The human body is a complex machine, a combination of structure and purpose. At the foundation of our medical studies lies anatomy, the study of our bodily structure and internal workings. While our bodies may seem to be in a perfect equilibrium, the stability of our health is constantly in danger from unseen threats. Various conditions have the potential to warp cells - the foundation of our existence - and can have a profound impact on the organs, tissues and systems that dictate the delicate balance of our health, altering our daily functions and challenging our bodies’ defence mechanisms. This article will explore the influence of certain conditions on our physiology, specifically the latest findings about the consequences of Alzheimer’s on the nervous system and two contrastingly severe conditions of the skin.
Alzheimer's and the Nervous System
The nervous system is highly intricate, containing nerves that extend all over the body as well as the most complex organ of them all – the brain. This system is responsible for all the body’s functions and keeps our bodies in harmony by communicating with all the other systems in the body. Consequently, disrupting this can have potentially lethal effects. One example of this is Alzheimer’s disease which was responsible for 20.7% of all deaths in the UK in 2022. Alzheimer’s disease is a brain disorder that slowly destroys memory, thinking skills, and eventually the ability to carry out simple tasks. It typically afflicts those over the age of 65, however in rare cases it can be present in younger people (early onset).
While the causes and mechanics underlying Alzheimer’s disease are not fully understood, it is assumed to be a combination of hereditary and environmental factors, as well as social factors including loneliness. Alzheimer’s disease causes parts of neurones (in particular axons and synapses) to be damaged and ultimately destroyed. These are parts which are responsible for transporting electrical impulses to and from the brain and this damage to neuronal transport results in impairment to cognitive functions such as memory.
While the cause of this damage is also still unknown, the prime suspects are neuritic plaques. These are deposits formed from defective clumps of a protein, which then bind to neural receptors, triggering the erosion of synapses. Additionally, a protein ‘tau’ undergoes abnormal chemical changes, detaching from microtubules (responsible for determining the shape of a cell) and instead binding with other tau molecules. These form threads that tangle inside neurones, known as neurofibrillary tangles. These tangles restrict the neurones’ transport systems, harming the electrical communications between neurones and eventually resulting in cell death. This causes a reduction in brain matter. Unfortunately, while this is a partial explanation, the causes of Alzheimer’s are still largely unknown and this explains its high mortality rate, combined with how complex the brain is as an organ which makes any operations precarious and difficult.
Conditions of the Skin
The skin plays a very different role than the brain. It has three main functions: protection, thermoregulation (heat regulation) and sensation. The skin is constantly detecting information from multiple stimuli and receptors making it a very complex sense organ. When this system is hindered by disease it can have hugely varying effects, from inflammatory disorders such as acne, to fatal skin diseases such as melanoma (skin cancer). Acne affects approximately 85% of people between the ages of 12-24 and nearly everyone will experience some form of acne within their lifetime. On the other hand, more serious diseases such as melanoma impact only around 2% of the global population. While acne mainly affects the younger population melanoma affects all ages with the majority being aged 65+.
Three major factors contribute to acne – a plug of skin cells that becomes trapped within the pore, a surplus of the skin’s natural oil and the acne-inducing bacterium called Propionibacterium (P. acnes). P. acnes is harmless but when a plug of dead skin cells and oil blocks the pore opening, it creates an anaerobic environment where the P. acnes thrives. The bacteria irritate the pore lining, creating redness and inflammation. A hormone that also plays a big role in acne is the sex hormone androgen which increases sebum (oil) production causing more inflammation due to the excess sebum.
Melanoma has one major cause: UV radiation. Be it a history of childhood sunburn or deliberate tanning, long periods of unprotected UV radiation exposure or a pattern of short, intense periods of the same, this overexposure to UV radiation damages the DNA in our skin cells. DNA tells our cells how to function so if enough DNA damage builds up over time, it can cause cells to start growing out of control. Melanoma develops when melanocytes (the cells that give skin browner colour) start to grow out of control. It begins on the skin where it is easy to see and treat. However, it can grow into the skin, reaching the blood vessels and lymph nodes and can then spread within the body to various organs (where it can then be fatal). This is displayed in Figure 1 where you can see the uncontrolled cell growth starting to grow into the skin towards the muscle layer.
After exploring the topic, we can conclude that disease affects anatomy in a variety of different ways, varying from serious cases such as Alzheimer’s and melanoma, to minor hindrances such as acne. We see the varying range of these diseases with melanoma affecting mainly the skin but with the potential to spread to other parts of the body while Alzheimer’s affects only the brain and neurones with no potential to directly harm other parts. By revealing the delicate balance between disease and human anatomy, our exploration highlights the necessity for this knowledge in the medical setting and wider research. Recognising what effect diseases can have on our cellular structure is crucial for any attempt at a cure, and by understanding these topics we can push the boundaries of our knowledge of diseases as a whole, leading to a healthier future for humans.