Monday, April 29, 2013

Science in a Song

On the way to school today I hear my oldest rapping in the back seat... turns out this is what she was singing



In looking trying to find it I also found this one



Which of course ended up wormhole-ing me to this one:


Too bad I didn't find these when I was studying for my cell exam!  Would have been a fun addition to my studying!

Also because I'm making this random post of awesome science song videos I'm going to include this one.  My baby girl #1 knows this entire thing and is singing it at her school closing ceremonies this month with her class.  I'm also proud to say that when they introduced it to the last she already knew who several of the people were in it, and came home all excited telling me about it!


Now it's time to get back to all those final projects I have to get completed in the next week!

Thursday, April 25, 2013

Discussion 3: Lyme borreliosis

For this discussion we were asked to wrote about an emerging infection disease.  An emerging infectious disease is one that is relatively new, or one that is newly more active.  Some of the diseases listed as emerging are actually ones that we have known about for a long time, but that are simply now infecting many more people.  One such disease is Lyme borreliosis.  Lyme disease is caused by bacteria that is transmitted to people by Western black legged ticks, and deer ticks.

The surge in incidence of Lyme disease my be linked to the protection of white tailed deer.  After white tailed deer became protected, their numbers began to rise.  Now they are much more prevalent than they were just fifty years ago, and many have moved into suburban neighborhoods where they eat landscapes and drop off ticks.  The deer serve as a reservoir for Lyme disease.  Infected deer, infect the ticks that they then leave behind.  When these ticks bite humans, they contract Lyme disease as well.  A comparison of maps showing the dispersion of Lyme disease carrying ticks, and white deer populations is indicative of this connection



The similarity in range is clear between the the tick distribution map, and the white tailed deer population dispersal map from 1982.  Now look at the population growth of white tailed deer as shown in this population map from 2008 and you can see how there could be a parallel increase in deer tick populations.

This information is only applicable to the United States, but Lyme disease also occurs in parts of Europe and Asia.

When a person contracts Lyme disease, it is typically identified by the symptoms, combined with likelihood of exposure.  As previously mentioned, with deer moving into more urban areas the likelihood of exposure is growing.  Blood tests can also be used to determine Lyme infection.  Patients typically present with a distinct rash that spreads outward in a ring shape from lesions.  This is accompanied by fever, aches and other flu-like symptoms.  Occasionally the rash does not occur, and in people with more melanin it can be hard to spot.  After a couple of weeks the rash will subside.  As the disease progresses it attacks the joints and causes severe stiffness and pain.  Further complications including ones involving the central nervous system and Bell's Palsy can develop as much as months later if it is left untreated.

There is however, some good news about Lyme disease.  If ticks are removed within the first 36 hours it is possible to prevent Lyme disease.  Although ticks are tiny, they can be spotted and removed through vigilance.  If Lyme disease is contracted, because it is caused by a bacteria, it is fully treatable with a three week course of antibiotics.  It is best to start antibiotics as soon as possible to prevent progress of the disease and to minimize complications.  Lyme disease is also not transferable directly between humans, which helps to limit it's spread.  For those who do contract Lyme disease, there is an online support organization called Lyme Buddies that provides support and information.  The organization also sponsors a 5K to raise awareness of Lyme Disease.  The even better news is that Lyme disease can be prevented by making sure to check for ticks after being outside in areas where they are likely to be present, and through the use of insect repellent and tick habitat management.

Emerging infectious diseases are something of which we all should be aware.  Bacteria and viruses mutate at a much faster rate that humans because their life cycles are much shorter, so we will continue to face new disease threats.  It is important however to make sure we continue to be aware of diseases that have made huge impacts in the past, but that have been mostly contained, although not eradicated for many years. Yellow fever has had devastating effects on populations in the past, but is relatively unknown today, despite the fact that authorities continue to mandate that even a single case  be treated as an epidemic.  Epidemiological awareness is something that is key to ultimate human survival and well being.



Sources:
Lyme Borreliosis (Lyme Disease). WHO. http://www.who.int/ith/diseases/lyme/en/. Accessed 25 April, 2013
Lyme Disease. CDC. http://www.cdc.gov/lyme/. Accessed 25 April 2013.
Lyme Disease. Targret Woman. http://www.targetwoman.com/articles/lyme-disease.html. Accessed 25 April 2013.

Wednesday, April 17, 2013

Unit Paper 3 Bone Remodeling


Section 1

One of the things that we leaned about in our study of bone is that they are constantly being remodeled.  While I was aware that bones grow during childhood, and that their density typically decreases through adulthood, I had no idea that they were remodeled in this kind of way throughout adulthood, and even to the extent of changing the entire shape of the bone.  The process of bone remodeling is important to keeping bones strong and healthy.  Older tissue is removed by osteoclasts, and then a new matrix is formed by osteoblasts, which is then filled in my minerals.



Osteoblasts, and osteoclasts work in concert to turn over bone material.  This process ensures that bone density is maintained at a healthy level, and that bone material is turned over.  The rate of bone turnover in adults is about 10% per year.  Through this process bones are continually being strengthened and rebuilt.

The idea that bones continue to be remodeled and change throughout our lives is quit compelling   Know thing really gives us a great amount of information about how we can protect ourselves against diseases like osteoporosis   Since exercise can have a huge impact on bone density, it is possible to affect this even later in life.  I couldn't find a good image to use that showed this, but in the textbook there is an image that shows how the curvature of a bone can be changed through this process.  This indicates that through therapy it may be possibly to stimulate even adult bones to change shape and grow in a certain way.

Sources:
Hadjidakis, DJ. Bone remodeling. http://www.ncbi.nlm.nih.gov/pubmed/17308163. Accessed April 17, 2013.
What is Bone Remodeling. WiseGeek. http://www.wisegeek.org/what-is-bone-remodeling.htm. Accessed April 16, 2013.

Section 2
1. What one assignment or activity you performed in this unit are you the most proud of?
My favorite assignment was actually the researching on the first portion of this paper.  Although the information between resources doesn't seem to be very varied I was able to find some really neat graphics that helped to explain the process better.  Sometimes those little things can make all the difference!

2. Why did you enroll in this biology class?
I enrolled in this class to fulfill my requirements for graduation   There aren't a lot of science courses that can be done from home and my schedule kind of requires that.  I did have a few classes to choose from and thought I would like to learn more about people physiologically to help my understanding of people and their cultural developments as well.  Understanding the physiological needs of people is a way to help understand their varied methods of fulfilling those needs.  This ties into my major educational focus of cultural anthropology.

3. Did you feel prepared for this experience when you registered?
4. How was your experience different from your expectations?
I had taken a human physiology class in high school that was designed for students who were planning on being premed, so I thought I had a good idea of what I was getting into with this class.  There were a lot of things that I remembered, but I think there was probably more that I had forgotten!  There are definitely areas where this class went into more depth!


5. What can I do to help you?
There hasn't been much that I feel our instructor hasn't done to help the students in this class.  She has always offered to help with and questions or problems that might arise for us and has been very flexible about things when the material has been challenging for the class.  I wouldn't want to take this class with anyone else!

Tuesday, April 16, 2013

Chicken Leg Dissection Lab

To get a better feeling for how muscles and bones work we were assigned to do a dissection of a chicken leg.  By completing this exercise we were able to look at how the different systems are constructed and how they interact to make movement possible in different kinds of joints.

Ready to start the dissection we have a full leg quarter with skin still intact, and the tools.

The first step was to remove the skin.  As it's peeled back you can see the clear connective tissue that secures the skin to the underlying muscles.

Now that the skin has been removed, the muscles of the leg are clearly visible.

The muscles within the leg can be separated into bundles.  There are muscle bundles that run parallel to, and along the bone, and others that run diagonally over the underlying parallel muscles.
At joints there are muscles that cross the joint to aid in it's movement and stabilization.  This Photo shows a muscle from the thigh (held on the left) that crosses the joint, and attaches diagonally under the muscles of the lower leg.

Muscles are attached to the bones by tendons like the one shown here.  The origin of a tendon is stationary and does not move when it's muscle contracts, while the insertion is moveable.


Once the tendons are cut at one end, the muscles peel back to reveal the bones.  The tibia is obviously visible, while the fibula on the right of the leg is much smaller and more difficult to see.
The leg muscles, when examined individually have stripes across them indicating that they are striated skeletal muscles.  Although I was unable to locate them in my specimen nerves run along the muscle tissues and serve to send messages to control the muscle and thus the movement of the animal.

After pulling away the knee cap (top left), you can see into the knee joining and the ligaments that hold the bones together are clearly visible.  Tendons are made of collagen which makes them strong and flexible.

After removing the muscles from the entire leg the bones and joints are clearly visible.
Although we didn't open the bones in this dissection, they are full of tissue called marrow.  This soft material is comprised of different cells.  Yellow bone marrow is primarily fat cells.  Red bone marrow contains hematopoietic stem cells, which are undifferentiated cells that ultimately differentiate in
to different kinds of blood cells.  Bone marrow also contains mesenchymal stem cells that differentiate into many other types of cells.


This diagram shows the basic leg anatomy of a chicken and the two different kinds of joints present.  The hinge joint of the knee functions like a hinge and allows the lower leg to swing, while the hip joint is a ball and socket that allows for rotation, and much greater movement.