Chapter 22:Homeostasis Flashcards
Flashcard 1:
- Q: What is homeostasis?
- A: The maintenance of a constant internal environment.
Flashcard 2:
- Q: What are the two environments in living organisms?
- A: External environment (the surroundings) and internal environment (space inside the body filled with tissue fluid).
Flashcard 3:
- Q: How does homeostasis help enzymes work effectively?
- A: By maintaining a constant internal body temperature around 37˚C.
Flashcard 4:
- Q: Why is maintaining a constant amount of water important for the body?
- A: To prevent damage to body cells or losing too much water by osmosis.
Flashcard 5:
- Q: What is the importance of maintaining constant blood glucose levels?
- A: To ensure there is always enough fuel for respiration.
Flashcard 6:
- Q: Why must blood pH be kept constant at about 7.4?
- A: Because variations in pH can lead to denaturation of enzymes.
Flashcard 7:
- Q: What does negative feedback do in homeostasis?
- A: It automatically brings about a correction to return a condition to its normal state.
Flashcard 8:
- Q: How does negative feedback work?
- A: Receptor cells detect changes and send messages to the brain, which issues instructions to effectors to correct the change.
Flashcard 9:
- Q: What happens if a factor is within its normal range after correction?
- A: Nothing more happens.
Flashcard 10:
- Q: What happens if a factor is still out of limits after initial correction?
- A: The receptor cells send another message to the brain, and the effector responds again.
Flashcard 11:
- Q: How does the body prevent overcorrection in negative feedback?
- A: By sending a negative message from the receptor to the effector to stop its corrective action.
Flashcard 12:
- Q: What are ectothermic animals?
- A: Animals that cannot generate sufficient heat inside the body and rely on external sources such as the sun for body heat.
Flashcard 13:
- Q: Give examples of ectothermic animals.
- A: Reptiles and insects.
Flashcard 14:
- Q: How do ectothermic animals regulate temperature in cold weather?
- A: By basking in the sun, darkening their skin, and hibernating.
Flashcard 15:
- Q: How do ectothermic animals regulate temperature in warm weather?
- A: By seeking shade, panting, and aestivating.
Flashcard 16:
- Q: What are endothermic animals?
- A: Animals that rely on heat produced within their bodies by metabolic reactions to control their body temperature.
Flashcard 17:
- Q: Give examples of endothermic animals.
- A: Mammals and birds.
Flashcard 18:
- Q: How do endothermic animals generate heat when it is cold?
- A: Through cellular respiration and increased metabolic rates due to adrenaline.
Flashcard 19:
- Q: How do endothermic animals lose heat when it is hot?
- A: Through radiation, evaporation, convection, and conduction.
Flashcard 20:
- Q: What is the role of insulation in temperature regulation?
- A: To prevent heat loss from the body; fats under the skin act as insulation.
Flashcard 21:
- Q: What happens to hair erector muscles in cold temperatures?
- A: They contract, making hairs stand upright to trap a layer of air for insulation.
Flashcard 22:
- Q: What happens to hair erector muscles in hot temperatures?
- A: They relax, making hairs lie flat and preventing insulation.
Flashcard 23:
- Q: How does sweating help regulate body temperature?
- A: By increasing evaporation of sweat from the skin surface, which leads to heat loss.
Flashcard 24:
- Q: What is vasoconstriction and its effect?
- A: Narrowing of blood vessels, reducing blood flow to the skin, and decreasing heat loss.
