Answer:
Magnetism
Explanation:
The refrigerator doors are made of <u>metal</u>, and we use <u>magnets</u> to hold papers and photos on their surfaces. Magnets attract metals such as iron, cobalt, nickel, etc. That is due to the physical property of matter called <u>magnetism</u>, which is related to the attraction force generated by a magnetic field.
<span>Because it is an opioid, hydromorphone is classified as a Schedule II drug. Hydromorphone, which is derived from morphine, is also called dihydromorphinone, and is sold under various brand names. One of the most common brand names for this drug is Dilaudid.</span>
It is stored in the hypothalamus, but is secreted by the pituitary gland. Hope this helped!
Striated muscles contain repeating sarcomeres of overlapping arrays of long, thin actin and thicker myosin filaments. Myosin filaments contains the myosin heads, which are enzymes that can bind to actin, split and make use of the energy from ATP. When muscle contraction starts, myosin heads bind to actin, change their configuration on actin, liberating the products of ATP hydrolysis and causing slide of the actin and myosin filaments. The action of the proteins troponin and tropomyosin on the actin filaments regulates vertebrae striated muscle contraction. The release of calcium ions from the sarcoplasmic reticulum is triggered by the nervous stimulation which causes depolarization of muscle membrane. Calcium ions bind to troponin and thus cause or allow the tropomyosin strands on the actin filament to move so that the part of the actin surface where myosin heads need to bind is uncovered. Contraction then occurs and only stops when the sarcoplasmic reticulum pumps calcium out of the muscle interior.
So basically, what triggers the uncovering of the myosin binding site on actin is the calcium ions binding to troponin and changing configuration.
