Rat Dissection Lab. Background

Transcription

1 Anatomy & Physiology Corvallis High School Rat Dissection Lab Name: Class Period: Background Dissection of any organism or organ allows a 3-dimensional look at structural connections within the body. It is a valuable tool in learning and understanding these relationships. While texts can provide amazing and colorful pictures it does not replace the experience of seeing and manipulating the real thing. Imagine if you tried to learn about the structure of a car engine from only pictures but never had a look under the hood! Why dissect a rat? The Norway rat has been a valuable tool in medical research and is commonly used in studies of comparative anatomy. In other words, what you learn by dissection of the rat is broadly applicable to most other mammals. Even if your primary interest is human anatomy, the rat is very similar in construction, and most of the names that you will learn apply to human structures as well. Please note that one very important requirement for this lab is respectful treatment of your lab specimen. Your rat has been a living creature and that should be recognized through your treatment of the specimen throughout the duration of the lab. Any inappropriate behavior will result in your removal from the lab for the day. General Lab Instructions Laboratory Procedures Materials: You will use the same materials for the entire lab. Your group is responsible for the well being and cleanliness of these materials. Dissecting tray Dissecting tools - Scalpel - Scissors - 2 Wooden needles - Forceps - Metal Probe Preserved rat Goggles for each person Gloves for each person dissecting Aprons Lab Notes Colored pencils Pen/Pencil Handouts Beginning of each dissection day: Record specific dissection instructions given for the section. One person obtains the rat and gloves, goggles, aprons, materials. During each dissection: Follow specific instructions for each dissection section Read all directions before beginning Cut as little as possible!! Keep in mind that you are dissecting not butchering. Any cuts will alter the original structural relationships. There will be a daily work grade, straying from your task will result in your losing points on your rat lab. End of each dissection day: Wrap rat in skin and return to plastic bag; save all the dissecting fluid. Clean and dry lab tray, tools and work area, clean out the sink at your lab station Complete normal lab clean up (check your group activity/lab guidelines) Replace goggles, aprons and wash hands Safety Goggles and gloves must be worn at all times Caution: preserving fluid may squirt out when the first incision is made. Dissection tools are extremely sharp! Handle with care. The scalpel should never leave the table. Any cuts must be washed and sterilized promptly and reported to Mr. Rahman. If preserving fluid should get in the eye(s) they must be washed with the eyewash. Do not put any dissecting tools in your mouth EVER! Any accident must be reported to Ms. Luftig IMMEDIATELY!

2 Lab Writeup Procedures Binder set up: 1. Record in the table of contents as Rat Dissection Lab. For each section of this lab you will have an indented section in the table of contents. Example (do not use the exact example): Rat Dissection Lab Pg. 6 External Anatomy Pg. 7 Cardiovascular System Pg Make a title page for this lab with lab group names and rat name. On this page write the purpose for the overall lab. 3. Handouts should be included in your lab write-up in the appropriate sections General Instructions for each section: 1. Each section should have a title. 2. Sections must be in the order covered in class. 3. Look up all terms you are not familiar with. 4. For assigned terms to identify do the following: Identify on your rat Draw and label accurately and precisely on your diagram what is seen for each term, do NOT copy diagrams from handouts. Draw and label an analogous diagram of the human unless otherwise noted All drawings should be in color In a chart (see example below) 1. write a description of what you see in the rat 2. identify the function 3. comparative notes for human (i.e. location difference or functional difference, diagram if needed) 5. Answer the analysis questions for each section. 6. Some sections may also have microscope lab components and these should be kept in the same section. Details of these labs will be given at the time of each lab. Example: Term Description Function * Comparison Liver Big, smooth, lobed, brown organ in abdominal cavity; sits immediately caudal to diaphragm. Involved in digestive functions such as producing bile to help digest fat. Also involved in many metabolic functions including storage and release of glucose, detoxifying substances such as alcohol. *These can and will usually be done for homework not in class unless the rest of the dissection assignment for that day is complete. Terms and for Individual Sections External Anatomy (section1)-meet your rat Pinna (or aurical) external nares (nostrils) vibrissae incisors thoracic region eyelids anus hind and fore limbs papillae (nipples) tail external genitalia abdominal region Note: no corresponding human drawing is required for this section, but you must draw both a male and female rat. : 1. Is your rat is male or female? Be sure to also look at a rat of the opposite gender. 2. Choose two examples of external structures and explain how they connect to internal body structures/systems.

3 Integumentary System (section2) Dermis Epidermis Fur/hair Nails Skin your rat Skin your rat using the instructions given in class. You should remove the skin all in one piece. Save the skin for wrapping your rat in to prevent it from drying out. : 1. How do the fur on a rat and hair on a human serve similar purposes? How are they different in function and location? 2. What is the difference between the dermis and epidermis in location? 3. There are six functions of the Integumentary system identify 2 and describe each thoroughly in your own words. Bones and Skeletal System (section 3) *Omit chart for this section Draw the human skeleton as seen in your reference text and label all parts. Also draw and label the vertebral column as seen in your reference text. What are the special names for the first 2 cervical vertebrae? Label them on your drawing. 1. What are 4 functions of the skeletal system? Explain each. 2. Identify two ways muscles attach to bone and draw an example of each. 3. Explain how the skeletal system and the muscular system are connected to each other in both structure and function. 4. Compare and contrast the rat, human and one other skeletal structures. How are they skeletons specially adapted to the needs of the particular animal? Muscles (section 4) *Different chart for this section use second table not first *In addition to your rat diagram for this section, draw a human diagram and label the terms on the human diagramthe human drawing will have additional muscles listed below in another table Table 1: rat muscles Sternomastoid (in human External oblique Gluteus maximus sternocleidomastoid) Biceps brachii Achilles tendon Spinodeltoid (in human deltoid) Latissimus Dorsi Biceps femoris Gastrocnemius You should make a chart for humans including a description of the muscle (including location and shape); origin and insertion; when will you use this muscle (describe it's action)? LABEL on DIAGRAM(s) Table 2: Human muscles Trapezius Gluteus maximus Platysma Triceps brachii Biceps femoris Pectoralis major Brachialis Semitendinosous Serratus anterior Deltoid Semimebranosous Rectus abdominus Rhomboid major Gastrocnemius Biceps Brachii Latissimus dorsi Soleus Rectus femoris Pronator Teres Tibialis anterior Vastus lateralis Brachioradialis Extensor carpi radialis Vastus medialis Flexor carpi radialis Flexor carpi ulnaris Intercostal muscles Palmaris Longus Extensor carpi ulnaris Extensor digitorum

4 1. What is the main function of the muscular system? 2. What is the leverage relationship with bones? 3. Explain the different ways muscle fibers can be arranged and how it affects contractions. 4. There are two other types of muscles in the body besides skeletal muscles. Identify both of these and give an example of where each might be found. 5. Compare and contrast the rat and human muscular structures. Abdominal Cavity and Digestive System (section 5) Liver Stomach Esophagus Pancreas Spleen Small Intestine Gallbladder (not in the rat) Large Intestine - Cecum - Vermiform appendix - Colon - Rectum - Anus 1. Identify the function of the digestive system. 2. What are the names and functions of the sphincter muscles at either end of the stomach? 3. Choose two organs from the abdominal cavity and explain how the structure of each organ complements its function. 4. Which term is located primarily in the thoracic cavity? Which are located in the pelvic cavity? 5. The spleen is not a part of the digestive system. What system does it belong to and what is its function? 6. The liver is an extremely important organ of the body with very complex function. Explain and support this statement using specific examples. Urinary System (section 6) Kidneys Ureters Urethra Urinary Bladder Renal arteries Renal Veins Adrenal Glands 1. Describe the functions of the urinary system. 2. The adrenal glands are not a part of the urinary system. What system do these belong to? What are the two parts of the adrenal glands and what is the function of each part? 3. Kidney failure is a life-threatening condition. Explain what this is and why it is life threatening. Support your answer with specific examples. 4. The renal arteries and veins are not part of the urinary system. What system are they part of? What is the function of each? How do they relate to the kidneys?

5 Reproductive System (section 7) **Note: You are responsible for being able to identify both male and female, so switch rats with another group to view the opposite gender. You also need to have both male and female diagrams and terms chart. Male Female Testes Ovary Scrotum Oviducts (Also called Fallopian Penis Tubes) Seminal Vesicle Uterus (Uterine horn in rat) Vas Deferens Vagina Epididymis Fate awaits U Prostate Gland Vesicular Gland Coagulating Gland Ampullary Gland Cowper s Gland (bulbourethral) Preputial Gland 1. What is the function for the reproductive system? Address both male and female systems in your answer. 2. Trace the life of a sperm from initial development until it leaves the male body. State the locations of each stage and the functions of the different organs that it passes. 3. How is the clitoris in the rat different than that of a human? (hint: think urinary system) 4. Where is the egg in a female developed, fertilized, and where does the fertilized egg develop (fetal development)? 5. Explain why there is such a structural difference between the human uterus and the rat uterine horn. Include the structure and function relationship in your explanation. Thoracic Cavity (section 8) Lungs Heart Trachea Thymus Diaphragm Arteries Veins InferiorVena Cava Descending aorta Aortic Arch Common Carotid Arteries External Jugular Veins 1. Describe the importance of the rib cage in the thoracic area. 2. Why does the rib cage have cartilage where the ribs and sternum attach? 3. Note the rings of cartilage on the trachea of the rat, what are these rings for? 4. Identify the appropriate body system for each of the above organs. (More than just the cardiovascular and the respiratory are represented) 5. The lungs surround the heart on both sides. They are not of the same size, nor do they have the same amount of lobes. Why?