<span>Smooth endoplasmic reticulum is the organelle synthesizes steroids in the ovary and stores calcium in muscle cells. In addition, smooth endoplasmic reticulum is found in hepatocyes. Hepatocytes are liver cells that are specialized in detoxifying drugs or other chemicals.</span>
Answer:
Action potential arrives at the axon terminal.
Calcium ions enter the axon terminal.
Synaptic vesicles fuse to membrane of axon terminal.
Acetylcholine is released into the synaptic cleft.
Acetylcholine binds to its receptors on the junctional folds.
Junctional folds become depolarized.
Action potential is initiated on the sarcolemma.
Explanation:
When the electrical signal (action potential) reaches the axon terminal it opens Ca channels that release Ca ions from the outside inside the axon terminal. Ca ions trigger the fusion of vesicle with membrane of the presynaptic cell (axon terminal). As a consequence, neurotransmitter-acetylcholine is released into the synaptic cleft. It diffuses to the postsynaptic cell and binds to its receptor (nicotinic acetylcholine receptor). The binding of acetylcholine leads to the depolarization of the sarcolemma.
Answer:
B. Lipid
Lipids are molecules that include fats, waxes, and some vitamins, among others. Each phospholipid is made up of two fatty acids, a phosphate group, and a glycerol molecule. When many phospholipids line up, they form a double layer that is characteristic of all cell membranes.
