All flashcards
Flashcard 1: Which effectors primarily increase heat loss during hyperthermia?
Answer: Sweating and cutaneous vasodilation. These mechanisms enhance evaporative cooling and heat radiation to counteract elevated body temperature.
Flashcard 2: What is a positive feedback loop in physiological regulation?
Answer: A response that amplifies the initial change. Positive feedback intensifies a process to completion, like oxytocin enhancing uterine contractions during childbirth.
Flashcard 3: What is homeostasis in physiology?
Answer: Maintenance of internal conditions near a set point. Homeostasis ensures physiological stability by regulating variables like temperature and pH around optimal levels despite external changes.
Flashcard 4: Choose the phrase that best defines allostasis in regulation.
Answer: Stability through change by adjusting the set point. Allostasis achieves stability by adapting set points to chronic stressors, differing from fixed homeostasis.
Flashcard 5: What is the response in a physiological feedback loop?
Answer: Effector action that changes the regulated variable. The response corrects the deviation detected by the sensor, bringing the system back toward the set point.
Flashcard 6: What is the stimulus in a physiological feedback loop?
Answer: Deviation of a regulated variable from its set point. The stimulus triggers the feedback loop by signaling a need for adjustment to maintain homeostasis.
Flashcard 7: What is the function of an effector in a homeostatic control system?
Answer: Carries out the response to adjust the variable. Effectors execute commands from the control center to restore the regulated variable to its set point.
Flashcard 8: What is the function of an integrator (control center) in homeostasis?
Answer: Compares to set point and generates an output signal. The integrator evaluates sensor input against the set point to initiate appropriate corrective actions via effectors.
Flashcard 9: What is the function of a sensor (receptor) in a feedback loop?
Answer: Detects a change in a regulated variable (stimulus). Sensors monitor environmental or internal changes and relay information to maintain homeostasis.
Flashcard 10: Identify the three core components of a homeostatic control loop.
Answer: Sensor, integrator (control center), effector. These components form the basic structure of feedback systems, detecting changes, processing information, and enacting responses.
Flashcard 11: Which option best describes a regulated variable in homeostasis?
Answer: A measurable condition maintained within a narrow range. Regulated variables are essential parameters like blood pressure that homeostasis keeps stable for optimal function.
Flashcard 12: What is a negative feedback loop in homeostatic regulation?
Answer: A response that counteracts the initial change. Negative feedback restores equilibrium by opposing deviations, such as insulin lowering high blood glucose.
Flashcard 13: What is the set point in a homeostatic control system?
Answer: Target value or range for a regulated variable. The set point represents the ideal physiological value that feedback mechanisms aim to restore when deviations occur.
Flashcard 14: Which option best defines feedforward control in physiology?
Answer: Anticipatory response that occurs before a variable changes. Feedforward mechanisms preemptively adjust physiology, like salivation before eating to aid digestion.
Flashcard 15: Identify the classic positive feedback example involving blood vessel repair.
Answer: Platelet aggregation during blood clotting. Initial platelet activation releases factors that recruit more platelets, accelerating clot formation.
Flashcard 16: Identify the classic human positive feedback example involving uterine contractions.
Answer: Oxytocin-driven labor (parturition). Oxytocin release amplifies contractions, creating a positive loop that progresses labor to delivery.
Flashcard 17: What is the net effect of glucagon on blood glucose?
Answer: Increases blood glucose. Glucagon stimulates glycogenolysis and gluconeogenesis to elevate blood sugar during fasting states.
Flashcard 18: What is the net effect of insulin on blood glucose?
Answer: Decreases blood glucose. Insulin facilitates glucose uptake by cells and inhibits gluconeogenesis, normalizing high blood sugar.
Flashcard 19: What is the primary stimulus for glucagon secretion by pancreatic b^1 cells?
Answer: Decreased blood glucose. Low glucose triggers glucagon to mobilize stores and raise levels, preventing hypoglycemia.
Flashcard 20: What is the primary stimulus for insulin secretion by pancreatic b^2 cells?
Answer: Increased blood glucose. Elevated glucose levels prompt insulin release to promote uptake and storage, restoring normoglycemia.
Flashcard 21: Which effectors primarily conserve or generate heat during hypothermia?
Answer: Shivering and cutaneous vasoconstriction. These responses reduce heat loss and increase heat production to restore normal body temperature.
Flashcard 22: What is the thermoregulatory control center in humans?
Answer: Hypothalamus. The hypothalamus integrates thermal signals and coordinates responses to maintain core body temperature.
Flashcard 23: Which option best defines an antagonist effector pair in homeostasis?
Answer: Two effectors that produce opposing effects on a variable. Antagonist pairs allow precise control by balancing increases and decreases in the regulated variable.
Flashcard 24: Identify the term for stable oscillations around a set point in homeostasis.
Answer: Dynamic equilibrium. Dynamic equilibrium describes the steady state where variables fluctuate minimally around the set point.