White Adipose Tissue

Question 1

White adipose tissue

Answer 1

characterizes obesity, based on the excess amount

Question 2

Adipocyte

Answer 2

a fat cell, that stores triglycerides. It’s a fat droplet, that is considered to be an energy storage

Question 3

3 compartments of adipocyte:

Answer 3

Nucleus, cytoplasm, and fat reservoir

Question 4

Are adipocytes present in other species:

Answer 4

Yes and no! The more complex the species became, like chickens, fish, frogs, and rats.

Question 5

Worms Fat distribution:

Answer 5

stores fat droplets inside of the intestinal cells

Question 6

Flies fat distribution

Answer 6

have fat bodies, and serve as dual organs for liver and adipose tissue. Humans can also store in the liver (not common though)

Question 7

Evolution of Adipose depots:

Answer 7

lower organisms have evolved specialized cells to hold lipids but they are not adipocytes.

Question 8

Amphibians and Reptiles:

Answer 8

have dedicated visceral (intra-abdominal) WAT depots

Question 9

Mammals:

Answer 9

have specialized subcutaneous and visceral WAT depots

Question 10

Why do we have specialized locations to store fat?:

Answer 10

So that way we have a safe harbor for excess energy. Furthermore, it is also viewed as an active endocrine organ / complex tissue that controls energy metabolism and lipid homeostasis

Question 11

Why is WAT an active endocrine organ:

Answer 11

Its because it helps with energy storage, appetite, glucose, and fatty acid metabolism. Involved in thermogenesis, fecundity (fertility), and reproduction. Immune responses and storage of toxins. [Growth factors, complement factors, cytokines, hormones adipokines, and oxidized fatty acids.

Question 12

Mammalian WAT:

Answer 12

has adipose tissues which contain connective tissue matrix, nerve tissue, stromovascular cells, and immune cells. All these components are integrated and control metabolism

Question 13

Behavioral Fat

Answer 13

Male orangutan has adipose flanges and the females lack them. The females look for males with the flanges for mating purposes. This leads to reproductive success

Question 14

Mechanical Fat:

Answer 14

elephants have plantar adipose tissues which cause pressure dissipation when they are walking because of their weight

Question 15

Energy Suppling Fat:

Answer 15

camels have hump adipose tissue. It uses the energy from the tissues to mobilize fats and generate water

Question 16

Metabolic WAT:

Answer 16

the color is yellow/orange because of Vitamin A (hydrophobic)

Question 17

Is WAT higly plastic ?

Answer 17

yes it can range from 4-70% of someone’s total body weight because it’s a soft/connective tissue. Collagen allows for it to expand and contract based on the amount of energy

Question 18

Anatomy of White adipose tissue:

Answer 18

• 30-40% adipocytes
• 60-70% other cells fraction is called stromal vascular compartment
• SV compartment contains: Vascular endothelium, Vascular smooth muscle cells, Fibrolast, Immune Cells, and Adipose stem cells

Question 19

Mammalian Adipocyte Compartments

Answer 19

lipid droplet, nucleus, and mitochondria

Question 20

2 Distributions of Adipose:

Answer 20

Subcutaneous fat and Visceral Fat

Question 21

Dermal vs Subcutaneous:

Answer 21

dermal supports hair follicle growth and skin health.

Question 22

Subcutaneous Fat:

Answer 22

• not uniformed shaped
• fat below the skin
• Heterogeneous adipocytes- small adipocytes interspersed with larger adipocytes
• High metabolic activity
• High vascularized
• Better immunological outcome
• Healthy fat/metabolically protective

Question 23

Visceral Fat:

Answer 23

• bad fat!
• uniformed shape
• Abdominal fat
• Homogenous adipocytes- same-sized adipocytes
• Decreased stimulated lipolysis but increased triglyceride synthesis
• Less vascularization
• Poor immunological outcome

Question 24

Does having a specific fat type matter?

Answer 24

Yes. Those with the same BMI, the person with more subcutaneous fat [pear shape] had a lower risk of health problems versus the person with more visceral fat [apple shape]

Question 25

Gynoid -Type (pear shape):

Answer 25

• Lower body obesity, more subcutaneous fat storage
• More metabolically active {insulin sensitive}
• Protective role

Question 26

Android-Type (apple shape):

Answer 26

• Abdominal obesity
• Decreased stimulated lipolysis but increased triglyceride synthesis. Increased lipoprotein lipase activity
• Greater risks of: metallic disease, chronic inflammation, and coagulation
• Men tend to accumulate this fat in the abdominal region

Question 27

How to test which fat is worse:

Answer 27

transplantation studies, transplantation of subcutaneous fat to the visceral cavity. They found if you switch it becomes more like what it was switched to [sub to vis the vis became more sub]

Question 28

What accounts for differences in fat distribution:

Answer 28

sex steroids (testosterone and estrogen). Those with low testosterone have more vis fat because it’s not being used towards building muscle. Estrogen promotes subcutaneous fat and burns visceral. But when they go through menopause they have more visceral fat and are more at risk of metabolic problems

Question 29

Cushing Syndromes:

Answer 29

• High levels of cortisol
• Increase in fat in shoulder blades
• Activation of nuclear hormone receptor, glucocorticoid receptor
  Deposition of fat between the scapula

Question 30

Is there a single gene that contributes fat distriubtion ?

Answer 30

No single gene contributes to fat distribution. It’s been difficult to determine between mouse and humans because mouse have different fat storages .