Adipose tissue Flashcards
2 types of adipose tissue and location of each
WHITE: unnilobular, subcutaneous layer, interor of abdominal cavity, around kidneys, bone marrow of adult bones
BROWN: multilobular, armits and mediastinum (chest cavity)
characterists of white adipose tissue
-cytoplasm contains only 1 large lipid drop
-cytoplasm, nuc and other organelles (mitochonria) pushed to periphery
why does adipose tissue appear as white empty space?
the lipids within the fat droplet are dissovled during the tissue slide prep
what dye can be used to visualise adipose (and colour)
OSMIUM STAIN - droplets appear like black dots
characteristics of brown adipose tissue
-cytoplasm has several lipid droplets
-highly vascularised (reason for brown colour)
-very rich in mitochondria
functions of white adipose tissue (4)
- energy storage
- mechanical support and organ protection
- ability to produce hormones such as leptin
- thermoregulation
what does the abundance of white adipose depend on
-nutritional status
-hormone regulation (insulin/glucagon)
function of brown adipose tissue
THERMOGENESIS:
-lipid degradation to produce heat
-UCP1: uncoupling protein1: instead of oxidation of lipids producing ATP in oxidative phosphorylation, they generate heat
origin and lineage of white adipose tissue cells
PARENCHYMAL cells of perivascular origin:
early lipoblast
middle lipoblast
late lipoblast
!!! early stage contains several lipid droplets that merge together to form 1 until the end stage
origin and lineage of brown adipose tissue cells
SKELETAL MYOGENIC PROGENITOR CELLS:
early lipoblast
brown adipocyte
what is the process of transdifferentiation
DEF: the process by which white and brown adipose change between eachother
- WHITE TO BROWN: due to chronic exposure of cold (for heat generation)
- BROWN TO WHITE: under obesogenic nutrition (to satisfy energy storage)
