Course: Livestock Production TEKS: 130.3(c)(5)(a) Unit Title: Digestive Systems Instructor: Ms. Hutchinson Objectives: After completion of this unit of instruction, students will: A. Define what a digestive system does; B. List the five functions of the digestive system; C. Explain the difference between a Ruminant and Non-Ruminant; D. List the 6 major parts of the digestive system; E. Explain what each part of the digestive system does; F. List the compartments of a ruminant stomach; G. Label the parts of a ruminant stomach; H. Write where the absorption sites are for water and nutrients; I. Label the parts of a small intestine; J. Label the parts of a large intestine; K. Label the digestive system of a chicken; L. List the accessory digestive organs; M. List the three digestive process actions; N. List the mechanical actions of digestion; O. Collect pictures of the parts of real polygastric and monogastric digestive tracts; P. Distinguish the parts of the digestive tracts for each picture their classmates brought; and Q. Rearrange an incorrect digestive tract to make it correct.
Interest Approach: Bring cookies and juice for the class for the students to eat while going through the lesson. Every animal has a process by which they go through to get the nutrients out of what they consume. As we go through this unit, think about how the food you are consuming goes through your own body as well as other animal s bodies to get the nutrients needed. Curriculum & Instruction: Curriculum: A. Define what a digestive system does; The digestive system is there to break down food into smaller particles so the body can absorb and utilize the nutrients. B. List the 5 functions of the digestive system; Functions of the Digestive System: 1. Ingesting Food 2. Grinding Food 3. Digesting Food 4. Absorbing nutrients 5. Eliminating Body Waste C. Explain the difference between a Ruminant and Non- Ruminant; Ruminant vs. Non-Ruminant - Ruminant animals have a 4 compartment stomach (polygastric) that includes a large rumen. Has large digestive system for utilizing bulky, forage-type feeds. - Non-ruminant animals have a single compartment stomach (monogastric). Examples of Ruminant animals: - Cattle, Sheep, Goat, Deer Instruction & CFU s: PPT slide 5-9 On a piece of paper answer the following questions: What is the main purpose of the digestive system? What are the 5 functions of the digestive system? Which digestive system has a 4 compartment stomach? How many compartments does a monogastric stomach have? Give 4 examples of animals that are considered ruminants:
Examples of Monogastric animals: - Swine, Chicken, Human Give 3 examples of animals that have a monogastric digestive system:
D. List the 6 major parts of the digestive system; Major Parts of Digestive System: - Mouth - Pharynx - Esophagus - Stomach - Small Intestine - Large Intestine Digestive tract extends from the lips to the anus. E. Explain what each part of the digestive system does; Mouth: - Grasp food, grind food, and mix the food with saliva - Accomplishes these tasks with the use of the lips, tongue, teeth, cheeks, jaw, and salivary glands PPT slide 10-34 What are the 6 major parts of the digestive system? Digestive tract extends from the to the. What is the purpose of the mouth? Lips: - Horse lips are used to grasp food - Sheep & Cattle s lips are to simply close the mouth Tongue: - Used by most animals to grasp food - Helps in the chewing process & formation of boluses (cud) In ruminants, large quantities of ingested food are regurgitated as boluses to that it can be rechewed. - Papillae cover the top of the surface and contain taste buds Papillae finger-line projections Teeth: - Responsible for cutting (incisors) and grinding (premolars & molars) food. - New born animals develop milk teeth or baby teeth - Milk teeth are replaced with permanent teeth as the animal ages What is the purpose of the tongue? What is a boluses? What is the function of the teeth?
Cheeks: - Consist mostly of muscle that is lined with a mucous membrane - Cheeks line up the food with teeth. Pharynx: - Common pathway for food and air - Food passes through mouth to pharynx - Pharyngeal muscles force food to the esophagus What is the purpose of the cheeks? What muscles help force food from the pharynx to the esophagus? Esophagus: - A muscular tube that connects the pharynx to the stomach - The esophagus passes through the chest cavity and connects with the stomach just after passing through the diaphragm. Stomach - Serves to digest food - Monogastric 1 true stomach - Polygastric 4 compartments Monogastrics: - Single stomach compartment true stomach - Location: just beyond the diaphragm on the left side of the body - Has folds in the lining the creates gastric pits - Glands secrete digestive fluids into the pits: Hydrochloric acid Pepsin Rennin F. List the compartments of the ruminant stomach; Polygastrics: - AKA: Ruminants - 4 compartments: Rumen Reticulum Omasum Abomasum What does the esophagus connect to? What is the main purpose of the stomach? Where is the stomach on a monogastric system located? What type of stomach does a ruminant have? What are the 4 compartments of a polygastric stomach?
G. Label the parts of a ruminant stomach; Polygastric System: Rumen, Reticulum, & Omasum: - Contain no glands - Soak food - Allow microbial digestion to take place Rumen: - 1 st compartment - Fills most of the left side of abdomen - Thick muscular wall - 2 sacs that contain many papillae: Dorsal sac Ventral sac - Food passes into rumen, where it can be regurgitated as cud. - Site of 60%-90% of digestion in ruminants - Becomes functional at 6-8 weeks of age in a calf - Makes up 80% of total stomach capacity when animal reaches maturity Reticulum: - Forward most portion of the stomach - Inner surface has inward folds - Resembles a honeycomb shape Esophageal Groove: - Capable of closing off the rumen and reticulum - Food passes straight to the omasum - Seen in calves before the rumen is functional What is the first compartment of a polygastric stomach? Where is the rumen located? The rumen is the site of % digestion in ruminants. How much of the stomach does the rumen make up when the animal reaches maturity? Where is the reticulum located? Describe the Esophageal Groove When does the Rumen become functional in a calf?
Omasum: - 3 rd compartment - Contain muscular projections Covered by mucous membrane Contain many small papillae - Papillae in omasum is responsible for grinding roughage Abomasum: - true stomach - Only glandular stomach of ruminants - Located under omasum - Lining and glands are the same as those in the stomach of a non-ruminant What is responsible for grinding roughage in the Omasum? What is also called the true stomach of a polygastric digestive system? Which compartment of the ruminant stomach is the only compartment that has glands in it? Guided Practice: As a group, draw out the diagram of the ruminant stomach. Each person in the group (4 to a group) is responsible for one of the 4 compartments of the stomach. Each person is to use their own color marker and draw their section of the stomach. After drawing your section of the stomach, write inside or around your compartment the important aspects of the specific compartment. Discuss with your group the details of each compartment. H. Write where the absorption sites are for water and nutrients; I. Label the parts of the small intestine; Small Intestine: - 3 part tube: Duodenum Jejunum Ileum - Site of digestion & absorption of nutrients - Lined with many villi, which absorb nutrients Villi tiny finger-like projections that protrude from the lining of the intestinal wall Use big post-it notes, each group gets one and a set of markers. What are the 3 parts of the small intestine? Define villi:
J. Label the parts of the large intestine; Large Intestine: - Larger tube of digestive tract - Consists of: Cecum (a blind pouch) Colon - Cecum is much larger in horses & rabbits than in other domestic animals - Colon site of water absorption - Excretes waste from the body - Little nutrients other than water are absorbed here Large Intestine Cecum - Cecum is larger in horses & rabbits - Action of microorganisms allow for digestion of fiber (roughage) What are the parts of the Large intestine? Where is the site of nutrient absorption? Where is the site of water absorption? Why are rabbits and horses able to eat roughage? K. Label the digestive system of a chicken; Poultry Digestive System: - Differs from other animals - Do not have teeth - Prehensile structure is the beak Prehensile body part adapted for grasping or holding PPT slide 35-38 Define prehensile: What is the prehensile structure on a chicken?
Poultry Digestive Process: - Food passes from mouth to esophagus to the crop Crop enlargement of the gullet - Crop temporarily stores food & softens it - Food passes to the glandular stomach - Food passes to the gizzard - Mouth > Esophagus > Crop > Glandular Stomach > Gizzard Gizzard: - Crushes & grinds coarse feed Aided by grit & gravel that has accumulated in the gizzard during the bird s life - Food then goes to the small intestine In what order does food go through the chicken s digestive system? Describe the function of a gizzard: Where does food go after being in the gizzard? Guided Practice: In groups of 3, use the blank drawing provided to label the different parts of the digestive system of the chicken. (Each person is to use their own color marker.) Each person is to pick one of the choices below to contribute to the drawing provided. 1. Label and describe the beak, esophagus, crop, glandular stomach, and gizzard. 2. Label and describe the functions of the small intestine. 3. Label and describe the functions of the large intestine. L. List the accessory digestive organs; Accessory Digestive Organs: - Salivary Glands - Pancreas - Liver - Gall Bladder Salivary Glands: - Secretes saliva that softens food, which aids in swallowing - Contains mostly water - Contains some enzymes that begins the chemical breakdown Provide a blanket drawing of the digestive system of the chicken. Provide markers. PPT slide 39-47 What are the 4 accessory digestive organs? What is the purpose of salivary glands?
- In pairs Salivary Glands Parotid: - Located under the ears - Ducts pass over the rear of the mandible (jaw) to near the middle of the cheek - Penetrate mucous membrane of the mouth & secrete saliva Salivary Glands Mandibular: - Mandibular pertaining to the jaw of an animal - Location: under & to the rear of the parotid glands - Ducts pass in the middle of the mandibles & open into the mouth under the tongue Salivary Glands Sublingual - Located: under mucous membrane around the outer sides of the tongue - Empty into the floor of the mouth Salivary Glands Classifications: - Serous Secretes clear, watery fluid Parotid & Mandibular glands - Mucous Secretes a thick, cloudy substance Serves as a protective coating to the mucous membranes - Mixed Secretes both serous & mucous Sublingual glands Pancreas: - An elongated, lobe-shaped organ - Location: beginning of small intestine, behind the liver - Exocrine functions: Largest function Produces digestive juices Pass through pancreatic duct & empty into the duodenum - Endocrine functions: Produce insulin, which lowers blood sugar Insulin goes directly into the bloodstream - Exocrine secreting externally via a duct - Endocrine secreting internally Where do the parotid glands penetrate? Where do the mandibular glands open into? Where do the sublingual glands empty into? What classification are the parotid glands in? What classfication are the mandibular glands in? What classification are the sublingual glands in? Where is the pancreas located? What is the endocrine function of the pancreas? What is the exocrine function of the pancreas?
Liver: - A lobed-shaped organ - Location: behind the diaphragm on the right side of the body - Receives blood from the hepatic artery - Purifies blood it receives from: Stomach Spleen Pancreas intestines - Produces bile (waste) Where is the liver located? What is the function of the liver? Gall Bladder: - Small, sac-like organ attached to the liver - Collects bile produced by liver Secretes it into the duodenum - Horses are the ONLY domestic animal that does not have a gall bladder Guided Practice: In groups of 4, describe the function of the Accessory Digestive Organs. Each person should use their own color marker. Draw pictures to help the group remember what each organ does. You must include all 4 Accessory Digestive Organs: 1. Salivary Glands 2. Pancreas 3. Liver 4. Gall Bladder What does the gall bladder do? Where is the duodenum? What domesticated animal does not have a gall bladder? Provide big post-its and markers. M. List the 3 digestive process actions; N. List the mechanical actions of digestion; Digestive Process Actions: - Mechanical Actions Mastication (chewing) Deglutition (swallowing) Regurgitation Gastric & Intestinal motility Defecation - Chemical Actions Actions of enzymes & glandual secretions - Microbial Actions Activities of bacteria & protozoa PPT slide 48 What are the 5 mechanical actions? Give two examples of chemical actions. Give two examples of microbial actions.
Appetite Influences: - Glucose level - Amount of feed in the stomach - Environmental temperature (hot or cold) - Appetite is controlled in the hypothalamus gland Absorption: - Digested nutrients pass through the walls of the digestive tract into the blood - Small intestine site for nutrient absorption Villi are responsible for collecting and absorbing nutrients Very little nutrients are absorbed in the mouth, esophagus, or stomach - Colon of large intestine site for water absorption PPT slide 49 What controls and influences the appetite of animals? PPT slide 50-51 How does absorption take place? Where is the site of nutrient absorption? Where is the site of water absorption? Digestion is complete after absorption has made the nutrients available for other parts of the body. O. Collect pictures of the parts of a real polygastric and monogastric digestive tracts; P. Distinguish the parts of the digestive tracts for each picture their classmates brought; and Homework: Collect at least 4 pictures of animal digestive tracts (2 polygastric and 2 monogastric). Try to find pictures that do not have the digestive tract labeled. In your groups, you will discuss what pictures go to which digestive tract and why. Then label the parts we discussed in class on the pictures. Q. Rearrange an incorrect digestive tract to make it correct. Guided Practice: I have made digestive tracts, but they are not in the correct order they should be in the animal. As a group decide where each piece should go and rearrange the digestive tract in the correct locations. Independent Practice: On your own, answer the practice paper on the information of the digestive system. If you have any questions of where to find an answer, first consult with a member in your group. If neither you nor the person you asked for help knows where the answer is to be located at, you may then raise your hand and I will come to you to help. Neither your group member nor I will give you the answer to your question! We will go over the answers as a class after everyone is thru.
Review & Evaluation Objectives will be reviewed before examinations. Exams will be developed based on onjectives as taught in class. Instructional Support A. References - IMS online curriculum B. Teaching Aids & Equipment - PowerPoint - Jumbo Post-It Notes - Markers - Cookies and Juice - Digestive System of a Chicken worksheet - Digestive System Puzzle Boards for each group - Question/Answer worksheet C. Facilities - Agriculture Classroom