Download lab: digestive system of a rabbit

E = /6
THE VICTORIA SCHOOL
TEACHER: DIANA ANGÉLICA CARVAJAL BERNAL
LAB: DIGESTIVE SYSTEM OF A RABBIT
April 23rd 2013
BIOLOGY MYP YEAR 3
Criteria Evaluated: E: Processing Data
AIMS:
 Identify the parts of the rabbit’s digestive system
1. DATA COLLECTION:
Materials
Dissection kit
Rubber/latex gloves
Rabbit
Pencil/pen
Dissection guide and results table
Ruler
The digestive system of mammals consists of the alimentary canal (mouth, oral cavity, pharynx, esophagus, stomach,
small intestine, large intestine, rectum, anus) and other associated structures/organs/glands (salivary glands, gall bladder,
liver, pancreas). The cavity behind the teeth and gums is the oral cavity. Note the papillae on the tongue. These provide
friction for food handling and contain taste buds.
Internal Anatomy of the Digestive System
As you prepare to open up your rabbit, remember that most internal organs, including the digestive system, are located
in the body cavity. Fluid fills the space between membrane layers. This moisture acts as a lubricant, allowing organs
some degree of easy movement. The organs are connected to each other and to the inner body wall by thin sheets of
connective tissue called mesenteries, which suspend the organs and provide bridges for blood vessels, nerves, and ducts.
1. Make a mid-ventral incision through the skin (but not through the underlying wall or too deeply or you will damage
internal organs) and cut forward as far as the lower jaw (mandible), and backwards to the anus.
2. Cut around the urethra so it does not get damaged.
3. Carefully peel back the flaps and pin them beneath your rabbit. It may be necessary to cut through the ventral part of
the rib cage (very carefully) with a pair of scissors to separate the upper flaps.
4. Locate the structures located in Figure 1. Locate the caecum, a small blind-ended sac found at the juncture of the
ileum and the colon (large intestine). Many herbivorous mammals (pigs, horses, rodents, rabbits) use "hindgut
fermentation" in the caecum to digest cellulose. In humans the caecum is known as the appendix and is not used in
digestion.
The rabbit has a larger stomach than the cat to store large amounts of grasses. It has a longer small intestine and a very
long & "sac-like" cecum for hindgut fermentation of grasses. Within the cecum, bacteria digest cellulose by a
fermentation process. The rabbit absorbs some of these metabolic products produced by the bacteria.
- Digestive System: esophagus, stomach, liver, pancreas, small intestine (duodenum & ileum regions), cecum & large
intestine (proximal colon and distal colon).
Figure 1. Rabbit’s digestive system
Taken from: http://lyricsdog.eu/s/digestive%20system%20of%20rabbit
2.
Structure
Fill up this information from your observations in the lab. For the length, leave space
Table 1. Lengths and description of organs of the rabbit’s digestive system.
Length (cm)
Observations (general description, color and texture,)
Stomach
Small intestine
Large intestine
Caecum
3. What is the caecum function?
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4. Humans do not have a caecum, but which is the structure that comes from it? Why we do not have such a big
one as rabbits do?
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5. Fill up the table:
Structure
Group 1
Stomach
Small
intestine
Large
intestine
Caecum
Table 2. Summary of lengths of organs of the rabbit’s digestive system.
Length (cm ±0,1)
Ranges
Average (cm±0,1)
Minimum
Maximum
Group 2
Group 3
Group 4
value
value
6. In humans, the stomach is 30,5 cm in length, the small intestine measures between 6 to 7 m in length, the length
of large intestine stretches up to 1.5 m long and the appendix averages 11 cm in length. Make a graph where you
compare the length of the main organs of the digestive system in both humans and rabbits. Your graph should
include the ranges (minimum and maximum) of the measurements done for the rabbit in Biology Lab.
7. Analyze the graph comparing the human and rabbit’s digestive system. Include similarities and differences.
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