observation of digestive and circulatory systems

Observation of Digestive and Circulatory System

Introduction/Background:
This week’s lab is about digestion and the circulatory system. Students will be learning about the different types of digestion and circulatory systems for different types of animals. Students will learn not only about the mechanical and chemical components of digestion, but also the complete and incomplete digestions. The lab will also teach the open and closed, single and double, circulation patterns. Several different models of the systems will be shown in lab. Learning these different systems and patterns will be very helpful in the health care community in the future.
Hypothesis:
No hypothesis is necessary as this lab is an observational lab.
Objectives:
The objective of today is to learn and understand digestion and circulatory systems, especially the human track. Students will be viewing different examples of the digestive track and circulatory system, and will also research and answer questions.
Materials:
1. Lab notebook
2. Research facility (book, internet, etcetera)
3. Observational digestive and circulatory system models.
a. Earthworm
b. Frog
c. Human digestion
d. Human circulatory system
Procedures:
1. View each model that is presented in the lab
2. Take a picture, draw or describe each model
3. Answer all of the questions in the lab worksheet
4. Record any and all observations in the lab book
Results:
Exercise 1: Observation of Digestive System
1. Look at the models of the Digestive system from organisms of different order.
Models of the Digestive system were successfully viewed in the lab.
2. Identify the Structures in the Abdominal Cavity.

3. List the structures and organs associated with the tubular digestive tract.
The structure and organs associated with the tubular digestive tract include the mouth, the esophagus, the stomach, the small intestines, large intestines, the rectum, and the anus.
4. Which are the organs that lie outside the digestive tube and are important in the digestive process?
The organs that lie outside the digestive tube and are important in the digestive process are the salivary glands, gall bladder, liver, and the pancreas. They are also known as accessory organs.
5. What will be the outcome if food passes too slowly to too rapidly through the Colon?
When food passes too slowly through the colon, too much water is absorbed and constipation occurs. When food passes too quickly through the colon, not enough water is absorbed leading to diarrhea.
6. How is the digestive system adapted to terrestrial mode of life considering the fact that conservation of water is a critical problem?
The digestive system is adapted to terrestrial mode of life considering the fact that conservation of water is a critical problem through the colon. The colon can re-absorb about 90% of water that passes through it.
7. Referring to your textbook, describe the process of food absorption in small Intestine.
Virtually all nutrients from the diet are absorbed into blood across the mucosa of the small intestine. In addition, the intestine absorbs water and electrolytes, thus playing a critical role in maintenance of body water and acid-base balance. In the duodenum, chyme from the stomach mixes with digestive fluids from the pancreas, liver, GB, and from the glands in the intestinal wall. Most digestion occurs in the duodenum and absorption occurs in the other two parts of the small intestine. Sugars are absorbed through passive transport from the lumen to the epithelial cells. Other nutrients are pumped out of the epithelial cells of the villus into the bloodstream.

8. List the salient features associated with each of the Order.
Salivary glands secrete enzymes to begin chemical digestion.
Esophagus is the pathway between mouth and stomach.
Stomach stores food and begins digestion of proteins.

Exercise 2: Observation of Circulatory System

1. Look at the models of the Circulatory system from organisms of different order.
The models of the circulatory system were successfully viewed in the lab.
2. Draw, label and Identify parts.

3. Although pulmonary circuit exists, the heart in amphibians and reptiles is made up of only three chambers-two atria and one ventricle. The latter receives blood from both atria. Speculate the possible disadvantage of this circulatory pathway.
The possible disadvantage of the circulatory pathway when one ventricle is receiving blood from both atria could be that there is a possibility of the oxygenated blood and deoxygenated blood mixing, so it is not nearly as effective.
4. List the salient features associated with each of the Order.

Discussion:
Students learned a lot about the processes of digestion and circulation. The process of digestion has two components, mechanical and chemical. The mechanical is the actual chewing/grinding of the food. The chemical component is the different enzymes/ chemicals that break it down further. With digestion, Cnidarians and flatworms have a gastro vascular cavity. Most animals have a complete digestive system (or alimentary canal) that begins with the mouth and ends with the anus (tubular structure). The gizzard is an organ that grinds and breaks things down more heavy duty like a mortar and pestle. The human digestive system is made up of the mouth, salivary glands, pharynx, esophagus, stomach, small intestine, gall bladder, liver, pancreas, large intestine, rectum and anus. Carnivores, herbivores, and omnivores have different types of teeth according to their diets. Carnivores have very sharp teeth, herbivores have flatter teeth, and omnivores have teeth that are adapted to eat both meat and plants. The length of a carnivore’s digestive tract is comparatively much shorter than that of the herbivore. Ruminant digestion consists of four different chambers. Circulation and Gas Exchange for cnidarians and flatworms is not a true circulatory system because their anatomical structure allows them to rely on diffusion for nutrient and gas exchange. Those with a true circulatory system have to have three things present. They must have circulatory fluid, system of inter connecting vessels, and a muscular pump or heart. There are two types of circulatory systems, open and closed. Open circulatory system is has hemolymph found in arthropods mollusks, and crustaceans. Closed circulatory system has blood and is found in annelids, cephalopods, and vertebrates. Vessel organization, arteries carry blood AWAY from the heart. Arteries branch into arterioles and then capillaries (where the oxygen and carbon dioxide is exchanged). Then the capillaries move into venules, and then veins which carry blood TOWARDS the heart. Blood flow is unidirectional. Single circulation means blood passes through the heart once for a complete cycle. Double circulation would need two cycles of blood, left and right ventricles, has to go through the heart two separate times to make a whole cycle. The superior and inferior vena cava flow into the right atrium, which goes into the right ventricle, then through a semilunar valve into the pulmonary arteries on both sides to go to the lungs. The blood comes back through the pulmonary veins on each side which flows into the left atrium and into the left ventricle which goes through a semilunar valve and out through the aorta.
Conclusion:
In conclusion, students successfully viewed all of the given examples of the circulatory and digestive systems. Students learned that the structure and organs associated with the tubular digestive tract include the mouth, the esophagus, the stomach, the small intestines, large intestines, the rectum, and the anus. The accessory organs were also learned. These are the organs that lie outside the digestive tube and are important in the digestive process are the salivary glands, gall bladder, liver, and the pancreas. Students learned that about some of the intricacies of the colon. When food passes too slowly through the colon, too much water is absorbed and constipation occurs. When food passes too quickly through the colon, not enough water is absorbed leading to diarrhea. The colon can re-absorb about 90% of water that passes through it. Students also learned that virtually all nutrients from the diet are absorbed into blood across the mucosa of the small intestine. In the duodenum, chyme from the stomach mixes with digestive fluids from the pancreas, liver, GB, and from the glands in the intestinal wall. Most digestion occurs in the duodenum and absorption occurs in the other two parts of the small intestine. Sugars are absorbed through passive transport from the lumen to the epithelial cells. Other nutrients are pumped out of the epithelial cells of the villus into the bloodstream. Students also learned about the Circulatory system. The circulatory systems in animals can prove to be very different than that of humans including both open and closed systems. Students learned that arteries carry blood AWAY from the heart. Arteries branch into arterioles and then capillaries (where the oxygen and carbon dioxide is exchanged). Then the capillaries move into venules, and then veins which carry blood TOWARDS the heart. This lab was very informative and will be extremely helpful towards anatomy classes and health care professions in the future.
Lab Questions:
There are no designated questions for this specific lab, instead, all questions are integrated into the results section.
References:
Drake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. p. 273. ISBN 978-0-8089-2306-0.
Personal Communication. Dr. Bledsoe. November 2014.
Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 349–353. ISBN 0-03-910284-X.
Schoenwolf, Gary C.; Bleyl, Steven B.; Brauer, Philip R.; Francis-West, Philippa H. (2009). "Development of the Urogenital system". Larsen's human embryology (4th ed.). Philadelphia: Churchill Livingstone/Elsevier. p. 237. ISBN 9780443068119.