Unit 7 Reflection

Unit 7 is all about the muscular system. We began with how synovial joints let us perform different actions, for example, flexion and extension. We created mini dances that included all the different movements and performed them in front of the class. It was all in good fun, but also uniquely helpful in memorizing each different synovial movement. We also learnt the basic anatomy of muscles: the major muscles in our body, and in a chicken (by dissection), such as the major and minor pectoralis, the deltoid, and the trapezius. The dissection was really cool - seeing all the different muscles and how similar they are to a humans was really impressive.

We then moved onto how muscles are separated and classified into different groups. Next, we zoned in and learnt about how muscles specifically work, right in each muscle fiber. I found the sliding filament theory particularly interesting - how the muscle shortens and lengthens when contracting and relaxing. We made a short video showing how a muscle works. It was challenging, finding a way to portray it clearly, but it was a great learning experience and it was cool how we made an actual short movie on it. Next, we moved onto how muscle fibers respond to different exercise - slow oxidative fibers in marathoners, fast oxidative fibers in a regular person, and fast glycolytic fibers in high intensity/ short burst workout, like sprinters. Finally, we covered performance enhancing substances and how the affect the mind body. The mini project for this section was that we made a satirical ad promoting P.E. substances.

The thing that really stood out to me about this is that none of them are FDA approved, or regulated in anyway, which in turn makes them all very unsafe for consumption. 

I'm really interested in learning more about performance enhancing substances, not only in the body, but those made for the mind as well. They are all so dangerous but many people treat them like no big deal - maybe not the ones aimed at body-building, but the ones that aid in focus and improve mental performance. Overall, I like a lot how my 20 time project is coming along, I'm really satisfied with my progress so far. Going back to my New Year's Goals, I am still working on more actively participating in class but in small groups I am participating a lot more. I am sleeping a fair amount every night - losing an hour to daylight saving wasn't great but I'm making it work the best I can. For horse riding, I am working hard to get to where I want to be - and hopefully a new horse is coming my way in the near future! 

Performance Enhancement Advertisement

Performance enhancing drugs can be very dangerous. They can affect growth, mood, overall health, and longevity. Performance enhancing substances are taken to benefit athletic performance, build muscle, increase body mass, or lose body fat. They are all unregulated, non-FDA approved, or safe. 

Chicken Dissection Analysis

We skinned the chicken and got a good look at all the muscles, first and foremost the pectoralis major and minor. The muscles help the chicken move and hold itself up. The allow for the chicken to walk, hop, stand, and sit. For example, the pectoralis major gives chickens the ability to move its wings ventrally. The pectoralis minor allows the chicken to move its wings dorsally. The bones give the chicken its skeleton and are what allows it to have the anatomy to move. The tendons attach the muscles to the bone so that the muscles can move in different directions, which in turn allow the chicken to perform movements. 

The insertion of the muscle in the wings are quite shiny and white. When they move, the muscle is lengthened or shortened, and they glide against each other - as the chicken would when performing that movement.

Surprisingly, the chicken's muscles were quite similar to those of a human. The chicken has biceps and triceps like humans, obviously on a much smaller scale, but we quickly identified them. The trapezius was on the back, same as in humans, despite the overall difference in anatomy. It was also not hard to identify. The sartorius are on the front of the thigh, and allows for the crossing of the legs. Same on a human, they were also pretty easily spotted. The shape of a chicken is very different from a humans, but the muscles it has are not so different.

Pulls the hand back

Flexion of the leg

Includes sartorius, iliotibialis,
biceps femoris, semimebranosus,
semientendinosus, and quadriceps

Extends foot, flexes
lower leg. Allows us to
stand on our toes

Flexion of the hand

Extends the thigh,
flexes the leg

Flexes the thigh, extends
the lower leg

Deltoid: raise the upper arm/ wing
Biceps: flexion of arm/ wing
Triceps: extension of arm/ wing

                                                                            

Pulls the wing ventrally,
in most birds it allows
for flight

Lifts the wing dorsally, or
in humans in pulls the
shoulder down and forward

Extends the thigh

Pull the shoulder back

Extends the thigh

The white, shiny tendon
in the wing that attaches the
bone to muscle

Flexes the thigh, allows
crossing of legs

Our chicken,
before any cuts were made

What Happens When You Stretch?

1) "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."

- This quote explains what happens when stretching -- how the muscle lengthens fully to accommodate what is being asked of the body. There are many sarcomeres, and a full stretch occurs when all of the sarcomeres are fully extended. 

2) "Some sources suggest that with extensive training, the stretch reflex of certain muscles can be controlled so that their is little or no reflex contraction in response to a sudden stretch."

- Some think that if people train enough, they can control which muscles stretch and which ones contract. The less contraction, the more stretch possible. It is not easy to achieve; as the sources say only the top of the top athletes achieve it.   -- but it is very rewarding once achieved.

3) "When stretching, it is easier to stretch a muscle that is relaxed than to stretch a muscle that is contracting. By taking advantage of the situations when reciprocal inhibition does occur, you can get a more effective stretch..."

- To increase the ease of stretching, it is very important to be relaxed , so contracting muscles are not opposing. Contracting certain muscles while trying to stretch others is very contradictory when trying to elongate the muscle. 

Relate & Review

This reading was about what happens when you stretch. It's important to try to control the muscle contraction when trying to stretch =, so the sarcomeres can fully extend and stretch out as much as possible; and also to improve the ease of stretching muscles. Gymnasts and dancers seem to be about to control when the muscle contractions occur, which totally changes the game when the sports are both very focused on extension of limbs. As a former gymnast and dancer, it is easy to recognize how helpful it is the be able to control sudden muscle contractions.