Body Designs Not Often Considered
There’s more going on under the skin
and on the skin than we know
That Gut Feeling Is Right
“Gut Feeling” Takes on New Meaning (The Scientist, 23 Jan 2023). How do we know how our gut is feeling? Why can we tell that the bowel has become irritated, or that something bad is occurring? How do we know the satisfaction of a full stomach after a delicious meal? Things don’t just happen. Status information must be sent to the brain by sensors in the locations where we notice changes. Dr Iris Kulbatski explains, “Mechanically sensitive gut cells similar to touch sensors in the skin allow the intestine to feel and assess the physical properties of its contents.” The solution is elegant, says Dr Kulbatski:
The mammalian gut is self-sufficient. Its contents are physically isolated from the rest of the body by the intestinal lining, which forms a semipermeable barrier that allows the gut to digest food while confining potential foodborne pathogens. The vast network of nerve cells embedded in the intestinal lining—known as the “second brain”—interacts with sensory cells that assess the chemical and physical properties of the gut’s contents. This elegant system coordinates digestion autonomously, even if the vagus nerve—the main nerve carrying signals between the gut and brain—is cut.
The article goes on to describe the cellular sensors that monitor the gut’s status. They are called “Piezo2” ion channels after the ability of some materials to produce electricity from mechanical force (the piezoelectric effect). These mechanosensitive channels line the cells of the gastrointestinal system to monitor the gut, just like they do for the skin. Dr Arthur Beyder of the Mayo Clinic describes what he found:
Beyder’s team concluded that these Piezo2 sensory cells allow the gut to sense the physical properties of its contents, redistribute those contents along its length, and regulate how often it contracts in response to these subtle mechanical forces. “The gut is interested in squeezing out every possible useful nutrient—like this independent machine that has its own little fingers that manipulate [its contents] without you ever having to think about it. When we take the colons out and put them in an organ bath, this mechanism is fully intact,” Beyder said.
Unfortunately, Beyder lapsed into a short evolutionary story after that, but the actual scientific facts supported good engineering design in this monitor and control system.
Adipose tissue is a source of regenerative cells that augment the repair of skeletal muscle after injury (Nature Communications, 5 Jan 2023). Fat is something we want to get rid of, but here’s a different reason to pat that belly and say thank you. Read the open-access paper for details on new findings:
Fibro-adipogenic progenitors (FAPs) play a crucial role in skeletal muscle regeneration, as they generate a favorable niche that allows satellite cells to perform efficient muscle regeneration. After muscle injury, FAP content increases rapidly within the injured muscle, the origin of which has been attributed to their proliferation within the muscle itself. However, recent single-cell RNAseq approaches have revealed phenotype and functional heterogeneity in FAPs, raising the question of how this differentiation of regenerative subtypes occurs. Here we report that FAP-like cells residing in subcutaneous adipose tissue (ScAT), the adipose stromal cells (ASCs), are rapidly released from ScAT in response to muscle injury. Additionally, we find that released ASCs infiltrate the damaged muscle, via a platelet-dependent mechanism and thus contribute to the FAP heterogeneity. Moreover, we show that either blocking ASCs infiltration or removing ASCs tissue source impair muscle regeneration. Collectively, our data reveal that ScAT is an unsuspected physiological reservoir of regenerative cells that support skeletal muscle regeneration, underlining a beneficial relationship between muscle and fat.
Bald Is Beautiful but Hair is Fairer
Human scalp hair as a thermoregulatory adaptation (bioRxiv, 22 Jan 2022). Evolutionists like to describe humans as naked apes, but human skin and scalp are actually wonderfully designed. When Darwinians speak of an “evolutionary function” they really mean a design, but wrongly assume it just happened. Read the abstract and see if an “evolutionary framework” makes sense compared to an engineering framework:
Humans are unique among mammals in having a functionally naked body with a hair-covered scalp. Scalp hair is exceptionally variable across populations within Homo sapiens. Neither the function of human scalp hair nor the consequences of variation in its morphology have been studied within an evolutionary framework. A thermoregulatory role for human scalp hair has been previously suggested. Here, we present experimental evidence on the potential evolutionary function of human scalp hair and variation in its morphology. … We find evidence for a significant reduction in solar radiation influx to the scalp in the presence of hair. Maximal evaporative heat loss potential from the scalp is reduced by the presence of hair, but the amount of sweat required on the scalp to balance the incoming solar heat (i.e. zero heat gain) is reduced in the presence of hair. Particularly, we find that hair that is more tightly curled offers increased protection against heat gain from solar radiation.
This implies that black people are more fit for these beneficial functions. Maybe whites devolved from them.
Cat Locomotion Could Unlock Better Human Spinal Cord Injury Treatment (Georgia Tech, 5 Jan 2023). Cats are notable for landing on their feet when dropped upside down, but “Their unique sense of balance has more in common with humans than it may appear,” this press release says. Scientists at the Georgia Institute of Technology”are studying cat locomotion to better understand how the spinal cord works to help humans with partial spinal cord damage walk and maintain balance.”
Understanding the mechanisms of this type of balance control is particularly relevant to older people who often have balance issues and can injure themselves in falls. Eventually, the researchers hope this could bring new understanding to somatosensory feedback’s role in balance control. It could also lead to progress in spinal cord injury treatment because the research suggests activation of somatosensory neurons can improve spinal neural networks’ function below the site of spinal cord damage.
The new book Your Designed Body by engineer Steven Laufmann and medical doctor Howard Glicksman notes that when a person falls, they have just 1/2 second to react before hitting the ground (p 218). To prevent frequent falls, the balance organs in the inner ear must have fast-response neurons. Myelin sheaths speed up neuronal transmission by a factor of 100. More detail on our ability to avoid falls was provided by scientists from four US universities, described below.
Nonquantal transmission at the vestibular hair cell–calyx synapse: KLV currents modulate fast electrical and slow K+ potentials (Govindaraju et al., PNAS, 3 Jan 2023). These scientists found that neurons in the balance organs of the inner ear have the fastest reflexes in the body due to specialized engineering that minimizes delay:
The ability of the vestibular system to drive the fastest reflexes in the nervous system depends on rapid transmission of mechanosensory signals at vestibular hair cell synapses. In mammals and other amniotes, afferent neurons form unusually large calyx terminals on certain hair cells, and communication at these synapses includes nonquantal transmission (NQT), which avoids the synaptic delay of quantal transmission. We present a quantitative model that shows how NQT depends on the extent of the calyx covering the hair cell and attributes the short latency of NQT to changes in synaptic cleft electrical potential caused by current flowing through open potassium channels in the hair cell.
Note: “Quantal” transmission (i.e., packetized) is normally made across neurons by exocytosis of neurotransmitters between synapses. Though rapid, quantal transmission has a tiny bit of unavoidable delay. A previously mysterious “non-quantal” form of transmission in the vestibular apparatus is now shown to bypass the latency of quantal transmission by direct amplification of current flowing through mechanosensitive ion channels.
People may not realize how electrical their bodies are! The flow of ions is just as electrical as the flow of electrons in copper wire, but has the advantage of not shorting out when we get wet. The super-fast action of neurons in the hair cells inside our inner ear balance organs is usually adequate to respond quickly enough to avoid falls, even when hopping, skipping or jumping. The superb design in our balance capabilities can be appreciated when watching Olympic gymnasts perform their rapid, complex routines and end by “sticking” the landing.
The last sentence of the PNAS paper contains this howler: “our model supports the idea that the calyx evolved to support faster transmission in response to increased locomotory challenges presented by the tetrapod transition from water to land.” Oh come on. I need to fly; will the Stuff Happens Law ship wings to me in an Amazon box? Does a need cause a solution? What is evolution, some Genie that grants our every wish? This is magical thinking.
Our hope is that these wonders of the body will help you thank God, your Creator. Put Your Designed Body on your must-read list. It will be hard for anyone reading the book to entertain atheism.