Antibodies in breast milk

[kjle]

But, internally we are not bilaterally symmetrical. Only externally. Otherwise we'd need two hearts, two livers, two stomachs...etc. This doesn't make any sense.

I think the post about failsafe feature makes the most sense.

[MrMistery]

I agree with you kjile. That is what i said too. We evolved that way, probably because evolution favours having two tests as a backup. I am also thinking of this(although it is kinda stupid): two tests, more sperms, higher probability of woman getting pregnant during intercourse=> higher fitness.
But anyway, these are just speculations. You can't really answer this question, being 100% sure that you are right, now can yoi?

[Darby]

We are bilateral inside. All of the single structures, even the ones on one side or another, began as midline structures. Your digestive system, from which your stomach and liver and associated glands develop, begins as a central tube, then things develop off it and migrate to their final places.

The doubled structures like lungs and kidneys develop away from the midline, so you get two, although some modifications happen to keep them from being exactly mirror images.

[Revenged]

yes Darby...but i'm having a question too...the antibodies we are talking about, IgG more exactly, are proteins, right?aren't they supposed to be digested by the baby's digestive enzymes?

There is some confusion here about antibodies passing from the material circulation to the foetus...

I think that only IgG antibodies passes from the mother to the foetus via the placenta... and this is why other antibodies such as IgA are found in high levels in the breast milk...

3 important antibodies are...

IgG, which is a monomer
IgM, which is a tetramer (consists of 5 units joined together)
IgA, which is a dimer

I'm not sure why IgG can pass through the placenta but I have a feeling its due to its structure...

[xand_3r]

Ph in the baby's stomach is higher than in the adult stomach (about 4.5-5 instead of the normal 1.5-3). Lower pH is needed for pepsin to be activated, so at a pH of 4.5-5 pepsin has little activity, so many proteins can escape digestion.