All About Skeletal Muscle Cells

The Skeletal Muscle Cell

     Skeletal muscle cells are the cells found in about 40% of the body. Skeletal muscle cells help with the movement of all the muscles in the body. The muscles give the body its shape and maintains posture. They also stabilize joints. Skeletal muscle cells form from smaller cells. This is what makes the muscles striated. Proteins, actin and myosin, in the cells make these stripes called myofibrils that can be seen under a microscope. There are hundreds of these cylindrical structures in each muscle fiber. Myofibrils give muscles the strength to move. Myofibrils are divided into sections called sarcomeres. Z discs, which look like dark stripes, mark the ends of these sarcomeres.

     Skeletal muscle cells are covered by the sarcolemma, a plasma membrane, that help with muscle contraction. Cytoplasm is found in all cells, however the cytoplasm in skeletal muscle cells is called sarcoplasm. The sarcoplasm contains lots of mitochondria, which produces ATP. ATP, or adenosine triphospate, is necessary for muscle contraction. ATP also moves around chromosomes and substances around the cell. It is essential that the many mitochondria in each cell produce a lot of ATP or the muscle cells would not be able to function. Sarcoplasmic reticulum, membrane enclosed tubules like the smooth endoplasmic reticulum, store calcium ions, which is necessary for muscle contraction as well. Transverse tubules look like tunnels and they pass through the muscle fiber. Myoglobin, which is also found in the sarcoplasm, stores oxygen and gives muscles its red/pink pigment.

Works Cited:

    "Muscles- Skeletal, Smooth, and Cardiac." BBC News. BBC, n.d. Web. 31 Aug. 2015.

    "Structure of a Muscle Cell." (Muscle Fibre). N.p., n.d. Web. 31 Aug. 2015.           

    "Muscle Cell Types." InnerBody. N.p., n.d. Web. 31 Aug. 2015.

Sweetness Lab Reflection

     In this lab, we tasted different carbohydrates to test their sweetness. We found that the monosaccharides, like fructose and sucrose, were a lot sweeter than the polysaccharides were. Fructose is used as a sweetner and sucrose is found in fruit which explains why they were the sweetest carbohydrates out of the eight that we tried. Some of the disaccharides, like galactose and maltose, were slightly sweet but not as sweet as glucose or fructose. The monosaccharides were granular, while the disaccharides and the polysaccharides were powdery. Lactose is found in milk, which is not very sweet. The starch was very bland and not sweet at all. 

    Humans taste sweetness through the taste buds on their tongue. The taste buds send messages to the brain telling us whether what we are tasting is sweet or not. According to Popular Science, people who have lots of papillae on their tongues may find some flavors overwhelming. The taste buds on our tongue detect different molecules. The strength of this ability varies in different people because of evolution. The ancestors of someone who is more sensitive to bitter tastes probably would have developed different receptors depend on the plants they ate at that time.