Unit 7 Reflection

 This Unit was about muscles and how they move, contract, function, and help the body. First, we leafed about directional terms and joint movements such as abduction (away from the body), and adduction (towards the body). After learning movements, our teacher Mr. Orre assigned us a project where we had to come up with out own dance that involved all of the movement we were taught prior.  The next lecture taught us about the muscular system. Here we learned about the different tissues used to make up muscles, the properties of muscles, muscle classification, and muscle names. For example we learned muscle names are named according to any of the following criteria; directions, size, shape, action, location and number of attachments. Piriformis means pear shaped; Gracilis means slender; Brachii means arm; and tensor means to make a body part more rigid. These are just examples of some of the terms we learned.

The next thing we learned about was muscle contractions. In this lecture we learned that each muscle is composed of many bundles of fibers, and that in each little fiber, it is an individual cell, it contains myofibrils and has a sarcolemma. Muscle contractions are when a muscle contracts and the myosin and actin filaments slide past each other causing the muscle to shorten. To help us learn it better, me and three other teammates created a Stop Motion Video presentation on a white board. The step of a contraction are 
1) Nerve sends impulse to muscle fiber 
2) Ca2+ ions are released from sarcoplasmic reticulum into the cytoplasm
3) Ca2+ ions bind to proteins wrapped around actin filaments 
4) Binding of Ca2+ ions causes myosin filaments to bind to and pull on actin filaments (like tugging a rope) 
5) Sarcomere shortens 

Then we learned about the different types of muscles such as Biceps, triceps, deltoids, external obliques, gluteus maximus, Hamstrings, quadriceps, gracilis, and tibialis anterior. 

Finally we learned about muscle twitches and the effects of steroids. For muscle twitches, there are slow and fast. Slow tend to be more dependent on oxygen, high amounts of myoglobin, mitochondria and capillaries, and are slow to fatigue. Then theres fast. Fast Oxidative ( moderately high oxygen capacity, fatigue resistant, high blood flow, capillary density, and mitochondrial content). Fast Glycolytic is basically the opposite in fast oxidative. Then in the same lecture, it talked about types of muscle contractions. 
Eccentric contraction: Muscle actively lengthening (walking, quads lengthen when knee flexes after taking a step)
Concentric Contraction: Muscle actively shortening (bicep curl)

Isometric Contraction: Muscle actively held at fixed length. (holding weight in front of you)

Passive Stretch: Muscle passively lengthening (touching your toes)

To end the unit, we learned about how bad steroids are for teenagers and adults as they do many things to your body such as baldness, joint pain, stroke, heart attack, stress on organs and so much more. 

I want to learn more about muscles in direct relativity to sports. Such as what sports affect what muscles and how can you take care of those muscle better. As a second semester senior this year, I am beginning to learn that planning/scheduling is very important in life. I feel as if I've gotten a little better this semester too. 

Chicken Dissection Analysis

For the Chicken Dissection lab, my group and I got a full, uncooked chicken from Foster Farms at Safeway. We then were expected to take pictures of all major muscles underlined after dissecting the chicken. Each of

the pictures I post below will be captioned with the major muscle and the characteristics of that muscle.

1. What I learned from this lab is that chickens are very similar to humans in their muscular structure. However some differences my group and I noticed was that chickens have bigger pectorals due to the breeders breeding chickens to eat, not look good. Most/all chickens that humans get from grocery stores are bread to be eaten. This means that the farmers don't care about how the chickens look, but how big and muscular they are.

A) Muscles, bones, and tendons each have a major role in movement for chickens and even humans. Muscles help support the chicken and each specific muscle has a certain job. For example the deltoid muscle abducts, flexes and extends the arm and this is what helps the chicken flap its wings. Another example of an important muscle for the chicken is the Gluteus Maximus which extends and rotates the thigh laterally and chickens. Next tendons help move the wings up and down helping in flight and vertical movement. Tendons rely on muscles which rely on bones because they all connect to eachother. Muscles help initiate movement and with being attached to bones by the tendons, the wings are being pushed back and fourth. The bones in the wings consist of the humeras, ulna, and the radius which all connect to the elbow joint. This helps the wing move up and down. Other important muscles in the chicken such as in its legs are the Peroneus longus which extends the foot and allows the chicken to walk/run.

B) Some physical and functional differences in the tendon of the insertion when compared to the origin are the tendons are a shiny white small band and these are at the ends of muscles. When you pull or tug on one of the tendons, the muscle contracts and moves. The origin of the tendon has no movement, but the insertion allows contraction of the tendon pulling on bones to where ever it is pulled/tugged on.

C) Compare and Contrast Human and Chicken Muscles: Chicken, unlikely, have a lot of the same muscles as humans do. For example, in the chicken wing, they have deltoids, biceps and tricpes to aid them in flight and vertical movement. Sartorius which is the muscle that runs down the front edge of the thigh from the ilium to the knee in birds, but in humans, it runs across the front thigh. Also in a chicken they have the flexor carpi ulnaris which is the largest muscle on the posterior side of the lower wing and it runs from the back elbow to the side of the hand away from the thumb. In humans that muscle is used in doing reverse wrist curls. Finally the Gastrocnemius Is the primary muscle of the dorsal and medial sides of the drumstick. It has two distinct heads in both birds and humans and both are attached to the achilles tendon. It extends the foot and flexes the lower leg. This is primarily to help standing on your toes.

What Happens When You Stretch

When you stretch:

- begins with the sacromere, and when the sarcomere contacts, the are of overlap between the thick and think myofilaments increases. As it stretches, this area of overlap decreases allowing the muscle fiber to elongate. 

- "The nerve endings that relay all the information about the musculoskeletal system to the central nervous system are called proprioceptors"

- "When you perform a sirup, one would, normally assume that the stomach muscles inhibit the contraction of the muscles in the lumbar, or lower region of the back. In the particular instance however, the back muscles also contract. This is one reason why sit-ups are good for strenghting the back as well as the stomach." 

- " the stretch reflex has a both dynamic component and a static component. the static component of the stretch reflex persists as long as the muscle is being stretched. the dynamic component of the stretch reflex ( which can be very powerful) lasts for only a moment and is in response to the initial sudden increase in muscle length." 

Relate and Review

This packet of notes was about what happens to your muscles when you stretch. When you stretch you involve a majority of your muscles. It  begins with the sarcomere, and when the sarcomere contacts, the are of overlap between the thick and think myofilaments increases. As it stretches, this area of overlap decreases allowing the muscle fiber to elongate. Additional stretching places force on the surrounding connective tissue and as the tension increases the collagen fibers in the connective tissue align themselves along the same line of force as the tension. When as muscle is stretched, some of its fiber lengthen, but other fibers may remain at rest. The Current length of the entire muscle depends upon the number of stretched fibers.