“it was trapped between two lungs”
Thyroid, Human (H&E stain)
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An unidentified fungi - picked from bread mold.
Some of these can cause disease, specially if you have immune-issues (as in AIDS).
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From left to right: T. saginata, Ascaris lumbricoides and Fasciola hepatica.
Some of the many parasites that can live inside us - some causing disease.
Woven bone is the primitive bone first laid down during fracture repair or new bone formation. It consists of a higher percentage of osteocytes than normal. The gross structure is highly disorganized and thus much weaker. It is eventually replaced by concentrically organized lamellar bone with much lower proportions of osteocytes. The histology slide shown demonstrates woven bone arising directly from surrounding mesenchymal tissue.
Taenia solium, 1-10
1-3. Eggs and embryos of Taenia solium
4. Cysticercus cellulosae in the flesh
5. The same, six weeks after feeding a pig with Taenia solium
6. The same, in the retina of a human eye
Taenia mediocanellata, 11-16
Echinococcus scolicipariens, 17-19
On Animal and Vegetable Parasites of the Human Body. Translated by Edwin Lankester,1857.
And then there’s Loa Loa, who is much like guinea worm but has a nice affinity for your conjunctiva. Transmitted by a host of different fleas, people who experience Loa Loa come to the doctor complaining of seeing something move in their eye.
Dissection of neck next friday. I’m anxious…
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So we were studying the different ways our DNA can mutate and, pretty much, kill us. One of them is the ionizing rays (viz. X-rays, gamma-rays, cosmic rays) which induce big changes in our chromosome structure, including deletions, duplications, inversions and translocations of our DNA. Other of them, non-ionizing rays which is basically UV rays may not change that much our DNA, but it may be absorbed by many of our molecules on our DNA altering them.
What happens if son ionizing radiation comes and alters the DNA that produces the ATM protein? Well, we get Ataxia Telangiectasia. The Ataxia Telangiectasia Mutated (ATM) protein avoids, indeed, this disease. The gene located in the chromosome 11 in q23 produces ATM, which regulates many other proteins, which are pretty important for our body: protein p53, CHK2, H2AX which are tumor suppressors.
In overview, the absence or malfunctioning of ATM alters the normal apoptosis of cells, the normal mitotic division and the DNA repairs processes. Then, what happens next? Well, Ataxia Telangiectasia “attacks” primarly the cerebellum, making it smaller and thus reducing coordination of movements. That sign is called Ataxia. Then it goes to our vessels and makes them bigger, specially the ones in the whites of the eyes, cheeks and nose, this is called Telangiectasia, which isn’t dangerous at all, those vessels won’t hurt and won’t burst.
Besides from these: people with A-T may develop cancer and tumors pretty easily. That’s why they should never be exposed to x-rays, only if it is crucially needed. Pulmonary cancer or infections, lymphomas and leukemia are the mayor cause of death among the people with A-T.
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I’ve been thinking a lot about my medical specialty after the med school and this is one of the processes that move my inner self. I actually can’t lecture or hold a class about this right now! But it’s one of the topics that I’m widely exited about in my medical career.
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Duchenne Muscular Dystrophy
It has been a week since med-school began. First semester seems to be saturated with information of many classes, but in one of them, Biochemistry, we studied one interesting disease that’s related to the cell structure.
Duchenne Muscular Dystrophy (DMD) was the topic to study and then talk about in the classroom. It is an X-chromosome-recessive-related disease where a mutation in one of the genes (actually, the biggest one) causes our cells to stop producing dystrophin which has an important role in our body.
This protein, dystrophin, is the link between the cell’s cytoskeleton and the cell membrane (sarcolemma) in the muscle cells. It gives a strong structure in the cell to undergo the stress of movement.
What would happen if we don’t have it? The cell membrane loses stability and may leak it’s contents, or other fluids like water may enter and burst the mitochondria. In any of the cases, the muscle cell dies and is replaced with adipose cells or fiber cells, thus, removing the functionality of a muscle.
DMD is progressive. It gets worst every day. Since it is a X-recessive-related disease, women only carries the bad gene and men suffer the pathology. Children from 3 years old and on start to develop muscle weakness, they’ll show what’s called the “Gower’s sign”; later, from 6 to 7 years old the child will hardly walk, needing a chair-wheel sometimes, then, from 12 years and on will need it always and may encounter cardiovascular, respiratory and digestive problems because the muscles in those systems may stop working. No coughing, because of the weak diaphragm will cause a pneumonia; a weak heart may cause a mind’s activity loss, and finally, it is expected to live until the 20s.
Isn’t it amazing how a simple malfunction in the cell, the loss of a protein, causes all of that?
This did not sit well during lecture. This is a parasite, specifically a kind of intestinal helminth. You can get this parasite inside of you by ingesting contaminated foods laced with its eggs. The larvae hatch from the eggs in your small intestine and then proceed to enter your blood stream to reach the lungs, where they grow in the alveoli. When matured, they move up the bronchus, causing coughing and swallowing of the larvae where they eventually mature into adults in your large intestine.
The adults can get up to 20-30cm in length. For most people this infection is asymptomatic, but if there is large numbers of matured ascaris in your colon, you can get obstruction and that can get nasty really fast. Just imagine a plumbing pipe clogged with lots and lots of hair. With that last description and the above imagery, I may have ruined spaghetti for you forever.
Interesting. How come something can grow that big… and we don’t notice anything about it? Even parasites have evolved to success in survival. And a extra tip: avoid eating on poor hygienic places to avoid this kind of infection and parasites.
Flexor Withdrawl Reflex - classic example of a spinal reflex. what does that mean? your brain is not required for the body to sense injury and pull your hand away.
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