Dictionary > White adipose tissue

White adipose tissue

Definition
noun, plural: white adipose tissues
A type of adipose tissue found in mammals used to store energy and acts as thermal insulator that helps maintain body temperature
Supplement
The adipose tissue is a special type of connective tissue that stores fat (lipids). The fat that the adipose tissue stores is usually in the form of triglycerides. This lipid may be degraded later in order to provide energy upon demand. Other functions of the adipose tissue are for cushioning and insulating the body. It also produces hormones. There are two major types of adipose tissues: (1) white adipose tissue (WAT) and (2) brown adipose tissue (BAT).
The white adipose tissue is used to store energy and acts as thermal insulator that helps maintain body temperature. The adipocytes in white adipose tissue are characterized by having a large fat droplet. They also have receptors for insulin, certain hormones, norepinephrine and glucocorticoids. They also produce and secrete hormones, leptin and asprosin.
Breakdown of lipids by lipolysis
When insulin level is low and epinephrine level is high, the rate of lipolysis is high. Lipolysis is the process of lipid hydrolysis catalyzed by enzymes, particularly hormone-sensitive lipases. The epinephrine from the bloodstream binds to the beta-adrenergic receptors of the adipocyte. This causes the adipocyte to produce more cAMPs. cAMP, in turn, binds and activates protein kinase A. Activated protein kinase A activates in turn the hormone-sensitive lipases. The lipases in the adipocyte catalyze the breakdown of triglyceride into glycerol and fatty acid, which will then be released into the bloodstream to reach target cells. For instance, free fatty acids are taken up by myocytes whereas glycerol is taken up by the liver for gluconeogenesis.
Storage of lipids
When insulin is released by the pancreas to the bloodstream, the level of insulin increases. This results in the slowing down of lipolysis by inducing series of reactions that reduce cAMP level and lower sympathetic nervous outflow. Insulin also stimulates pyruvate dehydrogenase phosphatase that removes phosphate from pyruvate dehydrogenase, thereby activating the latter to convert pyruvate to acetyl-CoA. The acetyl-CoA is carboxylated to form malonyl-CoA through the action of acetyl-CoA carboxylase. The malonyl-CoA plays a role in the chain elongation in fatty acid biosynthesis.
In humans, the white adipose tissue is about 20% of the body weight in men and 25% of the body weight in women. The white adipose tissues occur in kidney, mesentery, omenta, behind the eyeball, hypodermis of skin, etc. In other animals, they are found in the blubbers of elephant and whale, the hump of a camel, the fat bodies of frogs, and the tail of Marino sheep.1
Abbreviation/Acronym:

  • WAT

Synonym(s):

  • White fat
  • See also:

    Reference(s):

    1 White adipose tissue. (n.d.). Wikipedia.org. Retrieved from ://en.wikipedia.org/wiki/White-adipose-tissue


    You will also like...

    Neural Control Mechanisms
    Neural Control Mechanisms

    Neurons generate electric signals that they pass along to the other neurons or target tissues. In this tutorial, you wil..

    Crossing Over and Genetic Diversity
    Inheritance and Probability

    Gregor Mendel, an Austrian monk, is most famous in this field for his study of the phenotype of pea plants, including ..

    Geological Periods
    Geological Periods

    Geological periods is a study guide that cites the different geological periods on Earth's timeline. Each has a brief ov..

    Biological Cell Defense
    Biological Cell Defense

    Organisms employ different strategies to boost its defenses against antigens. Humans have an immune system to combat pat..

    Control of body movement
    Control of Body Movement

    Some of the body movements can be controlled at will, others cannot. The body has a motor program, which is the pattern ..

    Pink Lotus plant on a pond
    Freshwater Lentic Communities & Animals

    This tutorial looks at some of the communities in freshwater lentic habitats. For instance, symbiosis occurs in a commun..

    Related Articles...

    No related articles found

    See all Related Topics