Exercise essay

Exercise, its for everyone

There is very little controversy when it comes to exercise and whether doing more physical activity is better for you then doing less or even none. There is not one expert of group of experts who can argue that doing more physical activity to stay healthy is bad for you. So if everyone agrees on the simple fact that we as a obese nation need to engage ourselves in more physical activity to stay healthy, is there still an epidemic. In this essay I will attempt to identify some of the primary reasons and viewpoints for why this is and how some groups/countries are taking measures to make improvements.


After reading the informative article by three prominent doctors called “Modify the Environment to Reverse Obesity” the answer seems clear, we are a lazy nation. The problem is many of us are glad we are a lazy nation. As a culture we have worked long and hard over the years to get and maintain the lifestyles and amenities we have today which we enjoy. As Americans we wanted cheap quick food we could eat on the run when time was short. So we got fast food joints and made them our primary source of food because time is always short. We need to rent a movie tonight, instead of walking to the movie store we take our automobiles after all we work long hard hours to buy the cars we love. At the end of the day why go out and play basketball or go for a walk, the sports game is on and we just bought that big screen TV. Americans have worked hard at becoming the laziest nation in the world and many of us including myself to some degree are perfectly happy with our situation not realizing the long term implications this lifestyle will have.


The second major contributor to our obese nation besides are personal desire to sit around at work and home is the media. For this essay we will use the term media to include food marketing and advertisements as well. Every time you turn on the tv there are commercials for eating new fast food (which they claim is good for you) or the newest video game or move to watch. Even buying tickets for major sporting events which must of us like to watch in person decreases our health. I don’t know about you but when I go to a basketball game it is pizza a few beers and sitting for three hours, not very healthy but very entertaining. Not only does the media advertise the new great tasting hamburger or beer to adults but they also viciously peruse marketing ads at kids and young adults. How about the tobacco company which in the past has had advertisements in many magazines which kids like to read showing individuals which kids may idolize smoking cigarettes. Where are the advertisements for getting outside and doing something active with the community, not on television.


The third example I want to point out is like father like son (or mother/daughter), as adults and role models for our kids if we do not encourage and even participate in physical activates with our kids then what is there motivation get outside and exercise. If you were overweight and your kid or significant other asked you to go to the park with them and throw the ball, or go for a hike, when you say next time in favor of watching the game you are contributing to your own laziness and also showing bad habits to your kids. Maybe our youth should be the best motivation we have for staying healthy.


The Changes:
Many of the online articles and publications suggest one of the main organizations which could help to jump start our society back to a healthy one is the government. Since they have there hand in everything else maybe they should start making policies and legislation which promotes more active lifestyles. Such as when designing or zoning new areas for buildings, make a requirement for parks, bike lanes, etc. There were some good suggestions by James O. Hill and his colleagues which suggested mandatory time when during the working day for employees to walk or do something physical for 15-20 minutes a day on the company dime.
There are currently many communities and organizations around the world who are trying to promote more active and healthier lifestyles by setting up community programs and city policies which reflect the desire for change. Some city councils in Scotland are developing guidelines and programs to keep there youth and elderly being active as part of there daily routine with easy leisurely activities. On Camino Island in the greater Seattle WA area there is community program to help the elderly stay active. They have set up a safe walking program with 30 designated neighborhoods where the elderly can walk and be active in a safe comfortable environment.


Many of us individuals enjoying the good life may not even think we do enough to keep us healthy, but this may not be entirely true. There are numerous websites and information about activity pyramids. These pyramids provide guidelines on how much an individual should be exercising and how often. Some of these pyramids use different criteria as the baseline (age, weight) for recommending daily activates or physical exercising regimes to stay active. These physical activity pyramids can be a great tool for people looking to get started on the road to better health.


In conclusion there were many good points I learned doing research for this essay explaining why we have formed a lazy society, and many ways we can change our ways. One of the best statements from James O. Hill and his team of authors I think states it best, there is no one reason for our nation of laziness and there is no one solution to fix our problem. What we have has taken years to develop and probably twice as long to undo, but one thing is for certain, if you want to improve your health the easiest thing to do is go outside and take a walk.

Compendium Review Ch.13

Table of contents:
Central Nervous System (CNS)
Peripheral Nervous System (PNS)
Neuron
Axon
Myelin Sheath
Sensory neuron
Motor neuron
Resting potential
Action potential
Synapse


The central nervous system and the peripheral nervous system are a combination of two systems which together receive information from the body, take the data and integrate into the spin or brain for analyzing the data, and then provide output in the form of either organ reaction or muscle contraction.


Central Nervous System (CNS):

Spinal Cord: The spinal cord provides a connection between the brain and the peripheral nerves.

Brain: The brain is divided into two hemispheres with some connected tissues in between them. The brain is responsible for reasoning, memory, language, and speech, as well as all upper level cognitive processing. Each hemisphere has four lobes for brain functions, frontal, parietal, occipital, and temporal.

The Diencephalon: The important task of keeping the body regulated and maintaining homeostasis is controlled by the hypothalamus.

The Cerebellum: The cerebellum takes in information from the senses and cerebral cortex to determine the position of the bodies limbs. After processing the information the cerebellum sends signals to the skeletal system for movement.

The Brain Stem: The brain stems primary function is to use the medulla oblongata and regulate breathing and the heartbeat.


Peripheral Nervous System (PNS): The peripheral nervous system is responsible for taking impulses from nerves and transmitting them to the brain and spinal cord. The PNS is composed entirely of nerves and ganglia. The PNS is made of two other systems the somatic system and the autonomic system.

Somatic System: Consists of functions that we control consciously or can occur by natural reflex which we still have some cognitive control over. The somatic system consists of the skin, skeletal muscles and tendons which can be controlled by reflex (automatic) or voluntary where the brain process information in the cerebral cortex.

Autonomic System: This system consists of the functions which are involuntary and are done automatically by processing in the brain. These functions include the organs and there processes and are based on cellular processing and impulses. Breathing and the heart pumping blood are good examples of autonomic functions. Within this system there are two other division the sympathetic division which has body responses in times of stress and the parasympathetic division which has reactions in times of relaxation.


Neuron: Neurons provide the path for nerve impulses to travel threw the body to the spinal cord or brain. Neurons uses axon as the pathway for transmitting the nerve signal, and dendrites which receive signals from other neurons or sensory receptors.

Axon: The axon is the part of a neuron which the nerve impulse travels along. The axon can extend from the nerve or neuron the entire length of the body and connect to the spinal cord.
Myelin Sheath: Protects the axon by insulating portions of the axon. The Myelin also allows the nerve signal to travel along the axon quicker by jumping over portions of where the myelin sheath is covered.

Sensory neuron: Are neurons that develop as you are very young and will stay with you for your entire life. The sensory neuron is dedicated to receiving nerve signals and transmitting them to the spinal cord.

Motor neuron: Are dedicated to taking instructions from the brain and spinal cord to a muscle or limb allowing the muscle to contract and perform human functions.

Resting Potential : When the axon does not have a nerve signal traveling threw it there is a negative charge of -65 mV inside the axon. Inside the axon there is a greater concentration of potassium ions (k+) then outside. Outside the axon there is a greater concentration of sodium ions (Na-) then on the inside this creates a negative charge when no signal is traveling threw. The amount of sodium and potassium ions inside and outside of the axon is controlled by gates which allows one or the other of the two ions to move in an out (sodium-potassium pump). The membrane of the axon is also permeable to potassium ions allowing them to move easily back into the axon.

Action Potential: When a nerve signal is traveling threw an axon as it approaches then next portion of the axon the sodium-potassium pump activates and pushes out sodium ions and takes in potassium ions to have a net positive charge of +40 mV inside the axon membrane. This process allows the signal to travel along the axon at 1/1000 of a second. After the signal has passed through that portion of the axon it depolarizes and goes back to the resting potential. When we talk about the negative and positive charges of the axon there is no middle voltage potential either the axon is a resting or action potential. Depending on how strong the nerve impulse is will tell how many impulses travel in rapid succession (frequency).

Synapse: The synapse is the function which allows the signal from the sending neuron to transmit its data to the receiving neuron threw the synaptic cleft. This process uses synaptic vesicles to enclose the neurotransmitter cross the synaptic cleft and pass threw the receiving neurons neurotransmitter receptor.

Compendium Review Diagrams Ch.13

Muscle experiments lab

1. Placing my finger along my jaw line and then clenching my teeth. The jaw muscle seems to expand. Instead of the lower jaw muscle being smooth, there is a bulge in the skin under the ear where the jaw muscle expands out to the side of the jaw.


2. When the arm is extended fully the width of my thumb and finger fully stretched out goes from the elbow joint the full length of the upper bicep muscle. When I bend my arm so my hand comes back to my shoulder my finger and thumb get much closer to each other. The upper arm muscle is contracting and becoming smaller when my are is bent and then extending when my hand stretches back out to full length.


3. Using two strips of paper connected together I measured my bicep circumference. After clenching my fist the circumference of my arm muscles increase to ¾ inch longer then my arm muscles without a clenched fist.
Clenching the fist expands the upper arm muscles increasing there overall circumference.


Temp.
Normal 32 clenched fists in 20sec.
Cold water 41 clenched fists in 20sec.


Effect of Fatigue on Muscle action
Trial # of squeezes in 20 sec
1. 51
2. 45
3. 45
4. 37
5. 42
6. 38
7. 39
8. 37
9. 37
10. 37


1. What are the three changes you observed in a muscle while it is working (contracted)?
The three changes I observed is when I was flexing my upper arm bicep muscle was first the bicep brachii muscle contracted and became shorter as my forearm moved upward so my fist was close to my deltoid muscle. The bicep muscle gets shorter because the actin is moving across the myosin until the sarcomeres are fully contracted making the bicep muscle the shortest it can become.


The second thing I observed was the total circumference of my bicep brachii increased as I flexed the arm muscle. From my understanding of the contraction process as the thousands of sarcomeres start the process of contracting the actin begins to slide over the myosin. As this process happens it would make sense that the muscle would go from longer and thinner to shorter and bulkier. I think the increase in circumference is the result of thousands of sarcomeres fully compacted and slightly bulging then they were when the muscle was relaxed.


The third thing I observed is when I flex the bicep muscle as I bring the forearm up to meet my shoulder muscle the bicep muscle is not the only muscle at work. For every muscle I move or contract another one or more muscle are also moving with that muscle. When the bicep muscle is contracting and becoming shorter the triceps brachii is relaxed as possible to allow the opposite muscle to be as tight as possible. Its like that saying for every action there is an opposite reaction, it seems with muscles for everyone that does one thing there are multiple other muscles either doing the opposite or helping with the primary function (primary vs. synergist vs. antagonists).


2. What effect did the cold temperature have on the action of your hand muscles? Explain.
This little experiment was fun to try, at first I assumed I had done the experiment wrong because the results I got were different from what I expected. So I had my roommate try it and he got the same results. So I reviewed the chapter 12 material again and I think I now understand the results. From the data I collected you can see I was able to do more clenched fists after my hand was freezing cold from the water. I think there are a few primary reasons why this happened. One is homeostasis, when my hand was in the ice cold water the core temperature of my hand decreased the longer my hand was in the water. Since my body automatically wants to get that temperature back to where it should be my hand wants to do work. As the muscles in my hand use ATP to contract they are doing work, as the muscles do work they are producing heat as a by product of work. So as soon as I withdrew my hand from the water and started making fists I could go faster because my hand muscles were eager to start heating up and therefore getting that temperature back to normal. When people are in a very cold environment they start to shiver and naturally clench there fists and tighten up there muscles almost automatically. I think this helps explain the situation as we shiver are muscles are again contracting and trying to produce enough heat to raise the body temperature back up. I would guess if you were really cold you could do a few more pushups then if you were in a hot environment where the muscles said we are as hot as we want to be so they don’t want to do as much activity, they you have to start sweating the keep the temperature down.


3. Why at the cellular level would cold and fatigue affect muscular action?
Being in cold weather or under strenuous physical activity will cause a strong response from the nervous system and how your muscle will react. In cold conditions the body temperature will decrease as the environmental conditions your are in decreases. The body does not like this and will automatically want to raise the core body temperature back up to normal levels to maintain homeostasis. To accomplish this on the cellular level the cells will want to start using energy and doing work to produce body heat. An example of this could be shivering or tightening of muscles. The results from the cold water and fist experiment shows the body wanting to perform functions quickly which will help to raise the temperature. The more the cells in your body produce ATP for use by the muscle cells in contracting and relaxing the muscles of the body the more heat the body can produce. With physical activity the body is also going to experience some effects to the nervous and muscular system. When we start doing physical activity the body and respiratory system start working harder to get red blood cells and oxygen to the different muscles which need them most. If we are doing hard physical activity the body and cells may not be able to produce enough ATP for the muscle cells and oxygen for the regular cells to make the ATP, thus fatigue starts to set in. We have three main sources for the body to get energy and depending on what type of activity your body is used will determine which of the three sources you will use of first. If you are doing short bursts of activity the creatine phosphate pathway may be the first source of energy but once it is depleted fatigue will set in quickly. If you are a runner then your body will mostly run on cellular respiration especially if you have trained the body to build up excess stores of ATP and a larger production of cellular respiration. This source is a good steady supply and will take a long time to deplete. Fermentation is another source of energy for the muscles to use during activity. When I did the cloths pin experiment I was able to maintain and level number of reps even though my fingers were feeling the strain, this is because even though my finger muscles and forearm muscle were feeling fatigue at the cellular level only a certain percentage of muscle cells were fatigued. When we use are cellular muscles they do not all contract at once with every myofibril being used at the same time. Some are used for a certain period and then they rest and others take up the role, in this way your muscles will start to become fatigued but it’s the bodies way of saving some energy to keep up that movement as long as possible. This is a great evolutionary trait to have selective cellular muscles being worked and not all at once, allowing us to perform functions for extended periods before experiencing extreme muscle fatigue.

Movable Limb Lab

Introduction:
For this lab I wanted to make a three dimensional structure to represent the complexity of a moving limb. It was not an easy task to build a model with all the major characteristics of an actual moving limb. So for my model I chose to take the concepts and simplify them as much as possible so they can be represented visually. My goal was to have a moving limb model that actually looked similar to a human limb, this makes it easier for the imagination to see the more complex parts of the limb.


Limb parts:
Humerus bone = plastic piping
Radius and Ulna bone = plastic piping
Bicep brachii and tricep brachii = paint roller cover (red)
Bundle of muscle fibers with thousands of myofibril = weather proofing insulation (white)
Elbow joint = small metal hinge
Neuron with dendrites = kids squishy toy (purple and teal)
Sensory Neuron (purple)
Motor Neuron (teal)
Axon = copper wiring
Myelin sheath = yellow wire clamps
Large muscle cell (sarcolemma) = blue pencil tip eraser
T-tubules = circular pencil grips (green)
Calcium = small round wooden balls
Sarcomere with single actin-myosin unit = adjustable metal device
Myosin with double-stranded DNA = Dark teal and purple pencil grips


Here are the basic components I used to construct my movable limb. In this photo I have already cut the paint roller cover and started building the bicep and bundle of muscle fibers.

I used a dremel to seperate the paint roller cover, I did not relize the inside was a strong plastic which turned out to be much stronger then I originally thought.

This is a good photo of my basic arm and joint structure with the basic components labeled. This photo also shows the metal device which would later become the actin-myosin unit.

This photo shows the completed movable limb and all the major components. This is a good photo for me to explain how I decided to design my limb the way I did. You can see the adjustable metal connector right above the elbow joint which represents the a single sarcomere. When a human bicep muscle contracts its normally due to the forearm moving upwards, as in someone flexing there bicep with forearm at a 90 degree angle to the upper arm. This movement of the forearm upwards causes the sarcomeres in the bicep to contract. This is the type of movement I wanted to portray on my limb, in a human limb the contraction of all the myofibril would be in the bicep muscle and this is where a little imagination comes into play. I decided that setting up my limb the way I did would best show the mechanics of something which happens on the microscopic level. This photo also shows how the axon with the myelin sheath goes from one group of neurons (sensory in my model) in the forearm the entrie length of the arm and gives nerve signals to the other group of neurons (both motor and sensory in my model) at the upper arm.

In this photo I have a close up shot of the sensory and motor neurons and there associated axon. For simplification I have one axon with the myelin sheath representing the hundreds which would go from both the sensory and motor neurons. Here you can visualize the nerve signal traveling along the axon at almost a hundred miles per hour through the arm. The signal can travel extremely quickly becuase it jumps over the myelin sheath, this means only small portions of the axon need to be positevly charged by the use of the sodium-potassium pump at any one time. The part of the axon where the singal is passing threw will go from a resting potential with a negative charge (-65mV) to the action potential with a positive charge (+ 40mV) and then depolarization back to resting potential, this process occurs with the use of the sodium-potassium pump. This requires much less processing of energy then if the entire axon had to be charged at once. This signal will go all the way to the spinal cord and depending on the type of nerve signal up to the brain. In my model the nerve signal has gone to the spinal cord and a separate signal with direction on what the reaction should be has traveled back through the upper arm to the motor neuron (blue).

This photo shows the process which occurs after the motor neuron has received the signal with directions from the spinal cord. The signal goes to the bundle of muscle fibers also called sarcolemma (the white mass around the bone). There are thousands of these large muscle cells in the bicep and each one has sarcoplasmic reticulum, myofibril’s and T tubules. I have shown one muscle cell with the T tubules coming from the sarcoplasmic reticulum in the cell to the myofibril. When the muscle cell gets the signal from the motor neuron another signal is sent threw the T tubules to the sarcoplasmic reticulum where calcium deposits are released (wooden balls). When the calcium is released in to the myofibril the sarcomeres start the process of contracting the actin-myosin unit.

This is one of my favorite photos of the actin-myosin unit, as I said before a little imagination is used for this representation. First you can see the axon with the myelin sheath carrying signals right along the muscles. The main focus here is on the sarcomere. In my model the sarcomere is fully contracted. In the human muscle the myosin is the unit which does all the work or physical movements to contract the muscle. With the release of ATP from one of three different energy process (fermentation, cellular respiration or creatine phosphate) the myosin unit uses its hooks to move upwards and connect with the binding sites of the actin, this pulls the actin unit over myosin unit. When another ATP molecule attaches to the myosin the hook retracts and resets for the next pull. This function is very similar to the adjustable metal connector seen in the photo. The metal connector has circular grooves which when turned bring the inside portion closer together there by causing contraction. So the inside portion of the device is the myosin with the binding heads, and the outside is the actin where the calcium attaches and turns the double-stranded DNA pairs so the binding sites are ready for the ATP molecule. The actin is a double-stranded base pair which you can see represented.

This photo shows the details of the elbow joint and how it allows for movement up and down but very little flexibility from side to side (that is by a rotating joint in the upper arm) This joint also shows there is a limit to the flexibility in the downward vertical plain, most peoples arm will not extend much further past straight and level.

In this photo you can see where my model first gets the sensory signal, this could be from touch of the finger sending a nerve impulse to the sensory neuron or something brushing up against the skin where a nerve signal is sent to the dendrites and then transmitted through the axon.

Here is the final picture of my movable limb. In this one the limb is rotated on its side to get a detailed shot as if you were looking at a top view from above the arm. The axon extends the full length of the arm and is the connecting point which allows the transmission of all signals to and from every part of the body to the spinal cord first.

Conclusion:

I thought this lab was challenging and very helpful in developing a better understanding of the nervous system. To take the concepts in the book and try to combine them in a visual model is very tricky, but does help to bring a deeper understanding of complexity in your arm. I know there are parts of my model which do not show some of the process which occur in a human arm, but my goal was to capture the major functions and I think I did that. One of the most important functions I wanted to capture was the actin-myosin unit and I think I designed an arm which shows how this process works. Overall someone who did not have an strong background in human biology could view my model and the lab write up and begin to grasp the basic mechanics of what makes an arm move on the microscopic level.

Leech lab.

1. What is the electrode measuring?

The electrode is measuring the difference in electrical potential from the inside of the neuron and the outside. When the neuron is at rest its resting potential is at -65 millivolts, there are no ions moving threw the axon. When an ion signal is moving along the axon the action potential will cause the inside of the axon to have a + 45 millivolt electrical charge. The axon will go back to -65mV after depolarization to its resting potential with in 1/1000 of a second.

2. Why use leeches in neurophysiology experiments?

Leeches are chosen for biologists to measure the resting and action potential because there nervous system is easily accessible. The leech has 21 segmental ganglia and each is containing 175 pairs of neurons. With the leeches small size and large neurons they are the best subjects to use for neurobiologists.

3. What is the difference between a sensory and a motor neuron?

A sensory neuron takes a signal from a nerve in your body to the spinal cord and depending on the nerve impulse to the brain. When the spinal cord and brain receive the impulse from the sensory neurons the signal is processed and another signal is sent to the motor neuron which then activates a muscle for a reaction to the nerve stimuli this is called somatic reaction (you control what the body does).

4. Do you think a leech experiences pain? What is pain?

Yes, if the leech was alive as you were cutting it open I think it would. I have not done the research on the leech but if they respond to touch and stimuli then they have nerves that send signals to there brain threw sensory neurons. If there version of a central nervous system can respond to stimuli then it would make sense that pain would also be a function of the nerves.5. What were the two most interesting things about doing this lab?
I thought the lab was very interesting and the fact that to actually perform the lab you would need a variety of specialized equipment. I think that is the nice thing about doing online labs being able to see more in depth procedures which would be harder to do in real life. The second thing I found very interesting was the image you get when you ad the colored dye and use the UV switch. After viewing the atlas it was cool to see the different neurons you could identify.

6. Anything you found confusing or didn't like about the lab?

No!