Sonne slides 101-151 Flashcards
What reproductive issues were observed in Baltic seals due to pollutants?
Females had:
- uterine stenoses, preventing egg transport
Also:
- kidney damage
- tooth loss caused by bone inflammation.
What is the Testicular Dysgenesis Syndrome (TDS)?
Male reproduction-related condition
Symptoms and embryonal-based disorders:
- hypospadias (opening of the urethra is on the underside of the penis instead of at the tip)
- cryptorchidism, absence of at least 1 testicle from the scrotum
- poor semen quality
- testicular cancer
How did the Baltic seal disease complex become a template for Arctic research?
It showed how simultaneous marine and terrestrial issues, like DDT, mercury, and reproductive problems, can inform studies on polar bears and other Arctic species.
What causes the decrease in polar bear skull bone density (osteoporosis), and why does it affect only males?
Males face stronger selection pressures due to less calcium recycling, while females mobilize calcium for pups during hibernation, preserving their bone density.
How does PCB exposure vary geographically in polar bears?
PCB concentrations increase demographically from west to east in the Arctic, reflecting regional pollution sources
What is the role of the hypothalamic-pituitary-adrenal/gonadal axis (HPA/G-axis)?
It regulates endocrine functions, including stress responses and reproductive hormones, but can be disrupted by pollutants like mercury.
How do pollutants like PFAS affect polar bear testosterone levels?
High PFAS concentrations lower testosterone, reducing fertility and altering male behavior, such as decreased mating interest.
Why do female polar bears avoid osteoporosis, CVD, and DMII despite extreme physiological stress?
Their endocrine systems are adapted to preserve bone density and overall health during reproductive cycles, even under massive calcium demands.
What does melatonin do in polar bears, and how is it linked to hormonal changes?
Produced by the pineal gland, melatonin regulates seasonal cycles, influencing reproductive hormone levels like testosterone and estrogen during maturation
How do pollutants disrupt endocrine systems in female polar bears?
Pollutants like DDT increase male hormone production in females, causing abnormal genital development and reproductive issues.
How does mercury impact brain function in humans and wildlife?
Mercury exposure reduces antibody production, slows cognitive functions, and disrupts neurological development, as seen in studies on polar bears and children.
What are the effects of PFAS on cognitive and motor functions?
PFAS impair both motor and cognitive abilities by disrupting the nervous system and testosterone regulation, affecting behavior and brain health.
Why are tissues from wildlife essential for studying ecotoxicology?
Wildlife tissues, like polar bear brains, provide critical insights into pollutant effects on hormones, immune systems, and neurological health.
How does mercury exposure in polar bear-based diets affect humans?
Communities consuming polar bears, like those in the Faroe Islands, experience reduced brain function and slower cognitive responses, particularly in children.
How do endocrine-disrupting pollutants affect polar bear behavior?
Pollutants like PFOS and mercury lower testosterone, disrupting mating behaviors and reducing reproductive success.
What is the connection between mercury, the pituitary gland, and brain function?
Mercury disrupts the pituitary gland’s steroid production, leading to impaired brain development and function, particularly in exposed children.
What did research on Baltic seals reveal about the impact of chemical cocktails?
A mix of pollutants caused severe health issues like reproductive failure, kidney damage, and tooth loss, showing the importance of studying combined toxic effects.
Why is the concept of “cocktail pollution” important?
It highlights how multiple pollutants interact to exacerbate toxic effects, such as impaired immunity and reproductive health, which might not be apparent from single pollutant studies.
What is the target organ if you want to learn more about the effects of pollutants in polar bears?
Liver
Why are Ito cells (liver) and Vitamin A crucial for polar bears?
Ito cells store Vitamin A, essential for polar bear health.
A deficiency can lead to conditions like cancer, as observed in captivity studies.
What was the significance of the sled dog study in polar bear diet research?
Sled dogs were fed diets with and without blubber to study pollutant effects, revealing how contaminants like PCBs impact metabolism and health.
What is hypogonadism?
When the body’s sex glands (gonads) produce little or no hormones
Why are sister pairs used in genetic studies of pollution effects?
Using sister pairs minimizes genetic variability, reducing the number of animals needed for laboratory studies and ensuring more reliable results.
What are the differences between unhealthy fatty acids from pigs and healthy ones from whales?
Pig fatty acids are immune-suppressive, while whale fatty acids promote health, showcasing the role of dietary fatty acid composition in disease resistance.
How does melatonin regulate polar bear reproduction?
Melatonin production, controlled by light cycles, triggers hormonal changes that initiate mating seasons in spring when food becomes available.
How does PCB exposure correlate with hypothyroidism in sled dogs?
Sled dogs exposed to PCBs showed a significant link to hypothyroidism, with PCB exposure affecting thyroid hormone concentrations and metabolism.
What is hypothyroidism?
Hypothyroidism is when your thyroid gland doesn’t make enough hormone. It can make you feel tired or gain weight unexpectedly.
Why do polar bears in Svalbard produce fewer antibodies?
Higher PCB concentrations in Svalbard reduce immune responses, leaving polar bears less able to fight infections or survive without vaccination.
How does light availability affect polar bear reproduction?
Polar bears’ reproduction is synchronized with seasonal light and seal abundance, highlighting their physiological reliance on evolutionary adaptations.
What challenges do polar bears face without sea ice?
Without sea ice, polar bears lose access to prey like seals, disrupting their metabolism and endocrine systems, potentially forcing migration or adaptation.
How do oil spills affect Arctic wildlife differently?
Oil kills birds by impairing thermoregulation, poisons polar bears when licked off their fur, and forces narwhals to dive or navigate around it
How do selenium and Vitamin C mitigate mercury toxicity?
Selenium and Vitamin C bind to mercury in a 1:1 ratio, reducing its bioaccumulation. Inuit diets rich in narwhal skin provide both nutrients.
What systems are most susceptible to PFAS exposure in humans?
PFAS disrupt immune, endocrine, and metabolic systems by lowering lymphocyte activity, reducing antibody production, and mimicking hormone structures.
How do endocrine pollutants disrupt thyroid hormone function?
Endocrine pollutants mimic hormone structures, disrupting thyroid function in both mothers and offspring, impacting growth and development.
Why is carbon sequestration nearly zero in the Amazon rainforest now?
Deforestation and environmental degradation have diminished the Amazon’s ability to act as a carbon sink, releasing stored carbon instead.
How do fatty acids influence immune responses in polar bears?
Fatty acid consumption may reduce immune responses, as observed in polar bears exposed to contaminants that affect antibody production.
What are future challenges for Inuit populations in the Arctic?
Inuits face increased disease risks due to climate change, reliance on contaminated marine food, and disruptions to traditional lifestyles.
Why is sunrise critical for polar bear reproduction?
Sunrise signals the start of seal availability and reproductive cycles, with light-regulated hormones driving mating behaviors.
What is the “future challenge” for researchers studying Arctic pollutants?
Researchers must address the impacts of climate change, pollution, and the resulting physiological and ecological changes in Arctic wildlife and human populations.
