Unit 7 Reflection Muscles

There are many different ways synovial joints move. The directions include flexion, movement that decreases the angle between 2 bones: extension, movement that increases between 2 bones: abduction, movement of limbs away from the body: adduction, movement of limbs toward the body: and a couple ore that include rotation, supanation, pronation, circumduction, eversion, dorsiflexion, protaction, refraction, inversion, plantar flexion, elevation, depression, and thumb opposition.
The muscle system starts at the muscular fibers all the way to the body. Muscles help with the movement of bones or fluids, maintaining posture and body position, stabilizing joints, and heat generation (especially skeletal muscle). Excitability, contrability, extensibility, and elasticity are all properties of the muscle. Mucles are supplied with blood to get their energy. Muscles are classified by their size, shape, action, number of origins, and location.
Each muscle is composed of many bundles of muscle fibers. Scaromeres make up myofibrils, which make up muscle fibers. Muscle contraction is activated by a motor neuron, which releases calcium from the sacroplamic reticulum which causes myosin and actin filaments to slide past each other. Relaxation occurs when calcium ions stop being released when the nerve stops. We made a stop motion video showing how muscle contraction works.
There are many muscles in our body. Soe of them include the masseter, temporalis, trapezium, lattissimus dorsi, deltoid, pectoralis major and minor, biceps branchii, rectus abdominus and so on. The largest muscle is the gluteus maximus which extends and rotates the thigh laterally. The longest muscle is the satonius, which rotates the hip laterally and flexes thigh, and is responsible for knee flexion. In my chicken dissection lab I discovered how some of these muscle looked and functioned.



There are three types of muscle fibers. Slow twitch muscles contract slowly, have a high oxidative capacity, and are red in color because of the all blood that travels to these muscles. Fast-twitchA muscle fibers have a moderately high oxidative capacity, high glycogen stores. Fast-twitchB have a low oxidative capacity and is often used during fast and high intensity workouts like lifting weights. The ratio of these fibers depend on genetics and exercise. Hypertrophy is when cells increase in size/volume due to more myofibrils. Cells remain same size, but increase in number. Muscle inactivity many of the beneficial effects of exercise training, from both endurance and resistance activities, diminish within 2 weeks if physical activity is substantially reduced. Soreness is caused by the result of structural damage to sacromeres from eccentric exercise, followed by inflammatory response. Keeping muscles healthy includes daily exercise and a proper diet.
My previous blog post about performance enhancing drugs talk about how drugs help increase an athlete's ability to perform but have severe damages if taken improperly to too frequently.
Reflecting on my previous goals, I feel like I am still not getting enough sleep but I have been working out because I have the time to do so now.

Performance Enhancing Drugs

There are many myths relating to performance enhancing drugs such as steroids are safe or on the other end of the spectrum steroids lead to immediate death, steroids won't stunt growth, or there is no such thing as roid rage. All these claims are untrue. Performance enhancing drugs are manufactured products for oral ingestion or intranasal application or through inhalation containing compounds. They are intended to increase athletic performance, promote muscle growth, induce weight loss, or increase an individual's endurance or capacity for exercise. They boost athletic performance, build muscle, increase body mass, lose body fat. They are dangerous because they can damage a person's mental and physical health and if used by adolescents can have permanent negative consequences, not to mention that they are illegal in most cases. Some health risks include acne, baldness, stunted growth, increased risks of HIV and AIDS, liver damage, liver cancer, jaundice, high blood pressure, heart disease, headaches, muscle and stomach cramps, low sperm count, increased breast size in males, breast shrinkage in females, increased body hair growth for females, enlarged prostate for males and enlarged clitoris for females, increased problems with menstrual cycles for females and the list goes on and on. Psychological health risks include roid range, increased aggressiveness, severe mood swings, paranoia, anxiety, and depression. Stimulates are often used by athletes to stimulate the central nervous system and increase heart rate and pressure, but can result in dehydration, heatstroke, insomnia, and nervousness. Like stimulants, there are so many other types of performance enhancing drugs and activities that all come with thier own short-term benefits and risks. Caffeine is a stimulant that decreases reaction time but prevents fatigue for a short-term period.  Risks include nervousness, irritability, dehydration, insomnia, and aggressiveness, and an individual can very easily become psychologically addicted to it.  Bottom line, although performance enhancing drugs have some temporary benefits that also have long term risks that far outweigh the benefits.

Here is a fun ad we made to endorse caffeine!

Chicken Dissection Lab

In this dissection, my group and I found and took pictures of all the major muscles underlined in the lab packet we got in class. We also played around with the chicken by moving around the tendons and muscles and seeing how a part of the chicken moves. Muscles and bones work together in tandem meaning that the muscles attach to tendons and ligaments and the tendons and ligaments attach to bones. The muscles pull the bones, causing movement. The major difference when comparing the tendons of the insertion and the tendons of the origin is the flexibility and the amount of red blood nerve vessels found nearer to the origin than the insertion. In this lab, we examined several specific and major muscles to get a better sense of this.

A. Pectoralis major: This is the muscle that runs from the shoulder to the humerus. It pulls the wing ventrally  powering flight.

B. Pectoralis minor: This muscle is directly underneath and runs parallel to the pectoralis major. It lifts the wing dorsally, which is the recovery stroke of the wing in flight. In humans this muscle pulls the shoulder down and forward. 

A. Trapezius: These muscles run perpendicular from the backbone to the shoulder of the bird and pull the shoulder back. 

B. Latissimus dorsi: These muscles are directly distal to the trapeziuses on the bird's and the human's back. In both species they extend or pull the wing or arm.

A. Deltoid: This is the muscle on the center top of the shoulder and help to raise the upper arm or wing.

B. Biceps Branchii: This muscle is located near the uppxer part of the wing or arm. It flexes the wing or arm.

It is called "biceps" because it has 2 origins.

A. Triceps humeralis: This muscle is located in the inferior side of the upper arm or wing. It extends the wing or arm. It is called "triceps" because it has three origins.

A. Flexor carpi ulnaris: This is the largest muscle on the posterior side of the lower wing and it runs from the back of the elbow to the side of the "pinky finger" of humans. It flexes the hand.

B. Branchioradialis: This is the largest muscle on the superior side of the lower wing. It runs from the elbow to the thumb side of the hand. It pulls the hand back.

A. Sartorius: This muscle runs down the front edge of the thigh from the illium to the knee in birds. It flexes the thigh and allows for the crossing of the legs.

B. Iliotibialis, Gluteus maximus (humans): This muscle covers the whole lateral side of the thigh in birds and in humans it runs from the dorsal and lateral sides of the the pelvis to the lateral side of the knee. It extends the thigh and flexes the leg.

C. Biceps femoris: This muscle lies medial to the inferior section of the iliotibilalis. It flexes the leg.

D. Semimembranosus: This muscle is just inferior and medial to the thigh a bird. It extends the thigh.

E. Semitendinosus: This muscle is just anterior and medial to the semimembranosus of the inside of the thigh. It  also extends the thigh.

F. Quadriceps femoris (birds) Rectus femoris (humans): This muscle lies on the inside of the thigh just medial to the sartorius in the bird. It is a group of four muscles, hence its name "quadriceps," which make up the bulk of the front of the thigh in humans. It flexes the thigh and extends the lower leg. 

A. Gastrocnemius: This is the primary muscle of the dorsal and medial sides of the drumstick.  It extends the foot and flexes the lower leg.

B. Peroneus longus: This is the primary superfificial muscle on the lateral side of the drumstick in birds. It is smaller and runs up the lateral side of the lower leg in humans. 

C. Tibialis anterior: This muscle is larger than and directly under the Perneus longus in birds. In humans it runs along the lateral side of the shin bone (tibia) on the very front of the lower leg. It is the muscle that causes pain in the disorder known as "shin splints." It flexes the foot.

"What Happens When You Stretch"

Today for homework I read the article "What Happens When You Stretch," When you stretch, the muscle fiber is pulled out to its full length sacromere by sacromere, 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 rehabilitate scarred tissue back to health. Proprioceptors are nerve endings that relay all the information about the musculoskeletal system to
the central nervous system. They aide in the perception of one's own body position and movement. The proprioceptors related to stretching are located in the tendons and in the muscle fibers. There are two kinds of muscle fibers fibers: intrafusal muscle fibers and extrafusal muscle fibers.
When muscles contract, they produce tension at the point where the muscle is connected to the tendon. When the tension caused by stretching exceeds a certain threshold, it triggers the lengthening reaction which inhibits the muscles from contracting and causes them to relax.  Another reason for holding a stretch for a prolonged period of time is to allow this lengthening reaction to occur, thus helping the stretched muscles to relax.
When an agonist contracts, in order to cause the desired motion it usually forces the antagonists to relax and this phenomenon is called the reciprocal inhibition. When stretching, it is easier to stretch a muscle that is relaxed than to stretch a muscle that is contracting. You want to relax any muscles used as synergists by the muscle you are trying yo stretch. For example, when you want to stretch your calf, you want to contract the shin muscles by flexing your foot.
The muscle spindle records the change in length (and how fast) and sends signals to the spine which convey this information. This triggers the stretch reflex which attempts to resist the change in muscle length by causing the stretched muscle to contract. Another reason for holding a stretch for a prolonged period of time, is so you can gradually train your stretch receptors to allow greater lengthening of the muscles.
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.
That is why when we are young it advised to play money bars which stretches out our arm muscles making us taller.