Who We Are

Comparing the central nervous system and the peripheral nervous system.

Jon Tyndall

UAF Community and Technical College, University of Alaska Fairbanks

Biol F111: Human Anatomy and Physiology 1

Professor Don Lardon

July 23, 2021

Amy’s grip on Ryan’s hand felt like a vice, but he didn’t dare pull back. In the twisting confusion of the moment, her grip turned inward until her fingernails dug deep into his flesh. He was pretty sure they pierced through the latex gloves he was wearing, but that didn’t matter. The pain reminded him that this was real. Electrical signals in the axons from his hand to his brain transferred information to chemical neurotransmitters in the synapses, back to electrical signals from neuron to neuron through his thalamus and ultimately to his cerebral cortex to register this reality. His hand hurt. That was real. But the part where his wife was dying of rabies? That couldn’t be real. Could it?

They strapped her down to the hospital bed because her convulsions were getting that violent. Her skin was pale, paler than her tangled and mussed blonde hair. They’d come to the hospital straight from a camping trip where these symptoms had started and hadn’t stopped for a shower. She loved nature and animals. More simply put, she loved. She loved him! The way she looked at him on their wedding day four years ago, and every day since, spoke of an endless love that echoed into eternity. But, right now, the whole hospital bed shook and rattled as she desperately strained against her straps. A mix of white foam and blood dripped from her lips. She stared at him like he’d killed her favorite puppy. He couldn’t look back at her like this. It hurt too much. His vision blurred with tears anyway, so he just closed his eyes and felt the pain in his hand, choosing to see her in his mind’s eye as she’d always been before – as he wanted to remember her forever.

After a few moments, the convulsing stopped. The hospital bed rattling stopped. All he could hear was her ragged breath. His hand still hurt, but her grip on it loosened. He opened his eyes. She was looking at him still, but this time instead of rage he saw pain and sadness, and tears.

“Baby?” he said softly. “Are you okay?” What a dumb question, but he was too scared to ask what he meant. Is that you, Amy? Are you back?

“Oh god,” she said. “Look at your hand.”

Ryan looked down. He was bleeding from a gash she dug just below his pinkie finger. “That’s okay, love,” he said immediately.

“No it’s not,” she spit a little to clear the foam from her mouth.

The nurse, a kind and patient man with a calming facial expression hidden behind a mask, set upon the task of cleaning her face. He pointed to the sink nearby. “You’ll need to wash up, and cover that wound.”

Ryan nodded and gave Amy’s hand one more gentle pat before releasing her and washing up. The cabinets had antibiotic cream and bandages prepared, thankfully. They’d told him that human to human transmission of rabies is rare, but, precautions were necessary anyway. Given that he’d been kissing her just a couple of days ago and that they’d been out in the woods together with minor scraps and open wounds he’d be at risk. He already started his own regimen of rabies postexposure prophylaxis just to be certain. But hell if he was going to leave her side during this, no matter what the risks. It didn’t matter what she said or did.

Who knew rabies was this bad? Somehow the virus took control of the central nervous system. It changed behavior and thought patterns, but, only for short outbursts usually no longer than a few minutes. Amy was completely lucid the rest of the time, or, at least as lucid as she could be given her fever. He was determined to be there for every second of that lucid experience, even if it meant being there for every second of whatever she became when the virus took control.

By the time he’d returned to her side her face was clear. Her eyes were darting all over the room, and she was shifting uncomfortably all over her bed, or at least as much as her restraints allowed. She insisted on remaining restrained even between outbursts. She didn’t want to risk hurting anyone.

She closed hers eyes tight. “I’m so sorry,” she said.

“No, baby,” Ryan grabbed a damp cloth from nearby and mopped her brow. “No. What can I do for you?”

“Tell me about our wedding. I want to live in that day.” She opened her eyes again to look up at him. Her eyes, though bloodshot, looked at him the way they had back then. He’d always loved looking at the green in her iris, it reminded him of the forest they both spent so much time in.

Ryan nodded, but took a moment to free the knot caught in the back of his throat. “Me too,” he finally said. “We’d driven back to Georgia so our friends could be there. You were so anxious to get everything done. So was I. Remember how you sent me to get the wine bottles, but I didn’t bring a cork screw?”

Amy laughed a little. “We had wine, but no one could drink.”

The faintest of smiles curved his lips. “It was so beautiful that day. You were beautiful. You still are.”

“Bullshit,” she said, her voice a mix of good-natured sarcasm and grim reality.

Ryan wanted to pull her away from the here and now, so he ignored it and went on. “Mia was the flower girl, and Hilda the ring-bearer,” he stroked her temple while he talked. Those were their dogs, though, Mia has passed away a couple of years ago. How could such a happy day be so fraught with so many little landmines of sadness? He went on describing that day, about how he’d choked up during the vows, about how they’d forgotten the broom they were supposed to jump over, and about how they all played dungeons and dragons that night as the perfect cap to the perfect geek’s wedding. They’d camped out in the park that night where they had the ceremony, and spent hours talking and staring at the stars. They’d held hands, just like they were right now. That was real. That’s what reality was really about. Living in these long-gone moments through momentary connections, like holding hands. It didn’t matter how the synapses were being disrupted by the virus. All the mattered was what they were telling her about her happiness.

It was painful to think about the dogs. She loved dogs so much. He’d never owned a dog until he met her and Mia. Between the two of them, they’d convinced him that dog ownership was the greatest thing on earth. So, literally on a whim, he’d adopted Hilda from a kill shelter. Hilda taught him just how right Amy and Mia had been. Dog ownership was great. So what fucking twisted irony had lead Amy’s love of dogs to this? Two months ago, she spotted a stray dog on her way through a small rural town. Being the animal lover she is, she stopped to coax it in and take it to a shelter. It nipped her ankle just enough to draw blood, before running away and disappearing in the woods. They thought nothing of it. How stupid could they be? They were responsible dog owners; they got their dog’s rabies vaccinated. Why had it not occurred to them to get her checked? Ryan would spend the rest of his life trying to not hate himself for that, but, right now he was failing in that endeavor.

Some monumentally insensitive doctor had walked them through how it happened. The virus incubated in her muscle for two months, trying to find its way to the synapse of the motor nerves. Somehow the boring and otherwise dry anatomical words burned in his memory forever. Peroneus Longus in the ankle, innervated by the superficial fibular nerve, to the common peroneal nerve, to the sciatic nerve up the leg, and then on to the central nervous system in the spinal cord. It was too late by then. They were out in the woods, a two-day hike from their car, when the fever first hit. Getting her back to the car had been miserable. She convulsed involuntarily every time he tried to give her water. It didn’t make sense. She ended up throwing his water bottle down a steep hill in a fit of rage. Eventually, even the wind would send her into a fit, kind of like a seizure. The constant shifting between rage and apologetic crying brought them both near to madness as they struggled to get her back to civilization in her state. But it all made sense when she started foaming at the mouth.

The doctors said the virus was already in her brain. The virus effected the autonomic reflexes for swallowing in the medulla, and that hydrophobia and aerophobia were common effects of rabies. They said it was the hypoglossal nucleus for the air, and nucleus tractus solitari for the swallowing reflex with the water. The virus spread through saliva, so, it didn’t want the host swallowing. High amounts of virus in midbrain infected the raphe nuclei, altereing the brain’s ability to produce serotonin. They said that impacted her fits of rage and aggression. It spread to the central nervous system to effect behavior, then back to the peripheral system to infect salivary glands in the superior cervical ganglion. That’s why she foamed at the mouth.

Amy was more than her serotonin levels, or any other neurotransmitter. What a cruel virus to try to mask a human being like that, but she was more. She was love, and loved coffee, and hikes, and animals, and sitting under a blanket with a book on a rainy day.

She was a twisted, pale, and damp with sweat woman looking desperately up at him on a hospital bed right now. “Love?” she said. “You went away on me for a second there. Are you okay?”

Had he? “I’m sorry,” he said.

“It’s okay.” She squeezed his hand, but her fingers restlessly fidgeted in a way that they never had before. The doctor’s said that she would be like this, restless and agitated. The virus played havoc on the signals being sent back down her motor neurons. “I can tell this is hard on you.”

Ryan couldn’t hold back the tears. The weight of the world pulled down on the sides of his mouth. He sniffed against the mucus trying to run down his face. “Of course it is.”

“I’m so glad to have these moments with you,” she said, “but love, these are becoming fewer and farther between. I hurt your hand, and I don’t want you to remember me like this. I’m strapped to a bed, for god’s sake.”

As Ryan considered the pathway of his thoughts over the last few minutes, he had to acknowledge the truth of her fears. Every time he tried to disappear in happy memories his thoughts pulled him back to the reality of the physical world around him. The sounds of her breath, the feel of her hand, the pain of the wound on his hand. It was a nightmare he couldn’t escape. Would it always be this way? Could he ever think of her again with out this room, and these sensations infecting his experience? He couldn’t say.

“No,” he said, “I’m not leaving you. Never.”

“I know you,” she said, “And I love you.”

“I love you too,” he cut in quickly.

She went on. “I know you do. And you’re going to torture yourself with this. This isn’t your fault, Ryan. You couldn’t help this. You loved me, and you made life great. It’s still great, even with this. I wouldn’t change a thing. I need you to know that.”

Ryan couldn’t find any words. He felt his face contort into a sob. She held his hand in silence for a moment. Tears ran down her face too, but somehow, she was stronger and braver than he could ever be about this.

“I’m at peace, love, I am,” she assured him. “Just,” her breathing was becoming ragged.

Was she about to slip into another fit? He gripped her hand with both of his. “I’m here.”

She closed her eyes, and her body twitched and tensed against her restraints. She swung her head side to side in wide arcs. She sucked in deep breaths. “Just, go. I don’t want you to see me…” She trailed off, starting into an unintelligible grunt. Her twitching turned to violent lurches. This is time, the nurse stepped over and shook his head, lightly placing a hand on Ryan’s elbow to indicate he should let go to avoid being hurt again.

Reluctantly, he did. He let go. He backed up until he bumped into the counter behind him and slid to the ground and curled up into a ball as he watched Amy turn into something else. The rattling of her bed and the vicious screech of her voice consumed his experience. He tried to hang on to who she really was, to memories of her before all of this happened. But that sound wouldn’t allow it. It penetrated his being, so, he clapped his hands over his ears and sobbed on the floor.

When it was over, and she gasped to get air and the nurse mopped up her face, he pulled himself over to her side.

“Okay,” he said, between sobs. “I’ll go.”

“Be with family.” She said. “Please go straight to see your sister.”

“I will.” He sniffled and rubbed his tears away with his wrist.

“I love you,” she looked him in the eyes. Her beautiful green eyes. “I always will”

“I’ll always love you too.” He said, helpless to express the true depth of his feeling.

“This is the perfect goodbye.” She smiled. “I love you. I’ll always be with you, and I’ll be patiently waiting.”

Ryan nodded, barely registering the sensation of standing up and stepped backwards. He kept his eyes locked on hers. “I’ll always be right here.” He didn’t know what that meant, but he didn’t know what else to say. “It’ll be okay. I’m so sorry.”

“No,” she said, “not sorry. Say you love me.”

Ryan nodded, and shook his head, and nodded again. He was at the door. “I love you.”

“I love you too,” she mouthed a kiss in the air. “Now go.”

He pulled the door open, spilled himself into the hall, and collapsed on the other side after he shut the door.

After a long time, he picked himself back up. The real Amy was still with him, in his memories, and he’d never let go.

_________________________________________________

The objective chosen for this story is to compare and contrast the peripheral and central nervous systems. This was a difficult story to write. I don’t know if any artistry came through, but I couldn’t stop crying while I wrote it. I’m glad to be done. Rabies is a much crueler disease than I realized before doing the research for this.

The central nervous system is comprised of the brain and spinal cord and operates as the locus of control of the body. What we experience as consciousness, the concept of “who we are”, is a product of the functions of the central nervous system. This story explores this concept as Ryan struggles to identify “who” Amy is as her central nervous system is hijacked by rabies, a viral infection. According to my research, victims of rabies go through short bursts of aggression and periods of complete consciousness and lucid experience between (Wertheim, H. F. L., 2009). The virus hijacks the central nervous system to change the behavior of the host to maximize its opportunities to spread to another host: through biting. Ryan struggles to hang on to who he believes Amy really is as he watches her become something else that the virus changes her into by infecting her central nervous system. It’s represented by how the virus effects the serotonin levels in Amy’s Raphe Nuclei in her midbrain (brain stem area) (Jackson, A., 2016).

The central nervous system is more than the experience of consciousness. It also controls the autonomic nervous system, which is a complex series of involuntary responses the body uses to maintain homeostasis, like a beating heart. It is represented in this story by exploring how the virus infects the medulla in the brainstem area, causing convulsive reflexes and induced hydrophobia and aerophobia in rabies patients (Hussain Biology, 2017).

The peripheral nervous system comprises the rest of the nerves in the body outside of the brain and spinal cord. These are both sensory signals sent from extremities to the brain for processing, and motor signals sent from the brain back to muscles and organs to act. This is both somatic (voluntary) and autonomic (involuntary). This is represented in this story by the way Ryan’s pain in his hand grounds him in reality, and a brief description of the course of the virus from Amy’s ankle muscle to her spinal cord (central nervous system). The Peroneus Longus muscle connects to the superficial fibular nerve, then to the common peroneal nerve, to the sciatic nerve, and then up to the spinal cord (entering the central nervous system) through the L4 to the S3 vertebrae, through the Cauda equina nerve bundle at the bottom of the spinal cord, into the spinal cord itself (Taylor, T., 2015). The spinal cord connects into the brain stem. The virus would encounter the medulla first, inducing hydrophobia and aerophobia, through the pons and into the midbrain where it would infect the raphe nuclei to impact serotonin and behavior. As it spreads through the brain and the rest of the central nervous system, it would travel back into the peripheral nervous system to the superior cervical ganglion which controls the salivary glands.

A few other notable representations of the central nervous system featured in the story. It references memories and emotions several times, functions of the connections between the hippocampus and amygdala found in the limbic system. Ryan briefly considers how his sensation of pain ran through axons of neurons as electrical signals, to be turned to chemical signals in the synapses as neurotransmitters, and back to electrical signals as the information ran from his peripheral nervous system to is center of conscious experience in the cerebral cortex in his central nervous system.

References

Hussain, [Hussain Biology]. (2017, Feb 25). Why does Rabies cause HYDROPHOBIA ? Mechanism Behind It [Video]. Youtube. https://www.youtube.com/watch?v=fNfi_c0sQbI

Jackson, A.C. (2016) Diabolical effects of rabies encephalitis. J. Neurovirol. 22, 8–13. https://doi.org/10.1007/s13365-015-0351-1

Lackay, S. N., Kuang, Y., & Fu, Z. F. (2008). Rabies in small animals. The Veterinary clinics of North America. Small animal practice, 38(4), 851–ix. https://doi.org/10.1016/j.cvsm.2008.03.003

Muyila, D. I., Aloni, M. N., Lose-Ekanga, M. J., Nzita, J. M., Kalala-Mbikay, A., Bongo, H. L., Esako, M. N., Malonga-Biapi, J. P., Mputu-Dibwe, B., Aloni, M. L., & Ekila, M. B. (2014). Human rabies: a descriptive observation of 21 children in Kinshasa, the Democratic Republic of Congo. Pathogens and global health, 108(7), 317–322. https://doi.org/10.1179/2047773214Y.0000000161

Taylor, T. (2015, June 23). Nervous System. innerbody research. https://www.innerbody.com/image/nervov.html

Wang, X., Yu, X., & Guan, Y. (2015). Case report of rabies-induced persistent mental symptoms. Shanghai archives of psychiatry, 27(1), 52–54. https://doi.org/10.11919/j.issn.1002-0829.214174

Wertheim, H. F. L., Nguyen, T. Q., Nguyen, K. A. T., Jong, M. D. J., Taylor, W. R. J., Le, T. V., Nguyen, H. H., Nguyen, H. T. H., Farrar, J., Horby, P., & Nguyen, H. D. (2009). Furious Rabies after an Atypical Exposure. PLOS Medicine, 6(3): e1000044. https://doi.org/10.1371/journal.pmed.1000044

One Comment

  1. I like the way in which the love story is combined to illustrate the subject of compare and contrast the peripheral and central nervous systems. The story revolves around the heroine Amy who suffers from rabies. Jon analyzed the concepts of peripheral nervous system and central nervous system, as well as the differences and connections between them, in his later essay based on some details in the story. As we know, the nervous system plays a leading role in the body, can accept all kinds of information from the external environment, through the peripheral nervous system to the central nervous system for integration, then people can make a variety of responses. Amy appears fuzzy thinking, is one of the most obvious disorders of nervous system, because the main function of the nervous system is to maintain the human body normal thinking, judgment, etc., so when the nervous system disorders, can cause a person’s mind in disorder, this is embodied in nonsense or behavior, and even shouting, yelling, etc. ”Her twitching turned to violent lurches”, so poor Amy was trapped down to the hospital bed; In addition, the disorders of human nervous system leads to the decline of people’s judgment ability. When the nervous system is disturbed, it can lead to the decline of the judgment ability of the brain, which is manifested in the inability to judge whether things are correct or not, or the inability to judge the nature of things and the inability to judge right and wrong. Amy feels she is not herself anymore, “The real Amy was still with him, in his memories, and he’d never let go.” Nervous system disorders cause behavioral abnormalities or behavioral impairments, the ability to act is out of control, but love is always there. It’s a great story. I love it.

    Joy Huang

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