Alzheimers

As a group, we recently created and presented a Prezi for the class.  The base of our project surrounded neurons and the brain and how that is related to alzheimers.  Our work can be seen here.  

http://prezi.com/ehnj2if1x4ud/alzhimers-cant-spell/

Neurophysiology Lab

Objective Record electrical activities of individual neurons while you deliver mechanical stimulus to the attached skin. Inject flurescent dyes into the neurons to visualize their morphology. Identify the neurons based on the morphology and the response to stimuli, comparing them to previously published results.

Equipment List
	Feather: Used to give the leech skin a very gentle touch stimulation. It really doesn't need to be a feather, it could be q-tips or something. Cost: free.
	Probe: A blunt metal rod attached to a wooden handle useful for lifting, pushing, pressing, moving of specimen. Here you use it to lift tissue, and to push the skin as a stimulus. Typical price: $1.00 ~ 10.00
	Forceps: Fine forceps for very fine manipulations. The very fine ones are known as Dumont #5 forceps, with tip size of about 0.1 mm X 0.06 mm or smaller. Typical price: $15.00 ~ 45.00
	Scissors: Good dissecting angled scissors used here to cut open the body wall. Teaching scissors are cheaper, but some ultra-fine dissecting scissors could cost upward of $400, and you better not drop that, because once you drop it, chances are, it's ruined. Typical price: $15.00 ~ 60.00
	Pins: Stainless steel dissecting pins for pinning tissue to a dissecting dish or board. You can drop these and not worry about it. $1.00
	Scalpel: For microsurgery, disposable scalpel blades are better and much more economical than the fixed blade scalpel which needs to be sharpened periodically. Blade: $0.50 Handle: $10.00 Used here to cut all kinds of things.
	Dissection Tray: A tray half-filled with hard wax so that you can stick pins into it to stabilize specimen for dissection.
	Leech Tank: Leeches are kept in pond-water (you can actually buy an instant pond-water mix to add to tap water.) If kept in a refrigerator, they can stay happy in it for weeks at a time without feeding.
	20% Ethanol: Used to anesthetize the leech. Besides being more humane, it has the added benefit that it stops them from moving, making it easier to pin down the leech.
	Leech Tongs: These are basically gross anatomy forceps with blunt tips so that you will not harm the leech as you pick it up. Maybe about $ 10.00
	Dissection Microscope: These are binocular microscopes specifically designed for dissection and other micromanipulations. Essentially, it's a high quality high power magnifying glass. The price varies on quality and if you've looked through binoculars of different quality, you can appreciate what a difference good optic makes. On a good one, you can clearly see individual cells in a leech's nervous system. Cost about $1,000.00 ~ $7,000.00
	Micromanipulator: A device used to position items with sub-micrometer precision in three dimensions. Here we mount our electrode on it to guide it accurately to a neuron. For work on a leech, a mechanical manipulator would suffice which is about $700.00. More accurate hydraulic or electronic ones may cost up to $10,000.00
	Oscilloscope: Basically a sophisticated voltmeter. What you see on the screen is a real time display of voltage (vertical) plotted against time (horizontal). Useful because voltmeters can't track rapidly changing voltages, and even if they could, you couldn't read anything. Cost $2,000.00 and up.
	Leech: Medicinal leeches are about $15.00 each. When fully extended, they can reach 15 to 20 cm long. When fully contracted, diameter is roughly 1 ~ 2 cm.

Procedure

Step 1

Catch and anesthetize the leech in 20% ethanol solution. Ethanol is not an anesthetic for vertebrate animals, but can be an effective anesthesia for small creatures that breathe through the skin like the leech. Like in many things, too high a concentration will be harmful or fatal. 

Step 2

Pin the animal dorsal side up through the anterior and posterior suckers onto a dissection tray, stretching the animal in the process.

Step 3

Using scissors, make a cut in the skin along the mid-line on the dorsal surface, taking care not to damage deep structures.


Using forceps, carefully tease apart the skin along the cut and pin down the left and right halves of the skin to each side, so that the leech is pinned open with the inside of the skin facing up. This exposes the innards of the leech, including the digestive, excretory and reproductive organs. You cannot see the nervous system yet, because they are located ventrally.

Step 4 Carefully remove the gut and other internal structures to expose the ventrally located nerve cord. The nervous system of the leech is encased within the ventral sinus, which is dark green in color. Step 5 Notice that there are many swellings up and down the sinus. These contain the segmental ganglia of the nervous system. To make one of them accessible, first we cut a window in the body wall underneath a ganglion, taking care not to damage the nerve cord or any attached nerves in the process.  Step 6 Isolate a section of the animal by making 2 parallel cuts across the animal (perpendicular to the anterior-posterior axis), but sufficently separated so that the strip you remove contains at least one ganglion. Then, with forceps, flip the piece of skin over so that the outer skin is now face up. Pin the skin down. If you don't know why you are doing this, go read the Why are we doing this? of Step 5 and come back.  Step 7 Cut the sinus with an ultra fine scalpel and using fine forceps, carefully tease apart the sinus to expose the ganglion In reality, you would only use the scalpel here only if you are extremely good at microdissection. It's very difficult to cut just the sinus without accidentally damaging the ganglion underneath, but hey, we are all perfect in cyberland. Normally, this is done with a pair of very fine forceps. Step 8 Now you've come to the crux of the matter. All the preparation so far has been to make this step possible. You might want to review Nervous System background or Electrical Equipment background at this point. Click on the electrode to gain control of it. Move the electrode to somewhere over the ganglion then click on the mouse button. This simulates the process of penetrating the cell, which is much more demanding in reality (see "What it's like in reality." for details). Keep your eyes glued to the oscilloscope display while you are doing this. If you find a cell, the display will change. If you see no change, then you have not found a cell. Keep moving your electrode around and clicking until you find a cell. The sound you hear is the oscilloscope display you are seeing fed into an audio amplifier. It provides an audio feedback to what you see on the screen. Now using a feather, probe or forceps, push around the skin of the animal. Observe if the cell you have penetrated responds to weak (feather), medium (probe), strong (forceps) or any stimulus. Note the pattern of response. The cell may fire action potentials or spikes. The response characteristics will be used when you are comparing your data with published data compiled in the atlas. When you are satisfied with the electrophysiology, you can start the anatomical investigation by injecting the cell with a fluorescent dye. Push the button labeled "Dye Injection."  Step 9 Next, we will visualize the morphology of the neuron from which you have just recorded using a fluorescent dye. Having pushed the button labeled "Dye Injection," the amplifier system has passed an electric current from the electrode that resulted in the ejection of Lucifer Yellow from the tip of the electrode into the intracellular space. Lucifer Yellow will passively spread throughout the cell after a while. Now you can turn on ultraviolet (UV) light by pushing "UV Switch.". Lucifer Yellow fluoresces bright yellow-green under UV and you will be able to visualize the cell in question, including its axon, dendrites, cell body and so on. Step 10 You now have electrophysiological data and neuroanatomical data from your experiment. Try to identify the cell based on published data (Atlas)There are many cells in different locations of this ganglion. Repeat the whole procedure for as many cells as you would like. Go to the Atlas page to identify the cell.  Results Review Really, I thought this was a nice way to perform a dissection based lab.  I don't have serious issues with dissections but it's always been rather unsettling, cutting up and poking around in dead things.  It was nice going step by step with the computer so as not to forget anything,  which we seem to do rather often in real labs.  It was also nice to have explanations as to what exactly each step meant and what we were supposed to be getting out of it.  I didn't do extremely well at the quiz section at the end mainly because my computer refused to give me proper options....still unsure as to why this happened.

Neuromuscular junction

The neuromuscular junction is the site where an axon and a muscle fiber meet.  Nic, Brianna, Katy, Gena and myself, created this video to demonstrate the function of the junction, haha that rhymed!  To be perfectly honest it's not my favorite project, I feel we fell a little short on what we had in mind.  We had several ideas at the beginning of the project but not all of them translated very well to film.  We ended up with a simple drawing film.  Unfortunately, our editing program also fell a little flat and not everything we wanted, effects wise, was able to be produced.  However, I think our group is now quite able to tell you exactly what the neuromuscular junction is and what it looks like.  Here's a link to our work.  

http://www.youtube.com/watch?v=Spj60iQ_qjc&feature=youtu.be

I would also like to give props to Nic Libby for being so persistant with youtube!  Couldn't have done it without him!

Vertebrae Site

My mother recently came across a rather interesting site a few weeks ago that had been sent to her by a friend.  The site mainly goes into depth about the chiropractic side of things, but I found it rather interesting how each of the vertebrae in our spine effects a certain part of our body.  This may mean organs, or just certain areas.  This makes sense then, why, massage therapy, acupuncture, and chiropractic sessions can effect our movement and mood so much.  These alternative medicines, as they're classified, are really quite important to keeping our bodies happy, and healthy.  According to this site, effecting a certain vertebrae, could help with problems occurring in other places of the body.  The chart is helpful in guiding you through and matching your aches and pains to certain vertebrae in the spine.  It was convenient that my mum came across it just as we were exploring and memorizing the skeletal system.  It's really quite interesting, take a look!  http://www.chiroone.net/why_chiropractic/index.html

Chewin' chewin' all day long chewin' chewin' chewin'

The lab we performed in class was quite tasty...or interesting, interesting yes.  We tested the amount of energy/power it takes the jaw to consume a variety of foods.  We did this by attaching several sensory cords or electrode tabs to our very cooperative test subject, Seth.  These cords ran to a probe of sorts that was connected to our lap top that recorded the energy being used.  Before we began testing we created a hypothesis.  Our hypothesis stated that we believed it would take more jaw power to chew harder foods than it would softer foods.  After we made our prediction we began the test.  Our test subject started with a softer food, a banana.  The computer recorded the results.  He then consumed a carrot, celery, gatorade, a marshmallow, and finally a pop tart.  After collecting the data we concluded that our hypothesis was actually incorrect.  The graph below shows that foods like the banana actually generated more energy when being eaten.  I personally find this rather strange that the softer the food the more energy created.  

Skeletal System

(not anatomically correct)

      Bones, obviously, are the body's framework and support system.  They provide a "case" for the organs of the body, allow movement with muscles, store essential minerals, and allow blood cell formation. Though bones are often thought of as perfectly smooth rounded pieces they're really not.  There are various bulges, depressions, and holes that allow muscles and tendons to attach and join.

        Bones and cartilage are everywhere in the body.  There are three types of cartilage Hyaline, Elastic, and Fibrocartilage.  Hyaline cartilage is biggest portion of of skeletal cartilage.  It not only supports but is  resilient and flexible.  It can also be seen in articular, costal, respiratory, and nasal cartilage.  Elastic cartilage is quite similar to hyaline but is seen more in the epiglottis and ear areas.  Finally Fibrocartilage, this cartilage contains collagen fibers and is thus one of the strongest types of cartilage.  This type of cartilage is found in the knee as well as the intervertebral discs.  In order to create cartilage it must go through 3 phases, Appositional, Interstitial, and calcification.

             The bones of the body are classified into many sections.  Axial are the bones of the skull, vertebra, and ribs.  Appendicular, like the name implies, make up the appendages-arms and legs.  They are then classified by shape.  Long Bones are obviously longer than they are wide.  There are then short bones that can be cube shaped these can be found in the wrist and ankle areas.  Flat Bones are tin and...flat, and occasionally curved.  Lastly Irregular bones, which are basically everything that can't fit into any of the other categories.  These bones are oddly shaped and complicated.  

        There are many, many markings on the the bones which include: Tuberosity which is a rounded projection, Crest a narrow ridge of bone, Trochanter a large blunt irregular surface, and Line a ridge of bone.  Tubercle is a small rounded area, Epicondyle is the raised area above the condyle, a Spine is a sharp area, and Process is obvious prominence.  The Head is a bony expansion carried on a narrow neck, a Facet is a smooth flat area, a Condyle is a rounded projection, a Ramus is an arm like bar of bone.  The Meatus is a canal, Sinus is a basic cavity, Fossa is a basin like depression, a Groove is a furrow, a Fissure is narrow slit, and the Foramen is a round opening in bone.

               Bones are also classified with textures such as compact bone which is the dense outer layer, and spongy bone which is honeycomb like.  Bones are then classified into structures such as long bones that consist of diaphysis and an epiphysis, diaphysis is a shaft that forms the axis of bones.  Epiphyses are the expansions of long bones the inside is spongy and the joint surface is covered with articular cartilage.  The epiphyseal line separates these two sections.  The structure of short, flat, and irregular bones is, on the other hand, quite different.  They are thin sections of periosteum covered in compact bone on the outer section with endosteum, on the opposite side is spongey bone.  These bones do not have diaphysis or epiphyses and contain marrow between the trabeculae.  The microscopic strucure of the compact bone is the aversion system or the structural unit.  The Lamella is the weight bearing column, and the Haversian is the central canal that contains blood vessels and nerves.  Volkmann's canal are channels lying at right angles to the central canal connecting blood and nerve supply.  Osteocytes are mature bone cells and Launae are tiny cavities that hold the osteocytes.  And Canaliculi are hairlike canals that connect lacunae to the central canal.  Hydroxyapatites are mineral salts that make up more than half of the bone mass.  Since it's a salt it's mainly calcium phosphates which is thus responsible for the hardness of bones.  

          Bone development begins in embryos and doesn't stop until early adulthood, the process of of bone formation is called Osteogensis and Ossification.  Ossification forms most flat bones, the skull and clavicles.  This process is located mainly in the center of the fibrous connective tissues membranes.  The bone matrix is set within the fibrous membrane.  The woven bone and periosteum forms and the collar bone of compact bone forms and red marrow appears. Long bone's growth zone is when the cartilage cells undergo mitosis this results in the separation of epiphysis and diaphysis.  It then undergoes the transformation where old cells enlarge and the matrix becomes calcified.  The Cartilage cells then die and the matrix begins to deteriorate.  The Osteogenic zone is when new bone forms after the deterioration of the matrix.  Bone growth is most active during youth and adolescence.  The epiphyseal plate or growth plate is quite active.  When the person is fully grown the growth plate closes, or seals.


Spiral Fracture

           Obviously the stress we put our bodies under is tremendous.  Our bones are put to the test on a daily basis, some far more than others.  Which is why our bones simply give out under such stress.  Breaking bones isn't uncommon and they come in a whole array of forms.  Breaks can range anywhere from a tiny, but still painful, hairline fracture, to a compound fracture, which is most severe...and revolting.  Bone breaks are classified by the position of the bone after break, the completeness of the break, the orientation of the bone in comparison to the long axis, and if the bone penetrates the skin (compound).  Within these classifications there are more condensed classifications as to what type of break it is.  For example there is displaced and non-displaced also known as a dislocation, where the bone slips out of its typical position.  Complete and incomplete where the bone is either broken all the way through or not.  Linear where the bone breaks parallel to the axis of the bone, and Transverse where it is perpendicular to the axis.  Compound fractures penetrate the skin and Simple does not.  Typical types of fractures are Comminuted where the bone breaks into several pieces, ew!  A spiral fracture where it twists throughout the bone.  My dance teacher suffered this type of fracture just before she was to go to London to dance with the Royal Danish Ballet,  it's tragic, I don't know how she could have taken it so well, her career as a dancer slipping away so quickly...Anywho,  Depressed fractures are sections where the bone is pressed inward.  A compression is where the bone is entirely crushed, again ew!  Epiphyseal is where the epiphysis seperates from the diaphysis.  Greenstick is a partial break where the bone breaks some of the way through but not all the way, these are particularly common in children because their bone are so pliable.  A bone heals itself by first forming hematoma at the break this causes swelling.  Fibrocartilaginous then begins forming then granulation tissue forms finally capillaries begin to grow through again phagocytic cells begin cleaning.  All of this is typically done while the bone is supported/structured by a cast or splint of some sort in order the help the bone heal properly.

         Bone breakage is caused not only by serious amounts of force are placed on the bone but also an inadequate diet causing weakness in bones, this is called Osteomalacia.  Rickets are deformations in the bones, commonly seen in children.  Osteoporosis is when the bones become incredibly fragile and brittle.  This is caused when bone reabsorbing outpaces bone deposit.  Osteoporosis is most commonly seen in postmenopausal women.
       Bones can also believe it or not, bruise.  Bruising is caused similar to breaking where a huge amount of force is placed on a certain area.  Bruising typically occurs withing the marrow or withing the structures of the joints.  Several years ago when I was still competing in gymnastics I was warming up as I did every day.  We were going back and forth across the floor.  Our last warm up before we went to our events was a simple round-off, back handspring, back tuck.  When I came down out of my tuck I landed a bit funny, like I rolled out of it on my heels.  I felt an immediate sharp pain.  I have a fairly high tolerance for pain so I thought I would be able to just walk it off.  I tried rolling my ankle, thinking that maybe I just needed to pop it.  When I tried walking again the pain persisted.  I didn't want to be hurt I wanted to keep working out, but the pain in my heel was persistent.  So I was forced to condition on bars for the rest of the night.  I went home and lazed about.  When I needed to get up I forgot about my foot and tried bounding off of the couch, not my best idea, the sharp pain pierced through my heel again.  I lay on the floor a moment holding my foot, this is so stupid I thought.  Before too long I was taken to the doctor's office to have it looked at.  After quite a bit squeezing and poking and a couple of X-Rays the doctors concluded that I had damaged my growth plate.  They were unsure of what exactly I had done because the pain seemed to be right on my growth plates; and growth plates, until they are sealed, cannot be seen on an X-Ray.  It was most likely that I had either bruised it or received a hair line fracture.  They ended up suiting me up with a clunky boot for the next 3 weeks, not what I wanted.  After some of the injuries I've seen however, I should consider myself lucky.  I thought about adding a video here but then I thought, breaking bones is rather horrific, and I really have no intention of screening videos of people breaking themselves.  So I'm going to leave it up to you, the reader, to explore the world of these graphic examples on your own time. 

Integumentary System

         The integumentary system is the makeup of the skin, which is in fact the body's largest organ.  There are three layers of the skin consist of the epidermis, dermis, and hypodermis.  The epidermis is the outermost layer that acts as a barrier and thus protection, it is actually made up of many layers of dead skin cells, kinda nasty! There are four or five distinct cells types that lie in this layer. These cell types are keratinocytes, meloncytes, merkel, and langerhans.  Keratinocytes produce the protein keratin.  Meloncytes produce the brown pigment melanin.  Langerhans help with the immune system and Merkel are associated with sensory  nerve endings.  The deepest layer of the Epidermis layer consists of one row of keratinocytes.  The layers of the Epidermis layer are Stratum Spinosum, Stratum Granulosum, Stratum Lucidum, Stratum Corneum-this is the outermost layer that protects from moisture and the basic environment effects.    

          Beneath this layer is the Dermis layer.  This layer is a strong flexible layer made up of connective tissue.  The Dermis is only made up of two layers versus the four of the epidermis, these layers are papillary and reticular.  Within these layers are cells such as fibroblasts, macrophages, and occasionally white blood cells.  The reticular layer of the Dermis makes up nearly 80% of the skin's thickness!  Since it is so thick it acts as a strong barrier of the skin that can stretch and recoil.  The papillary layer is also quite elastic.    

          Finally below this is the hypodermis layer, the deepest of the layers in the skin.  Within this layers is adipose and areolar connective tissue.  

          Skin Color is effected by three basic pigments.  Melanin is the reddish brown/black color which is seen in most darker skin colors.  However, it can also be seen in freckles and moles where there is a build up of melanin.  The pinkish orange color on palms and feet are from the pigment found in Carotene.  Blushing or flushing, usually seen in our faces from working hard or emotions is caused from Hemoglobin, a pinkish red pigment.
          Sweat glands are found all over the body, from head to toe, literally.  The glands found in the palms, feet and forehead are all eccrine sweat glands.  Cerimonious glands are found in the ear and secrete cerumen. Apocrine glands are found in the axillary and anogenital areas.  And finally the Mammary glands, that as the name suggests, secrete milk.  These four types of glands all help with keeping the body from overheating.  Sebaceous glands are found all over the body and control sebum, an oily secretion.  These glands just like many of the others can become clogged and result in a rather nasty cyst if not taken care of.  Skin changes as a human grows.  During teen years sweat glands often over work and result in excess oil in the skin thus creating acne.  As the become elderly these glands slow, often too much, and result in scaly rough skin.

Melanoma.  EW!

           Now let's take it into cancers of the skin.  There are three major types of skin cancer Basal cell carcinoma, Squamous cell carcinoma, and Melanoma.  Basal is the most common of these three types.  This type of cancer takes over the dermis and hypodermic layers.  However, since it's slow growing and doesn't metastasize (spread) it can be cured quite easily with surgery.  Squamous cell carcinoma comes from keratinocytes of stratum spinosum.  It is found in the ears, around the mouth, and scalp.  This cancer unlike Basal grows very quickly and spreads if not taken care of.  This can be taken care of surgericaly or through radiation therapy.  Finally, there is Melanoma, the most serious and dangerous type of skin cancers.  Melanomas can be distinguished by their color, size, texture, and shape.  This type of cancer is highly metastatic and is resistant to chemotherapy.  There are some treatments that involve surgery and immunotherapy however, the chance of survival is low, especially depending on the size.
          Not only must the skin protect the body from the environment and face the possibility of cancer it must also take on the idea of burns.  Burns range in degree from 1-3.  Most everyone has endured a first degree burn that only damages the epidermis.  In second degree burns the epidermis and small portions of the dermis are damaged.  Third degree however, is where it gets nasty.  The entire thickness of the skin is damaged.  The skin is basically destroyed and takes ages to restore itself.  In third degree burns infection is the most important thing to worry about.

        Hair on the body is similar to much of the skin, in the since that, it's dead.  Hair is actually dead strands of keratinized cells produced by hair follicles.  Hair follicles project from an embedded root in the skin.  The center of the root is called the medulla, then the cortex and finally the outermost cuticle.  Hair is naturally colored at the bottom by melanocytes.  Hair helps with warmth as well as protection from environmental effects like sunlight, heat loss, insects etc.   And lets face it, hair is very important in physical appearance!  Which is why balding, or Alopecia is rather sad.  It is natural however, for human's  hair to become thin and fall out as they become elderly.
          The Integumentary system is obviously a huge part of the human body.  It protects against the harmful rays of the sun, fights against infection, helps regulate temperature, and really, holds us all together.  Keep it healthy!