Hole in the Brain

So recently I read an article on a woman who was missing her cerebellum. Apparently she had the space that was originally taken up by the cerebellum was replaced with a fluid. I found this remarkable and so did the article as only 9 other people have survived such a condition into adulthood. Personally, I was curious as to what would happen if the fluid drained and if the fluid had made any other complications, or if it was actually beneficial in other ways (knowing the cleansing power of the fluid). Then I wondered what would happen if the pons part of the brain was missing.

Pons is located in the brain stem and is involved in sensory analysis. It is also involved in regulating levels of consciousness and sleep. Injury to pons is known to cause comas as well. Given all this information, I would assume that if the pons portion of the brain stem were to be missing, or removed, the patient would likely enter a coma, and likely lead to death. Unlike the cerebellum, the pons most likely could not be replaced due to its essential function.

Chicken Dissection Lab

Unfortunately I was absent for this assignment/dissection, however, I am still educated on the material. I asked class members who did do the lab, how it went and how the process of determining muscles went. They all, for the most part, referred to their in-class notes handouts of the human body. In general, the size of the muscles differed from chickens to humans, however the locations stayed the same. For example, the pectoralis major was far larger in the chicken than in the human. This difference is likely caused by the fact that to lift itself off the ground, the muscle would have to be larger. This causation ultimately results to form fits function. As the chicken needs to lift itself off the ground, the muscles need to be stronger, and therefore larger. In contrast, humans are far less reliant on the pectoralis major as we don't fly (if only). Some characteristic similarities are are in the trapezius and the deltoid. An important reminder is that muscles grow and atrophy depending on usage and resistance the muscle receives. This can help determine the physical activity and nature of the animal, for instance our largest muscle is the gluteus maximus which is due to our nature as a 2 legged animal.  

Not only are muscles used for movement, but so are bones and tendons. Muscles connect to the bone through tendons and help to show increase the range of motion and release tension. The bones allow for stability. As muscles contract, certain muscles contract as others relax. The muscle that contracts is called the agonist whereas the muscle that relaxes is the antagonist. For example in elbow extension, the triceps contracts, whereas the biceps relaxes. The lever system in this interaction allow the bicep to contract with less stress. These levers vary in class; each class identifies a different type of lever system.

Just as levers vary in class, so do tendons. There are two types, named, the origin, and the insertion. The origin is the end that does not move when the muscle moves while the insertion is the tendon that does move when the muscle contracts. The origin also tends to be more proximal while insertion tends to be more distal. The origin of a muscle attaches to a less movable bone whereas the insertion of a muscle attaches to a more moveable bone. The insertion also has less mass than the site of origin.

• The pectorals are predominantly used to control the movement of the arm, with the contractions of the pectoralis major pulling on the humerus to create lateral, vertical, or rotational motion
• large muscle in the upper chest, fanning across the chest from the shoulder to the breastbone

• thin, flat muscle found immediately underneath the pectoralis major

• The primary actions of this muscle include the stabilization, depression, abduction or protraction, upward tilt, and downward rotation of the scapula

1. The muscle also covers the lower tip of the scapula, or shoulder blade. When flexed, the muscle works at extending, adducting and rotating the arm.
2. One of the widest back muscles. Broad muscle bands cross the back, providing upright posture support. The trapezius muscle is a postural and active movement muscle, used to tilt and turn the head and neck, shrug, steady the shoulders, and twist the arms

• The deltoid muscle is responsible for the brunt of all arm rotation and allows a person to keep carried objects at a safer distance from the body.

2.  The triceps run along the humerus (the main bone of the upper arm) between the shoulder and the elbow. When the triceps are contracted, the forearm extends and the elbow straightens; if the triceps are relaxed and the biceps flexed, the forearm retracts and the elbow bends.

3.  The biceps brachii is a bi-articular muscle, which means that it helps control the motion of two different joints, the shoulder and the elbow. The function of the biceps at the elbow is essential to the function of the forearm in lifting.

1. Also called the brachialis anticus, its primary action is to flex the forearm muscles at the elbow
2. flexes the wrist and adducts it

1. Is a muscle located on the back portion of the lower leg, being one of the two major muscles that make up the calf. The flexing of this muscle during walking and bending of the knee creates traction on the femur, pulling it toward the tibia in the lower leg and causing the knee to bend.
2. It serves to steady the leg upon the foot.
3. the largest muscle located in the anterior compartment of the leg. Helps with dorsiflexion, which is the action of pulling the foot toward the shin.

- a group of muscles located in the front of the thigh

- The quadriceps assist in extending the knee

1. The muscle helps flex, adduct, and rotate the hip.
2. a tiny muscle, inferior to the iliotibial band.  It also provides lateral stability to the knee.

1. It is found on the back of the thigh and runs from the base of the pelvis to the back of the tibia, one of the bones that make up the lower leg. The muscle has several functions, including enabling the leg to flex and rotate, and serving as a thigh extensor
2. One of three hamstring muscles that are located at the back of the thigh. These three muscles work collectively to flex the knee and extend the hip.

1. The biceps femoris muscle is a double-headed muscle located on the back of thigh. It is important for knee flexion, internal and external rotation, and hip extension.
2. A large muscle group that includes the four prevailing muscles on the front of the thigh.They are crucial in walking, running, jumping and squatting. Because rectus femoris attaches to the ilium, it is also a flexor of the hip.

Unit 7 Reflection

In this unit we learned about the muscular system. We learned the physiological effects, as well as the anatomical features. We even learned about performance enhancing supplements affected the body.

So from an anatomical standpoint, we all know what muscles are and or do on a basic level. ‘They are the long stringy things that allow us to lift stuff? Right?’. Well yes, muscle fibers are essentially very long, thin, tubular cells, but they are not all just, “tubular’ dude” (smooth muscle). What is tubular however, are the components of the skeletal muscles. The skeletal muscles contain tubes, inside of tubes, inside of tubes. It’s tubeception! Anatomically speaking, the epimysium is the fascia that surrounds the entire muscles, the alpha tube if you will. Within the epimysium, muscle fibers are further contained in perimysium. The perimysium separates the bundles into 10- 100 muscles. Within the perimysium lies the endomysium, fascia that surround and capture individual muscle fibers. This structure allows the muscle's major  functions such as contractility and elasticity. Other characteristics of muscle include a pulley/lever system which reduces strain on muscles and allows for greater range of motion. A key example of such a system is shown in this gif, depicting the tensions of muscles required to move with and without the kneecap (the small rock represents the kneecap). A common theme that I’ve noticed is that where a limbs connect, there is usually such a system.

We also learned about how to properly name the muscles and such. Personally this subject was little bland and has little substance that can be commented on other than the fact that the muscles are named off of their form, function, and location. For example, the bicep has 2 origins, therefore, the bi- in bicep. We did a lab in which we explored the muscles and their joints and labeled them appropriately.

Then we learned how muscles move during stretches, notably the steps of contraction. One of the many steps include the chemical signals transferred through the neuron. This reminded me of the myelitis sheets and how these membranes allow the signal to be sent faster throughout the cell’s axon terminal. (check out our video here to see how contractions work)

After that we learned about the effects of muscle enhancements. This was probably my favorite section as we were able to talk about the pro’s and con’s of using such enhancements. A common theme I noticed was that the negative effects of the drugs will stay, while the positive effects will diminish with time. To enforce this idea, I made an advertisement.

In regards to my twenty time progress, you can click on the hyperlink to follow my progress. Other than missing a week of school, I really don’t have any questions as the unit answered most of them.

Steve Rogers did what?

I would first off like to say that Chris Evans is body goals. This man is not only the definition of a handsome, but I mean c'mon, look at those chiseled abs, defined chest, and V-shaped body. Others probably have this dream of obtaining this body as well, however some people will turn to performance enhancing supplements in order to achieve this goal. On such P.E. that can help in doing so is androstenedione. This steroid can be injected into the body and is naturally found in the adrenal glands, testies and ovaries. This steroid is suggested to increase muscle mass and blood cell mass, as well as allow endurance athletes to work harder and longer by reducing catabolic effects of heavy training. Personally I might be tempted to take these supplements to achieve that ^ sexy body up there. What prevents me from taking them though is the fact that I don't want to mess with my bodies chemistry..... is it worth it..... that is the question that I ask my self everyday. "My minds telling me no, but my body, my body is telling me yes!" 

The Value Held in Stretching

"This triggers the stretch reflex (also called the myotatic reflex) which attempts to resist the change in muscle length by causing the stretched muscle to contract" 

I chose this quote because I had previously not fully considered the tension that occurs within the muscles. After reading over the sentence I grasped the concept that the contraction of muscle is a mechanism to prevent over exertion. 

"Hence when you stretch, the muscle fiber is pulled out to its full length sarcomere by sarcomere, and then the connective tissue takes up the remaining slack. When this occurs, it helps to realign any disorganized fibers in the direction of the tension. This realignment is what helps to rehabilitate scarred tissue back to health."

I chose this quote as I had previously never thought about connective tissues role in muscle tension before. Apparently it takes a major role that I would have otherwise have missed.

"lasts for only a moment and is in response to the initial sudden increase in muscle length. The reason that the stretch reflex has two components is because there are actually two kinds of intrafusal muscle fibers"

I chose this quote because it really made me think about what really happened on a microscopic level. It helped bring the realization that there are more than just one type of muscle fiber and each type specializes in different functions. So not only are the muscle fibers different, anatomically, from what I had previously conceived, but is their physiology.

R&R

In this reading we learned the anatomical and physiological effects of stretching. Although the reading dives into the specific details about the fibers and their names, the reading didn't mention the long term effects of over stretching. The reading remarks that, "Only consummate professional athletes and dancers at the top of their sport (or art) are believed to actually possess this level of muscular control". What I was wondering was what specifically makes it so that these athletes are superior in their sport, for instance, would a swimmer be genetically superior in regards to flexibility than a gymnast. I was also wondering how exactly stretching could negatively impact performance. I was also wondering the effects of a warm down. We already know that by doing a warm down, our lymphatic system cleans the body, but what about the fibers in the muscle? 

Unit 6 Reflection

During this unit we learn about the bones and the processes they undergo to maintain structural integrity as well as the anatomical features of the bone. Bones are made of many parts, namely, osteons (the portion of the bones that house the osteo, -cytes, -blasts, and -clasts. Osteons also contain the blood vessels, nerves, and lymphatic vessels of the bones. This conglomeration of various vessels, canals, and cells is called the Haversian system), spongy bone, compact bone, nutrient arteries and the periosteum. There is a lot of detail that could go into the function and classification of the bones, however these are some of the more notable anatomical features. The spongy bone for instance, comes in two forms, red and yellow. Yellow contains fat and red contains blood cells. Compact bone is composed of osteons and collagen as well as several different minerals. The minerals is what gives bone its hardness and the collagen is what gives them an elastic element.

The way they keep this integrity is through constant degradation and regeneration of bones through specialized cells.These cells are known as the osteoblasts and osteoclasts. Osteoblasts are the cells that regenerate the bone cells that were destroyed by the osteoclasts. These cells not only maintain bone strength but also help in repairing breaks in the bones. They do this through connecting the separate pieces and then evening out the curves. Not only did we learn about the bones but the joints of bones and how they work. Labs that we did include the Owl Pellet Dissection Lab (previously blogged about) in which we dissected an Owl pellet and identified key structures.

Through the lab we were challenged on our knowledge of common structures as well as general locations of these structures. As we attempted to create a basic skeletal formation of the bones of the pellets, we were also being tested on our ability to acknowledge common joints.

These joints could come in many forms, for instance, the bones of the ribs and the sternum are connected by cartilaginous synarthroses joints. These joints are virtually immovable and are joined by cartilage. We also learned the effects of the knee cap which was really cool. Ultimately I have no further questions. I would just like to say I loved doing these labs.

Owl Pellet Disection

In this lab we worked with owl pellets and dissected them to discover the animals the owl had eaten. The purpose of the lab was to identify what type of animal our owl had eaten, weather it be a rodent or bird. To unearth the bones we had to use tweezers and a prod and slowly chip away at the vomit… gross. Once we classify as a rodent or bird, we were told to use our bone identity sheet in which we would identify key features of the bones. After identifying the key bones, we then put together as much of a skeleton as possible. For us we did not have a skull to confirm our speculations, so we had to base them off of the pelvis we found.

Claim: The animal that the owl had eaten was a shrew.

Evidence:

^ Femur joins to the target bone and the target bones parallelism of structures and the way they seem to fit together

^ bones laying flat depicts similarities. Joint location on bone above loops.

Reasoning:

We can conclude that the animal consumed by the owl was a shrew as the pelvis bones resemble that of the classification table. The bones are long and skinny, similar to that of a shrew. Another defining characteristic of the bone is the location of the loops. In the shrew the loops are very large and are composed of very little bone in comparison to the other rodents pelvis. Another defining characteristic is the # of loops found in the pelvis. The shrew only has 2 loops whereas the mole has 4. This evidence immediately eliminates a mole as the possible animal. Another defining characteristic is the smoothness of the bones. Where vole has a rigid pelvis, the shrew has a smooth one. This means that the animal that was likely consumed was a shrew.

Compare and contrast to humans:

Similarities of structures:

• Both bones serve the same function which is allowing the animal to move
• Both skeletons contain lumbar vertebrae
• Both skeletons contain ribs that protect vital organs

Differences in structures:

• elongated pelvic bone as the shrew uses all 4 limbs to move whereas humans only use our legs
• the pubis is proportionally longer
• The pelvis of humans is anatomically different as it allows the vertebrate to connect, leaving a ‘hole’ in the middle of the pelvis