The Romance of Meiosis

Posted by on Aug 31, 2015 | 0 comments

Another entry in the Woven Together series talking about the fascinating development of a little person. This series deviates from the main content of the blog – how things go wrong – to tell how things go right. I hope you enjoy!

Meiosis. This word probably conjures up memories of high school biology class where you had to memorize a lot of meaningless terms, but today I want to show you how it is a romantic word.  Yes, you read that right.

A couple comes together pretty intimately in the body of their child. She has Mom’s nose and Dad’s eyes, Mom’s chin and Dad’s smile. But meiosis allows the couple to come even closer in the cells of their grandchildren. Let’s dive in!

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Rh Disease – Sweet, Sweet Blood Cells – Part 2

Posted by on Aug 4, 2015 | 0 comments

Welcome back!  Click here for Part 1.  Last time we left off with mom’s body sending anti-RhD antibodies through the placenta to her second baby.

What happens to baby? 

In all cases of Rh disease, baby loses some RBCs – in fact, baby’s own immune system destroys the RBCs because they were marked with maternal antibodies.   What happens next depends on how many antibodies baby was exposed to.

In mild cases, baby has slight anemia – too few oxygen-carrying RBCs.  Baby might show no symptoms at all.

Baby might develop jaundice1 after he’s born.  When RBCs are destroyed, they release their hemoglobin.2  Baby starts to break down the hemoglobin so he can recycle the iron, and one of the breakdown products is a yellow substance called bilirubin.  In large amounts, it can damage baby’s brain.  While he’s still in the womb, baby passes the bilirubin back to mom’s liver for disposal.  However, right after birth, mom is no longer taking care of the bilirubin and baby’s liver doesn’t know what to do yet, so the yellow-colored substance accumulates in baby’s skin.  Blue lights break down the bilirubin into small enough pieces that baby’s liver can handle it.3

Blue light breaks up the bilirubin into small enough pieces that baby's liver can digest them.

Blue light breaks up the bilirubin into small enough pieces that baby’s liver can digest them.

In severe cases, baby loses a lot of RBCs.  Baby’s heart is pumping harder and harder to get the remaining RBCs around his body to deliver oxygen.  Sometimes, this effort is too much for the heart and baby dies.

How it’s treated

  1. the yellow-colored skin for which babies are placed under blue lights []
  2. the red, oxygen-carrying protein []
  3. The superficial cause of jaundice is always the same – excess bilirubin in the blood. However, all sorts of things besides blood type differences can cause an excess of bilirubin, some of which may be covered in another post. []
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Rh Disease – Sweet, Sweet Blood Cells – Part 1

Posted by on Aug 2, 2015 | 0 comments

… and, we’re back!  Grad school and life kept me pretty busy in the last year.  The Ebola and Disneyland measles outbreaks almost roused me into writing a post, but it was an article on Rh disease that finally did it.

Do you know your blood type?  I… don’t actually know mine.  Barring emergency circumstances, most people first become acquainted with the complications of blood type when they have a baby.  Certain mothers who are Rh- (“R h negative”) need shots during their pregnancy to protect their next baby.  Which mothers?  Why do they need shots?  Why is it for the next baby?  Let’s dive in!

Blood Types

First, let’s talk about blood types.  Red blood cells (RBCs) are decorated with various sugars for… unknown reasons.1

The most important sugars we call A and B, from which we get the blood types A, B, AB, and O (O means simply the absence of A and B).  The types of sugars on your RBCs determine your blood type.

Blood type is determined by which sugars are on your red blood cells: A sugars, B sugars, both! (AB), or none (O).

Blood type is determined by which sugars are on your red blood cells: A sugars, B sugars, both (AB), or none (O).

The next most important blood sugar is the Rhesus D sugar2, abbreviated RhD or simply Rh.  If you have this sugar,

  1. Seriously, we don’t know why.  See, “Why do we have blood types?” in the Further Reading section. []
  2. discovered using the blood of Rhesus monkeys []
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Fetal Circulation – The Secret’s in the Lungs

Posted by on Jun 25, 2014 | 0 comments

I’m starting a new series about babies called Woven Together because the development of a little person is fascinating. For the most part, this series will deviate from the main content of the blog – how things go wrong – to tell how things go right. I hope you enjoy!

Babies in the womb have to make some adjustments to account for the fact that they’re in the womb: there’s no air to breathe and no food to eat. Today, we’re going to learn how their adjusted circulatory system works.

First off, mother and baby don’t share blood. They have two completely separate circulatory systems.1 Baby’s heart starts beating about 22 days after conception so that he can pump his blood to deliver nutrients to all the parts of his rapidly-growing body. The heart is baby’s first organ to

  1. That’s how mother and baby can have two separate blood types with relatively few problems. []
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Flu – Virus in a Wooden Horse

Posted by on Mar 22, 2014 | 0 comments

We’ve talked about one major class of infectious agents: bacteria. Let’s look at the other major class: viruses.

What is a virus?
A virus is a piece of genetic material wrapped in a protein coat: essentially an instruction sheet inside a box. We’re not really sure if viruses are alive. They reproduce and evolve like life, but they don’t have cells, metabolism, and don’t react to being poked, as all other lifeforms do. They also can’t reproduce without the help of a living cell. Have a handful of scientists debate this idea at your next dinner party – it’ll be fun.

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