EKG analysis

An EKG (electrocardiogram) is a painless medical procedure that monitors the movements of cardiac muscles. EKG's are used to detect abnormalities in heart rhythm that may be indicators of serious defects in the heart. Electrodes are attached to the patient where the heart rhythms can be read, usually the chest area. Not too long ago, my class experimented with EKG's. I put 3 small electrodes on my arms. one on each wrist and another on my upper right arm. The placement of the electrodes resulted in how the graph looked on the computer I was monitoring on. If I switched two of the electrodes' places, the graph looked different.  For example, when I switched the places of the electrodes on my left wrist and right upper arm, the graph produced on the computer was the inverse of when they were in the normal positions. On the graph, my heart rhythms looked somewhat like this:

On this EKG graph, the P wave represents the depolarization of both atria. From the P wave to the Q wave, which may not always be present in a normal EKG, is the PR interval, the time from atrial depolarization to the start of ventricular depolarization. The Q waves are the first downward deflections before the R waves, the first upward deflections. After the S waves represent the time left for ventricular depolarization. The QRS complex is the electrical wave that signals the depolarizations of myocardial cells of the ventricles. The T wave represents the re-polarization of the ventricles. The ST segment is a period of diastole from the end of systole to re-polarization in the ventricles.

Getting this data from the EKG sensor was much easier than understanding just what it all meant. 

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Leech Neurophysiology Lab

Purpose- To record electrical activities of individual neurons while you deliver mechanical stimulus to the attached skin. Inject florescent dyes into the neurons to visualize their morphology.

Hypothesis- Each of the areas of the neurons are specialized to each do a different specific job.

Materials- Leech tank, dissection tray, 20% ethanol, dissecting microscope, oscilloscope, micromanipulator, scalpel, probe, forceps, scissors, dissection pins, leech tongs.

Procedure-

Anesthetize the leech with 20% ethanol and cut into it using the scissors.

Use forceps to pull skin flaps open and pin down with the dissection pins.

Remove leech innards with the probe and observe ganglion

Cut out the ganglion window using scissors

Isolate one ganglion

Cut the ganglion sinus using the scalpel

Probed and identified ganglion sensory cells using the forceps to pull the skin open and the pins to keep it open.

Observe cells under dissecting microscope, using the micromanipulator to inject dye into different areas of the neuron and put under UV light to identify the different cell types. Also, use different stimuli such as a feather or forceps to see if there is a reaction of action potential in the cell that is being probed.

Results- Each of the sensory cells examined in different areas of the ganglion had different shapes with different functions. Different stimuli produced different types of responses. The atlas used helped to identify which type of cell responded to which type of stimuli in which way.

Conclusions- Different cells in the neuron have different functions based on their structure and location. Also, the different stimuli (the feather, probe and forceps) made the different types of cells respond in different ways. The different types of cells and their locations were easily identified using the different stimuli used in combination with indication from the atlas below:

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Bone Fractures

Bone fractures are classified by:

• The position of the bone ends after the fracture
• The completeness of the break
• The orientation of the bone to the long axis
• Whether or not the bone ends penetrate the skin

-Nondisplaced- Bone ends retain their normal position
-Displaced- Bone ends are out of normal alignment
-Complete- Bone is broken all the way through
-Incomplete- Bone is not broken all the way through
-Linear- The fracture is parallel to the long axis of the bone
-Transverse- The fracture is perpendicular to the long axis of the bone
-Compound (open)- Bone ends penetrate the skin
-Simple (closed)- Bone ends don't penetrate the skin
-Comminuted- Bone fragments into 3 or more pieces; common in the elderly, whose bones are more brittle
-Spiral- Ragged break when bone is excessively twisted; common sports injury
-Depression- Broken bone portion pressed inward; typical skull fracture
-Compression- Bone is crushed; common in porous bones subjected to extreme trauma
-Epiphyseal- Epiphysis separates from diaphysis along epiphyseal line; occurs where cartilage cells are dying and calcification of the matrix is occurring
-Greenstick- Incomplete fracture where one side of the bone breaks and the other side bends; common in children, whose bones have relatively more organic matrix and are more flexible than those of adults

Artificial tissue response

      I can honestly say that I find this an incredible breakthrough in science. They very idea of growing human tissues in a lab seems like the stuff of science fiction. Yet, there it is. I like the idea very much: make human tissues for people with burns, heart & kidney diseases and other life-threatening illnesses. This is a great help to patients in desperate need of tissue replacements. I also find it appeasing that these tissues don't require the use of embryonic stem cells to grow. I, myself, don't have a problem with that aspect, but a good number of people do. It's good to see that those people can't start a controversy of stem cells with this project.

     I have to admit, when I first saw that mouse with an ear on its back, I was more than a little freaked out. I mean, to watch tissues grow outside of the body has got to be quite a spectacle. But passed the freaky appearance, there was some really hard work backing all of this up. Considering what these people had to do to get the tissues to grow the right way, they had their hands full. For example, growing tissues in a simulated weightless environment was genius. I never would have guessed to cultivate cells in a rotating bioreactor to put them in simulated free fall. That's some pretty good thinking. They also had to closely mimic the environment in which those cells would normally grow in the human body. You can't tell me that it wouldn't be arduous to unlock biochemical signals to get cells to grow and multiply. In my opinion, these researchers should be commended for their work.
http://www.pbs.org/saf/1107/features/body.htm

Levels of organization of the body

Okay, so it all starts with chemicals.
Chemicals form molecules
Molecules make up cells
Groups of similar types of cells make tissues
Tissues come together to form organs
Organs that work close together make organ systems
Organ systems all work together to form an organism.
That's you: an organism that is a group of organ systems, made of organs, which are made of tissues, formed by cells, that are comprised of chemicals.