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Functions and dysfunctions of neurotransmitters
Functions and dysfunctions of neurotransmitters
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1) What is the role of calcium ions during contraction of a skeletal muscle?
Calcium is an important element for live. Calcium is found in the bones of animals and humans. In muscle contraction is produce as a result of Calcium ions , Ca2+, It comes from rapid release from the cisternae of the sarcoplasmic reticulum which cause a chemical reaction between ATP and the myofilaments. Another important function of Calcium ions occurs during the state of resting muscle. During the state of resting muscle, calcium Ion is “maintaining the relative impermeability of the cell membranes. If the calcium concentration falls, the potential difference across the membrane also falls so that muscles may spontaneously contract without activation by acetylcholine” This spontaneous contraction can cause spams. The presence of Calcium ion in skeletal muscle is also important to stimulus glycogen breakdown.
The low levels of calcium can also be the cause of muscle cramps. Muscle cramps are painful involuntary contraction that can take place in various muscles. (Dictionary of Biology, 2005).
2) The phrase all-or-none response describes a neuron-generated action potential. Explain what
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Many scientific have concluded that neurotransmitter have an important role in the production of hormones. Some researchers have found that patient with anorexia nervosa also have abnormal levels of certain neurotransmitter. Lower levels of the neurotransmitter serotonin are connected to bulimia, depression and food disorders; lower levels of nor epinephrine was found on anorexic patients. It is possible that abnormal levels of the nor epinephrine neurotransmitter could cause weight loss on anorexic patients. These are some examples that support the scientific researches. (Encyclopedia of Obesity and Eating disorders,
In the beginning phases of muscle contraction, a “cocked” motor neuron in the spinal cord is activated to form a neuromuscular junction with each muscle fiber when it begins branching out to each cell. An action potential is passed down the nerve, releasing calcium, which simultaneously stimulates the release of acetylcholine onto the sarcolemma. As long as calcium and ATP are present, the contraction will continue. Acetylcholine then initiates the resting potential’s change under the motor end plate, stimulates the action potential, and passes along both directions on the surface of the muscle fiber. Sodium ions rush into the cell through the open channels to depolarize the sarcolemma. The depolarization spreads. The potassium channels open while the sodium channels close off, which repolarizes the entire cell. The action potential is dispersed throughout the cell through the transverse tubule, causing the sarcoplasmic reticulum to release
Parameters of CAL 1 were changed to zero grams and CAL 2 was changed to fifty grams. Nerve stimulation was induced for every fifteen seconds at an increment frequency of 0.5 pps (parts per second), 1.0 pps, 2.0 pps, 4.0 pps, 8.0 pps, 15 pps, and 25 pps. Every increment trial has a thirty-second waiting period. To witness the effects of tubocurare on muscle activity, the baseline was maintained between 20-30 grams and a control was established by turning the stimulator on repeat for 60-120 seconds. Then 0.25 ml of tubocurare was infused into the gastrocnemius muscle.
The production of physical movement in humans requires a close interaction between the central nervous system (CNS) and the skeletal muscles. Understanding the interaction behind the mechanisms of these two forces, and how they are activated to provide the smooth coordinated movements (such as walking or picking up a pencil) of everyday life is essential to the study of motor control. Skeletal muscles require the activation of compartmental motor units that generate their own action potentials, and produce a voltage force within the muscle fibers that can be detected and recorded with the use of a electromyography (EMG). Therefore, the purpose of this lab was to determine the differences between the timing of force production
Contrast the differences between force and torque. Use each term to describe a particular aspect of a muscle’s contraction relative to a joint. (6 pts)
...st the sacrolemma will depolarized, thus activation potentials along the T-tubules. This signal will transmit from along the T-tubules to sarcroplasmic reticulum's terminal sacs. Next, sarcoplasmic reticulum will release the calcium into the sarcroplasm leading to the next second event called contraction. The released calcium ions will now bind to troponin. This will cause the inhibition of actin and mysoin interaction to be released. The crossbridge of myosin filaments that are attached to the actin filaments, thus causing tension to be exerted and the muscles will shorten by sliding filament mechanism. The last event is called Relaxation. After the sliding of the filament mechanism, the calcium will be slowly pumped back into the scaroplasmic reticulum. The crossbridges will detach from the filaments. The inhibition of the actin and myosin will go back to normal.
For the lab test part, in this case we can do a muscle biopsy on him. A muscle biopsy is a procedure that removes a small sample of tissue for testing in a laboratory. The test can identify the disease is caused by nerve or by the muscle atrophy.
For muscles to contract then there must be a presence of calcium within the fibers as it connects with troponin protein and orders tropomyosin to clear the binding sites to allow myosin to attach to these sites, which allows the muscle to contract and produces movement. Without all of these elements working in sync then the function of skeletal muscle would no longer work or even exist.
Creatine serves as an energy reserve in muscle cells. Muscular contraction is powered by the breakdown of ATP (adenosine triphosphate) to ADP (adenosinediphosphate). When all the ATP is broken down, creatine phosphate in the muscle donates a phosphate group to ADP, and further energy reactions can occur. Creatine monohydrate is a precursor to creatine phosphate. By supplementing with CM, CP levels in muscle apparently are maximized, and more muscular work can occur, since there are greater energy reserves to use.
Calcium and Potassium modifications are specialized individual according to a specific disease, age and inadequate amounts of calcium or potassium higher or lower than normal value.
Then, rigor mortis occurs. Rigor mortis is the stiffening of the muscles due to the disappareance of ATP (adenosin triphosphate). The proteins responsible for muscle contraction, actin and myosin, need ATP to create crossbridges and make the muscles contract, and then relax. When ATP is no longer produced by the cells, the cycle of contraction cannot be completed and the muscles remain contracted. [3]
The contraction of a muscle is a complex process, requiring several molecules including ATP and Cl-, and certain regulatory mechanisms [1]. Myosin is motor protein that converts chemical bond energy from ATP into mechanical energy of motion [1]. Muscle contraction is also regulated by the amount of action potentials that the muscle receives [2]. A greater number of actions potentials are required to elicit more muscles fibers to contract thus increasing the contraction strength [2]. Studied indicate that the larger motor units, which were recruited at higher threshold forces, tended to have shorter contraction times than the smaller units [3]. The aims of the experiment were to reinforce the concept that many chemicals are required for skeletal muscle contraction to occur by using the rabbit muscle (Lepus curpaeums) [2]. In addition, the experiment was an opportunity to measure the strength of contraction and to observe the number of motor units that need to be recruited to maintain a constant force as the muscles begin to fatigue [2]. Hypothetically, the rabbit muscle fiber should contract most with ATP and salt solution; and the amount of motor units involved would increase with a decreasing level of force applied until fatigue stage is reached.
In 1978, Brunch called anorexia nervosa a 'new disease' and noted that the condition seemed to overtake ?the daughters of the well-to-do, educated and successful families.? Today it is acknowledged and accepted that anorexia affects more than just one gender or socio-economic class; however, much of the current research is focused on the female gender. ?Anorexia nervosa is characterized by extreme dieting, intense fear of gaining weight, and obsessive exercising. The weight loss eventually produces a variety of physical symptoms associated with starvation: sleep disturbance, cessation of menstruation, insensitivity to pain, loss of hair on the head, low blood pressure, a variety of cardiovascular problems and reduced body temperature. Between 10% and 15% of anorexics literally starve themselves to death; others die because of some type of cardiovascular dysfunction (Bee and Boyd, 2001).?
Anorexia nervosa and Bulimia nervosa are described as psychological eating disorders (Keel and Levitt, 1). They are both characterized by an over evaluation of weight. Despite being primarily eating disorders, the manifestations of bulimia and anorexia are different. They both present a very conspicuous example of dangerous psychological disorders, as according to the South Carolina Department of Health, “Eating disorders have the highest mortality rate of any mental illness” (Eating Order Statistics, 1). While Bulimia and anorexia both psychological disorders primarily prevalent in women, anorexia tend to have different diagnostic complexities, symptoms and physiological effects as compared to bulimia.
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 (pp.212-216). The heart beats nonstop about 100,000 times each day (p.18). 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 (Martini, 2000). 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.
Muscles are very vital to the human body and as seen above mankind could not survive without this system. It helps for energy, movement, temperature stabilization, pumps blood, and keeps everything working properly as well as many more things. Muscles don’t just do it all by themselves though, muscles work with every other system in the body especially the nervous system because that is were in gets all of its impulse signals from the brain so that the muscle are able to do the things they are capable of.