Rat Dissection
1) The length of the tail: 18.5 cm 2) The length of the body ( from the tip of the nose to the base of the tail: 22cm
What is their relative proportion? 1.2:1
PART A (Overview) pg. 462-464 a) Draw a diagram of the rat when it is first cut opened and the internal organs are exposed. Identify and label the diaphragm, the stomach, the small intestine, the caecum, the heart, the left and right lung, the trachea and the esophagus. (Note: see Figure 22 on pg 470 for an example)
b) What structure divides the thoracic and abdominal cavities? The Diaphragm divides the thoracic and abdominal cavities.
c) What is the sex of your rat? Male.
Part C Digestive System pg 467
Skip the Salivary glands on pg 467 and continue with the Mouth on pg 468 d) Compare the length of the upper and lower pairs of incisors in the mouth. Which is longer? The upper incisor is longer than the lower incisor.
e) What does the surface of the tongue feel like? The tongue feels smooth and soft.
f) What are the functions of the tongue? The tongue is used to move the food around the mouth and to taste.
Esophagus: Carries bolus into stomach.
Epiglottis: Prevents food from entering the trachea.
Trachea: A tube which air passes from the mouth to the lungs.
g) Using a probe determine whether the esophagus or the trachea is more rigid. Can you explain why this might be so? The trachea is more rigid as the esophagus needs to be more flexible to adapt to the different size boluses.
h) To what organ is the esophagus attached? The Stomach.
i) What shape is the stomach? The stomach is j-shaped
J) Describe the interior wall of the stomach once you have cut it open. The interior wall of the stomach was thin. It was almost transparent, and was very flexible. It was like this so the rat could fit large amounts of food inside. The top portion of the stomach wall however, was thick and rough.
K) Measure the length of the small intestine and compare it to the body length
What is their relative proportion? 1.2:1
PART A (Overview) pg. 462-464 a) Draw a diagram of the rat when it is first cut opened and the internal organs are exposed. Identify and label the diaphragm, the stomach, the small intestine, the caecum, the heart, the left and right lung, the trachea and the esophagus. (Note: see Figure 22 on pg 470 for an example)
b) What structure divides the thoracic and abdominal cavities? The Diaphragm divides the thoracic and abdominal cavities.
c) What is the sex of your rat? Male.
Part C Digestive System pg 467
Skip the Salivary glands on pg 467 and continue with the Mouth on pg 468 d) Compare the length of the upper and lower pairs of incisors in the mouth. Which is longer? The upper incisor is longer than the lower incisor.
e) What does the surface of the tongue feel like? The tongue feels smooth and soft.
f) What are the functions of the tongue? The tongue is used to move the food around the mouth and to taste.
Esophagus: Carries bolus into stomach.
Epiglottis: Prevents food from entering the trachea.
Trachea: A tube which air passes from the mouth to the lungs.
g) Using a probe determine whether the esophagus or the trachea is more rigid. Can you explain why this might be so? The trachea is more rigid as the esophagus needs to be more flexible to adapt to the different size boluses.
h) To what organ is the esophagus attached? The Stomach.
i) What shape is the stomach? The stomach is j-shaped
J) Describe the interior wall of the stomach once you have cut it open. The interior wall of the stomach was thin. It was almost transparent, and was very flexible. It was like this so the rat could fit large amounts of food inside. The top portion of the stomach wall however, was thick and rough.
K) Measure the length of the small intestine and compare it to the body length
Cited: "Cecum." Wikipedia, the Free Encyclopedia. Web. 18 Jan. 2011. <http://en.wikipedia.org/wiki/Cecum>. "Ileum (anatomy) -- Britannica Online Encyclopedia." Encyclopedia - Britannica Online Encyclopedia "Jejunum." The Worlds of David Darling. Web. 18 Jan. 2011. <http://www.daviddarling.info/encyclopedia/J/jejunum.html>. Ng, David “Gallbladder.” Mamas Health. Web. 18 Jan. 2011. http://www.mamashealth.com/organs/gallbladder.asp “Larynx.” Get Body Smart “Liver.” Mamas Health. Web. 18 Jan. 2011. http://www.mamashealth.com/organs/liver.asp “Lungs.” Mamas Health “Pancreas.” Mamas Health. Web. 18 Jan. 2011. http://www.mamashealth.com/organs/pancreas.asp “Intestine.” Mamas Health “Stomach.” Mamas Health. Web. 18 Jan. 2011. http://www.mamashealth.com/organs/stomach.asp Jackson, W