasma proteins, draws fluid into the capillaries. It opposes hydrostatic pressure, which pushes fluid out.
Category: Osmotic Equilibrium
Question 9
Hormonal changes in pregnancy, including higher progesterone levels, affect fluid and electrolyte regulation.
Correct Answer
True
True. Pregnancy brings increased blood volume and fluid retention along with hormonal shifts. These changes make pregnant clients more susceptible to edema and electrolyte imbalances.
Category: Special Populations
Question 10
Body water is divided into two main compartments, the intracellular fluid and the extracellular fluid.
Correct Answer
True
True. Intracellular fluid is inside the cells, and extracellular fluid is outside them. Extracellular fluid is further divided into interstitial, intravascular, and transcellular fluid.
Category: Fluid Compartments
Question 11
A negative feedback loop amplifies the original change in a body variable.
Correct Answer
False
False. A negative feedback loop opposes the original change and returns the variable toward its set point. Amplifying a change is the work of positive feedback.
Category: Feedback Loops
Question 12
Milk release during breastfeeding is an example of negative feedback.
Correct Answer
False
False. Lactation is a positive feedback loop: the infant's sucking triggers oxytocin release, which releases milk, and continued sucking keeps the cycle going. The response reinforces the stimulus instead of stopping it.
Category: Feedback Loops
Question 13
Hypoosmolality means the concentration of solutes in a body fluid is higher than normal.
Correct Answer
False
False. Hypoosmolality means the solute concentration is lower than normal, as can happen with excessive water intake. A higher than normal concentration is hyperosmolality.
Category: Osmolality and Tonicity
Question 14
Evaporation of sweat from the skin adds heat to the body.
Correct Answer
False
False. Evaporation of sweat removes heat from the skin, which is why sweat glands are effectors that cool the body when it is too warm.
Category: Temperature Regulation
Question 15
A semipermeable membrane allows all molecules and ions to pass through it freely.
Correct Answer
False
False. A semipermeable membrane lets only certain molecules or ions pass, by diffusion or active transport. This selectivity is what allows cells to keep their internal fluid different from the fluid outside.
Category: Osmotic Equilibrium
Question 16
Osmotic equilibrium is a state in which solute concentrations differ greatly on the two sides of a membrane.
Correct Answer
False
False. Osmotic equilibrium is reached when solute concentrations are equal on both sides of a semipermeable membrane. At that point there is no net movement of water.
Category: Osmotic Equilibrium
Question 17
Homeostasis keeps body conditions such as temperature and pH within a wide range that shifts with the outside environment.
Correct Answer
False
False. Homeostasis keeps these conditions within a narrow range and holds them steady even when the outside environment changes. Moving outside that range can cause cell death and organ damage.
Category: Homeostasis Basics
Question 18
Drinking an excessive amount of water can cause hyperosmolality of body fluids.
Correct Answer
False
False. Excessive water intake dilutes body fluids and causes hypoosmolality. Hyperosmolality is caused by problems such as dehydration or very high blood glucose.
Category: Osmolality and Tonicity
Question 19
The control center of a feedback loop is usually located in the skin.
Correct Answer
False
False. The control center is usually in the brain or another part of the nervous system, such as the hypothalamus. The skin contains receptors and effectors, such as nerve endings and sweat glands.
Category: Feedback Loops
Question 20
A transient change is a permanent shift in the body's set point.
Correct Answer
False
False. A transient change is a temporary disturbance, such as a brief shift in temperature or pH, after which the body returns to a steady state. It does not permanently alter the set point.
Category: Homeostasis Basics