Two types of radiometric dating
An "activator" chemical made by cells lining the lumen is secreted into the lumen and transforms the inactive enzyme into an aggressive digestive form.
This activated enzyme then acts like an activator to "turn on" other inactive enzymes in a coordinated digestive cascade.
"Parietal" cells secrete a very acidic concentration of hydrochloric acid (p H about 2.5) with a hydrogen ion concentration 100,000 times higher than in blood.
Food is ground and dissolved into fine paste, but the stomach itself is protected from this harsh environment by an inner blanket of "goblet" cells joined very tightly to each other to contain the acid.
The first vital step involves the brain readying the digestive organs for an influx of food.
Able to sense ratios of fat, protein, and sugar content, as well as the volume of food, the duodenum modulates a control valve exiting the stomach by a tandem of neurologic and hormonal networks.Plants use biological systems that harvest light energy from the sun to convert environmental water and carbon dioxide into tiny carbon/hydrogen energy units stored within them.When people eat those energy units, the extraordinary human digestive and metabolic systems convert the work of plants into energy that is useful to people and give back water and carbon dioxide to the environment that can be used by plants. Journey to the Stomach Ingested food encounters precisely-shaped teeth that cut and grind it into small pieces--which, surprisingly, is the second step of the digestion process.Through three extraordinary processes involving dozens of enzymes, coenzymes, electron carrier proteins, and intermediate products, the atoms are stripped off the molecule. The electron transport process uses the hydrogen atoms.Special proteins pump these atoms to one side of a hydrogen-impermeable membrane, while at the same time splitting the hydrogen into a positively-charged proton and an electron.