이번 해부 실험은 나에게 있어 매우 중요한 수업이였다.
내가 수의학을 전공하겠다는 결심을 갖게한 계기가 된 수업이였다.
This dissection experiment was a very important lesson for me.
It was a lesson that made me decide to major in veterinary medicine.
Animal
Anatomy & Physiology Dissections
Purpose:
I perform a
dissection to analyze the relationships between the respiratory, circulatory,
and digestive systems. As well, to learn the anatomy and importance of the 3
systems.
Dissection Pre-Lab
1. Classify the pig and the human for all levels of taxonomy from
Kingdom to Genus.
Domestic Pig(1)
· Domain: Eukarya
· Kingdom: Animalia
· Phylum: Chordata
· Class: Mammalia
· Order: Artiodactyla
· Family: Suidae
· Genus: Sus
· Species: S. scrofa
|
Human(2)
· Domain: Eukarya
· Kingdom: Animalia
· Phylum: Chordata
· Class: Mammalia
· Order: Primates
· Family: Hominidae
· Genus: Homo
· Species: sapiens
|
2. Identify the classifications that humans and pigs have in common & explain what the classification is indicating about the kingdom.
The
classifications that domestic pigs and humans both have in common are the
kingdom (Animalia), phylum (Chordata), and class (Mammalia). Chordata is a
phylum in the kingdom Animalia that include the vertebrates and the few closely
related invertebrates. Animals in the phylum Chordata share four key features
that appear at some stage during their development: a notochord, dorsal hollow
nerve cord, pharyngeal slits, and the post-anal tail. Some of these are present
only during embryonic development(3)(4). In addition, pigs and humans are both in
the class Mammalia. Mammals (belong to class Mammalia) are vertebrate animals
which feed their young on milk produced by the mammary glands and all have hair
at some point in their lives, even if they have only a few. Also, they are
generally endothermic(5). The more similarities two species share a
classification, they are genetically closer.
3. Compare the
classifications that are different for humans and pigs and explain what the classifications are indicating about the organisms.
The humans and
the pigs have different classifications of order, family, genus, and species.
Even though humans and domestic pigs belong to the same kingdom, phylum, and class
differences in the other classifications made differences in their phenotype
and genotype. For example, the order primates where humans belong, when
compared to body weight, their brain is larger than that of other terrestrial
mammals(6). However, animals in Artiodactyla such as
pigs, camels, cows, deer, and etc. instead of having a bigger brain, they have
other advantages so that they can well adapt to the grassland environments. The
more different classifications they have, the more genetically different(7).
Part 1: External Structures & Muscles
1. Examine
the exterior of your specimen. Take a picture of the specimen & label the
specimen showing the lateral, ventral & dorsal surfaces, and the anterior
& posterior ends. As well, label the ears, eyes, nostrils, teeth, claws
& umbilical cord.
2. Identify the organ a system that each structure belongs to and explain the importance of each structure to the survival of the pig. (Don’t just say the nostrils let it breathe, Instead, explain why breathing is important to survival.)
The ears, and
eyes belong to the nervous system. The ears are organs that provide two main
functions, hearing and balancing. The ears make the pig hear sounds which are
important for survival because hearing helps the pig to stay safe by warning
the pig from dangerous noises and keep them connected to the world. Balance is
achieved through a combination of the sensory organ in the inner ear, visual
input, and information received from receptors in the body, especially around
joints. The information processed in the cerebellum and cerebral cortex of the
brain allows the pig’s body to cope with changes in speed and the direction of
the head. The eyes allow the pig to see and this is significant to pig’s
survival. Because of sight, the pig can avoid obstacles, avoid enemies, and
find food. The nostrils belong to the respiratory system. The nostrils help the
pig to breathe and smell. Breathing is important for survival because, without
oxygen, the pig’s body cells will not function. Smelling is important because
it keeps the pig away from the toxins and helps it to track down food and
water. The teeth belong to the digestive system. The teeth help the pig to
crush its food into smaller molecules so that its body can use for survival by
absorbing nutrients from small molecules. The claws belong to the
musculoskeletal system. The claws of the pig allow it to dig, move, and hunt
preys. The umbilical cord belongs to the circulatory system. It is necessary
for the fetal pig because it connects the fetus to its mom. The mother pig can
provide its fetus with nutrients, blood, and oxygen so that it can develop into
a healthy pig(8).
Our pig was a male pig because the urogenital opening is located near the umbilical cord and it did not have genital papilla. If it was a female pig, I would expect to see the genital papilla near the anus and urogenital opening located behind the papilla(9).
Muscles
can only cause the bones to move by contracting. However, skeletal muscles only
pull in one direction. For this reason, muscles always come in pairs (layers).
When one muscle in pair contracts, bend a joint, for example, its counterpart,
then contracts and pulls in the opposite direction to straighten the joint out
again (one muscle contracts while the other relaxes). In addition, when your
bicep muscles in your upper arm contracts, it pulls your lower arm in towards
your shoulder. However, when it relaxes, your biceps cannot push your arm back
out. To do this, your tricep muscles, on the underside of your upper arm,
contracts and straightens your arm out. These interactions within different
layers of muscles allow us or pigs to move a limb. Therefore, different layers
are necessary for our limb movement(10)(11).
Part 2: Respiratory & Circulatory System
The
trachea connects the larynx to the bronchi and allows air to pass through the
neck and into the thorax. The rings of cartilage making up the trachea allow it
to remain open to air at all times. The open end of the cartilage rings faces
posteriorly toward the esophagus, allowing the esophagus to expand into the
space occupied by the trachea to accommodate masses of food moving through the
esophagus. The main function of the trachea is to provide a clear airway for
air to enter and exit the lungs. In addition, the epithelium lining the trachea
produces mucus that traps dust and other contaminants and prevents it from
reaching the lungs(12).
3. Describe how gas
exchange occurs in the lungs. Include the types of gases, where & how they are exchanged, and how they will be used or how they were created.
The lungs are
specially adapted to make the gas exchange more efficient and the function of the
lung is to transfer oxygen to the blood and move waste carbon dioxide. During
external respiration, the thin walls of the alveoli and the capillaries allow
gases to diffuse through their cell membrane easily. The air that enters the
alveoli after inhalation has a higher concentration of oxygen than the blood in
the capillaries next to the lungs (oxygen in the blood in capillaries has
diffuse out into the tissue cells). As a result, oxygen diffuses out of the
alveoli into the blood in the capillaries. The blood in the capillaries has a higher
concentration of carbon dioxide than the air in the alveoli because the blood
that diffuses into the capillaries is returning from the body tissue cells.
Thus, the carbon dioxide diffuses into the alveoli from the capillaries. The
carbon dioxide is then exhaled into the air. Once oxygen and carbon dioxide
have been exchanged between the capillaries and the alveoli, the blood in the
capillaries begins its journey back to the heart and then on to the tissue
cells. There, oxygen diffuses from the blood into the tissue cells and is
exchanged for carbon dioxide once again(9)(13).
The diaphragm and
the intercostal muscles work together at the same time to move air into and out
of the lungs. Inhalation begins when the external intercostal muscles and the
diaphragm contract, and the diaphragm moves down. This action expands the rib
cage upward and outward, and the floor of the chest cavity moves downward. Since
the chest cavity is airtight, its volume increases. The increase in volume
means that the same amount of air is contained in a larger space. When the
molecules of a gas are farther apart, as they are when the volume of the chest
cavity increases, the gas molecules exert less outward pressure. As a result,
the air pressure in the thoracic cavity decreases. The opposite muscle
movements expel air from the lungs. Exhalation begins when the diaphragm and
the rib muscles relax, thus reducing the volume of the chest cavity. As a
result, the volume of the lungs decreases, the air pressure inside the lungs
increases, and air move from the lungs to the lower-pressure environment
outside the body. In other words, a change in air pressure causes air to move
from an area of high pressure (the lungs) to an area of lower pressure (outside
the body)(9).
Rib
|
Diaphragm
|
Chest cavity
volume
|
Chest cavity
pressure
|
Lung volume
|
Lung inside
pressure
|
Air move
|
|
Inhalation
|
Up
|
Down
|
Increase
|
Decrease
|
Increase
|
Decrease
|
Out → Lung
|
Exhalation
|
Down
|
Up
|
Reduce
|
Increase
|
Reduce
|
Increase
|
Lung → Out
|
5. What are the main
functions of the circulatory system? Explain the importance of at least 3
ideas and describe which component of the circulatory system is responsible and how.
The circulatory system is responsible for transporting gases, nutrient molecules,
and waste materials. The heart, blood vessels, and blood help to transport
vital nutrients throughout the body as well as remove metabolic waste. The
blood vessels are categorized into 3 main parts, arteries, veins, and
capillaries. The arteries carry oxygenated blood away from the heart and
throughout the rest of the body. The veins carry deoxygenated blood to the
lungs and the heart, they also help with getting rid of waste. Capillaries are
very thin and connect the arteries to the veins and allow gas, nutrients, and
wastes to pass. The heart is responsible for pumping blood to all parts of your
body. Moreover, the blood act as a medium for transporting materials in the body.
Especially red blood cells in the blood contain a substance called hemoglobin
which carries oxygen in the blood.
The circulatory system regulates internal temperature and transports chemical
substances that are vital to health from one part of the body to the other. A
mammal’s circulatory system is able to control heat loss by changing the volume
of blood flowing near the body surface. An increase in blood flow by widening
or dilation the vessels is called vasodilation. This occurs when the core of
the body becomes hot as a result of vigorous activity or high external
temperature. Vasodilation helps the body to lose heat more rapidly. A decrease
in the flow of blood by narrowing or constricting the blood vessels near the
surface of the skin is called vasoconstriction. This reduces the amount of heat
that is dissipated from the skin and helps the body to conserve heat.
The circulatory system protects against blood loss from injury and against
disease-causing microbes or toxic substances introduced into the body. The
platelets produce chemicals to produce the enzyme thromboplastin. As long as
calcium ions are present, thromboplastin reacts with prothrombin to produce
another enzyme called thrombin. Thrombin reacts with fibrinogen to produce
fibrin. Fibrin is an insoluble protein that forms a fibrous mesh over the site
of injury. This mesh prevents the loss of blood cells and eventually solidifies
to form a clot. The white blood cells, antibodies, and complement proteins that
circulate in the blood defend the body against foreign microbes and toxins.
These
three main functions of the circulatory system are important for survival
because our body cells need gases and nutrients to function. Also, since
mammals are not ectothermic we need to regulate our body temperature by
regulating our blood pressure. Finally, we need to protect our body from
invaders so we won’t die from diseases and we need to have an ability to clot
the blood or we will die from excessive bleeding(14)(15).
7. What kind of blood (oxygenated or deoxygenated) is carried to the right side of the heart? What are the red blood cells carrying when they leave the right side of the heart where are they going?
Deoxygenated
blood enters into the right atrium through two veins, called the inferior and
superior vena cava. When the right atrium contracts, the blood flows from the
right atrium into the right ventricle through the tricuspid valve. After all
the blood is emptied into the right ventricle the tricuspid valve closes to
make sure that the blood doesn’t flow back to the atrium. As the right
ventricle contracts, the carbon dioxide carrying blood (hemoglobin in the red
blood cells carry carbon dioxide) leaves the heart using the pulmonary trunk.
From there, it enters the left and right pulmonary arteries. It then continues
to the left and right lungs for gas exchange (pulmonary arteries contain
deoxygenated blood)(9).
* It was hard to see the valves so I couldn't label them. So I just labelled what I can see
Similarities
|
Differences
|
· Both the right and left sides have atrium and ventricle.
· Both right and left sides pump blood out to the lungs or our body.
|
· Right side of the heart receives deoxygenated blood that is coming back from the body and then pumps this blood out to lungs.
· Left side of the heart receives oxygenated blood that is coming back from the lungs and then pumps this blood out to the rest of the body.
· Superior vena cava and inferior vena cava bring blood to the right side of the heart while only pulmonary vein brings blood to the left side.
· Blood in the right side of the heart is pumped through the pulmonary artery, whereas blood in the left side is pumped through the aorta.
· The left ventricle has a thicker muscle wall than the right ventricle.
· Right side drives a short, low-pressure pulmonary circulation while the left side drives longer, high-pressure systemic circuit.
|
(16)(17)
Part 3: Digestive System
Mouth, Esophagus, Stomach, Liver, Pancreas, Large Intestine, Small Intestine, Gallbladder
The food first
enters the mouth. The teeth crush the food into small pieces (mechanical
digestion). The chemical digestion begins with Saliva that is produced from
three pairs of salivary glands in the mouth. Contains an enzyme called amylase
that breaks starts to break down the starches in food into simpler sugars.
Saliva dissolves water soluble and lubricates the food to make it easier to
swallow. As you chew your food, your tongue helps to mould and smooth it into a
soft mass, a bolus. The bolus travels down the esophagus. Esophagus transports
each bolus of food to the stomach in a series of wavelike contraction,
peristalsis. Peristalsis makes sure that the food travels down to the stomach
and doesn’t go back up. The ring muscle, the esophageal sphincter relaxes and
allow each bolus of food to enter the stomach. The stomach produces an enzyme
called pepsin to digest proteins and covers the food with a gastric juice,
produced by gastric glands. Gastric juice is made up of hydrochloric acid,
salts, enzymes, water, and mucus. The mucus coats the walls of the stomach,
protecting it from attack by the strongly acidic gastric juice. The rest of the
gastric juice continues the chemical digestion of the food. Also, the stomach
has three layers of muscles fibres that mechanically break up pieces of food
and mix them with gastric juice, This result in a thick liquid called chyme. When
the small intestine is empty, the pyloric sphincter opens and the stomach
pushes chyme into the first part of the small intestine. The small intestine
continues the process of breaking down food by using enzymes released by the
pancreas and bile from the liver. Enzymes produced by the pancreas break down
protein, fat, and carbohydrates from the food we eat. The liver produces bile
and stores it in the gallbladder. When the food enters the duodenum, the liver
secretes bile into the hepatic duct. The hepatic duct takes the bile and sends
it down to the duodenum to help with the breakdown of lipids/fats. Peristalsis
is also at work in this organ, moving food through and mixing it up with
digestive secretions. The duodenum is largely responsible for continuing the
process of breaking down food, with the jejunum and ileum being mainly
responsible for the absorption of nutrients into the bloodstream. After the
food is broken down it goes to the small intestine. The remaining material
moves into the large intestine or colon. The large intestine absorbs water from
the alimentary canal. Billions of anaerobic bacteria in the colon break down
undigested matter further. Some of these bacteria produce important vitamins,
including folic acid, vitamin B, and vitamin K. The leftover matter forms
feces, which are pushed by the contractions of the colon into the rectum. The
stores the feces until they are eliminated at the anus, the last part of the
digestive tract(9)(18)(19).
Pig:
48cm Small Intestine: 312cm
If the
length of the small intestine was decreased, I think we won’t be able to absorb
all the nutrients that we need or the nutrients won’t be absorbed properly.
Moreover, if the length of the large intestine was increased, it will take too
long for the food to reach the rectum. Therefore, too much water will be
absorbed and this will cause constipation or the food may rot in our bodies
before we discharge it
The food in the small
intestine still has water so it is semi-liquid and the food in the large
intestine is drier because the water is absorbed and it is mostly a waste. I
couldn’t see the food in the stomach. However, I could see a layer of muscle
that helps mechanical digestion in the stomach(9).
The human body is
designed to function in a manner that every part works cooperatively. In fact,
no organ or body system is superior over the others, and each system just
supports one another to keep you healthy. The respiratory system and the
circulatory system work together by performing gas exchange which is passed of
oxygen from the alveoli into the blood flow and then the carbon dioxide passes
through the blood flow and is breathed out of the body. So if the respiratory
system wasn’t there, then the circulatory system wouldn’t have oxygen to send
in the body. If the circulatory system wasn’t there, then the oxygen couldn’t
be transported to the body and if the gas exchange didn’t take place then it will
result in the cells dying. The digestive system and respiratory system interact
with each other too. The digestive system metabolizes food to provide the body
with nutrients and at the same time, fuel your respiratory system so that it
can produce enough oxygen in your body. When it comes to digestive and
circulatory systems, they both process and transport essential nutrients your
cells need to fuel your body. Without one of these systems, the other systems will
fail to work and so your body will fail to function(20)(21).
Work
Cited
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SWEETPAKISTAN.NET,
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Biology.” YouTube, YouTube, 4 Sept.
2017, www.youtube.com/watch?v=N3-htnYnb3c.
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www.cliffsnotes.com/study-guides/anatomy-and-physiology/the-cardiovascular-system/functions-of-the-cardiovascular-system.
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17) Admin, and About the Author: AdminComing
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www.differencebetween.com/difference-between-left-and-vs-right-side-of-heart/.
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