"Wisdom begins in wonder" – Socrates
Category: Physiology
Connective Tissue
09/23/26
“What holds your body together?”
Your body is a complex vessel composed of a myriad of interrelated systems. But what exactly holds everything together? Well, this is the role of Connective Tissue. Connective tissue attaches, cushions, flexes, protects, separates, supports, and supplies all systems in your body. Examples of connective tissue range from bones to blood to cartilage.
Nervous Tissue
09/22/26
“How do neuron cells form a complex communication network?”
Neuron cells are the gears that run our nervous system. But how do they coalesce into a greater communication system? Well, it turns out they and their glial cell protetcors make up a Nervous Tissue system that detects changes, funnel them to the appropriate place, processes it, and produces an appropriate reaction. To illustrate, if you touch a cold glass of water, your sensory neuron nervous tissue will alert you of the icy feel.
Muscle Tissues
09/20/26
“What makes muscles function?”
Complex animal bodies use movement to get around. Muscle Tissues are specialized groups of cells that can contract and relax to generate movement. Muscle tissues can be voluntary (controlled at will, such as a human moving their thumb) to involunray (heart pumping).
Tissues (Biology)
09/19/26
“How can biological cells come together to perform a specific function?”
Biological cells are the building blocks of life. However, they cannot do much by themselves. But what if they were to work together to perform a specific function? Well, these come in the form of Tissues. Tissues are one of the core parts of body functioning and serve as an intermediary between cells and organs.
Image credit: https://www.registrypartners.com/
Hazard Quotient
01/27/26
“How can we quantify the lethality of exposure to a substance?”
People are exposed to potentially hazardous substances all the time, whether it’s traces of air pollution or bacterial growth on food. We also know that if exposure breaches a certain level, it becomes dangerous. So how can we quantify the lethality of exposure to a substance? Well, what if we divide the exposure level by the reference dose? This is how the Hazard Quotient works, and it is a very useful tool in toxicology.
Noise Dose
01/24/26
“How can we quantify the level of noise someone is exposed to over time?”
Listening to too much loud noise is a well-known safety risk. The constant vibration in your ears can lead to long-term damage if not managed properly. The Noise Dose quantifies how much noise a person has been exposed to for the day, regarding safety levels. We can quantify noise dose by taking the hours someone listened to a certain decibel of noise and dividing it by the maximum number of hours it’s safe to listen to that noise level per day. We can sum this ratio for every noise decibel level heard throughout the day, multiplied by 100% to arrive at the total noise dose. If a noise dose exceeds 100 percent, then the person has breached the healthy recommended daily noise levels.
Chronic Daily Intake
01/23/26
“How can we calculate the amount of contaminant a person is exposed to daily?”
People are exposed to all kinds of substances throughout the day, whether it’s from the food we eat or the air we breathe. Some of these substances are harmful and can lead to health problems. We can measure how much of these contaminants we expose ourselves daily through Chronic Daily Intake. Chronic daily intake is typically expressed as milligrams of substance per kilogram of body weight per day. The US E.P.A uses chronic daily intake as part of health hazard assessment.
Acceptable Daily Intake (ADI)
01/21/2026
“How does the WHO measure how much a certain substance in food or drinking water can be consumed daily over a lifetime without an appreciable health risk?”
NOAELs document how much of a substance an organism can handle before a statistically significant health effect occurs. However, these studies may be conducted in controlled environments or on test animals that may not accurately reflect human conditions. To account for all of these variables, organizations such as the World Health Organization (WHO) and the European Food Safety Authority (EFSA) use Acceptable Daily Intake (ADI). Acceptable daily intake measures the amount of a certain substance in food or drinking water that can be consumed daily over a lifetime without an appreciable health risk to people. This is commonly expressed as milligrams of substance per kilogram of body weight and is applied by regulatory and health authorities all over the world to monitor food additives, pesticides, and much more. Acceptable daily intake is applied to food ingredients similar to how reference dose is applied to environmental toxins.
Reference Dose (RfD)
01/20/26
“How does the U.S. EPA produce recommended daily lifetime exposure limits for substances?”
NOAELs are the highest level of a substance a person can take without any statistically significant effects, according to research. However, this could be much higher than what may actually be safe for long-term use. The U.S. EPA has created the Reference Dose (RfD) in response. Reference does are the maximum acceptable oral dose of a toxic substance that has no adverse noncancer health effects from a lifetime of exposure. Reference doses are commonly found by dividing the NOAEL for a substance by uncertainty factors.
