Each region secretes its own set of hormones. The cortex itself is divided into three zones: the zona glomerulosa, the zona fasciculata, and the zona reticularis. The adrenal gland consists of an outer cortex of glandular tissue and an inner medulla of nervous tissue. This compound is then sent back to the mitochondria where it is finally transformed into the final product, cortisol.Ĭortisol freely crosses the membrane barrier and enters the bloodstream.View the University of Michigan WebScope at to explore the tissue sample in greater detail. Once inside, enzymes perform two chemical conversions, turning the cholesterol into 17-OH-pregnenolone.ġ7-OH-pregnenolone is then sent to the endoplasmic reticulum, where it is converted into 11-deoxycortisol. StAR is responsible for mediating the complicated task of importing cholesterol into the mitochondrion. See for a diagram of the entire protein complex. Only one protein is shown here for simplicity. Specialized function in the adrenal cortex. (steroidogenic acute regulatory protein) There are actually several interacting proteins that work together to perform this The activated PKA subunit then travels to the mitochondrial membrane and switches on (phosphorylates) a protein called StAR That releases its catalytic subunits (only one is shown here for simplicity). When cAMP binds to the regulatory subunits of Protein Kinase A (PKA), a conformational change occurs When the G protein stimulates it, Adenylate cyclase converts ATP (the cell's energy molecule) into cAMP (a signaling molecule).ĬAMP activates Protein Kinase A. This conformational change causes the G protein complex to When it binds, ACTH stimulates the receptor to change shape. Of the bronchiole muscle cells (seen later in the movie) when epinephrine binds to it. *NOTE: The MC2-R receptor system looks and works similarly to the beta-2 adrenergic receptor system, which initiates relaxation In the movie we see a simplified version of how it all works.īelow is a description, including some of the details we left out of the movie.ĪCTH Docks on an MC2-R Receptor* on a cell in the cortex of the adrenal gland.

Ways that organelles do important jobs that are not often explored when generally defining their function.

This particular signaling cascade is a great example of the complex

The adrenal cortex, it stimulates the production of cortisol. The signaling molecule ACTH is released by the pituitary gland in the brain and released into the bloodstream.

Adrenal cortex releases