Image Source – Attribution: By Leysi24 (Own work) [CC BY-SA 3.0 via Wikimedia Commons
Firstly, dismantle the human torso model in the science laboratory and describe what you know about each part of the alimentary canal and associated glands and organs. Draw and label a detailed diagram, showing each of the organs above. Then complete the “Cut-and-Paste your Guts” activity, identifying each organ from it’s description and pasting each description into your book, in the order that food would pass through, on it’s 12 hour journey through the 7 metres of the digestive system.
Next, match the skulls (noting the teeth structure and position of eye sockets) with the corresponding herbivore, omnivore and carnivore digestive systems. Describe the diet of each organism, explaining your reasoning in terms of teeth structure, size of stomach and length of intestines, any enlarged organs and corresponding diet.
Source: Biology Online
This Wednesday afternoon we will be dissecting laboratory rats, which are specially bred for scientific purposes. This practical exercise is optional, but an excellent way to gain scientific skills of careful observation, identification of body parts and an understanding of the structure and function of the digestive system of mammals. If you plan to continue your science education at university, you will find this a valuable introduction to laboratory dissections. Make sure you read the practical instructions thoroughly, work slowly and carefully and document your progress with video or a digital camera. Remember that ‘dissection’ does not mean ‘to cut up’, it means ‘to expose to view’ – once something has been cut, it can’t be undone, so know what organ or tissue you are cutting and why.
Rat Dissection – Part 1: Exposing the Abdomen
Rat Dissection – Part 2: The Digestive System (Warning – graphic images)
Rat Dissection – Part 3: Identifying the organs of digestion.
What did you learn about dissection and the digestive system of a mammal? Compared to the length of the rat, how long was it’s alimentary canal? What was the difference in the wall of the stomach and the small intestine? What did you notice about the contents of the alimentary canal as they moved towards the rectum? What surprised you most about the inside of a rat?
Procedure for rat dissection.
Classification of the rat and glossary of terms (dorsal, ventral, thoracic etc.)
Check out Miss Baker’s Biology Blog, “Extreme Biology” for a video of a dogfish shark dissection.