Eye Dissection Analysis

In the eye dissection, we dissected a sheep eye and walked through the different parts of the eye and learned about what each part did. Below are some pictures of the eye from our lab:

Here is a diagram of the eye, which is much easier to follow: 

Let's go through the anatomy of the eye. All the major parts of the eye are labeled in the diagram:
Structure A is vitreous humor, structure B is the lens, structure C is cornea, structure D is pupil, structure E is iris, structure F is retina, structure H is the choroid, and structure G is the optic nerve. My favorite part is the choroid because I really like the shimmery blue/green color of it. It also looks so cool when light shines through it because there is almost a fingerprint like "watermark" that shows up.

For the physiology of the eye, there are several major components. For example, there are many muscles around the eye that allow for eye movement, and fat that acts as cushion around the eye. The cornea protects the eye and allows light to pass through. large region of vitreous humor is the fluid between the cornea and the lens, and its function is to support eye shape. The lens focus images on the retina, and the retina is filled with rods and cones to take in different images of light that are then funneled to the back of the eye to the optical disk/blind spot. Finally, at the very back of the eye is the optic nerve cross (optic chiasm) that crosses over to the respective left and right hemispheres of the brain. The left eye's optic nerve crosses over to the right brain hemisphere, and the right eye's optic nerve crosses over to the left brain hemisphere.

The Clay Brain

In this lab we used play dough to reconstruct different views of the brain. We used the play dough to label different parts of the brain in each view. This lab was really fun in that it helped me learn where the parts of the brain are in a very hands on way. Below is a picture of our clay brain:

The Woman With A Hole In Her Brain

A women in her 20s was discovered to be missing her entire cerebellum. Prior to finding out that her cerebellum was missing, she had experienced dizziness and nausea, and had trouble learning to walk and talk. I thought this was really interesting because she was disabled her entire life with one of the most well known and important parts of the brain and yet she was not affected too severely and could still carry out normal everyday life. The cerebellum's primary job is to control voluntary actions of the body, and problems with the cerebellum can lead to severe mental disabilities. Therefore, the fact that this woman could survive quite normally without her entire cerebellum was very fascinating to me.

My part of the brain is the medulla oblongata. It is a continuation of the spinal chord within the skull and is a cone shaped nerve mass. It is responsible for autonomic actions such as digestion, breathing, and heart rate. Without the medulla oblongata, it would be impossible to survive without life support since other parts of the brain cannot take over and voluntarily produce a heart beat or digest food. The medulla Oblongata is definitely one of the most important parts of the brain, and one would definitely not want to be without it!

Unit 7 Reflection

This unit was about the different types of muscle movement, narrowing down to the classification of muscles and how each muscle worked at a cellular level. The essential understands were how muscles work in opposing pairs to produce various movements, as well as muscle contraction. How lifestyle choices affect muscle health and performance enhancement drugs were also other focuses of the unit. One other theme of the unit was again to live  a healthy lifestyle in order to make sure that your muscles are in peak condition for as long as possible. I would like to learn more about how performance enhancement drugs affect your body. I also wonder whether there are nay performance enhancement drugs that have no side effects, simply because all the ones we went over in class had very bad side effects. As a student, I have grown in that I spend a lot more time on my cooking blog now thanks to it being incorporated into my 20 time project.In this unit. I also learned how to make an animation video with my group during our project showing muscle contraction. 

My favorite part was the chicken dissection; here are a few photos from the lab showing various muscles in the chicken: 

As for my new year's goals, I have been getting in a lot of yoga recently, and I have also been eating healthily. I am trying to improve on my sleeping time, but life is really really busy right now so it is difficult to sleep early. 

Performance Enhancement Advertisement

I think that massages are often overlooked as a performance enhancement technique to non-athletes. Although many professional athletes do get massages, I think that the general public would find self-massage techniques very effective. For example, a swimmer who has arm pain could greatly benefit from doing a self massage on the arm muscle groups to relieve future pain and to greatly speed up recovery. I think that massage is one of the safest techniques for recovery, if not the safest. People can easily overstretch their muscles and pull a muscle, but with massage, it is quite difficult to damage your muscle as you have full control over the pressure and there is less strain on the muscle. Also, massage does not involve putting any artificial chemicals into your body in contrast to steroids or other enhancement technique. Massage also does not cause damage to your organs and body systems and is generally not a concern for addiction. A lingering question I have is whether it is better to work on sore muscles with more pressure or not, and how big a difference the amount of pressure you use has on the effectiveness and speed of the recovery process.

Chicken Dissection Analysis

In this lab, we dissected an entire chicken. The first thing we did was pat it dry and remove all the skin from the breast part, and then we identified the various muscles, even cutting off a wing to take a look close up at the muscles in the "arm" of the chicken. The bones provide the structural frame of the chicken, and the tendons attach to the bones and muscles to keep everything stable. The muscles are responsible for controlling the movement of the chicken and supporting is structure. For example, when we flexed and extended the leg of our chicken, we could clearly feel the quadriceps tensing and relaxing, so we knew that it was responsible for that movement.

One major difference between the tendon where it attaches to the origin and insertion site is that at the site of insertion, all the tendon fibers are bundled together very tightly and compactly, whereas at the origin, it fans out a bit and becomes a thinner layer of visible tendon fibers where it attaches. At the site of insertion, there must be a very strong foundation, so the tendon is very compact to ensure that it can hold all the weight. The site of origin requires the tendon to support the bone, so it is required to be more spread out in order for nerve impulses and motion neurons to reach it more easily.
The chicken has much larger pectoralis major that humans do, which is because chickens are farmed for food, and humans prefer chicken breast, so they select the chickens to breed so that all the offspring have larger pectoralis major. Compared to humans, chickens have a relatively small trapezius muscle, probably because they have such a small head and stubby neck, so they don't need that much muscles to hold their head up. Compared to chickens, we have very large and heavy heads with a relatively long neck, so we need stronger trapezius muscles to support our head movements. Finally, chickens also have a very large tibialis major, which is located on their leg, the drumstick part. This is also because humans really like to eat drumsticks, so chickens are bred to have large drumsticks. At the same scale, humans have much smaller tibialis major. Below are the pictures that we took of the muscles and other parts:

Deltoid allows arm abduction along frontal plane.

Trapezius muscle moves scapula and supports arm movements. 

Latissimus Dorsi allows for extension, flexion, rotation of shoulder joint, and more.

Pectoralis minor abducts and depresses the scapula toward the ribs. 

Pectoralis major moves the shoulder joint.

Biceps Brachii controls the movement between the shoulder and elbow joints.

Triceps Humeralis are supportive of arm structure and have populations of slow fibers. 

The flexor carpi ulnaris adducts and flexes the hand.

Biceps femoris supports the knee extension.

brachioradialis flexes forearm at elbow. 

Quadriceps extend the knee joint and are used for walking and running.

semimembranosus allows leg to flex and rotate and serves as a thigh extensor. 

Tendons are dense collagenous fibers that connect muscles to bones. 

Semitendinosus works with other hamstring muscles to flex knee and extend hip.

Iliotibialis flexes the thigh. 

The longest muscle in the body, the sartorius flexes, adducts and rotates the hip. 

Gastrocnemius flexes the knee and foot. 

Peronius Longus everts and pronates the foot. 

The tibialis anterior dorsiflexes and inverts the foot. 

What Happens When You Stretch Notes

1. "The nerve endings that relay all the information about the musculoskeletal system to the central nervous system are called proprioceptors. Proprioceptors (also called mechanoreceptors) are the source of all proprioception: the perception of one's own body position and movement." 

I thought that this quote was interesting because it showed how many words that are used in science are actually very easily definable despite the fact that they look complicated. this in large is due to the fact that many words, such as propioception, is made of prefixes and other parts that all mean words that we know in everyday life. 


2. "When muscles contract it places tension on the tendons where the golgi tendon organ is located. The golgi tendon organ is sensitive to the change in tension and the rate of change of the tension."

This makes me wonder about whether the golgi tendon organ is in anyway related to the golgi apparatus in the cell. Since they share a name, I would guess that they either perform similar functions or have some other correlation. 

3. "Some sources suggest that with extensive training, the stretch reflex of certain muscles can be controlled so that there is little or no reflex contraction in response to a sudden stretch. While this type of control provides the opportunity for the greatest gains in flexibility, it also provides the greatest risk of injury if used improperly. Only consummate professional athletes and dancers at the top of their sport (or art) are believed to actually possess this level of muscular control." 

I am curious about the stretch reflex and its control. How long does it take for athletes and dancers to develop this control? Do they have to do certain types of exercise in particular that help with this? 

Relate and Review:

I thought that this article was very interesting because it connected well to what we learned in class. In particular, I found it interesting how the sacromeres are stretched to their fullest when you stretch. I thought that it was great because even though it was an in depth article, because I already had prior knowledge in this topic and especially in how the muscle works when it contracts and relaxes, I was able to clearly visualize how muscles behave when they are stretched.  I also thought it was interesting how the stretching reflex could be trained and be controlled, especially by athletes. I am curious to learn more about the process of how it is controlled, as well as what goes on at a cellular level when it is changed. Are the genes that are expressed and proteins that are produced permanently altered? What mechanism makes it change?