We have one more skin system researcher to study about as we prepare for our in class discussions of skin physiology!  Linlin Sun is a research associate in a laboratory at the University of Maryland.  In May 2017, Dr. Sun coauthored the paper Anti-Aging Potentials of Methylene Blue for Human Skin Longevity, which appeared in the prestigious journal, Nature, and received much attention in the press.  Note that the topic of the paper, methylene blue, is a chemical you have worked with in our class!  Methylene blue is a very common stain used in creating microscope slides.  We recently finished using methylene blue to stain slides in our histology lab.

1) Please click here Download click here to read a brief biography of Dr. Sun.
2) Then, click hereLinks to an external site. to read one of the many news articles that reported on Dr. Sun's work with skin and methylene blue.
3) Finally, please take a quick look at the abstract and first paragraph of the Introduction in Dr. Sun's Nature articleLinks to an external site. (or feel free to read on farther if you like!).  Do NOT worry about understanding all the language or looking up unknown words.  Instead, simply try to look for whichever words you might have heard before and what the broad ideas might be.

After reviewing these resources, write a 250 word or more reflection with your responses. You might wish to discuss any or all of the following topics:

1)   What was most interesting or most confusing about the these resources?

2)   What can you learn from these resources regarding the cells, molecules, and aging processes in the skin?

3)   What do these resources tell you about the types of people that do science?

4)   What new questions do you have after reviewing these resources?

application 7

 Now that you have had an opportunity to reflect on this question and get some ideas from colleagues, take this opportunity to more formally record a response...

Courtroom 

Pretend you’re called as an expert witness in a court case about asbestos. The person suing (the plaintiff) worked in an asbestos mine in Canada and says it is now hard for him to breathe due to exposure to asbestos. As an expert witness, use your A&P knowledge to describe to the judge how the asbestos could relate to the plaintiff's difficulties.  You should...
Describe two different membranes that you think are likely impacted, including where those membranes are located, what specific tissue types they're are made of, and how you think the presence of spiky asbestos within those membranes could inhibit their normal functions.

You might want to open another window to go to earlier pages in this module and remind yourself of where asbestos can go to in the body.

Mostly Complete (10 pts): Describe mucous membranes and serous membranes in terms of their locations and cell/tissue composition.  Please be specific regarding tissue types (e.g., what type of epithelial or what type of connective tissue)!  Make a prediction (at least a guess!) at how the functions of those membranes might be impeded if stiff, spiky asbestos was embedded within them.

Partially Complete (6 pts): Mucous and serous membranes identified, but one of above details missing.

 Could the mucous membranes also be involved here? And what specific epithelial and connective tissues might be impacted in each membrane because of spiky asbestos

       When asbestos fibers are inhaled, they can reach the alveoli of the lungs. Asbestos fibers are not only penetrate the pleura but also reach the alveoli. The pleura consists of a serous membrane, composed of a layer of simple squamous cells called mesothelium which is supported by connective tissue. The pleura located double-layered membrane in the thoracic cavity covers the lungs called parietal pleura and visceral pleura consist of a serous membrane.The pleura acts as protective barrier, reducing friction during lung movement and facilitating efficient breathing.  

         When inhale asbestos fibers, that spiky asbestos fibers embedded within mucous membranes and serous membranes. Asbestos fibers stuck on the alveoli  cause chronic inflammation and damage to the alveolar cells and endothelial cells.Asbestos fibers can lead to fibrosis and scarring of the epithelial lining.Fibrosis develops within  squamous epithelial cells that form the alveolar walls .Asbestos fibres on cells affect blood flow within the alveoli  membrane. Chronic inflammation leading to thickening of the pleura that caused reduce the pleura’s elasticity and impair lung expansion follow by impaired gas diffusion, reducing the efficiency of oxygen uptake and carbon dioxide removal so that the patient presenting with breathing difficultly progressive shortness of breath.

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Pseudostratified ciliated columnar epithelium
The lungs are made of pseudostratified ciliated columnar epithelium. The structure of the cells is neither columnar nor cuboidal. 

Some cells are broader at the top while some cells are narrow at the top. They also possess cilia. Hence, they are called pseudostratified ciliated columnar epithelium.

 The epithelial tissues in  membranes are simple squamous epithelium, and as with mucous membranes, the connective tissue is typically areolar tissue.

1. Simple squamous epithelia are found in alveoli of lungs, capillaries, glomeruli and other tissues where rapid diffusion is required.
2. Simple cuboidal ephithelia are found in thyroid glands, kidney tubules, glandular ducts and ovaries, and the thyroid gland. On these surfaces, the simple cuboidal ephithelial cells perform secretion and absorption.
3. Non-ciliated simple columnar epithelium lines the organs of the digestive tract including stomach, small intestine and large intestine whereas the
4. Pseudostratified non-ciliated columnar epithelium lines the epididymis of the male reproductive system.
5. The transitional epithelium is made up of multiple layers of epithelial cells with an ability to expand and contract and are found in the urinary bladder, ureters and gland ducts of the prostrate.

 Pleura:
Location: The pleura is a double-layered membrane that lines the chest cavity (parietal pleura) and covers the lungs (visceral pleura).
Tissue Types: The pleura consists of connective tissue, including mesothelial cells. These cells play a crucial role in maintaining the integrity of the pleural space.
Function: The pleura serves as a protective barrier, reducing friction during lung movement and allowing efficient expansion and contraction during breathing.
Impact of Asbestos:
When asbestos fibers are inhaled, they can penetrate the pleura. These spiky fibers irritate and damage the mesothelial cells.
Over time, chronic inflammation occurs, leading to thickening of the pleura (known as pleural plaques). These plaques reduce the pleura’s elasticity and impair lung expansion.
Additionally, asbestos exposure can cause pleural effusion, where fluid accumulates between the pleural layers. This further restricts lung movement and impairs gas exchange.
The presence of asbestos fibers within the pleura can lead to fibrosis (scarring), making it harder for oxygen and carbon dioxide to pass through the pleural layers. Breathing becomes increasingly difficult for the plaintiff.
Alveolar-Capillary Membrane:
Location: The alveolar-capillary membrane is found within the lungs, specifically at the interface between the alveoli (air sacs) and the pulmonary capillaries.
Tissue Types: This membrane consists of:
Type I alveolar cells: Extremely thin squamous epithelial cells that form the alveolar walls.
Endothelial cells: Line the pulmonary capillaries.
Function: The alveolar-capillary membrane facilitates gas exchange—oxygen diffuses from the alveoli into the bloodstream, while carbon dioxide moves from the blood into the alveoli for exhalation.
Impact of Asbestos:
Asbestos fibers can reach the alveoli when inhaled. Once there, they interact with the alveolar-capillary membrane.
The spiky asbestos fibers cause chronic inflammation and damage to the delicate type I alveolar cells and endothelial cells.
Fibrosis develops within the alveolar walls, thickening the membrane. This impairs gas diffusion, reducing the efficiency of oxygen uptake and carbon dioxide removal.
The plaintiff may experience progressive dyspnea (shortness of breath) due to compromised gas exchange caused by the presence of asbestos within the alveolar-capillary membrane.
In summary, asbestos exposure affects both the pleura and the alveolar-capillary membrane, leading to respiratory difficulties. The plaintiff’s symptoms align with the well-documented health effects of asbestos exposure, including asbestosis, pleural disease, and increased risk of lung cancer and mesothelioma1234.