Bio Mod 4 discussion replies – 200 words each, 400 words total

Respond to at least 2 of your peers. In each of your response posts, include a link to a resource from a scientific journal that you think is excellent and provides information about homeostatic imbalances in either of the two organ systems discussed in this module.

First, directly copy a paragraph or excerpt from the chosen source that you think enhances your peer’s post.

Next, paraphrase and summarize the information from the paragraph you copied using your own words.

You should also explain why or how the information enhances or extends the information provided. See the Grading and Evaluation section in the Syllabus and Schedule module for links to research databases at the CCCOnline Library.

Consult the resources that are posted to your own post, and explain why each resource is or isn’t a valid resource.

All references must be cited using APA Style format. Please refer to the CCCOnline APA Citation Toolkit.

#1 NF: 

The three different types of muscle in the human body are skeletal, cardiac, and smooth muscles. The skeletal muscle is responsible for maintaining posture and moving orbits together with the axial skeleton and appendicular skeleton. This muscle also helps stabilize bones and joints, controlling the internal movement and generating heat. Skeletal muscles are tubular shaped. They consist of thousands of muscle fibers that are wrapped together by connective tissue sheaths.

Cardiac tissue cells are stripped or striated in appearance. They have lighter bands composed of actin and darker bands composed of myosin. The actin and myosin filaments are arranged in repeated units known as sarcomeres. Cardiac muscles cells help keep our heart pumping through involuntary movement.

Smooth muscles fibers are spindle shaped cells that are elongated. They are tapered at the ends. The function of smooth muscles is contraction.

Skeletal muscle and the nervous tissue have similar functions. The muscle tissue and nervous tissue are both considered excitable tissues. They fall under the electrical activity. Its muscle tissue creates the force to provide movement while the nervous tissue transmits the chemical signals throughout the human body.

There are two parts to the autonomic nervous system: Sympathetic nervous system and parasympathetic nervous system. Cardiac muscles are controlled by the autonomic nervous system. Smooth muscle cells are controlled by the autonomic nervous system. The cerebellum controls smooth muscle movement. Skeletal muscle cells are controlled by the somatic nervous system. The release of epinephrine and norepinephrine happens in the sympathetic nervous system which helps regulate the heart rate.

Structural and metabolic changes occur in skeletal muscle after a stroke. Muscle alterations are common and can include gross atrophy. In the cardiac muscle a stroke can affect parts of the brain that control the muscles and heart. In smooth muscle a stroke can affect the cerebral blood flow control. Cerebral ischemia can trigger the cells to switch to a phenotype.

Hafer-Macko, C. E., Ryan, A. S., Ivey, F. M., & Macko, R. F. (2008). Skeletal muscle changes after hemiparetic stroke and potential beneficial effects of exercise intervention strategies. Journal of rehabilitation research and development. Retrieved April 4, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2978978/

Histology, muscle – statpearls – NCBI bookshelf. (n.d.). Retrieved April 4, 2023, from https://www.ncbi.nlm.nih.gov/books/NBK537195/

#2 TB: 

. The three muscle types are skeletal(striated), cardiac, and smooth.

Skeletal muscle is made up of muscle fibers, composed of cells that are long and multinucleated. Skeletal muscle is cylindrically shaped and attached to the bone by elastic tissue and collagen fibers (tendons). The connective tissue that surrounds muscle fiber is called the perimysium and this allows nerve and blood vessels to get through the muscle itself. Functions of skeletal muscle include painting body posture, body movement, and involuntary muscle movements (Mukund, 2019). 

Cardiac muscle is only found in the heart and is continuously contracting to provide the circulation of blood throughout the body. Cardiac muscle is similar to smooth muscle regarding its muscle fiber patterns. Cardiac muscle is striated and contains cylindrically shaped cells with intercalated discs that join neighboring fibers. The functions of cardiac muscle include regulating the function of the heart, being involved in the movement of locomotion, and functioning as an involuntary muscle (Ripa R, 2022).

Smooth muscles are spindle-shaped fibers with a singular nucleus. Smooth muscle is shorter than skeletal muscle and lacks filaments, special proteins, actin, and myosin and produces its own connective tissue. Functions of smooth muscle include sealing orifices, maintaining the circulatory system by maintaining and controlling blood pressure and flow of oxygen through the body, transporting chyme for the contractions of the intestinal tube, contracting the iris, moving fluids through organs, raising the hair on arms, providing consistent and elastic tension (Hafen BB, 2022).

B. Skeletal muscle is a striated muscle and non-syncytial Nervous tissue is made of highly specialized nerve cells that create and conduct nerve impulses. The electrical events and distribution of ions across the muscle fiber membrane in skeletal muscle are similar to that in nerve fibers. Both are also made up of cells and both are present all over the body (Mukund, 2019).

C. Autonomic nervous system controls the cardiac muscle, the medulla that is lower on the brain stem, however, controls centers for the heart and lungs as well. The motor cortex and Broca area are found in the frontal lobe. The motor cortex allows the skeletal muscle to carry out voluntary movements and the Broca area allows these muscles to carry out functions responsible for producing language. Smooth muscle is controlled by the autonomic nervous system, which is responsible for involuntary movement (Thau L, 2022). 

D. During a stroke, metabolic and structural changes will occur in skeletal muscle. Muscle alterations could include gross atrophy and a muscle shift to the myosin-heavy chain. Smooth muscle is affected by a stroke because muscle weakness will arise and the risk of muscle contractions will go up significantly. Cardiac muscle will be affected by a stroke because the muscle being able to contract can be altered which can lead to bigger problems like heart failure, cardiac arrest, and abnormal heart rhythms (Veltkamp, 20218).

Sources:

Hafen BB, Burns B. Physiology, Smooth Muscle. [Updated 2022 Aug 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Accessed: 1 Apr 2023.

Ripa R, George T, Sattar Y. Physiology, Cardiac Muscle. [Updated 2022 Jun 2]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Accessed: 1 Apr 2023.

Mukund, K., & Subramaniam, S. (2019). Skeletal muscle: A review of molecular structure and function, in health and disease. WIREs Systems Biology and Medicine, 12(1). Accessed: 1 Apr 2023.

Thau L, Reddy V, Singh P. Anatomy, Central Nervous System. [Updated 2022 Oct 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Accessed: 1 Apr 2023.

Veltkamp, R., Uhlmann, S., Marinescu, M., Sticht, C., Finke, D., Gretz, N., Gröne, H. J., Katus, H. A., Backs, J., & Lehmann, L. H. (2018). Experimental ischaemic stroke induces transient cardiac atrophy and dysfunction. Journal of Cachexia, Sarcopenia and Muscle, 10(1), 54–62. Accessed: 1 Apr 2023.