Babies Internal Organs

[lndsy0502]

I was told that a baby is born with full size organs and that is why they have such fat tummies. My friend thinks this is rubbish. Can anyone settle this argument as it is driving us crazy !!!

[bernardo]

That's nonsense. A new baby's abdomen is much smaller than a grown person's - you only have to look at one to see that. The *relative* sizes of a baby's internal organs (compared with each other) are different from an adult's organs, partly because they have different jobs to do. For example, a new baby has to drink or eat its own bodyweight within just the first few weeks, and has a lot of growing to do, therefore it needs a relatively large tummy and digestive system. It doesn't need big lungs because it only has a small body to provide oxygen to. The relatively short arms and legs continue to grow more than the rest of the body throughout childhood, especially when boys go through puberty.

Similarly, there is no truth in the commonly-believed myth that babies' eyes are already adult size as soon as they arer born.

[theprof]

It is rubbish.

Human growth depends on the release of a naturally occurring polypetide hormone (HGH) from the anterior pituitary gland. The hormone is secreted into the general circulation.

HGH is one of the principal hormones influencing growth and development in humans. HGH controls energy production in the body and the storage of the energy produced. As far as growth is concerned, HGH ensures that humans grow linearly from birth to adulthood.

HGH is also known as Somatrophin but it also has other names too. There are also other growth hormones in the body, such as IGF1.

You need to remember that skin is the largest organ of the body. If we were born with sufficient adult skin for our lifetime, I doubt we�d look very attractive!

[boobesque]

Actually it is partly true, a baby is born with a full size liver, the rest of the organs though are baby size

[theprof]

I'm fascinated boobesque. Here's some facts:

Let's discuss liver weight:

The liver of an average adult usually weighs somewhere between 1.5 and 3.0 Kg. The reason for this variariation is because none of us are the same size as adults and the liver weight is usually proportional to body weight (except in the case of certain diseases). The average liver weight is around the 2.0 Kg mark.

Let's discuss liver size:

The liver of an average adult is about 21 to 23 cm across at its widest point, about 15 to 18 cm at its greatest vertical height and about 10 to 12.5 cm thick from front to back. Again the dimensions vary from adult to adult, but they usually fall within these parameters in the absence of disease.

Given the dimensions and weights I've mentioned above, it should be evident that it is impossible for a adult liver to fit within the abdomen of a neonate. The thickness alone (about six inches) should make that quite clear.

With regard to the weight of the neonate, I would ask what about premature babies? Does your theory claim that even premature babies have adult sized livers?

The truth is that a neonate is not capable of "running" an adult liver as there are many liver functions the body needs to monitor carefully. The means to do so are not present in the newborn or in young children.

The liver, like other body organs, grows progressively in size from birth to adulthood as a result of the release of growth hormones secreted into the circulation by the body.

[theprof]

For the sake of pedantry, I'll withdraw what I said about it being impossible for an adult liver to fit in the body of a neonate.

It would be possible. The trouble is, you'd have to chuck out every other organ and good part of the ribcage!

[lndsy0502]

Thanks to all for your answers. The more I thought about it the more I realised how preposterous it was.

The one good thing to come out of this was that I was finally able to prove that my mother was wrong about something. If any of you out there have one of those smug know it all mothers then you will appreciate how truly sweet this was for me !!!

Thanks again.

[tubeway]

The ossicular chain of bones in the ear - malleus, stapes and incus are the same size in an adult as a baby. In fact the ossicles are developed to adult size by the 16th week of gestation. I know this is true as I am an audiologist - as far as I am aware it is the only part of the body that is adult size at birth ( but I specialise only in ears so I may be wrong)

[stevie21]

I used to think that your eyes were the same size at birth as at adulthood but that's guff as well. They're about 65-70% adult size.

[theprof]

tubeway, you're absolutely right - babies are born with adult sized auditory ossicles.

The malleus and incus fully ossify between the 16th and 30th week of pregnancy and the stapes between the 18th and 21st week.

However, what I've always found fascinating is that the stapes is more often than not, remodelled a number of times between the 22nd week and the 38th week of pregnancy despite the ossification that has occurred.

It's almost as if the body is dissatisfied with the initial shapes of the bone.

[theprof]

stevie21, you're right - it is a load of guff. You're percentage figures are reasonably accurate.

The eyes of a neonate are 18mm in diameter, whilst those of a adult are 25mm diameter.

So a neonates eyes are 72% of the size of an adult eye.