BIOLOGY: LITTLE KNOWN DISEASES

BIOLOGY: LITTLE KNOWN DISEASES Questions: What is a fovea centralis? Where is it located? For what is it used? (1.5 marks) -->Compare peripheral vision to the vision at the fovea centralis. Provide an instance where peripheral vision proved to be useful. What are some of the limitations of peripheral vision? Are there any other differences between the two types of vision? (2 marks) -->How is peripheral vision tested? Name the condition that occurs when peripheral vision is lost. (1 mark) -->On moonless nights, why should you look at stars from the side of your eyes rather than directly? (1 mark)  -->Include the link to at least one website that you used to research this topic for the four questions above. Be sure the website you have used is appropriate and from a credible source. Do not copy and paste information from the website. Indicate the section on the webpage from which you have obtained the information. Your marker will verify the website and ensure that it contains relevant information. Your marker will determine if you wrote your answer using your own words. (1 mark) There are two types of hearing loss: conduction deafness and perception deafness. In perception (nerve) deafness, any of the structures of the organ of Corti have been damaged. In conduction deafness, the middle ear structures have been damaged. Instructions This is a set of research questions. You may type your answers using the answer box provided below. You may include graphs, charts, or pictures relevant to your answers. Cite the sources for all images and ensure that the images are sized appropriately (such as 400 pixels wide).  If you would prefer to answer this question using a word processor (such as MS Word), save your work and attach it to this question using the tools below. (If you are a Mac user, please contact your teacher.) -->Cochlear implants and hearing aids can restore hearing in individuals affected with deafness. For which type of deafness do these devices restore hearing? How? (2 marks) -->A cochlear implant can restore hearing in individuals with damages to the cochlea. Research how cochlear implants can restore the sense of hearing by researching the functions of the following 4 parts of a cochlear implant (microphone, processor, transmitter, electrode array) and comparing them to the sound pathway listed below. (4 marks)  pinna ? auditory canal ? tympanum (eardrum) ? ossicles ? oval window ? cochlea (organ of Corti) ? auditory nerve ? brain (temporal lobe) Cochlear implants and hearing aids can be very expensive. In Alberta, the cost of cochlear implants and surgery are covered by Alberta Health Care Insurance Plan (AHCIP). Hearing aids are not covered by AHCIP. Should hearing aids be covered by the government? To answer this question, select one of the following viewpoints (Societal or Ethical). Decide whether you are supporting or against public health care coverage of hearing aids. Ensure you have a solid reasoning that is backed up with research, not just an opinion. (2 marks) *information for next questions* Epilepsy is a neurological disorder that disrupts neural activities and causes recurrent seizures. About 70% of people with epilepsy can be treated with medication to prevent seizures from occurring. If medication does not work, surgery is an option for some patients. One of the procedures involve cutting the brain so that the seizures cannot be spread to other parts of the brain. -->A common goal of the surgical procedure to treat epileptic seizure is to reduce the connection between the two hemispheres of the brain. By cutting through this structure, an epileptic seizure occurring on one side of the brain will not be spread to the other side. Name the structure that connects the two hemispheres of the brain. (1 mark)  -->A person with epilepsy had a successful surgery to prevent the spread of epileptic activity between the two hemispheres of the brain. When an object is presented to the left visual fields of both eyes, this person can see the object but cannot verbally describe the object. When the object is presented to the right visual fields of both eyes, this person can see the object and is able to verbally describe the object.  Describe the visual pathway from left visual fields to perception. (1 mark)  Identify the areas of the brain responsible speech production. (1 mark)  Explain why there is a disconnect between vision and speech. (1 mark)  *information for next questions* To contract a single muscle fibre, the same all-or-none response occurs. Then, how is it possible to lift a heavier object? When lifting a heavier weight, more muscle fibres are stimulated. To lift a smaller weight, fewer muscles fibres are stimulated.  In an experiment, the strength of a neural stimulus and the resulting muscle contraction are compared. A single motor neuron that synapses with one muscle ?bre is observed in this experiment. One end of the muscle ?bre is attached to a mass. If an electrical stimulus is sufficient to cause an impulse in the neuron, the muscle will contract and lift the mass. The following data were obtained from the experiment.  Analyze the data, and answer the following questions.   number of travels. .strength of stimulus . mass lifted by muscle contraction 1 10. 0 2 20 0 3. 30. 20 4. 40. not tested -->What is threshold potential? In this experiment, what is the threshold potential for this motor neuron? (1 mark) -->What is all-or-none principle? What mass can be lifted at 40 mV stimulus? (2 marks) An example of a sensory neuron is one that leads from a pain receptor in the finger to the spinal cord. A pin can be pressed against the skin without eliciting a response from the pain receptor. However, if the pin is jabbed lightly into the finger, the pain receptor may be stimulated and the finger than be quickly withdrawn through reflex arc.  How do we sense different types of pain? Using what you understand about threshold potentials and all-or-none principle, explain how it is possible to sense different levels of pain. (2 marks)  *Alzheimer's disease is a progressive neurodegenerative disorder that affects almost 50 million people world wide. The cause of Alzheimer's disease is still not well understood. It is thought to be a combination of genetic, lifestyle and environmental causes. It is also difficult to diagnose the disease during the initial stages of Alzheimer's disease as symptoms can be mistaken for normal aging. Currently, there is no cure for the disease. Medication can help manage the symptoms but degeneration of brain tissue cannot be stopped or reversed. -->MRI an PET scans have shown that patients at early stages of Alzheimer's disease have medial temporal lobe atrophy and decreased neural activity in the parietal lobe and frontal lobe. List some of the symptoms of early onset Alzheimer's disease that can result from these affected areas of the brain. (3 marks) Currently, the medication that manages the symptoms is a type of cholinesterase inhibitor. In other words, the medication inhibits the function of cholinesterase and helps in brain functioning and memory. How does a cholinesterase inhibitor work in a synapse?  Name the neurotransmitter and explain the function of cholinesterase inhibitor in increasing brain functioning and memory. (3 marks) -->Alzheimer's disease is one of the oldest recorded diseases in history, dating back to 500 BC. However, there is no cure. There are five medications that are approved to manage the symptoms of the disease. Canadian government has invested 298 million dollars for Alzheimer's related research in the past 10 years. Should the government increase the funding for Alzheimer's research?  Choose one of the following viewpoints to answer this question: Societal, Medical, and Economical. Make sure you have completed a short research to back up your response. (3 marks)  (2 mark for the viewpoint; 1 mark for citing source(s))  *information for next questions * Dopamine is a neurotransmitter produced by certain neurons in the brain. In the brain, dopamine produces feelings of euphoria (pleasure) and it is also involved in the motor contol pathway. When dopamine neurotransmitters are secreted into the synapse, they are reabsorbed by transmitting neurons.  Parkinson's disease is neurodegenerative disorder that affect the movement. Most people affected with Parkinson's disease demonstrate rigidity, slow movement and shaking. The symptoms of Parkinson's disease occur when the cells that produce dopamine neurotransmitters die in the brain. -->What type of medication can help alleviate the symptoms of Parkinson's disease that result from reduced levels of dopamine? What type of medication will not work in alleviating the symptoms of Parkinson's disease? Explain in terms of nerve transmission and neurotransmitters in the synapse. (2 marks)  -->Many people affected with Parkinson's disease suffer from depression. Can you explain why? (1 mark) -->From what you have learned about synapse, explain how depression can be treated in people affected with Parkinson's disease? (1 mark) Solutions Fovea centralis Fovea centralis is a small are of about 1.5-2 mm in diameter inside the retina part of the eye, it is located specifically within the macula lutea. Peripheral vision is the ability of the eye to see upward, downwards and sideways while vision of fovea centralis is the central vision also can be termed as central vision The peripheral vision is only limited to the sides of the eye visionary. It is the one complete the vision angle of the eye The only difference between fovea centralis and peripheral vision is the focusing or the visionary angle of the eye where the vision of the fovea centralis is the central vision while the peripheral vision is the sideways vision The peripheral vision can be done physically where the doctor ask the patient to focus on an image, the then doctor asks the patient to describe the side objects while closing the other eye. When the peripheral vision is lost, the patient remains with a tunnel vision where he/she can only see images in straight focus. Looking at the sky in a moonless night with side is a testing of peripheral vision. It makes the person to adapt more in peripheral vision References https://www.healthgrades.com/symptoms/peripheral-vision-loss http://medical-dictionary.thefreedictionary.com/fovea+centralis http://www.eyeglassguide.com/my-visit/vision-testing/peripheral-vision-test.aspx Ears and deafness Cochlear implant can be used to restore conduction deafness. The conduction deafness which is caused by the impairment of the middle ear can be caused by the failing of the device that cause direct stimulation to the hearing nerve to fail. The cochlear implants restore stimulation of the sensory nerve in the inner ear. The microphone in the cochlear implant transmits the sound directly to the processor. The processor in the cochlear nucleus captures and translates the sound in order to give a clear signal and enable the patient to access the missing sounds. The transmitter receives the sound and converts it to electronic impulses An electrode array, which is a group of electrodes that collects the impulses from the stimulator and sends them to different regions of the auditory nerve Opinion Medical care is an important to each individuals, success is only achieved when every individual is healthy. Most governments have designed a budget which cutter for health insurance of their citizens. The charges of ear impairment implant is so much expensive something that cannot be afforded by most normal individuals. It could be better if the government cheap in and budget also for treatment of those need cochlear implant. References http://www.asha.org/public/hearing/Cochlear-Implant/ http://www.cochlear.com/wps/wcm/connect/us/home/treatment-options-for-hearing-loss/cochlear-implants/sound-processors Brain and the Nerve System The corpus callosum is the structure connecting two halves of the brain. When an object is placed on the left side of the eye the vision impulse is transimmited to the right side of the brain where it is connected to the left hemisphere of the brain by the corpus callosum for interpretation. The left hemisphere is the one responsible for speech Removing of the corpus callosum disconnect the left hemisphere to that of the right side. Whe an object is placed on the left sides of the eye it can be visualized but not interpreted by the brain hence disconnect between vision and speech References https://www.mayfieldclinic.com/PE-AnatBrain.htm https://www.google.com/#q=vision+interpretation+in+brain+hemisphere The muscle and threshold potential The threshold potential is the critical level to which a membrane potential must be depolarized to initiate an action potential. 30mV The all-or-none principle is a law that states that the strength by which a nerve or muscle fiber responds to a stimulus is not dependent on the strength of the stimulus. 30 Pains are different and use different paths to stimulate the central nervous system. Pain can last for long period or short period; also pain can be slow or faster. These differences of pain determine the path (nerve) fiber to be used. Researchers have discovered the four fibers used by pain to stimulate the CNS for a reaction. The four fibers are: The A-alpha fibers The A-beta fibers The A-delta fibers The C fibers Sharp pain uses the A-delta fibers while the dull pain uses the C fibers. The A-delta fiber is larger in size than the C delta. However, it should be noted that the process of pain transfer from the point of feeling to the CNS and the reaction process are the same. There are two types of action experienced during impulse transfer by the nerve these are the reflex action and the normal action. References http://www.news-medical.net/health/How-Do-We-Sense-Pain.aspx https://www.boundless.com/physiology/textbooks/boundless-anatomy-and-physiology-textbook/peripheral-nervous-system-13/reflexes-136/components-of-a-reflex-arc-727-2295/ The Alzheimer Disease The Alzheimer Disease is also known as Dalmatia disease. The disease has three stages of symptoms. The early symptoms include; Misplacing things Personality changes Repeating questions Impulsive behavior Hallucinations Wandering and getting lost The presence of cholinesterase inhibiting chemicals prevents the breakdown of acetylcholine. An electrical signal, or nerve impulse, is conducted by acetylcholine across the junction between the nerve and the muscle (the synapse) stimulating the muscle to move Serotonin. Cholinesterase inhibitors are used for inhibiting chemicals that conduct the breakdown of acetylcholine. The government has been pushing so much for the research of the diseases. However, there are no signs for fruits. This means that this should be the end of supporting the research. My opinion is the government should give more support considering the economic mighty of the nation and the effect of the disease to the society. References https://www.google.com/#q=+cholinesterase+inhibitor+work+in+a+synapse http://www.neurogistics.com/the-science/what-are-neurotransmitters Dopamine and Parkinson’s disease Dopamine is an excitatory neurotransmitter which stimulates excitement and pleasure. However, people suffering from Parkinson’s disease lack the neurotransmitter hence they are always depressed. On therapeutic strategy an inhibitor is introduced in the synapse which interrupts the function of MAO enzyme and hence prevents the breakdown of dopamine. This will allow more dopamine to remain in the synapse hence prevention of the Parkinson’s disease. References http://www.nejm.org/doi/pdf/10.1056/NEJM199309303291408 https://www.atrainceu.com/course-module-short-view/2441043-143_parkinsons-module-02