Unit 7 Reflection

This unit was about the muscular system. A system I actually learned quite a bit about in sports medicine last year. In this class specifically (A & P) we learned about the muscles from a macro and a micro level. Personally I've always been more of a fan of macro, for me its easier to understand/ relate to blah blah blah, but this unit the micro was actually quite comprehensible. We started off with the directional terms for joint movement and the types of joints. Then we went deeper learning about what goes on inside of muscles, its anatomy and physiology, when it contracts, etc. For contraction it was crazy to see how so many complicated steps can occur within a matter of seconds. After contraction we learned all the majors muscles, and after that we learned about muscle twitch (which is the type of muscle fibers used), and even after that we learned about performance enhancing drugs. We did things like the chicken dissection, the muscle contraction skit video,(which I have a picture of down below), and the performance enhancing collage to help further our understanding of each section. 

I'm doing better on my new year's goals, somedays sleep is good, other day sit is not, but I hunkering down on school work and focusing a lot better.

Performance Enhancement: Packing on the Protein

I see a lot of people in our community obsessed with this new "high-protein" fad. Constantly wanting to increase their muscle mass with endless protein shakes, raw eggs, and trips to the gym. I wouldn't say that I know of anybody who has experienced any harsh side effects from participating in this, but it definitely concerns me. I wonder how long it takes for people to be strongly affected, and also to what degree?

This image's purpose was to poke fun at the high protein diet
(and its stereotypes) and to also inform the public of a few of its repercussions. 

Chicken Dissection

Muscles, tendons, and bones all cooperate together to conduct movement. Tendons are what attach bones to muscles. When a muscle contracts it pulls on the tendon which then causes the bone to move. For example when the brachioradialis contracts it pulls of the forearm tendon which then moves the radius.

Tendons tend to be wider where they attach to the bone at the origin, but they are and narrower where they attach to moveable bone at insertion.

Similarities and differences of muscles between humans and chickens: Gastrocniemius, attaches to achilles tendon in both species, but runs down hock in birds and heel in humans. Sartorius in chickens runs down the front edge of thigh while it runs across the front of the thigh in humans, for both it flexes the thigh. Deltoid is the shoulder muscle in both and raises the arm/wing.

Pulls arm laterally               Pulls shoulder down and forward

Extends arm                  Shrugs and pulls shoulders back

Assists in raising arm                            Flexes arm

Extends arm                               connects bone to muscle

Flexes the hand                                 Pulls hand back

Extends thigh and flexes leg                    Flexes the thigh

Flexes the leg                      Extends the thigh

Extends foot and flexes lower leg                Flexes the foot

Extends the foot

What Happens When You Stretch?

Article: What Happens When You Stretch?

In this article it talks about what physiologically is occurring within your muscles that allows you (and does not allow you) to stretch. As the muscle stretches the area of overlap of myofilament decreases. Once the sarcomere is at its most elongated position the connective tissue does the rest of the stretching. Not all fibers are stretched, some are just relaxed. Muscoskeletal receptors are called proprioceptors. The one's that take part in stretching are located in tendons and muscle fibers. Intrafusal fibers are the primary proprioceptors in the muscle. They receive a message from the muscle and send it to the spinal receptors. In order for a muscle to stretch it must have a counterpart that is contracting. This is called reciprocal inhibition.

Quotes: "The basic function of the golgi tendon organ helps to protect the muscles, tendons, and ligaments from injury."

The golgi tendon essentially prevents us from over-stretching and that is why we feel pain when we push ourselves to far in a stretch because the golgi is telling our nervous system that we need to stop stretching.

"You also want to relax any muscle synergists by the muscle you are trying to stretch."

On top of there being counter contracting and relaxing of muscles, there also needs to be a coesive stretching among synergists muscles.

"One reason for holding a stretch for a prolonged period of time is that...the muscle spindles habituates"

By holding the stretch for a longer period of time you are essentially training your receptors to allow greater lengthening of muscle. The longer you hold, the more the signal is reduced. This is also why in dance class we hold stretches for minutes at a time.

  

Unit 6 Reflection

First off, I'd like to say that is one of my favorite units. Now that that is out of the way let's get back to reflecting. Unit 6 was the bones unit. We started off simple, learning about the basics of bones. The anatomy of the human skeleton (not all of it because we don't have time to memorize 206 different bones), the functions of bones, types of bone cells, types of bones, etc. Then we dove a little deeper, into something a little more applicable, disorders. Things like arthritis, scoliosis, and kyphosis which are painful deformities caused by things like genetics, age, or even poor posture. The process of bone remodeling came into play, because when a bone breaks a hematoma forms, then fibrocartilage and spongy bone form around and in the area, then a bone callus replaces fibrocartilage, and lastly osteoclasts remove excess bony tissue restoring the new structure. And thats only touching on the basics  of bone remodeling. The last thing we learned about was joints, they are classified by 2 categories, which are then broken down into 3 types per category. First is structural the types are: fibrous, cartilagenous, and synovial. Second is functional: Synathroses (immovable), Ampiathroses (some movement), and Diathroses (freely moveable). This is the general classification of joints. We also did a owl pellet lab, which really helped me understand the human skeleton.(link below) Well that just about covers everything we went over in this unit. 

As for personal experiences, I'm doing much better with my  goals. I've been sleeping better, instead of staying up late, I've been going to bed earlier and doing my hw in the morning. Seems to be efficient,and I'm more awake at school since my brain has already been functioning fully a couple hours prior. I need to time manage better, and even when I have 10 or 15 minutes of time before dance or some other activity, I should be doing hw instead of being on my phone.Because every minute counts.

Owl pellet Lab link

Owl Pellet Lab

In this lab I dissected an owl pellet, which is the remains that are not digestible enough to even pass through the whole owl. To tart off the lab I read a large packet on general information about owls, such as what kinds of animals they eat, what an owl pellet is, etc. Then I did a small hypothesis, based on prior knowledge, what I expected the differences to be with the human skeleton. I measured the mass , length, and width of the pellet. Then I started breaking up the pellet, separating the hair from the bones. I had a great array of bones which you can see in the photos below, I had the skull, ribs, scapula, some vertebrae, and majority of the lower extremities. I then measured the dimensions of the skull and lower jaw.

From my observations I concluded that the animal was a vole. Firstly, the molars were pointed, the skull length was 25mm, and the lower jaw was 20mm, which all the directly correspond with the standards of a vole. There is also striking similarity between the scapula, hip bone, tibia, fibula, and femur. (Shown in pictures below)

As for the comparison of the human skeleton to the rodent skeleton, the rodent's skeleton includes the 4 types of vertebrae much like a human, but also has an extra, the caudal vertebrae (tail bones). Human's have the coccyx which is a variation of that. Both have a scapula,which presume the same function, but the rodent's sticks out more instead of mainly being spread across the back like that of a human. The final similarity/ difference that I noticed was, while both have pelvises that attach to the femur, the pelvis of a rodent is much longer. A human's seems a lot wider and shorter by comparison, considering the rodent's is actually longer than its femur.