Heart Lab

This blog is to sum up the ECG lab. In this lab we measured our heartbeats. We were able to do this by hooking up electrodes to our arms and then connected by wires the electrical currents were able to be picked up. We measured several people and it was crazy to see how different all of them were. Jodi's was the highest of all of the graphs and I am not exactly sure why this was. Her R wave was definatly had the highest peak a long with the S wave having the highest dip. Then we also measured me and Nicks and ours were much different. Our heartbeats were very straight and did not have such extreme peaks and dips in the QRS complex unlike Jodi's. This could be because we were more relaxed or that it was low because we were in basketball and were in good condition. Whatever the case this blog showed the close up of these wiggly lines called the QRS complex.

At the finale of this lab we also got to play around with blood pressure while using interesting instruments. We used several different types of readers such as the normal velcrow and pump ones that are found in most doctors offices or the newer ones that are put around the wrist and automatically take the reading. From the lab I learned that is typical for women to have a slighty lower blood pressure for whatever reason that may be.

Nervous System

Pain,pleasure,being tickled is all apart of the wonderous nervous system. Laced through out the body the networks of cells communicate to stimulate muscles or glands to do various tasks. The nervous system is made mostly up of neural tissue but also has blood vessels and connective tissue. There are two different cells type: nerve cells and neuroglial cells. The Nerve cells are made to react to physical and or chemical changes to their surroundings. The communication of the cells is all started when the the small cells called dendrites receive the input and theen a longer process called a nerve fiber or axon carries the information away from the cell in the form of nerve impulses. When all the axons are bundled up this is what you call a nerve. Almost a coating over the Axon is what is called Myelin sheath which is a higher proportion lipid that contains a cytoplasm
Another important part of the nervous system are the small spaces between the neuron and the cell,which is called a synapse. Most of the job the nerouvs system has is to send and recieve messages between neurons and the other cells at the synapse. The conveyor belt of this whole nervous system is what you would call neurotransmitters. There are also organs in the nervous system that are split into two groups. One of the groups is called the central nervous system and it is made up of the brain and the spinal cord. THe other groups is called the peripheral nervous system and it is composed of nervous and is connected to the central nervous system. Sensory receptors gather information by detecting changes though out the body and also on the outside of it. They detect and monitor things like light,sound,remperature and oxygen concentration.Sensory receptors convert the information they recieve and then transmitt or send the information to the central nervous system. When they reach the CNS they come together to create sensations that help to produce thoughts.There are also motor functions of the nervous system and they are carried out by impulse carrying neurons that head to the central nervous system to help muscles contract in response to stimulation.

The diagram above shows the shape of the cell in simple form. As you can see the neuron is made up of dendrites on the edge that are almost tentacle like. Also you can see the axon that carries information to the axon endings. Lastly you see the myelin sheath that wraps around the axons almost like a bandage.

The next activity we did was we were assigned partners and had to put together a project on the nervous system. In our group we chose to go over how marijuana and alcohol effects the brain. From this assignment I learned many things including the part of the brain that is most effected by drugs and alcohol and how the brain is effected. I also learned about the short and long term effects of the two of those substances on the brain. Here is the link for the presentation that we did as a group.

Heart Anatomy

The heart is a major factor in circulating blood throughout the body and keep the body alive. The heart pumps around 7,000 liters though the body a day. Thats a huge amount for such a small organ. Around the heart there are vessels and viens that help with blood circulation, this system is called the cardiovascular system. There are two different circuits called the pulmonary and the systemic circuit. The pulmonary circuit is when the oxygen depleted blood is sent to the lungs to pick up oxygen and drop off carbon dioxide. The other circuit is called the systemic circuit and it is when oxygenated blood and nutrients are sent throughout the body cells and helps to remove wastes. The inside of the heart is divided into four chambers. The top chambers, the left and right atrium, have think walls that recieve blood returning to the heart. The lower chambers are the left and right ventricles and they force blood into the arteries.There are two septums in the heart called the interatrial septum and the interventrical septum. The interatrial septum seperates the left and right atrium and the interventricular septum seperates the two ventricles. The left and right atriums communicate to each other by a opening called the atrioventricular orifice and it is guarded by the av valve.
The right atrium recieves blood from two large veins called the superior,and inferior vena cava. The blood these veins return is low oxygen and from the tissues. As the blood travels through the heart it goes to the pulmonary trunk which is the only place for it to exit. While in the trunk it divides into either the left or right pulmonary arteries that eventually lead to the lungs. At the bottom of the trunk is the pulmonary valve. When the right ventricle contracts the valve opens and blood runs through. The left atrium receives the blood from for four pulmonary veins. Two are in each lung.

In class we had a lab when we disected a pig heart and viewed the different arteries and how they transported blood throughout the heart. From the lab I learned that the heart is a lot larger than I thought and is also much more complex than I gave it credit for. Down below are pictures of the disected pig heart.

Leach Lab Blog

During this lab we dissected a leach to test and observe the nervous system. The equipment for this lab were: Feather,Probe,Forceps,Scissors,Pins,Scalpel,Dissection Tray,Leech Tank,20% Ethanol Leech Tongs, Dissection Microscope,Micromanipulator,Oscilloscope, and finally of course the leech.
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. Individual cells can now be viewed under the microscope.

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.
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.
I showed the steps above just to show the exact steps I went through to complete the lab and see how the nervous system properly works. In this lab after taking all of the insides of the leech we found the central nervous system of the leech. Then we cut parts of the nervous system into pieces and tested them to see what kind of cells they are. At the end of the lab when you dye the cells and probe them to see what kind of cell in the nervous system you are testing. Certain cells did not stimulate when poked by the feather while others one were very stimulated by it. This Lab showed me how the different cells come together to form the nervous system. Also after doing this lab I got to see a new type of technology with the Oscilloscope. I have never even heard of the Oscilloscope but after using this lab I got to see what it can do. After taking the nervous system apart piece by piece I was able to see how amazing and mind blowing the nervous system is when it is all put together and functioning properly. Even though this lab was rather simple I believe I learned a lot about the nervous system.