# Diffusion rate of oxygen through skin

• fishes
In summary, the conversation discusses the diffusion rate for oxygen through human skin and the maximum diameter of a spherical organism that can meet its oxygen requirements through diffusion. The diffusion rate for oxygen through human skin is calculated to be 1.71 liters per hour per square centimeter. The maximum diameter of a spherical organism with the same diffusion rate as the person in question is determined to be 0.5 centimeters, assuming the same density as water and oxygen requirement per unit volume. The use of density and other equations such as Flick's law are considered but not fully understood. The answer is ultimately found online, but the question still remains unclear.
fishes

## Homework Statement

i) At rest a 70 kg person with an area of 1.7 m2 consumes around 14 litres of oxygen per hour. Around 2% of this is provided by diffusion through their skin. Calculate the diffusion rate for oxygen through human skin, in millilitres per second per square metre.
ii) What is the maximum diameter of a spherical organism whose oxygen requirements may be met entirely by diffusion through skin with the same diffusion rate as the person above? Assume that they have the same density as water and that the oxygen requirement per unit volume is the same as for the person.

## Homework Equations

I have no idea what specific diffusion equation to use for the first part :(

## The Attempt at a Solution

So I've figured out all of the easy stuff at the beginning. Like he consumes 0.29L of O2 and hour by diffusion and that the mass of one O2 molecule is 5.3x10^-23g but I am totally stumped from here. I've looked through my textbook and found a ton of different diffusion equations such as Flick's law but I can find all of the variables with what I've been given. I have an inkling that I have to use the density of animal fat for something but no luck so far. I was at one point thinking about calculating a concentration value somehow because i saw that in Flick's law but it all comes back to my main problem on me not knowing how to link any of this information together. Am I missing a constant that's well known?

For the second part I'm positive it is related to SA/V ratio and how smaller organisms = higher ratio values but I'm again stumped on generating a value. Seeing as this 70kg person only takes in 2% of O2 by diffusion I assume that the animal size would be very very small, like insect like?

Would really appreciate, I'm normally not this hopeless but this question has really confused me.

Okay so I managed to find the answers online but I would really like to fully understand the question and I still can't seem to figure it out. The answers are 1.71l/hrcm2 and 0.5. I think I'm getting closer to figuring out the second part though.

So I'm probably just as lost as you but seeing as the question mentions density for the second part shouldn't you be using the formula of a sphere's volume along with 1g/cm3?

## 1. What is diffusion and how does it work?

Diffusion is the process by which molecules move from an area of high concentration to an area of low concentration. This is due to the random movement of particles, and it helps to equalize the concentration of molecules in a given space.

## 2. How does oxygen diffuse through the skin?

Oxygen diffuses through the skin via a process called passive diffusion. This means that oxygen moves from an area of high concentration (air) to an area of low concentration (blood vessels) through the skin's layers, including the epidermis and dermis.

## 3. What factors affect the diffusion rate of oxygen through the skin?

Several factors can affect the diffusion rate of oxygen through the skin, including the thickness and health of the skin, the concentration gradient of oxygen, and the surface area of the skin. Additionally, temperature, humidity, and blood flow can also impact the diffusion rate.

## 4. How does the diffusion rate of oxygen through the skin differ from person to person?

The diffusion rate of oxygen through the skin can vary among individuals due to differences in skin thickness, health, and other factors. Age, gender, and underlying medical conditions can also affect the diffusion rate.

## 5. How is the diffusion rate of oxygen through the skin measured?

The diffusion rate of oxygen through the skin can be measured using methods such as transcutaneous oxygen tension (TcPO2) monitoring or oxygen electrode measurements. These techniques involve placing sensors on the skin to measure the concentration of oxygen and can provide valuable information about the diffusion rate.

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