Heart Murmurs

The key to understanding heart murmurs is realizing that:

Systole=ventricle contracting
Diastole=atria contracting or the aortic pressure pushing back on the aortic valve

Murmurs that occur during SYSTOLE:
1. Blood going forward through a narrow aortic valve (aortic stenosis, crescendo-decrescendo)
2. Blood going forward through a ventricular septal defect (VSD, holosystolic)
3. Blood going through a narrowed aortic outflow tract (hypertrophic cardiomyopathy)
4. Blood going back through a leaky mitral valve (mitral regurgitation, holosystolic)

Murmurs that occur during DIASTOLE (remember that diastole is when the atria contract or the aorta pushes back on the aortic valve):
1. Blood going forward through a narrow mitral valve (mitral stenosis)
2. Blood being pushed back through a leaky aortic valve (aortic regurgitation)

The murmur of an atrial septal defect (ASD) is a fixed split S2.

A video is worth a thousand words.

Let's say you're having a tough time visualizing the fetal circulation in your head and diagrams just aren't cutting it. Google has a cool feature that allows you to search for Flash videos by using the filetype:swf modifier. For example if I wanted flash videos on the fetal circulation, I typed fetal circulation filetype:swf.

Here's a nice flash animation on the fetal circulation that I found with this Google search.

Sloppy Joes!

Both HCV and HIV are sloppy reproducers, making their structure too variable to create a working vaccine against them.

Neisseria gonorrhea is usually tested on its highly variable pili, which makes it difficult to target with a vaccine.

Inguinal Canal and Hernias

Check out this flash animation!