Lipids 5

Question 1

What is the key physiological role of brown adipose tissue?

Answer 1

Maintenance of core body temperature

Question 2

What is shivering thermogenesis?

Answer 2

Involuntary muscle contraction
Elevates heat production in cold climates
In adult humans it can reach intensities equivalent to 40% of maximum oxygen consumption and involve the oxidation of mainly lipids and carbohydrates

Question 3

What is brown adipose tissue?

Answer 3

A thermogenic tissue

Question 4

Where was BAT first discovered?

Answer 4

In mice

Question 5

Main function of BAT?

Answer 5

Heat production when activated by cold exposure (cold exposure results in massive blood flow increases to rodent brown adipose tissue)

Question 6

What is white adipose tissue like?

Answer 6

Stores energy
Low in mitochondria
Fat sits in lipid vesicles
Pro-inflammatory

Question 7

What’s brown adipose tissue like?

Answer 7

Dissipates energy 
High mitochondria 
Anti-obesity 
Lots of little lipid vesicles 
PRDM16

Question 8

What is the proton circuit?

Answer 8

UCP1 causes a proton leak across the inner membrane of the mitochondria, thereby dissipating chemical energy in the form of heat

Question 9

Brown fat adipocytes are energy inefficient for ATP production but energy efficient for…

Answer 9

Heat production

Question 10

What carries protons across membranes like UCPI?

Answer 10

DNP; 2,4 dinitrophenol

Question 11

What activates BAT?

Answer 11

1. Stimulation of B-adrenergic receptors by norepinephrine (increases levels of cAMP)
2. Stimulation of deiodinase enzyme (D2)- converts thyroid pro hormone (thyroxine T4)
3. T3 stimulates expression of UCP-1 (increases UCPI; uncoupling of mito-respiration, loss of energy as heat; activation leads to increased uptake of substrate)

Question 12

What has a lot of brown adipose tissue?

Answer 12

Newborn babies (keep organs warm)
Warms blood in surrounding blood vessels before its distribution to the periphery