Biom9 Flashcards
(48 cards)
Which term describes the body’s process of anticipating and preparing for changes in internal and external conditions, such as a temperature increase?
A) Homeostasis
B) Allostasis
C) Positive feedback
D) Negative feedback
Answer: B) Allostasis.
Explanation: Allostasis refers to the body’s ability to anticipate needs and make adjustments based on environmental and internal cues, such as increasing thirst and reducing urine production when anticipating dehydration due to heat.
Which of the following is a key feature of homeostasis?
A) It only applies to maintaining body temperature.
B) It involves behavior modifications like moving to a cooler or warmer area.
C) It keeps physiological variables within a set range through negative feedback.
D) It anticipates the body’s future needs rather than simply responding to disturbances.
Answer: C) It keeps physiological variables within a set range through negative feedback.
Explanation: Homeostasis maintains body variables (e.g., temperature, blood pressure) within a narrow range using negative feedback mechanisms. For instance, the body shivers to increase heat when it’s cold.
What is the primary disadvantage of endothermy (the ability to regulate body temperature internally)?
A) Increased energy expenditure for temperature regulation
B) Limited adaptability to environmental changes
C) Inability to engage in vigorous activity in cold temperatures
D) Inability to enter hibernation during food scarcity
Answer: A) Increased energy expenditure for temperature regulation.
Explanation: Endothermic animals, like mammals and birds, need to continuously expend energy to maintain a constant body temperature. This comes at a metabolic cost, requiring more food and energy compared to ectotherms that rely on external sources for heat.
Which of the following mechanisms is NOT typically involved in regulating body temperature in humans?
A) Shivering to generate heat in cold conditions
B) Sweating to dissipate heat in hot conditions
C) Changing metabolic set points based on external temperature
D) Decreasing blood flow to the skin to preserve core temperature
Answer: C) Changing metabolic set points based on external temperature.
Explanation: Humans do not change their metabolic set points like ectotherms. Instead, they regulate body temperature through mechanisms such as sweating, shivering, and adjusting blood flow to the skin. Metabolic set points are relatively constant and only adjust slightly for physiological needs like fever.
What is the function of brown adipose tissue in mammals?
A) To store excess nutrients
B) To produce heat through metabolism
C) To store fat for long-term energy use
D) To regulate body temperature by constricting blood vessels
Answer: B) To produce heat through metabolism.
Explanation: Brown adipose tissue, found in some mammals, burns fuel to produce heat (thermogenesis) instead of storing it as fat. This helps maintain body temperature, especially in colder environments.
Which of the following brain areas primarily controls physiological mechanisms of body temperature regulation such as sweating and shivering?
a) Hippocampus
b) Preoptic area/anterior hypothalamus (POA/AH)
c) Raphe nucleus
d) Medulla oblongata
Answer: b) Preoptic area/anterior hypothalamus (POA/AH)
Explanation: The POA/AH is the primary area involved in regulating physiological temperature mechanisms, including sweating and shivering, based on input from temperature receptors in the body.
What happens to body temperature regulation in mammals after damage to the POA/AH?
a) Mammals cannot regulate body temperature at all.
b) They rely on behavioral mechanisms similar to those of reptiles and amphibians.
c) They become unable to sense temperature changes.
d) They exhibit enhanced sweating and shivering.
Answer: b) They rely on behavioral mechanisms similar to those of reptiles and amphibians.
Explanation: After damage to the POA/AH, mammals can still regulate body temperature, but they do so through behavioral means like seeking a warmer or colder environment, similar to how reptiles and amphibians adjust to temperature changes.
Which of the following best explains the mechanism behind a fever?
a) The body temperature rises due to an infection’s direct effect on the hypothalamus.
b) The hypothalamus sets a higher temperature threshold, causing the body to generate heat.
c) The body fails to regulate temperature, causing a direct rise in body heat.
d) Increased shivering and sweating are triggered by infection-induced changes in the immune system.
Answer: b) The hypothalamus sets a higher temperature threshold, causing the body to generate heat.
Explanation: Fever results from the hypothalamus setting a higher body temperature set point in response to infection, prompting the body to generate heat (e.g., through shivering) to maintain that higher temperature.
How does vasopressin help the body conserve water?
a) By increasing blood volume during dehydration
b) By promoting the excretion of diluted urine
c) By constricting blood vessels and promoting reabsorption of water in the kidneys
d) By stimulating the hypothalamus to induce thirst
Answer: c) By constricting blood vessels and promoting reabsorption of water in the kidneys
Explanation: Vasopressin, also known as antidiuretic hormone (ADH), constricts blood vessels to raise blood pressure and promotes the kidneys’ ability to reabsorb water, leading to more concentrated urine and helping the body conserve water during dehydration.
What causes osmotic thirst?
A) Eating salty foods
B) Losing fluid through bleeding or sweating
C) A decrease in blood volume
D) A drop in blood pressure
Answer: A) Eating salty foods
Explanation: Osmotic thirst is triggered by the consumption of salty foods, which increases the concentration of solutes outside cells, causing water to move out of cells and creating a need for water.
What is osmotic pressure?
A) The force that moves solutes from low to high concentration
B) The force that drives water across a semipermeable membrane from low to high solute concentration
C) The pressure that blood exerts on blood vessel walls
D) The pressure created by hormones like aldosterone
Answer: B) The force that drives water across a semipermeable membrane from low to high solute concentration
Explanation: Osmotic pressure refers to the movement of water across a membrane to balance the concentration of solutes, moving from an area of low solute concentration to one of higher concentration.
Which brain structure detects osmotic pressure and sodium content of the blood?
A) Hippocampus
B) Subfornical organ (SFO)
C) Organum vasculosum laminae terminalis (OVLT)
D) Medulla oblongata
Answer: C) Organum vasculosum laminae terminalis (OVLT)
Explanation: The OVLT, located around the third ventricle, detects osmotic pressure and sodium content of the blood, triggering mechanisms to restore balance.
Which hormone is involved in both osmotic thirst and the regulation of blood pressure?
A) Cortisol
B) Insulin
C) Vasopressin
D) Aldosterone
Answer: C) Vasopressin
Explanation: Vasopressin helps regulate osmotic thirst by promoting water retention in the kidneys, and it also constricts blood vessels to manage blood pressure.
What is hypovolemic thirst triggered by?
A) An increase in solute concentration in the blood
B) A decrease in blood volume
C) Increased intake of salty food
D) Dehydration caused by sweating
Answer: B) A decrease in blood volume
Explanation: Hypovolemic thirst occurs when there is a loss of body fluid (e.g., through bleeding or sweating), and the body needs to restore blood volume rather than just solute concentration.
What causes sodium-specific hunger?
A) An increase in blood sugar levels
B) A decrease in sodium reserves
C) An increase in osmotic pressure
D) A drop in water levels
Answer: B) A decrease in sodium reserves
Explanation: Sodium-specific hunger arises when sodium levels are low, causing the body to crave salty foods to replenish its sodium reserves.
Which brain region is responsible for controlling drinking behavior during osmotic thirst?
A) Hypothalamus
B) Thalamus
C) Medulla
D) Cerebellum
Answer: A) Hypothalamus
Explanation: The hypothalamus is involved in regulating thirst and controlling drinking behavior, responding to signals of osmotic and hypovolemic thirst.
What is the role of aldosterone in sodium-specific hunger?
A) It increases salt excretion in urine
B) It stimulates the release of vasopressin
C) It causes the kidneys and glands to retain sodium
D) It dilutes the concentration of solutes in the blood
Answer: C) It causes the kidneys and glands to retain sodium
Explanation: Aldosterone increases the retention of sodium by the kidneys, salivary glands, and sweat glands, playing a role in sodium-specific hunger when sodium levels are low.
Which of the following is true about the relationship between osmotic and hypovolemic thirst?
A) Osmotic thirst is triggered by a loss of blood volume, while hypovolemic thirst is triggered by a high concentration of solutes in the blood
B) Osmotic thirst involves water balance, while hypovolemic thirst involves salt and water balance
C) Osmotic thirst requires a higher intake of salt, while hypovolemic thirst requires pure water
D) Osmotic thirst is caused by dehydration, while hypovolemic thirst is not related to fluid loss
Answer: B) Osmotic thirst involves water balance, while hypovolemic thirst involves salt and water balance
Explanation: Osmotic thirst is related to the need for water due to an imbalance of solutes, while hypovolemic thirst involves the need for both salt and water due to a decrease in blood volume.
How does the body anticipate osmotic thirst before it occurs?
A) By reducing the production of vasopressin
B) By activating neurons in the digestive tract that detect salt intake
C) By decreasing the sensitivity of taste receptors to salty foods
D) By stimulating the release of aldosterone
Answer: B) By activating neurons in the digestive tract that detect salt intake
Explanation: The OVLT receives input from the digestive tract, allowing the body to anticipate the need for water after eating salty foods, before osmotic pressure changes occur.
Which of the following best describes the function of the small intestine in digestion? A) It absorbs water and minerals
B) It digests carbohydrates, proteins, and fats and absorbs nutrients into the blood
C) It produces bile to digest fats
D) It stores food for later digestion
Answer: B) It digests carbohydrates, proteins, and fats and absorbs nutrients into the blood
Explanation: The small intestine is primarily responsible for digesting food with enzymes and absorbing the resulting nutrients into the bloodstream.
Why do some adults in certain regions have the ability to metabolize lactose, while others do not?
A) The genetic ability to digest lactose evolved only in Europe
B) Lactase persistence is a universal trait in mammals
C) The prevalence of the necessary genes varies due to historical domestication of cattle
D) Lactase production is linked to childhood diet
Answer: C) The prevalence of the necessary genes varies due to historical domestication of cattle
Explanation: The ability to digest lactose in adulthood is primarily found in societies with a long history of cattle domestication, showing a genetic adaptation to dairy consumption.
Which statement is true regarding the process of satiety in eating?
A) Sham feeding satisfies hunger completely
B) Stomach distension is a critical factor for ending a meal
C) Tasting food is not necessary for satiety
D) The duodenum does not send signals about food intake
Answer: B) Stomach distension is a critical factor for ending a meal
Explanation: Stomach distension is one of the main signals for satiety. When the stomach stretches, it triggers mechanisms to end a meal.
What role does the hormone cholecystokinin (CCK) play in meal regulation?
A) It enhances digestion by increasing gastric acid production
B) It prevents hunger signals from reaching the brain
C) It slows down digestion by constricting the stomach sphincter and signaling satiety
D) It helps in the digestion of lactose
Answer: C) It slows down digestion by constricting the stomach sphincter and signaling satiety
Explanation: CCK reduces meal size by constricting the stomach sphincter and signaling the brain about fullness, thus contributing to meal termination.
Which factor is most likely responsible for the regulation of food intake through feedback from the intestines?
A) The amount of calories consumed
B) The taste receptors in the digestive tract
C) The secretion of insulin from the pancreas
D) The absorption of vitamins in the stomach
Answer: B) The taste receptors in the digestive tract
Explanation: The digestive tract contains taste receptors that help regulate food intake by altering brain activity, contributing to the sensation of satiety.
