Homeostasis Quiz
Questions: 16 · 10 minutes
1. Which situation most closely resembles a negative-feedback loop?
A microphone picks up sound from a speaker, making the sound increasingly louder
A blood clot recruits more platelets until a damaged vessel is sealed
A fruit releases a gas that speeds ripening in nearby fruit
A thermostat turns heating off when a room rises above its set temperature
2. Which statement best defines homeostasis?
The gradual adaptation of a population across generations
The maintenance of completely constant internal conditions at all times
The production of energy by breaking down nutrients inside cells
The regulation of internal conditions within workable ranges despite change
3. Someone enters a cold room and begins shivering. What is the main homeostatic effect of shivering?
It lowers metabolic activity to conserve glucose
Rapid muscle contractions generate heat and oppose the temperature drop
It reduces communication between temperature receptors and the brain
It widens skin blood vessels to release heat
4. A person's body temperature begins to rise during a run. Which response most directly illustrates negative feedback?
Muscles increase heat production so the temperature continues rising
The body permanently changes its normal temperature range
Sweating increases, helping move body temperature back toward its usual range
Temperature receptors stop communicating with the brain
5. Which organs play the most direct role in adjusting the amount of water and many dissolved ions in the blood?
The lungs
The kidneys
The pancreas
The spleen
6. If the pancreas produces little or no insulin, what is most likely after a meal containing carbohydrates?
Blood glucose remains elevated because normal uptake and storage are impaired
All absorbed glucose is immediately excreted before entering the blood
Blood calcium rises because glucose is converted into calcium ions
Blood glucose falls rapidly because glucagon action is blocked
7. In very humid conditions, sweat may remain on the skin instead of evaporating efficiently. Why can this challenge temperature homeostasis?
Reduced evaporation removes less heat, allowing core temperature to rise
Humidity causes skin receptors to stop detecting temperature
Sweat can cool the body only after it is reabsorbed into the bloodstream
Unevaporated sweat causes the body's temperature set point to disappear
8. After a carbohydrate-rich meal, blood glucose rises. Which response normally helps restore balance?
The pancreas releases glucagon, causing the liver to release more glucose
The kidneys immediately remove all glucose from the blood
The thyroid reduces metabolic activity until no glucose remains
The pancreas releases insulin, promoting glucose uptake and storage
9. Which process is a classic example of positive feedback?
Sweating helps lower an elevated body temperature
Insulin lowers blood glucose after a meal
Oxytocin strengthens uterine contractions, which stimulates further oxytocin release
Breathing rate changes to help stabilize blood carbon dioxide
10. A person becomes mildly dehydrated after exercising. What homeostatic response is expected?
ADH secretion decreases, producing a larger volume of dilute urine
Insulin secretion rises, moving more water into body cells
Kidney water reabsorption decreases so excess salts are retained
ADH secretion increases, promoting water reabsorption and more concentrated urine
11. During the early phase of a fever, a person may feel cold and shiver even though their measured temperature is elevated. What best explains this?
The regulatory set point has risen, so the current temperature is treated as too low
Sweat evaporation has lowered the skin and core to the same temperature
Insulin has redirected heat from the blood into body cells
Negative feedback has stopped operating throughout the body
12. Blood calcium begins to fall below its regulated range. Which response would help reverse the change?
More calcitonin is released to increase calcium deposition in bone
More insulin is released to move calcium into muscle cells
More parathyroid hormone is released, promoting processes that raise blood calcium
More ADH is released to remove calcium in dilute urine
13. On a hot day, how does widening blood vessels near the skin help regulate temperature?
It reduces blood flow to the skin and prevents heat loss
It increases heat transfer from the blood toward the body's surface
It causes muscles to contract rapidly and generate heat
It raises the body's temperature set point above normal
14. A plant experiences dry conditions and closes many of its stomata. How does this support homeostasis?
It increases evaporation so roots absorb less water
It reduces water loss through transpiration, helping preserve internal water balance
It permanently stops gas exchange in every leaf
It converts positive feedback into cellular respiration
15. Working muscles produce additional carbon dioxide during exercise. Which response helps limit the resulting change in blood pH?
The pancreas releases more insulin to convert carbon dioxide into glucose
The kidneys immediately stop filtering the blood
Ventilation increases, removing more carbon dioxide through the lungs
Skin blood vessels narrow to trap carbon dioxide in the tissues
16. Which sequence correctly describes the basic organization of a homeostatic control system?
Receptor detects change, control center processes it, effector produces a response
Effector detects change, receptor chooses a target, control center stops the response
Control center creates change, effector detects it, receptor stores the information
Receptor produces a response, effector sets the target, control center detects change