Larry Oliver
EXSC 223
08 November 2016
Assignment 3
1. Explain how smooth graded contractions of a skeletal muscle are produced.
When a single stimulus is delivered the muscle will contract and relax. But if another stimulus is applied before the muscle completely relaxes then the result is more tension. At higher stimulus frequencies there is no relaxation between stimuli which is called fused tetanus. At each point of the stimulus, more and more calcium is released increasing the amount of cross bridges being formed between myosin and actin. These types of contractions cannot continue indefinitely, as prolonged tetanus leads to muscle fatigue causing the muscle to no longer contract and tension dropping to zero.
Marieb, Elaine Nicpon, and
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Special Features of Smooth Muscle Contraction
(1) Smooth muscle initially contracts when stretched, but contraction is brief, and then the cells relax to accommodate the stretch
(2) Smooth muscle stretches more and generates more tension when stretched than skeletal muscle
(3) Hyperplasia, an increase in cell number through division, is possible in addition to hypertrophy, an increase in individual cell size
"Muscles and Muscle Tissue." Chapter 9: Muscles and Muscles Tissue. Midlands Tech, n.d. Web. 03 Nov. 2016.
Marieb, Elaine Nicpon, and Katja Hoehn. Human Anatomy & Physiology. 10th ed. N.p.: Pearson Education, 2016. Pg. 279-314. Print.
3. Describe the stimuli and controls of digestive activity.
Digestive activities within the GI tract are triggered by mechanical and chemical stimuli (mechanoreceptors and chemoreceptors that respond to stretch, changes in osmolarity and pH, as well as the presence of substrate and end products of digestion). External stimuli (sight, smell, taste, thought of food). Controls of the digestive activity are both extrinsic (CNS centers and autonomic nerves) and intrinsic (nerve plexuses and local hormone producing
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Although the parietal cells appear spherical when viewed with a light microscope, they actually have three prongs that bear dense microvilli (they look like fuzzy pitchforks!). This structure provides a huge surface area for secreting H and Cl into the stomach lumen. HCl makes the stomach contents extremely acidic (pH 1.5–3.5), a condition necessary for activation and optimal activity of pepsin. The acidity also helps in food digestion by denaturing proteins and breaking down cell walls of plant foods, and is harsh enough to kill many of the bacteria ingested with foods. Intrinsic factor is a glycoprotein required for vitamin B12 absorption in the small
Kinesiology: The Mechanics & Pathomechanics of Human Movement (Second ed.). Glenside, Pennsylvania: Lippincott Williams & Wilkins. Qiao T, Liu C and Ran F. (2005) The impact of gastrocnemius muscle cell changes in chronic venous insufficiency. Eur J Vasc Endovase Surg 30; 430-436.
Hyperplasia is the early stage development of cells to cancer cells. It increases in cells that have the capability to proliferate at a fast rate. Often times, hyperplasia is correlated with the increase in proliferation and the speed of mitosis. The increase in the number of cells with hyperplasia means that the proliferation is happening at a faster rate than normal. Hyperplasia is considered to be the early stage of dysplasia, though not all hyperplasia leads to dysplasia.
Every day we use our skeletal muscle to do simple task and without skeletal muscles, we will not be able to do anything. Szent-Gyorgyi (2011) muscle tissue contraction in rabbit’s muscles and discovered that ATP is a source for muscle contraction and not ADP. He proposed a mechanism to cellular respiration and was later used by Sir Hans Krebs to investigate the steps to glucose catabolism to make ATP. In this paper, I will be discussing the structure of muscle fibers and skeletal muscles, muscle contraction, biomechanics, and how glucose and fat are metabolized in the skeletal muscles.
Ingested vitamin B12 is typically protein bound, and is released by pepsin and gastric acid before binding with R-proteins in the stomach (a). Proteases in the small intestine then release B12, which binds the protein intrinsic factor (IF), protecting B12 from further degradation by intestinal bacteria (a). Binding IF is required for absorption by the intestinal epithelium, and subsequent entry into circulation (j).
Within skeletal muscle there are extremely small structures that form the muscle and allow contractions and movement to occur (epimysium, perimysium, endomysium, fascicles, fiber, sarcomere, sarcoplasmic reticulum and t tubules). These structures all play a role in protecting, connecting and transporting substances throughout the muscle fibers. They are also the main contributors to movement.
Marieb, E. N., (2006). Essentials of human anatomy and physiology. San Francisco, CA: Benjamin Cummings.
Introduction to Human Anatomy and Physiology Third Edition by Eldra Pear Soloman (pgs. 51 and 58)
Cardiac muscle is a type of involuntary muscle found only in the walls of the heart, specifically the myocardium. Cardiac muscles contract automatically to tighten the walls of the heart in a rhythmic fashion. The heart beats nonstop about 100,000 times each day. Smooth muscle is a type of involuntary muscle found within the walls of blood vessels such as in small arteries and veins. Smooth muscle is also found in the urinary bladder, uterus, male and female reproductive tracts, gastrointestinal tract, and the respiratory tract. Skeletal muscles are voluntarily controlled and are attached to bones by tendons. Skeletal muscles also vary considerably in size and shape. They range from extremely tiny strands such as in the muscle of the middle ear as large like in the muscles of the thigh. The three individual muscle types also serve five main functions. The five basic functions are movement, organ protection, pumping blood, aiding digestion, and ensuring blood flow.
The food digestion plays an undeniably important role in our body system, which is the main way for the human kind to gain nutrients and energy in order to growth, repairs the body cells, and carry out the daily routine (National Institutes of Health, 2013). The foods and drinks that people consume are required to be turned into the smaller nutrient-molecules before the blood absorbs and carries the various nutrients such as carbohydrates, proteins, fats, vitamins and minerals to the body cells (National Institutes of Health, 2013). According to National Institutes of Health (2013), the decomposition of food nutrients are completed through the digestive system which form by the gastrointestinal (GI) tract, also defined as digestive tract, and along liver, pancreas and gallbladder as well. The GI tract is made up of a series of hollow organs with the connection from mouth to anus, which consisting buccal cavity (mouth), esophagus, stomach, small intestine, and large intestine. Based on Batrisya (2013), the food digestive process are classified into four stages, that are ingestion, digestion, absorption, and egestion or elimination (refer to Figure 1 in Appendix 1).
http://kidshealth.org/kid/cancer_center/HTBW/digestive_system.html ( I didnt copy direct quotes, however I had used the idea of the beginning in my research on the digestive system to help the reader better understand the system)
Thibodeau, G & Patton, K. (2008) Structure and Function for the Body. 13th Edition. St. Louis: Mosby Elsevier.
Amsel, Sheri. [Webpage]. (2012). Anatomy Activities: Tissues - Epithelium, Muscle, Connective Tissue and Nervous Tissue. Exploring Nature Educational Resource. Retrieved from http://exploringnature.org/db/detail.php?dbID=21&detID=691
[2] Zelick, R. 2014. Muscle Lab Exercise. Bi253 Lab Manual. Portland State University, OR, pp. 1-5
Martini, F. H., & Nath, J. L. (8th Edition). (2009). Fundementals of human anatomy and physiology. San Francisco, CA: Pearson Benjamin Cummings.
Muscle tissues grow by means of physical activity in the same way they are able to become more well-defined (with regards to physical