Adipose Tissue Flashcards
(31 cards)
Adipose tissue is a specialized type of connective tissue the predominant cells type is
The adipocytes
adipose tissue represents % body weight for individuals of normal weight
Men: 15–20%
Women :20–25%
Adipocytes are key regulators of
The body’s energy metabolism
Caloric value triglycerides versus carbohydrates
9.3 kcal/g for triglycerides versus 4.1 kcal/g for
carbohydrates
Two types of adipose tissue
- White adipose tissue
- Brown adipose tissue
White adipose cells
(Size)
50 um and 150
um
White adipose tissue contains
(droplet)
one huge droplet of lipid that makes up 85% of the cell’s weight
White adipocytes are
called………….. because triglycerides are stored in a single locus.
Unilocular
Each adipose cell usually possesses minute lipid droplets in addition to the single large droplet seen with the light microscope; the droplets are not enveloped by a membrane but show many
vimentin intermediate filaments in their periphery
Each adipose cell is surrounded by a
thin external or basal lamina.
White adipose tissue is subdivided into incomplete lobules by
a partition of connective tissue containing a rich vascular bed and nerve network.
White adipose tissue triglycerides derived from
- Dietry fats transported as chylomicrons
- Triglycerides sythesised in the liver and transported as VLDLs
- Local synthesis of free fatty acids and glycerol from glucose
chylomicrons (size)
upto 1200 um in diameter.
chylomicrons (structure)
- Central core of mostly triglycerides+ small amounts of cholesterol esters
- Surrounded by stabilizing monolayer of apolipoproteins, cholesterol and phospholipids
Chylomicrons and VLDL are both hydrolyzed at the luminal surfaces of blood capillaries in adipose tissue by
lipoprotein lipase
lipoprotein lipaseis synthesized by the
adipocyte and transferred to the capillary cell membrane.
Free fatty acids enter the adipocyte
by both
active transport and diffusion
Within the adipocyte, the fatty acids
combine with glycerol phosphate, supplied by
glucose metabolism, to form triglycerides once again.
Insulin also stimulates
- Uptake of glucose into adipocytes
- Increases the synthesis of lipoprotein lipase.
Retroorbital fat pads resists
long periods of starvation
Adipocytes undergo differentiation from
embryonic mesenchymal cells
Early lipoblasts have the
appearance of
fibroblasts but are able to accumulate fat in their cytoplasm.
White adipose tissue begins to accumulate at week ……. of gestation
30
Brown adipose tissue constitutes …………..% of new born body weight
2-5%
