Adipose tissue

white adipose tissue storage process

1. Ingested lipids in digestive tract 2. Digested to triglycerides 3. Triglycerides transported across digestive epithelium and into circulation blood 4. Across capillary endothelium and into adipocytes 5. Concentration into single intracellular lipid droplet

White adipose tissue catabolism

1. Lipid droplet converted to triglycerides by lipase enzyme 2. Triglycerides re-enter circulation (blood), available to tissues as energy source

Brown adipose

AKA multilocular - generates heat: burning fat to create heat rather than to generate energy (ATP) and in upper back posterior neck region

white/yellow adipose tissue

AKA unilocular - storage of lipids and later catabolism and release stored piping as triglycerides as an energy source

Leptin signaling defects proposed

Decreased leptin production or decreased leptin sensitivity of hypothalamus

Adiopokines

Family of signals made and released by white adipose affecting various body systems like immune cell regulation adiponectin and angiotensinogen

Role of adipose tissue and obesity

Growth and leptin signaling defects proposed

White adipose tissue structure

Honeycomb appearance, rings of cell membrane, small cytoplasmic compartment, most of cell is for lipid storage Each circular shaped adipocyte is surrounded by connective tissue containing blood vessels

Growth and obesity

Hypertorphy and hyperplasia - enlargement of cells and cell proliferation - both leading to increased lipid storage capac

Regulation of brown adipose tissue

In adults it can expand in response to significant exposure to cold temperatures

Brown adipose tissue loaction

In newborns located in upper back between scapulas or posterior neck region, virtually non-existent in adults due to other heat generation mechanisms

Insulin

Increase glucose uptake by adipocytes, converge to triglycerides

Angiotensinogen

Increases blood pressure

Brown adipose tissue appearance

Multiple lipid droplets, higher concentration of mitochondria gives brown color

Glucagon

Promotes catabolism of stored fat

Hibernoma

Rare, benign, slow-growing tumors of brown fat; often found in the periscapular region; usually contain a mix of white and brown fat -Pure hibernomas are very rare

Adipose tissue

Tissue that stores fat.

Lipoma

a benign, slow-growing fatty tumor located between the skin and the muscle layer

Adiponectin

a protein produced by adipose cells that inhibits inflammation and protects against insulin resistance, type 2 diabetes, and cardiovascular disease

Visceral fat

fat stored within the abdominal cavity in association with the internal abdominal organs

hormones of adipose tissue

leptin, adiponectin, resistin

Liposarcoma

malignant tumor composed of fat

Lipase

pancreatic enzyme necessary to digest fats

Leptin

protein hormone secreted by fat cells; when abundant, causes brain to increase metabolism and decrease hunger