Unit 4 Reflection

Unit 4 was about the integumentary system and the immune system. We learned about how our bodies stay healthy by keeping pathogens out or defeating them when they enter the body. The body's most basic defense is the integumentary system, which includes things like skin and nails that give us a physical barrier from the outside. 

The epidermis contains melatonin to absorb some of the UV radiation because too much radiation can cause cancers such as basal cell carcinoma and malignant melanoma. The dermis of the skin is where many glands, receptors and blood vessel lie. The third major layer of the skin is the hypodermis and its main purpose is to anchor the skin to the organs. Nails and hair act as physical protection as well.

If we enter the body, mucus membranes trap pathogens that may have entered the body. Other mechanical methods of defense include the urinary tract, tears, sebum, and perspiration--all of which are non-specific defenses. Another common reaction to invaders is inflammation, triggered by tissue damage. Many different types of white blood cells activate and fight whatever harmful substances they find in the wound. Specific immunity is a little different in that it targets specific pathogens by creating the appropriate antibodies. Memory T and B cells remember the invaders and are more prepared for an attack by the same invader in the future. 

A lot of this unit's content overlapped with  the AP Biology course I took last year, but this class revealed more anatomical structures of the body, like hair and nail matrices, rather than solely focused on the chemical side of bodily defense. From the debate, I was able to see the various perspectives on nature deficiency disorder and the debate actually changed some of my opinions; for example, I was strong believer of the deficiency, but after hearing the debate out, I see now that maybe the deficiency doesn't really have enough evidence to back it up. For my groups debate, I researched a ton on organs markets--which I would have never been interested in doing on my own. I'm glad I did though, because it brought a new light to the problems with our current organ donation system that I never knew existed. 

This unit was pretty eye opening--I especially enjoyed the debates--and I do feel like I am a better, more well educated student now. I've learned about topics I never would have even thought about learning and I had the opportunity to participate in a debate myself. 
I'm pretty bad at staying focused when reading the textbook or handouts, so the note packets were harder for me to do. I think I was pretty successful in my debate though. My team was relatively prepared and I was ready to shoot down any pro organ market comments. 

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I have a multimodal learning preference which means I don't have a specific method that is better for me. Me scores for each VARK category were:

• Visual 8

• Aural 7 

• Read/Write 5

• Kinesthetic 10

The results didn't surprise me because I've been trying to figure out how I learn best for years and haven't found any answers except that I don't like to read academic texts and write. However, it does seem that kinesthetics was my strongest point. To play that to my benefit, I should engage my senses and put real life examples in my notes. Studying with another person is probably best.

Unit 3 Reflection

In Unit 3 we learned about the various components of the heart, blood vessels, blood, cardiovascular diseases, and circulatory system. At the very end, we touched on the respiratory system because it is in many important ways connected to the cardiovascular system. 

At the beginning of the unit, we covered how the cardiovascular system continuously circulates blood and oxygen throughout the body via arteries and veins. The heart is divided into four chambers--right/left atria and right/left ventricles--that pump blood to the heart for reoxygenation and also to the body to distribute nutrients and oxygen. The respiratory system brings oxygen into the lungs and fills the blood with oxygen through the alveoli and capillaries that surround them.

When the heart is unhealthy due to a bad diet, cardiovascular diseases may arise, the most well known being heart attacks. Heart attacks result from a severely reduced blood supply to the myocardium, no to be confused with cardiac arrests, which occurs when there's a malfunction in the electrical system of the heart. A big culprit of heart attacks is atherosclerosis, where a plaque develops in a blood vessel due to the excessive intake of fats and sugars and clogs the vessels enough to hinder blood flow. Similarly, strokes in the brain can be caused by atherosclerosis nearer to the brain, but also the bursting of vessels in the brain.

Cardiovascular health can be maintained by looking after diets, particularly the intake of HDL and LDL levels. HDL really help lower the risks for contracting a heart attack or stroke and is more important to have high HDL levels than low LDL levels. Exercise can prevent overweightness and the build up of fatty waste in blood vessels, thereby preventing problems like atherosclerosis.

I thought that just learning the various parts of a heart was really confusing because the heart has so many vessels leading blood in and out, and in addition, has so many small details like the chordae tendinae or semi lunar valves that made the heart overall just really complex and hard to grasp. I would perhaps be interested in learning more about how  electrical pluses work in pumping the heart because we only discussed it a little when talking about nodes.

This class is demanding in that it requires a lot of outside-of-class work, especially for the blogs, which I have to make sure to plan my time accordingly for. Unfortunately, I'm weak in the motivation department and have a hard time not procrastinating on homework that requires more effort. I am thankful, however, that this unit included a lot of group work, because I find it helpful to work with others that may understand parts of the lectures more than I do and can help me digest information better.

Looking that my Unit 2 goals, I am sad to report that I have not starting running like I wanted to, but I do make an effort to sleep earlier/more now. I've actually been noticing a small increase in energy in the mornings now when I wake up--progress! As for the remainder of the semester, I would like to continue working on my Unit 2 goals, but also try to become more self motivated so I can improve my academics and not fail school like I am right now.

Picture:

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Heart Dissection Lab

1. The pericardium protects the heart and keeps it in place. The membrane is made of an outer fibrous layer and an inner serous double layer.

2. Arteries are thicker than veins because they need to withstand more pressure as blood is being pumped out of the heart to the rest of the body. However, the veins carry more blood by volume than the arteries back to the heart for oxygenation.

3. The auricles are appendages connected to the outsides of the atria and serve to increase the blood holding capacity of the atria.

4. The ventricles are larger than the atria and do not have auricles attached to them.

5. The coronary sinus brings deoxygenated blood from the coronary veins into the right atrium. The inferior vena cava carried deoxygenated blood from the part of the body below the heart into the right atrium. The right atrioventricular valve (aka tricuspid valve) prevents the back flow of blood when the blood travels from the right atrium to the right ventricle.

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7. The heart valves need to be anchored by chordae tendinae to keep them from opening when the ventricle contracts and the blood pushes against the valves. The papillary muscles control when the valves open and close.

8. Down the pulmonary trunk, you can just see the bicuspid valve, which lies between the left atrium and ventricle.

9. The semi-lunar valves, located at the base of the aorta in the left ventricle and at the opening of the pulmonary trunk on the right ventricle, prevent the back flow of blood into the heart once it is pumped out.

10. Valvular Heart Disease:
      a) if the valve disease occurs on the right side of the heart, the feet and ankles may swell because the right ventricle/atrium are unable to pump all of the blood against gravity back into the heart for reoxygenation. The blood would leak back out and presumably into the foot area.
      b) the the disease occurs on the left side of the heart, not enough blood would be distributed to the rest of the body, which would starve the cells of oxygen and cause the heart to swell.

11. The right and left coronary arteries branch from the aorta and wrap around the heart. The aortic semilunar valve prevents blood from flowing from the aorta back into the left ventricle. The bicuspid valve prevents back flow from the left ventricle to the right atrium. Chordae tendinae attach the valve to the papillary muscle in the ventricle to make sure the valve can withstand pressure and stay closed when appropriate.

12. The left side of the heart has thicker walls because the extra muscle is needed to pump oxygenated blood to the rest of the body. The right side has much thinner walls because it only needs to pump blood to the heart for reoxygentation.

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