NEUR 3304 - Midterm 2 Exam Questions Answered Correctly Latest Update 2026/2027

NEUR 3304 - Midterm 2 Exam Questions Answered Correctly Latest Update 2026/2027 A researcher creates a mouse that lacks the SIM-1 gene. What hypothalamic nucleus do you expect to be underdeveloped in this mouse? What peptidergic cell groups would be underdeveloped in these mice? (you need to read the paper on hypothalamic development from the readings) - Answers In mice lacking the SIM-1 gene, the paraventricular nucelus (PVN) of the hypothalamus will be underdeveloped, leading to deficits in oxytocin, vasopressin, and corticotropic-releasing hormones (CRH) neuronal peptidergic cell groups that depend on the PVN for development and are ket to social behavoiur, fluid balance, and stress response. If a pregnant mouse is given the drug flutamide, an androgen receptor antagonist, during the second week of pregnancy, what do you expect to see in her male offspring? What would you expect if a similar pregnant mouse is given the drug finasteride (a 5-alpha reductase inhibitor) during the same period? - Answers If a pregnant mouse is given flutamide (an androgen receptor agonist) during the second week of pregnancy, her male offspring will have undermasculinized genitalia and bheaviour due to blocked androgen receptors (androgen = testosterone). With finasteride (a 5-alpha reductase inhibitor), male offspring will also have undermasculinized genitalia. Finasteride blocks 5-alpha reductase, preventing testosterone's conversion to dihydrotestosterone (DHT), a potent androgen required for genital development. Though behavioural effects may be less severe than with flutamide since testosterone can still partially act without conversion to DHT. A graduate student interested on how environmental toxins affect metabolism (Let's call her Zita), discovers that the bisphenol A BPA, a chemical compound used to make plastic bottles, can disrupt leptin levels in newborn pups. These pups will have lower levels of leptin during the first 2 weeks of life compared to animals not exposed to this chemical. What system is affected by this disruption? How is it affected? What do you expect the pups to look ike as adults? - Answers BPA exposure disrupts leptin levels, affecting the development of the hypothalamic neural circuits in the arcuate nucelus (ARC) that regulate appetite and energy balance. Lower leptin levels hinders the formation of POMC neurons (which reduce appetite) and NPY/AgRP neurons (which increase appetite). As adults, these mice likely show poor appetite control, lower energy expenditure, and are at higher rick of obesity due to this disrupted neural wiring. While watching the Ottawa senators, Dr. Alexander Edwards downs a jumbo bag of Doritos and a 2 litter bottle of coke. How would the salt in the doritos affect his osmotic balance? How would the sugar in the coke affect his osmotic balance? What do you expect his levels of angiotensin II, ADH and mineralocorticoids are like in response to the salt loading and then the glucose loading? - Answers The salt from the Doritos raises blood sodium concentration, leading to an increase in blood osmolarity. This rise in osmolarity draws water out of cells, disrupting osmotic balance and causing cellular dehydration. To counter this, his body would release antidiuretic hormone (ADH) to promote water reabsorption in the kidneys, helping dilute the sodium and restore osmotic balance. Angiotensin II and mineralocorticoids like aldosterone would also increase, promoting sodium and water reabsorption to stabilize blood volume and pressure. The sugar in the Coke, primarily glucose, would also raise blood osmolarity, albiet temporarily. High glucose levels increase osmotic pressure in the blood, potentially drawing more water out of cells to dilute. This, too, triggers ADH release to reabsorb water. However, unlike the response to salt, aldosterone levels may not rise significantly since sodium retention is not the primary need here. Angiotensin II might initially rise with the osmolarity increase but would likely stabilize as blood glucose is cleared from circulation. A cute puppy (his name is "Draco") has been going to the park since he was 2 months old, but lately, the puppy has become aggressive to other male dogs and rather "friendly" to female dogs. As he is "befriending" Lola, the neighbours sexy poodle who is in heat, what types of sensory information is Draco receiving to excite him and what brain pathways are conveying this information? (hint: there are two main pathways)? What brain region is critical for integratuing this sensory information with hormonal information? - Answers Draco's excitement toward Lola is driven by two olfactory pathways conveing pheromone and odor cues. The main olfactory pathway detects general odors and osme pheromones, sending signals from olfactory receptors to the main olfactory bulb, which relays information to the piriform cortex and amygdala. These areas process social cues and connect with medial preoptic area (MPOA) of the hypothalamus to influence sexual behaviors. Meanwhile, the accessory olfactory pathway specifically detects pheromones through the vomeronasal organ (VNO), which sends signals to the accessory olfactory bulb and then to the medial amygdala. The medial amygdala routes this information to the bed nucleus of the stria terminalis (BNST) and the hypothalamus. The hypothalamus integrates these sensory signals with hormonal cues, particularly testosterone, heightening Draco's attraction to Lola and influencing his social and mating behaviors. Describe the endocrine role of the liver and the kidney in modulating drinking behaviors - Answers The liver produces angiotensin, and kidney produces renin. The combination of angiotensin and renin creates angiotensin-1. Angiotensin-converting enzyme transforms angiotensin-1 into angiotensin-2. This stimulates the PVN and SON of the hypothalamus to release vasosuppressants and stimulates the adrenal cortex to release aldosterone. The vasosupressants in the kidney allow for large amounts of water reabsorption from the kidneys. Aldosterone allows for the reabsorption of salts from the kidneys. Angiotensin-2 also stimulates