A little knowledge is dangerous; especially when it relates to medicine. A recent article in the British newspaper, Daily Mirror discussed a medical study that attempted to prove there was a link between pregnant women’s sleeping positions and stillbirth. The author is of the opinion that the study was small and biased and therefore “there is a serious need for more research before we’re in a strong position to make ¬any recommendations.” Obviously this author has limited knowledge about the cardiovascular system of a pregnant woman.
Our organs and tissues require oxygen to function. Without it, they essentially die. Blood from the lower part of our body flows back to the heart where it receives oxygen, compliments of a large blood vessel called the Inferior Vena Cava (IVC). The inferior vena cava is a large, thin-walled blood vessel located near the spine. As the pregnant uterus becomes enlarged, it can press against the IVC and reduce the amount of its blood flow. Why is that not good? Because it reduces the circulating blood flow in the body that is commonly known as our cardiac output (CO). When the pregnant uterus squeezes the IVC and reduces cardiac output, a woman might feel dizzy and even faint. Her blood supply of oxygen is reduced and the unborn baby’s is as well. When a pregnant woman in her early or late third trimester feels faint after lying flat on her back, the syndrome is called Supine Hypotensive Disorder. Her blood pressure has dropped because her cardiac output has dropped. The heart can only pump out what comes into it, so less blood into the heart means less blood going out of the heart and the patient feels faint. How is this avoided? Read more »
*This blog post was originally published at Dr. Linda Burke-Galloway*
Did you know that Natalie Portman (under the name, Natalie Hershlag) published a paper in a scientific journal in 2002 while at Harvard?
Frontal lobe activation during object permanence: data from near-infrared spectroscopy.
The ability to create and hold a mental schema of an object is one of the milestones in cognitive development. Developmental scientists have named the behavioral manifestation of this competence object permanence. Convergent evidence indicates that frontal lobe maturation plays a critical role in the display of object permanence, but methodological and ethical constrains have made it difficult to collect neurophysiological evidence from awake, behaving infants. Near-infrared spectroscopy provides a noninvasive assessment of changes in oxy- and deoxyhemoglobin and total hemoglobin concentration within a prescribed region. The evidence described in this report reveals that the emergence of object permanence is related to an increase in hemoglobin concentration in frontal cortex.
*This blog post was originally published at ScienceRoll*
These last several weeks I have been absolutely overwhelmed with science, meetings, writing, and reviews. I might complain, but I should also be flattered that I am as busy as I am. Mama is in demand, little muffin. Still, things are beginning to slow down to a tolerable level on my end, which means I will be back to blogging.
Today I was working on some writing when I had cause to review some historical texts. It gives me pause to stop and consider things that we take for granted. For example, think about how blood flows through the heart and lungs…
Figure 1: Blood flows from right to left, across the lungs.
I can’t tell you how many times a day I look at a heart and take for granted that blood should flow from the venous circulation, into the right side of the heart, across the lungs, back to the left side of the heart, and out to the arterial circulation. When all is right with the world, such is the way it should be.
But, we didn’t always know that. Read more »
*This blog post was originally published at On Becoming a Domestic and Laboratory Goddess*
After shoveling the heavy, 18-inch layer of snow that fell overnight on my sidewalk and driveway, my back hurt, my left shoulder ached, and I was tired. Was my body warning me I was having a heart attack, or were these just the aftermath of a morning spent toiling with a shovel? Now that I’m of an AARP age, it’s a question I shouldn’t ignore.
Snow shoveling is a known trigger for heart attacks. Emergency rooms in the snowbelt gear up for extra cases when enough of the white stuff has fallen to force folks out of their homes armed with shovels or snow blowers.
What’s the connection? Many people who shovel snow rarely exercise. Picking up a shovel and moving hundreds of pounds of snow, particularly after doing nothing physical for several months, can put a big strain on the heart. Pushing a heavy snowblower can do the same thing. Cold weather is another contributor because it can boost blood pressure, interrupt blood flow to part of the heart, and make blood more likely to form clots.
When a clot forms inside a coronary artery (a vessel that nourishes the heart), it can completely block blood flow to part of the heart. Cut off from their supply of life-sustaining oxygen and nutrients, heart muscle cells begin to shut down, and then die. This is what doctors call a myocardial infarction or acute coronary syndrome. The rest of us call it a heart attack.
The so-called classic signs of a heart attack are a squeezing pain in the chest, shortness of breath, pain that radiates up to the left shoulder and down the left arm, or a cold sweat. Other signs that are equally common include jaw pain, lower back pain, unexplained fatigue or nausea, and anxiety. Read more »
*This blog post was originally published at Harvard Health Blog*