Unit 8 Reflection

This unit we explored the anatomy and physiology of the muscular system. The muscular system includes muscles and tendons and it works closely with the skeletal system for to achieve support and movement. The muscles are made of bundles that are also made of bundles of muscle fibers. This allows the muscle to stretch and contract. The epimysium bundles the outside of the muscle, the perimysium separates the bundles, and the endomysium contains individual muscle fibers. Fascia is throughout the muscle to help bind the fibers together. A tendon is connected to the end of the entire muscle as connects it to a bone. This allows it to move the bone. There are many different ways to move. Below is a video of the types of movements.

The movements are able to be performed due to the different types of synovial joints. The planar joint allows the bones to slide past one another, such as the carpals. The hinge joint has one bone inserted into the other and moves like a hinge. The elbow is a hinge joint. The Pivot joint has a ligament ring holding the bone in the dent, like the ulna and radius. The saddle joint has an indent like a saddle. This is found in the metacarpal of the thumb. A condyloid has an oval face that fits together and is found in the wrist. The ball and socket joint moves in many directions and is found in the hip or shoulder. The muscles that help to move our joint are named by the shape, location, movement, origin, size, and direction of fibers.

In order to contract the myosin must grab onto the actin and hold to hold the contraction. This happens when a nerve impulse comes through and Acetylcholine is released. This triggers a release of calcium ions from the sarcoplasmic reticulum into the cytoplasm. Ca2+ then binds with the troponin and opens up the binding sites also changing the troponin to tropomyosin. Then the power stroke of the myosin begins. ATP binds, then divides to ADP +P and releases energy that is used to swing the myosin head forward. P comes off and the myosin is attached to the Actin until the ADP comes off and the myosin detaches. Many heads on each myosin crawl up the until the nerve signal stops and stops the entire chain reaction.

The structure of a muscle by its bundles. Going down drawn of a smaller level. 

The different types of muscle fibers depend on the pathways that they use for energy. Fast oxidative fibers are used for short exercise. They do not have as effective blood vessels and rely on glycogen stores.  slow oxidative are used for long distance. They are red in color due to the blood vessels and fatigue slowly. 

fast glycolytic are used for quick sprints. They have few blood vessels and high glycogen. They fatigue quickly. 

In regards to my new year's goals, I have kept up on the relate and reviews and have not been running.

This video explains what happens after death. Muscles help us in ways we often do not realize. The earliest effects are seen when the muscles of the heart no longer pumps blood. The circulatory system relies on cardiac muscles and the skeletal muscles pumping the blood through the body. The first 1-2 minutes explain what the lack of muscles works; the second half explains more of the decomposition side of death. 

Rigor mortis happens when the myosin cannot detach from the actin due to the stop of flow of ATP. Eventually, the muscles go limp after the beginnings of decay of the fibers.