Pictured here is a molecular sequence that occurs every day in dairy milking parlors–milk let-down.
The chain of events involved in milk let-down is difficult to show because the sequence involves both the nervous system and circulatory system throughout the body. We’ve used numbers, callouts of specific body regions, and colored arrows to trace the pathway through the body.
As good as this illustration is, we think animation makes this idea easier to understand. As I write this, Don is working on the animation. We’ll post a link to the animation when it is available.
(1)Teat suckling (by calf or milking machine) sends nerve impulses to the brain’s hypothalamus(2) and on to the pituitary(3). The pituitary gland secrets oxytocin into the blood stream, which carries it to udder alveoli(4). Udder alveoli contract to let down milk.
Yellow arrows = nervous system pathway
Green arrows = circulatory system pathway
Note: oxytocin molecule in background