weird facts about the body

WTF Fun Fact 13442 – We Have More Bacterial Cells Than Human

The human body contains more bacterial cells than human cells. Weird, right?

The majority of the cells that constitute “you” are, in fact, not human. They are microscopic organisms that are hitching a ride, making a living off your body. It might sound like science fiction, but this is a confirmed scientific fact. The human body contains ten times more bacterial cells than human cells.

How can we contain more bacterial cells than human cells?

Now, before we allow our imagination to scare us into a frenzy, let’s unpack this a bit.

These bacterial cells, collectively known as the human microbiota, live mostly in harmony with our bodies. We provide them with a suitable habitat, and they return the favor by aiding in bodily functions like digestion and immune response. Our gut houses the vast majority of these organisms.

This raises some provocative questions: With our bodies being made up predominantly of non-human cells, what does that imply about our identity? What actually makes us human?

How are we fully human if we contain so many non-human cells?

Biologically speaking, being human is about more than just the number of cells. Human cells, while fewer in number, are much larger and more complex than bacterial cells. So, in terms of volume and genetic material, we are predominantly human.

But the philosophical implications are still fascinating to consider. We ten to link our human identity to our biological makeup. But the massive presence of non-human cells introduces an intriguing paradox.

Science has often categorized organisms based on their cellular composition. However, this fact might prompt us to reconsider such traditional boundaries. We need to acknowledge the complex symbiosis that constitutes our “self.” We are, in essence, a walking, talking microbiome.

Teamwork makes the dream work

These non-human inhabitants of our body have a far-reaching impact on our health and well-being. There’s a dynamic relationship between our human cells and these bacterial cells. When this relationship is in balance, we thrive. But when it’s out of whack, we may face health issues. This fact has driven researchers to explore the potential of microbiota in shaping future treatments for various diseases.

Yet, as we learn more about our microbial inhabitants, we also uncover deeper layers of what it means to be human. Are we individual entities, or are we, as some philosophers might argue, a “superorganism” made up of numerous symbiotic relationships?

Indeed, we might be more ‘alien’ than we ever imagined, yet this very fact underscores our extraordinary complexity as living beings.

So next time you glance at your reflection, remember: You’re not just looking at ‘you.’ You’re seeing an intricate ecosystem.

— WTF fun facts

Source: “NIH Human Microbiome Project defines normal bacterial makeup of the body” — National Institutes of Health

WTF Fun Fact 13344 – Humans Can’t Feel Wetness

The fact that humans can’t feel wetness seems ridiculous at first. You may have even read that it’s a misconception. But, technically speaking, we do not have the right “gear” to directly sense wetness – even though we all know when something is wet.

But how does that work?

Why humans can’t feel wet

Humans lack dedicated hydroreceptors – the specialized sensory receptors solely responsible for detecting wetness. As a result, wetness is not a distinct sensation for us, but rather an interpretation of multiple sensory inputs.

When a liquid, such as water, comes into contact with the skin, several different types of sensory receptors are activated. These include thermoreceptors, mechanoreceptors, and nociceptors. Thermoreceptors respond to temperature changes and can detect the cooling effect of the liquid on the skin. However, this response alone does not convey the specific quality of wetness.

Mechanoreceptors, responsible for sensing pressure and touch, provide information about the physical presence of the liquid. They detect the pressure exerted by the liquid and signal the brain accordingly. However, the activation of mechanoreceptors alone does not differentiate between wet and dry sensations.

Nociceptors, which detect pain and discomfort, may also play a role in the perception of wetness. If the liquid is extremely hot, cold, or otherwise causes discomfort, nociceptors are activated, contributing to the overall sensation. However, this response is not exclusive to wetness and can be triggered by other stimuli as well.

How we sense “wet”

Due to the absence of dedicated hydroreceptors, the brain must integrate and interpret these various signals to create the perception of wetness. It combines the inputs from thermoreceptors, mechanoreceptors, and nociceptors, along with other contextual cues, to generate the subjective experience of being wet.

While humans can recognize and differentiate wet sensations, it is important to note that wetness itself is not a distinct sensory modality. Rather, it is a perception resulting from the brain’s processing of multiple sensory inputs related to temperature, pressure, and even discomfort.

— WTF fun facts

Source: “Humans Technically Can’t Feel Wetness, And People Are Confused” — IFL Science

WTF Fun Fact 13273 – Men’s Nipples Lactate

It’s extremely rare unless something is wrong with the body, but technically, men’s nipples lactate. That is, they are capable of producing milk, which is the function of a nipple.

All fetuses develop nipples. Male, female, and intersex fetuses develop nipples during the early stages of fetal development, typically around 6 to 7 weeks gestation. This is because nipples are a fundamental part of the human anatomy. It is only later in fetal development that sex-specific features begin to emerge, such as the development of genitalia.

How, when, and why do men’s nipples lactate?

While lactation in men is a rare occurrence, it is not something that should be dismissed as a mere anomaly. Despite being uncommon, men can and do produce breast milk in certain circumstances. For example, it may happen during hormonal imbalances or after frequent stimulation of the nipples. This phenomenon has been documented in a variety of mammalian species, including humans. Yet much remains to be understood about the underlying biology and mechanisms driving male lactation.

Male lactation is also known to occur in response to the hormonal changes brought about by certain medical conditions. For example, in some cases, male lactation is triggered when a man experiences a rise in the hormone prolactin.

The role of prolactin

The hormone responsible for milk production in females plays a similar role in males. Prolactin stimulates milk production in the mammary glands, and in males, it is secreted by the anterior pituitary gland.

However, the prolactin levels in males are much lower than in females. This is why milk production in males is rare, and the amount produced is usually not enough to sustain an infant. The biology involved in male lactation involves the mammary glands, which are present in both men and women.

While these glands are not fully developed in men, they still have the potential to produce milk. The process of male lactation can also be triggered by stress, certain medications, or a tumor in the pituitary gland.

Stimulating lactation in men

Another cause of male lactation is the use of medications that can mimic the hormonal effects of pregnancy and breastfeeding. For example, medications containing estrogen can cause an increase in prolactin production, leading to milk production in men’s mammary glands.

Despite the rarity of male lactation, some men have been able to nurse their infants successfully. One example is a man named Jack Newman. After adopting a child, Newman was able to induce lactation through a combination of hormone treatments and frequent nursing sessions.

Male lactation may seem like a strange and abnormal occurrence. But the rare phenomenon of male lactation is a fascinating subject. And it has captured the interest of scientists and laypeople alike. While much remains to be discovered, continued research into male lactation could have significant implications for our understanding of infant nutrition and lactation science as a whole. The underlying mechanisms that allow men to produce milk could help to improve our understanding of the biology of lactation in general. This could lead to breakthroughs in lactation-related issues such as mastitis and low milk supply.

Despite these potential benefits, male lactation remains a largely unexplored field of study.

— WTF fun facts

Source: “Strange but True: Males Can Lactate” — Scientific American