Huntington disease skeletal muscle is hyperexcitable owing to chloride and potassium channel dysfunction For this experiment they wanted to exam how Huntington diseased muscle affects the contraction control in the membrane. They first measured the action potentials in the diseased mice and compared that to the wild type mice. In the R6/2 mice they noticed a significant lengthening (almost double) in the repolarization phase that was not present in the wild type mice. The fibers of the diseased mice were also more sensitive to current stimulation that was needed to produce an action potential versus the control mice. A spontaneous action potential occurred in the diseased mice as well after the depolarization. They hypothesized that the repolarization, hyperexcitability, and spontaneous action …show more content…
The results for their test using a three-pulse voltage clamp protocol showed significant chloride reductions in the R6/2 mice, compared to the control. This result confirmed their first hypothesis. A second hypothesis was that if self-triggered action potentials occur after a subthreshold stimuli (as was observed) then there must be hyperexcitability present in the Huntington’s disease muscle caused by a reduction in the inward flow of potassium conductance. To test this hypothesis they measured Kir currents from both the diseased and the control mice. Their results proved the second hypothesis correct because the R6/2 mice had significantly lower potassium conductance than the control mice. By focusing on the membrane itself within the muscle, this study was able to open up possible discoveries and treatments on how to control the horrible symptoms that go along with Huntington’s disease. Many of our treatments today in many different diseases start at the membrane and this may be able to
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
Nerve stimulation was induced for every fifteen seconds at an increment frequency of 0.5 pps (parts per seconds), 1.0 pps, 2.0 pps, 4.0 pps, 8.0 pps, 15 pps, and 25 pps. Every increment trial had a thirty-seconds 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 data was recorded for ten minutes.
Purpose- To identify the functions of the cranial nerve of the peripheral nervous system such as the olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory, and the hypoglossal nerves. I will examine these functions with a series of behavior tests on my partner who is Jazmine Cooley to see if all nerves are functioning properly and if they are not, then this will be considered an identified dysfunction of a cranial nerve which is a diagnosis.
As the solution pH can influence the stability of NaClO-NH3 blend and the elimination of SO2, NOx, the impact of the pH of NaClO-NH3 blend solution on the instantaneous removal as well as the duration time was investigated, and the final pH after reaction was also detected and shown in Fig. 5. It can be seen that the variation of solution pH has a negligible effect on the desulfurization, but the elevated pH has a great promotion on the NOx removal, the efficiencies are significantly increased from 36% to 99% for NO2 in the pH range of 5–12 and from 19% to 65% for NO when the pH is between 5 and 10, after where, both of them are constant. Hence, the optimal pH of the NaClO-NH3 solution for the
Amyotrophic lateral sclerosis, also known as ALS or Lou Gehrig's disease, is a disease of the nerve cells in the brain and spinal cord that control voluntary muscle movement (Dugdale, Koch, and Zieve 2010). In ALS, nerve c...
Huntington's disease is a progressive brain disorder that is caused by a single defective gene on chromosome 4 — which is one of the 23 human chromosomes that carry a person’s entire genetic code (alz.org, 2013). This defect is dominant, w...
Parkinson's disease is a neurological disorder that is named after "the English physician who first described it fully in 1817" (4). The disease causes disturbances in the motor functions resulting in patients having trouble moving. Other characteristics that are not always present in every patient are tremors and stiffening of limbs. All of these characteristics, of the disease are caused by "degeneration of a group of nerve cells deep within the center of the brain in an area called the substantia nigra" (5). Dopamine is the neurotransmitter for these cells to signal other nerve cells. However as the cluster of nerve cells fail to operate, the dopamine can not reach the areas of the brain that affects one's motor functions (5). On average Parkinson's patients have "less than half as much dopamine in their systems as healthy people do" (8). The problem and controversy that arises from this disease is in the cure. Researchers, for years, have been attempting to unravel the mystery of what causes Parkinson's disease and how it can be treated and or cur...
The brain is part of the central nervous system, which consists of neurons and glia. Neurons which are the excitable nerve cells of the nervous system that conduct electrical impulses, or signals, that serve as communication between the brain, sensory receptors, muscles, and spinal cord. In order to achieve rapid communication over a long distance, neurons have developed a special ability for sending electrical signals, called action potentials, along axons. The way in which the cell body of a neuron communicates with its own terminals via the axon is called conduction. In order for conduction to occur, an action potential which is an electrical signal that occurs in a neuron due to ions moving across the neuronal membrane which results in depolarization of a neuron, is to be generated near the cell body area of the axon. Wh...
Neuroscience refers to “the scientific study of the nervous system” It has been responsible for breakthroughs involving molecular, cellular, developmental, and medical aspects of human behaviors. Various organizations such as the “International society for neurochemistry” and the “European Brain and behavior Society” exist today to further the study of the nervous system and expand human understanding of medical and psychological ailments. The actual study of the nervous system dates all the way back to ancient Egypt where surgeons would drill holes into the human skull in order to alleviate a variety of aliments. The second half of the 20th century furthered the study of neuroscience via advancements in Molecular biology, and electrophysiology. These advancements are currently being used to study potential solutions to diseases such as (ALS) amyotrophic lateral sclerosis, strokes, and brain trauma. This research is funded by credible organizations such as the (NIH) National Institute of Health and the “National S...
This reduces the amount of current that would otherwise leak out of the axon and increases the distance that the current can flow passively. Myelination, aka axon insulation, increases action potential conduction up to 150m/s compared to 0.5-10m/s conduction velocities of unmyelinated axons! Speedy delivery of current information along axons is also due to the nodes of Ranvier. Nodes of Ranvier are gaps between insulated portions of the axon. The gaps create a place where the current can flow out of the axon so an action potential can be generated.
With motor neurone disease it attacks the nerves, in the brain and spinal cord. This means messages gradually stop reaching muscles, which leads to weakness and wasting. In the case study the
Since the gene for HD is dominant, there is a 50% chance of a sufferer's
Huntington’s disease is an inherited condition in which nerve cells in the brain break down over time. No cure exists for the disease, but drugs, physical therapy, and talk therapy can help manage some symptoms. Testing is done by blood sample. The genetic test analyzes DNA for the HD mutation by counting the number of repeats the Huntington gene made. Part of the gene repeats itself over and over again like a stutter. The results are near 100% accurate. The disease appears around age 40.
Huntington’s disease is caused by an abnormal dominant gene. Also called Huntington’s chorea, it is a complex disorder that affects a person capability to feel, think and move. The symptoms of Huntington’s disease consist of mood swings, irritability, depression, and anger. These symptoms are likely to worsen and the disease a lot of times runs in the family. If people have at least one parent with Huntington’s disease, the chances of them inheriting it are 50-50 chance. There is also a 50-50 chance that, that same person could pass the faulty gene on to their future child. This pattern of inheritance is called "autosomal dominant". The disease could also affect a person’s judgment and other mental functions. In some cases the person could
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.