Biology for dummies

Can someone please explain this to me in simple terms (I'm in crash, poor cognition):

Are all nutrients absorbed in the small intestine or does the stomach absorb some too?

It seems that at least some medications are absorbed in the stomach? Considering how quickly they can act. Can I access a list somewhere of which medications are absorbed in stomach and which in small intestine?

What about supplements? E.g. vitamins, minerals, but also botanicals such as turmeric.

Please include a line break in between each sentence of your answer.

 

From google
https://www.livestrong.com/article/436603-in-which-digestive-organ-are-nutrients-absorbed/

The small intestine is the main area of the GI tract for absorption. The small intestine has three separate sections, the duodenum, jejunum and ileum.

Most nutrient absorption takes place in the duodenum and jejunum.

The duodenum absorbs carbohydrates, proteins, and minerals including calcium, magnesium, iron, chloride, sodium and zinc.

Remaining starches in the form of glucose or proteins passed from the duodenum are absorbed in the jejunum in addition to vitamin C, thiamine, vitamin B-2 and B-6, and folic acid, Escott-Stump reports.

The last section of the small intestine known as the ileum absorbs amino acids, fat, cholesterol and fat-soluble vitamins like vitamins A, D, E and K.

 

And
https://www.merckmanuals.com/professional/clinical-pharmacology/pharmacokinetics/drug-absorption

Theoretically, weakly acidic drugs (eg, aspirin) are more readily absorbed from an acid medium (stomach) than are weakly basic drugs (eg, quinidine).

However, whether a drug is acidic or basic, most absorption occurs in the small intestine because the surface area is larger and membranes are more permeable (see Drug Absorption : Oral Administration).

 

Thank you wiggle

 

OK. If drugs are mostly absorbed in the small intestine then how come some drugs can work very quickly? The first time I took Zopiclone, it started to affect me within 5-10 minutes!!! (Not placebo as I wasn't expecting it to feel how it felt)

And when I take potassium for muscle problems, my muscle function improves within 10-15 mins.

 

Potassium
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4963920/

 

From the Wikipedia article on the stomach.

Nitroglycerin can be absorbed through the lining of the mouth.