I had the same problem: I plug in headphones, and sound comes out of the headphones and my laptop speakers. Here's how I fixed this problem: Go to Sound Preferences [click on the Sound icon in the top-right, on the bottom of the menu, you'll see sound preferences ].Next, go to the Output tab.Here, look at the bottom, where it says  Connector: . I think mine was on Analog Speakers [or possibly Analog Headphones]. had the same problem: I plug in headphones, and sound comes out of the headphones and my laptop speakers. Here's how I fixed this problem: Go to Sound Preferences [click on the Sound icon in the top-right, on the bottom of the menu, you'll see sound preferences ].
Amino acidâbased hormones (amines and peptide or protein hormones) are water-soluble and act on the surface of target cells via second messengers; steroid hormones, being lipid-soluble, move through the plasma membranes of target cells (both cytoplasmic and nuclear) to act within their nuclei. Hormone secretion may occur in many tissues.
Oxytocin in a nine amino acid peptide that is synthesized in hypothalamic neurons and transported down axons of the posterior pituitary for secretion into blood.timulation of milk ejection (milk letdown): Milk is initially secreted into small sacs within the mammary gland called alveoli, from which it must be ejected for consumption or harvesting. Mammary alveoli are surrounded by smooth muscle (myoepithelial) cells which are a prominant target cell for oxytocin.