Anatomy Lab
Abinaya Helbig
TPJ 3M0
Ms. Tran
04/22/2011
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1. The human body is composed of three types of muscles,
skeletal muscle, cardiac muscle and the smooth muscle. Skeletal
muscles are muscle fibers that attach to the human body’s
skeleton and it helps to form a smoother body contour. This type
of muscle is mostly attached to bones or to skin on face and it is
composed of single cells that are very long, cylindrical in shape
and striated. Also the skeletal muscle cells are multinucleated
and have a pink colour and the skeletal muscle itself is dense and
smooth. According to this lab, it is apparent that the chicken leg
is composed of 80% of skeletal muscles (see Figure 1). The
contraction of skeletal muscles, which interact with bones, cause
voluntary movement, which means that we can control the
muscles and its movements consciously. Basically, the skeletal
muscles connect 2 bones across its joint. So, when the skeletal
Figure 1: Skeletal Muscles of a Chicken muscles are contracted or shortened the bones start moving.
Leg
Ligaments are connective tissues that are fibrous (composed of collagen fiber strands) and
connect one bone to another in the human body, creating a joint. The ligaments are located in
between joints. For example, the ligaments for the chicken leg are found in between the patella
joint. In terms, of appearance and texture, ligaments are smooth, white, and slightly stretchy. Just
as the skeletal muscle is important for producing movement so are the ligaments, because
ligaments prevent dislocation and bending of joints and control joint movements, which are vital
for producing a movement. So it can be said that, while producing movement both the skeletal
muscle and the ligaments work together. In general terms, the skeletal muscles serve as the
production and control unit of movements and the ligaments act as security guards, where they
ensure that joints are held in place to avoid any injuries. Also the ligaments prevent friction
between bones and withstand pressure to avoid any harm to the bones using the feature of
elasticity.
2. Hypertrophy and atrophy are medical terminologies associated with the decrease and increase
of mass of an organ or tissue. Hypertrophy, a term derived from a Greek word which meant
“excess nourishment”, is a medical condition where there is an enlargement/ overgrowth of a
body part/ organ in terms of size and mass. This
condition is caused by the increased size of the cells
that belong to a specific body part that is affected.
Hypertrophy is often confused with hyperplasia;
however hypertrophy is different from hyperplasia,
because hyperplasia is the increase of the quantity of
cells (see Figure 2). There are 3 most common
hypertrophy examples: Muscle hypertrophy,
Ventricular hypertrophy (Athletic heart syndrome),
Gigantomastia. Muscle hypertrophy is the most
common type of hypertrophy, which is very
prominent for athletes, body builders ad
weightlifters. Individuals with hypertrophy have
visibly large muscles which are developed/
Figure 2: Normal Cells vs. Hypertrophic Cells
vs. Hyperplasia Cells
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maintained through daily intense work-out. Hypertrophy also applied in various other aspects,
for example it is applied to the enlargement of the uterus which supports birth during pregnancy.
While hypertrophy is the increase of cell size within an organ or tissue, which enlarges the organ
or tissue, atrophy is basically the opposite of hypertrophy.
Figure 3: Normal biceps brachii muscle vs.
Atrophic brachii muscle
Atrophy, a medical terminology which is often referred
to as “wasting”, is the degeneration or decrease of
partial/ entire body parts or tissues causing decreased
muscle strength (see Figure 3). This term is derived from
a Greek word which meant “nourishment shortage”. This
condition has the capability of affecting any part of the
body and can affect more than one area of the body all at
once. The cause for this disfunction are the lack of
nourishment, disease, disuse, mutation, obstructed blood
circulation, lack of physical movement, and obstructed
nerve connection. There are many examples associated
with atrophy, for example atrophy of muscles and nerves
are some of common examples of atrophy. Optical
atrophy is a common nerve related type of atrophy,
where the atrophy of the optic nerve nearly diminishes an
individual’s vision.
3. Isotonic and isometric exercises are two different
types of contractions. Isotonic movement is most
commonly used and everyone is aware of this type
of exercise. It is basically where a muscle is
narrowed down or shortened and the body part it is
attached to moves as well (see Figure 4). In other
words, the particular muscle is contracted while
movement is present. There various exercises that
are isotonic, which include: swinging a bat,
throwing a ball, lifting a weight, bicep curl, pushups, crunches, walking and many other activities.
The biological process behind this exercise is Figure 4: Isotonic Contraction vs. Isometric Contraction
simple to understand but is very beneficial for
toning muscles and weight balance. Toning muscles is mostly stimulated by isotonic exercises,
because this type of exercise causes muscle stress and strains, which in return leads to division of
muscle cells or enlargement of muscle cells to heal the weakened muscles due to strains and
stress. This return has a benefiting reaction effect, where muscle size and strength increases.
Also, isotonic exercises are more forceful, which is more ideal for the heart and ideal for burning
off calories present near muscle which give off a more toned look on the muscles.
Isometric movement greatly contrasts the isotonic movement’s features, because it lacks
movement. Isometric exercises are basically motionless or static exercises, where the joint and
the muscles do not move, but the muscles contract (see Figure 3). In other words, there is no
movement present, because the weight on the muscle increases the tension produced by the
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muscle that is being contracted. This happens when a muscle pushes or pulls a fixed/ immovable
object. There many types of isometric exercises, such as wall squat, plank, standing calf stretch,
standing hamstring stretch, and many more. This type of exercise helps toning the muscles by
straining he muscles. The principle of the biological process behind this type of movement is the
same as the one for isotonic exercise, except that bone joints are not strengthened. Besides toning
muscles, there are many other benefits, such as strengthening and working out muscle fibers
which would be inactive if not for isometric contraction. It also helps toning and building
muscles in a short amount of time and are more convenient.
4. Workplace injuries are very common and are caused by the simplest mistakes by workers. The
most common workplace injury is caused by lifting heavy objects in a harmless manner, which
can eventually cause harm to the back muscle and other physical damages. Usually people bend
down and attempt to lift the heavy object keeping it away from their body, this can cause severe
back pain and muscle tears. In this case, lifting posture must be paid attention to. So, instead of
just bending over to lift an object, which puts a lot of pressure on the back, one should do the
following: First, the worker should relax and take a deep breath and then stand directly in front
of an object to provide good balance. Then the worker should keep his/her balance in the center
of their body before lifting anything. It is very important that the feet are at equal distance from
his/ her center of gravity, because ignorance towards centre of gravity can lead to injuries to the
muscle of the pelvis and can cause sprains. Then he/she should use the handles of the item (if
there are any) when lifting. The worker should not carry items/ objects that will interrupt his/ her
line of field of view, so instead he/ she should always carry items below their lifting capacity.
Before lifting the objects, the worker should tighten
up his/ her abdominal muscles (rectus abdominis)
because it provides the worker with more stability and
strength. As mentioned before, it is very common for
people to bend over to lift an object, but this should be
avoided. Instead, the worker should bend the knees
and bring his/ her legs into a squatting position (see
Figure 5). This squatting position serves as the sold
base to the spine and back and it also keeps the back
vertical at 90 degrees. The squatting position greatly
contrasts the bending over motion, because it mostly
uses the muscles of the legs, whereas the bending over
Figure 5: Lifting Heavy Objects Properly
motion tremendously uses the back muscles. Then, the
worker should tightly and firmly hold the object with both hands, maintaining balance. The
worker then should start lifting the object using the strength of his/her legs but in the meantime
maintaining balance by distributing the weight of the object evenly. Finally, once the worker has
lifted the object he/she should maintain balance and keep the object close to the body at all times
because this will create resistance for any uncontrolled motions. Also, the worker must breath
constantly in order to provide oxygen for the muscles. While lifting, the worker must ensure to
slowly stand up and not to be jerking. Evidently, the most important tip for harmlessly lifting up
a heavy object is by squatting your leg and not by bending over the object, and also by keeping
the object as close to the body as possible.
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5. Not everyone notices this, but usually professional baseball pitchers’ one arm’s muscle is
more worked out/ toned than the muscle of the other arm, due to the frequent use of one arm and
the frequent repetition of pitching with one specific arm, depending on the player’s/ pitcher’s
preferences. Pitching a baseball involves four basic stages: a. wind up, b. cocking, c.
acceleration, d. deceleration (see Figure 6). First, the pitcher gets ready to pitch the baseball by
standing in a wind up position. Then
the arms are pulled towards the body
and the arm holding the baseball is bent
in a way that the biceps are contracted
and the point of insertion and the point
of origin come closer together. The
second phase of the pitch includes
cocking which basically requires the
pitcher to aim for a direction for the
baseball to go in. This position also
Figure 6: This image shows the 4 phases of throwing a baseball.
requires the pitcher to have the arm with
the baseball vertically behind the head. This positioning of the arm behind the head, contracts the
triceps whereas the biceps are relaxed. The transformation from the wind up position to the
cocking position requires the rotation of the pelvis girdle. The next two positions are acceleration
and deceleration, which basically require the pitcher to do a flexion of the arm from an
extension, where the insertion point and the origin point come closer together and the triceps
relax and the biceps contract. When the ball is thrown, the biceps go through extension and the
triceps are then contracted. These four phases contain a lot of relaxation, contraction, stretching,
flexion and extension, and the frequent repetition of these phases put enough stress on one arm’s
muscles for it to become worked out and toned. Depending on the pitcher’s arm preference, that
one arm will be more muscular due to the increased usage of the arm for pitching which works
the muscles. Therefore, the arm that is not used for pitching will be apparently weaker and frail
than the pitching hand.
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Work Cited
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http://www.wisegeek.com/what-is-hypertrophy.htm
Esme, H. (2007). What Is Atrophy?. wiseGEEK. Retrieved April 22, 2011, from
http://www.wisegeek.com/what-is-atrophy.htm
Esme, H. (2007). What are Ligaments? . wiseGEEK. Retrieved April 22, 2011, from
http://www.wisegeek.com/what-are-ligaments.htm
Fier, J. (2009). Isometric vs. Isotonic Exercises . Be Healthy and Relax. Retrieved April 22,
2011, from
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www.medterms.com/script/main/art.asp?articlekey=25464
Isometric-Isotonic Contractions. (2004). Animal Kingdom Workouts . Retrieved April 22, 2011,
from
http://www.animal-kingdom-workouts.com/isometric-isotonic.html
Skeletal Muscles . (n.d.). ThinkQuest. Retrieved April 22, 2011, from
http://library.thinkquest.org/5777/mus3.htm