Download Pig Dissection Answers

Procedure
(a) labelled diagram of pig as per Figure 1 in the Student Text
(b) Answers will vary. See Figure 2 in the Student Text.
(c) labels added as per Figure 3 in the Student Text
(d) The umbilical cord carries oxygenated blood from the placenta to the pig through the umbilical vein. It carries
deoxygenated
blood to the placenta through the umbilical arteries.
116 Unit 3 Student Book Solutions NEL
(e) Features should be added and labelled as they appear on students’ pigs.
(f) diagram labelled as per Figure 4 in the Student Text
(g) tongue: manipulates food during chewing and moves food to the back of the mouth for swallowing
esophagus: muscular tube that carries food from the mouth to the stomach
epiglottis: flap that prevents food and water from entering the trachea
trachea: airway from the oral cavity into the chest cavity; splits into two bronchi, one going into each lung
(h) the stomach
(i) labelled diagram as per Figure 6 in the Student Text
(j) The cardiac sphincter prevents food from leaving the stomach and entering the esophagus. The opening and
closing
of the pyloric sphincter controls the movement of food from the stomach into the small intestine.
(k) The pancreas produces digestive enzymes as well as the hormone insulin.
(l) Answers will vary with the size of the pig. The small intestine is much longer than the large intestine. Labels of
kidney,
caecum, pancreas, and gallbladder should be added to students’ diagrams.
(m)The kidneys are covered in tissue that attach them to the abdominal wall and are located underneath the
intestines.
(n) labelled diagram as per Figure 8 in the Student Text
(o) labelled diagram as per Figure 7 in the Student Text
(p) The lungs are soft and spongy in texture. Note that the preservative makes the lungs more rubbery than would be
the
case in a fresh specimen.
(q) The trachea is firm but highly flexible— much like a vacuum cleaner hose. The cartilaginous rings prevent the
trachea
from collapsing during inhalations while maintaining a flexible structure.
Analysis
(r) It is important to wear rubber gloves, a laboratory apron, and safety goggles during dissections. In addition, extra
care
must be taken to avoid being cut by the extremely sharp dissecting instruments— scalpels, scissors, forceps, etc.
Cleanliness is also very important. Dissected body tissues must be properly disposed of and a clean working area
must
be maintained. Between dissections the specimens must be kept well preserved to prevent possible decay.
(s) The liver performs many important functions including the breakdown of red blood cells and the formation of
bile, the
detoxification of harmful and foreign substances, deamination of amino acids and as a storage organ for various
nutrients
including glycogen and vitamin A.
(t)
Organ Location Function
gallbladder on the under surface of the right lobe stores and releases bile through the bile duct
of the liver to the small intestine
spleen on the left side of the body within the helps produce and maintain red blood cells
abdominal cavity just posterior to the stomach
small intestine a coiled tube within the abdomen connecting digestion and absorption of food nutrients
the stomach to the large intestine
large intestine a coiled tube within the abdomen connecting recovery of water from digestive tract;
the small intestine to the anus formation and expulsion of solid wastes
larynx at the top of the trachea just below voice box for producing sounds
the esophagus
kidneys on the dorsal internal abdominal wall remove wastes, unwanted solutes, and
excess water from the blood
stomach just below posterior to the liver within digestion of food, “acid bath” to kill off
the abdominal cavity microorganisms and partial liquefaction
of the food
(u) The great length of the small intestine increases its surface area for absorption and allows food to be in the
intestine
long enough to permit efficient digestion and absorption.
(v) right atrium and right ventricle— deoxygenated; left atrium and left ventricle— oxygenated
(w)The stiff rib cage in necessary for the mechanics of breathing. Expanding and contracting the volume of the
thoracic
cavity creates air pressure differences which result in inhalation and exhalation. In contrast, the softer abdominal wall
permits the belly to distend when large quantities of food are ingested and/or during pregnancy.
(x) The fetus obtains its oxygen supply from the placenta. The lungs need only enough blood to supply the lung
tissues
directly with the oxygen and nutrients they require for growth.
NEL Unit
3 Performance Task 117
(y) Immediately at birth the baby pig must begin to use its lungs. This requires the large blood supply to be cut off in
the
umbilical cord and redirected to the lungs.
(z) A heart G liver
B diaphragm H stomach
C gallbladder I spleen
D small intestine J pancreas
E bladder K large intestine
F lung
Evaluation
(aa) Fetal pigs are good models for human anatomy because they have an omnivorous diet similar to that of humans.
They
are also readily available and relatively large.
(bb) Answers will vary. The circulatory and reproductive systems can be difficult to observe in fine detail. In
addition, the
nervous system is very challenging to dissect as the main components are encased within the bones of the cranium
and spinal column.
(cc) Answers will vary. The dissection might benefit from the use of a dissecting microscope or fresh specimens
rather
than preserved animals. Larger pigs have more fully developed organs.
Synthesis
(dd) (i) W e have very similar organ systems. Although they differ somewhat in size, each organ/tissue found in
humans
has a homologous one in the pig.
(ii) The most significant differences are in human brain size/development and our bipedal locomotion with highly
dextrous hands. Students will note the differences in reproductive organs too.
(ee) This permits acidic stomach contents to enter the esophagus. The lining of the esophagus has only a thin mucus
layer
for protection and can be irritated and or seriously damaged by the stomach acid.
(ff) The kidneys lie directly against the dorsal surface of the abdominal wall and could be easily accessed through the
back wall.
Extension
(gg) The entire vertebral column and brain can be exposed through careful dissection. This will likely require an
additional
full period or time outside of class. Bone cutters or strong scissors will be required.