Seminar 4 Flashcards
Can you identify the location of brown adipose tissue and explain why it is called brown adipose tissue (BAT)?
- Location and Naming of Brown Adipose Tissue (BAT)
Location (especially in adults):
• Around the neck, supraclavicular area, shoulders, and along the spine.
• Also found around kidneys and heart in infants (where BAT is more abundant).
Why it’s called “brown”:
• The brown color comes from the high number of mitochondria that contain iron-rich cytochromes.
• BAT is also highly vascularized, contributing to the darker appearance.
Can you explain how a specific process in BAT is involved in the regulation of body temperature?
- How BAT Regulates Body Temperature
BAT plays a key role in non-shivering thermogenesis. Here’s how:
• When exposed to cold, the sympathetic nervous system releases norepinephrine.
• This stimulates BAT to oxidize fatty acids.
• Instead of making ATP, the energy is released as heat — helping maintain core body temperature without shivering.
Can you identify the unique protein that is involved in the regulation of body temperature by BAT?
- The Unique Protein Involved
The unique and essential protein in this heat-producing process is:
Uncoupling Protein 1 (UCP1)
• Found in the inner mitochondrial membrane of BAT.
• UCP1 uncouples oxidative phosphorylation, allowing protons to leak across the membrane without producing ATP.
• This generates heat instead of storing energy — a process called mitochondrial uncoupling.
Can you identify what scientific findings have been confirmed in research experiments where unhealthy participants were exposed to a colder living environment?
Findings from Cold Exposure in Unhealthy Individuals
Research on people with obesity or metabolic disease (like type 2 diabetes) exposed to cooler environments (e.g., ~17°C) has shown:
• Increased BAT activation.
• Improved insulin sensitivity.
• Higher glucose uptake into BAT and other tissues.
• Increased energy expenditure (slight boost in metabolism).
• Reduced fat mass and better glucose homeostasis over time.
This supports the idea that BAT can play a therapeutic role in metabolic health.
Can you explain why both endurance athletes and people with obesity/diabetes have higher amounts of lipid droplets/IMTG compared to lean, healthy individuals?
- Why Athletes and People with Obesity/Diabetes Have More Lipid Droplets/IMTG
Both groups store more intramyocellular triglycerides (IMTG), but for different reasons:
• Endurance Athletes: Store IMTG as a readily available fuel source for prolonged exercise.
• Obesity/Diabetes: Store IMTG due to lipid oversupply and metabolic inflexibility — not using the fat effectively.
So, the amount is similar, but the purpose and usage differ.
Can you explain the difference between lipid droplets/IMTG in endurance athletes and people with obesity/diabetes?
- Differences in IMTG Between Athletes and Metabolically Unhealthy Individuals
• In athletes, IMTGs are well-organized, accessible, and surrounded by healthy mitochondria — leading to efficient fat oxidation.
• In obese/diabetic individuals, IMTGs are often poorly organized, accumulate due to lipid spillover, and are associated with mitochondrial dysfunction and insulin resistance.
This difference lies in metabolic flexibility: athletes can quickly switch between fuels (fat vs glucose), while insulin-resistant individuals cannot.
Have you found the name for this paradox?
Athletes paradox
