Histology - Adipose Tissue Terms (Ch. 9)

Explain the factors affecting adipose tissue distribution

Adipose distribution can be affected by gender, genetics, menopause and yo-yo dieting. Men = android (apple) Women = gynoid (pear)

How does brown adipose tissue develop? What signals are necessary?

Brown adipose tissue develops from mesenchymal stem cells which turn into lipoblasts then brown adipocytes. Signals required: PRDM16/PGC-1

Explain the features and functions of Brown adipose tissue

Brown adipose tissue is brown fat that is present in a baby, but lost with age, as well as in hibernating animals. Brown tissue performs thermogenesis, which is a process that releases heat within tissue.

Explain the structure of brown adipose tissue and how it performs thermogenesis

Brown adipose tissue is very vascular, significantly more than white, and is separated into masses by connective tissue. It's able to generate heat through UCP-1 channels in the cell membranes that allow H+ to pass into cell to produce heat, NOT ATP.

What's the difference between glycogen and triglycerides?

Glycogen is energy stored in muscles and in the liver. Triglycerides is energy stored as fat droplets within adipocytes. **Glycogen is much easier to access and break down than triglycerides when our body needs energy during exercise.

Define hypertrophy and hyperplasia

Hypertrophy = growth in cell size Hyperplasia = increase in cell #

What are the 2 forms of lipid metabolism?

Lipogenesis = formation of fatty acids (allows for storage as triglycerides or glycogen) Lipid oxidation = break down of fatty acids for energy

Where is white adipose tissue located?

Located: subcutaneous fat, mammary glands, greater omentum, visceral pericardium.

Explain the long-term regulation of adipose tissue and the chemicals involved

Long-term regulation is meant to control hunger and metabolism over the long term. - Leptin is a chemical made by adipocytes that inhibits hunger. It monitors how much adipose tissue is present and alters its levels accordingly. **Obese people have higher levels of leptin, but they've developed a tolerance to it - Insulin controls the body's blood-glucose levels. Upon its release, cells are instructed to perform lipogenesis and uptake glucose from bloodstream.

What is Prader-Willi syndrome?

Prader-Willi syndrome is a defect on chromosome 15 that affects some or all of 7 genes that lead to short stature, low muscle, low cognition, and high level of ghrelin

Explain the short-term regulation of adipose tissue and the chemicals involved

Short-term regulation of adipose tissue controls appetite and metabolism daily. - Ghrelin is an appetite stimulant, it tells us when we're hungry and causes an increase in lipogenesis and decrease in lipid oxidation - Peptide YY is an appetite suppressant (generates feeling of fullness). Obese people have a decreased level of Peptide YY

What are the 2 types of fat cells, and what are the differences between them?

Subcutaneous and visceral fat cells. Subcutaneous fat cells have a pretty stable population, and can only grow larger in size, not in numbers. Visceral fat cells can increase in both size and number, and are much more detrimental to health.

Explain the structure of white (unilocular) adipocyte structure

The cytoplasm and nucleus of the cell have been pushed to the exterior ring of the cell. The vast majority of the cell is comprised of a large lipid droplet.

What's the major function of adipose tissue? What cell(s) is it made of?

The major function of adipose tissue is energy storage. It also provides insulation and protection for organs. Adipose tissue is primary made of adipocytes.

Explain the features and functions of White adipose tissue

White adipose tissue is the predominant type in adult humans. It is subcutaneous fat, lying below the epithelial layer and CT. Its main functions are energy storage, cushioning and insulation.

What are the 2 types of adipose tissue?

White/yellow (most prevalent) and brown

How does white/yellow adipose tissue develop? What signals are necessary?

White/yellow tissue differentiates from mesenchymal stem cells which turn into lipoblasts then into white adipocytes. Signals required: PPARy/RxR