The Tired Swimmer: resolving the scenario on nervous system issue

Part 1- Annie’s Swim Meet 

Question 1 

Annie exhibited several signs such as strained eyesight, pain in the hands and fingers, general body fatigue, and trouble breathing normally. When Annie was exiting the locker room, she notices blurred and vision and strain in her eyes. She also remembered that earlier in that semester, she was having trouble writing her papers due to pain in her hands. Additionally, we are shown how Annie was generally exhausted to a point where she was left lying in her bed with her eyes closed by her boyfriend. 

Question 2 

All the signs and symptoms portrayed by Annie are associated with the central nervous system. Annie has been experiencing challenges with her eyes, fingers, breathing techniques, and other body muscles, usually controlled by reflexes from the central nervous system. 

Question 3 

Annie appears to have strained communication between her muscles and the nervous system, which affects the normal functioning of the diaphragm, which aids in breathing. The diaphragm receives impulses from the central nervous system to contract and relax, which in return controls the breathing rate (Bordoni et al., 2018). Healthcare drive explained that shortness of breath might be caused by damage of nerves that control diaphragm movement. 

Question 4 

According to the signs and symptoms exhibited by Annie, she could be having a problem with motor neurons. There might be a broken communication between sensory neurons and motor neurons, leading to a decline in muscle function. Anemia could be another valid reason; she could be lacking enough red blood cells to transport oxygen to the tissues and thus fatigue. 

Part two: Doctor’s Office 

Question 1 

Before the doctor's visit, Annie developed some new symptoms such as unusual sleeping patterns, long sleeping time, frequent loss of breath, stress and anxiety, blurred vision, and drooping eyelids. 

Question 2 

Figure 1 

Cross-Section of a Mammalian Spinal Cord 

Question 3 

A reflex action is involved in controlling the amount of light getting into the eye. Light is directed into the eye through the refraction of the lens to the fovea centralis. In response, the fovea centralis, with the help of cones, sends a message to the brain. A loss of muscle function makes the ciliary body lose focus, and the signal to the brain is weak; this results in double or blurred vision. Moreover, there is a condition called myasthenia gravis (MG) which affects communication between nerve and muscle. According to Conquer Myasthenia gravis (2016), this condition destroys neurotransmitter receptors in the forces. People are suffering from myasthenia gravis disease experience general weakness in muscles requiring voluntary control. Among other symptoms, people suffering from myasthenia gravis experience drooping eyelids and double or blurred vision. 

Question 4 

Annie's condition could be attributed to a problem in the communication between sensory neurons and motor neurons. There could be a condition hindering neurotransmission between sensory neurons, interneurons, and motor neurons. Failed neurotransmission means that reflex action involving muscles will fail, and that's why Annie is unable to control the muscles in the eye, fingers, and diaphragm. 

Part Three: The Neurologist 

Question 1 

The conduction tests indicated that Anni's nerves were functioning normally. In the conduction tests, stimulation of the nerve at one end was detected at another end, meaning that the nerves were usually working. A nerve conduction test is used to identify any nerve damage, and the tests indicate whether nerves are conducting signals to the muscles usually. 

Question 2 

According to the neurologist, Annie's EMG test indicated that her skeletal muscles were not responding to the nerve signal normally. The doctor observed that Annie's muscles failed to react after a repeated nerve stimulation due to muscle fatigue. 

Question 3 

Annie's skeletal muscles were unable to maintain the response initiated by simultaneous stimulation from receptor neurons. Annie's muscle fatigued because there might have been a broken nerve way or an inadequate synapse of motor neuron and muscle. 

Question 4 

Figure 2 

The Neuromuscular Junction 

An action potential enters the presynaptic terminal. 

Voltage-gated channels open, and calcium and sodium ions enter the presynaptic terminal. 

Calcium ions cause presynaptic vesicles to fuse with the presynaptic membrane. 

Acetylcholine is liberated into the synaptic cleft. 

The neurotransmitter reacts with n icotinic Ach receptors on the muscle membrane. 

The neurotransmitter is broken down by acetylcholinesterase in the synaptic cleft. 

Channels open, and the muscle membrane depolarizes 

Choline is taken up into the presynaptic cell 

This produces an action potential in the muscle membrane. 

Question 5 

Sustained neuron activity could decrease muscle function after a series of motor nerve stimulation because the chemicals involve may be depleted. Initially, nerve impulses hit the presynaptic axonal terminal depolarization occurs. Consequently, voltage-gated calcium channels give in for the calcium ions to move into the presynaptic axon to activate SNARE proteins. SNARE proteins catalyze the combination of synaptic vesicles with the neuron's cell membrane leading to the formation of acetylcholine. Acetylcholine diffuses and binds with acetylcholine receptors, which aid in opening cation channels (Human Memory, 2019). The media let in both the sodium and potassium ions. Due to the higher concentration of sodium ions in the extracellular space, sodium ions diffuse through the channels to cause depolarization in the skeletal muscle. Calcium ions cause a cycle of skeletal muscle contraction. In the synaptic cleft, acetylcholine is immediately broken down by acetylcholinesterase to its metabolites, and this results in the withdrawal of its influence and muscle contraction stops. 

Part 4: The Neurologist 

Question 1 

The thymus is an organ responsible for maintaining the immune system by ensuring that the body is free of pathogens, tumors, and antigens. The thymus secretes a hormone called thymosin, which stimulates the maturation of T cells that are tasked with getting rid of the damaged cells and pathogens (Thapa & Farber, 2019). 

Question 2 

Antigens are defined as those substances that, when introduced in the blood system, trigger immune response. Antigens are any foreign substance and may include chemicals, toxins, bacteria, viruses, or fungus. 

Question 3 

The antibodies in Annie's blood will act against the formation of synaptic acetylcholine (Ach) receptors on the muscle membrane, thereby preventing the binding of Ach to its receptor. The result is delayed channel opening and lack of depolarization of the muscle membrane. Muscle contraction will fail due to a lack of action potential in the muscle membrane. 

Question 4 

Neostigmine inhibits the breakdown of acetylcholine molecules by acetylcholinesterase enzyme before reaching postsynaptic membrane receptors. The action enables the neurotransmission to be completed before the next neuron triggers a new impulse. In the case of myasthenia gravis, acetylcholine receptors are few, and therefore acetylcholine can bind with the few receptors and stimulate muscular contraction leading to fatigue. 

Question 5 

Since Annie’s condition has not been treated, the amplitude of her endplate potentials has decreased. This can be attributed to the broken communication between the brain and the neuromuscular junction. 

Question 6 

Annie has been feeling generally weak, especially after an exercise such as swimming, walking up the staircases, or studying. Her muscles are getting tired quickly due to myasthenia gravis, which causes a general weakness in muscles requiring voluntary control. 

References 

Bordoni, B., Purgol, S., Bizzarri, A., Modica, M., & Morabito, B. (2018). The influence of breathing on the central nervous system.  Cureus .  https://doi.org/10.7759/cureus.2724 

Conquer Myasthenia Gravis. (2016, June 21).  What are symptoms of myasthenia gravis (MG)?    https://www.myastheniagravis.org/about-mg/symptoms/ . 

Thapa, P., & Farber, D. L. (2019). The role of the thymus in the immune response.  Thoracic Surgery Clinics ,  29 (2), 123-131.  https://doi.org/10.1016/j.thorsurg.2018.12.001 

The Human Memory. (2019, November 26). Neuromuscular Junction .human-memory.net/neuromuscular-junction/.