What A Difference The Sun Makes: The Views From My Windows On A Sunny Sunday

I woke up and the first thing I saw was the view above. What a treat! It makes one want to practically leap out of bed.


And then the sun started to set, at fourish:





Above: My roommate's dogs in the downstairs window.

This morning there was real sunshine that lasted all morning long, not just brief sunshine showers like the day before. What a difference! Everything sparkled and glowed. I've learned to appreciate the subtle beauty of the many shades of grey that Ithaca has to offer, but there's still nothing quite like blue skies and sparkling icicles first thing in the morning.

You might have observed that it isn't snowing in these pictures. I've noticed that it tends to be sunny right after a big snow storm. All the more reason to love snow in my opinion! It's beautiful, and it portends sunshine.

I'm behind in my studying, and studied out! Right now I'm going over a lecture we had on histoanatomy and function of skin as part of our week on inflammation (I don't really think it fit well anywhere in our curriculum-- one of the drawbacks of an integrated curriculum is it has to go somewhere since we have no separate histology course-- so since the skin has all kinds of inflammatory conditions associated with it they stuck it there but I somehow overlooked it. On the plus side, Dr. Scott was a fabulous lecturer who also clearly knew what he was talking about-- he listed in his references three books he authored-- Muller and Kirk's Small Animal Dermatology VI, Large Animal Dermatology and Equine Dermatology. I've gotten spoiled and have become accustomed to having the same people who wrote the books on the subject being my lecturers at Cornell).

There's just so much minutia that my brain can remember. For example, hair follicles come in two flavors, simple and compound. Simple hair follicles have one hair per pore/infundibulum and compound have multiple hairs per pore. Cats and dogs have compound hair follicles. Horses and cows have simple hair follicles. Sounds easy enough to remember if my brain weren't pretty chock full to start.

It just goes on and on... There are also two kinds of sweat glands. Epitrichial/apocrine sweat glands are found throughout haired skin and secrete epitricheal sweat, which has moisturizing, antimicrobial, excretory, pheromonal and thermoregulatory functions. The thermoregulatory function is most significant in horses and cattle. Anihidrosis (lack of sweat) is a major problem in horses. (The opposite, excessive sweating, is called hyperhidrosis as you might have guessed). According to wikipedia, horses are the only non-primates that have armpits that sweat like humans (now there's a good cocktail party pleaser).

The other kind of sweat glands are atrichial/eccrine sweat glands and they are only on the footpads of carnivores (including dogs, which are usually classified as omnivores).

People do not follow these rules. Although we have the highest density of epitrichial sweat glands on our hands and feet, they are also distributed all over the rest of our bodies (which is one big reason that we don't pant to cool down like dogs).

Back to the grindstone...

When I worked in emergency, one of my favorite doctors stated on her profile for the hospital's website that she chose emergency because she "doesn't do skin." I admit to having similar feelings to hers-- I don't enjoy dealing with skin problems. That said, here's a whole list of inflammatory skin conditions I should know at least a modicum about before my final on Thursday:

Pemphigus Foliaceus (one of three kinds of pemphigus): autoimmune disease-- antibodies attack the desmosome, resulting in keratinocyte cells becoming separated from each other (=acantholysis) and the epidermis falling apart

Vitiligo: antibodies target the melanocytes resulting in a loss of people; in people the antibodies are directed against tyrosinase but the target molecule is unknown in dogs

Bullous Pemphigoid -- antibodies target collagen XVII> basement membrane loses part of its adhering function, epithelium becomes necotic and dies, and in the words of Dr. Scott, 'the animal turns into a walking ulcer'

Epidermolysis Bullosa (there are several forms of this disease)--laminin genetically absent> poor epidermal/dermal adherence from birth> ulcers form at pressure points and in the oral cavity

Sebaceous Adenitis: sebaceous glands consumed by inflammation> no sebum (oily secretion) is produced> abnormal keratinization process occurs> skin becomes a scaly, waxy mess

Sterile Panniculitis: inflammatory condition of the subcutis (fat containing layer, most deep layer of the skin)

Miscellaneous--

Langerhans cells are dendritic cells found in the spinous layer of the epidermis-- they are the outpost of the cutaneous immune system and function as the critical antigen presenting cells in the epidermis

And the Word Of The Day is Striae (I swear, at least half of vet school early on is acquiring a whole new language-- medical vocabulary):
Striae are colloquially referred to as stretch marks and are areas of papery thin skin where the elastin has ruptured and the skin has pulled apart. Histologically there are no elastin fibers in that area. Besides pregnancy and weight gain, too many glucocorticoids can lead to the formation of striae because elastin fibers become abnormal due to the hormonal imbalance.