Lab 1 – Introduction to Physiology Labs PDF

Lab 1 – Introduction to Physiology Labs In order to complete the lab in the required time, you must come to the lab well prepared, and with all lab reading done. Please note that spelling counts – a mistake will be half value deduction and zero if unrecognizable. Read the entire lab before comin...

Lab 1 – Introduction to Physiology Labs In order to complete the lab in the required time, you must come to the lab well prepared, and with all lab reading done. Please note that spelling counts – a mistake will be half value deduction and zero if unrecognizable. Read the entire lab before coming to lab. Come prepared with questions you have regarding the material presented in the lab manual. Complete the WHMIS training found on your D2L site. Watch the Biology Laboratory Orientation video posted on D2L. Read the Safety Practices in the Laboratory document posted on D2L. Read the posted Scientific paper and answer the pre-lab questions before coming to lab. Note: Be prepared to attend a library session, where attendance is required. Await further details of this mandatory session from your instructor. Post-Lab Assignments are due 24 hours after you leave the lab. These are found on your D2L site. You are free to work together with your peers; however, you must complete and submit the assignment individually. You are encouraged to work together using lab materials such as your lab manual and textbook to complete. Each student must submit their own PLA. You will have unlimited attempts within that 24 hours to achieve 10/10. Key terms you will be responsible for: WHMIS, hazard symbols, Scientific method, observation, hypothesis, independent variable, dependent variable, control group, experimental group, controlled variables, method and materials, introduction, data, results, graph, table, x-axis, y-axis, journal types (primary or secondary scientific sources), abstract, discussion, conclusion Objectives for Lab 1 1. Be familiar with MRU lab safety. Identify WHMIS labels. Describe safe handling and disposal of body fluids, chemicals, and sharp items. 2. Introduce and reinforce the steps and purpose of the scientific method. 3. Introduce the format of scientific literature and types of literature. Scientific paper is posted under Lab 1 on D2L. 1 Topics MRU lab safety. The Scientific method- Two stories about the scientific method for discussion. Design a gummi bear experiment. Reading scientific literature. PRELAB: Questions on posted scientific paper (Energy Drink vs Caffeine paper) Randomized Controlled Trial of High-Volume Energy Drink Versus Caffeine Consumption on ECG and Hemodynamic Parameters Answer the following questions on the research article (you need to be prepared to discuss these in lab): a) What is the research question (hypothesis) addressed by the study? b) What was the primary end point of assessment for the study? Provide a brief explanation of what that end point means. c) Based on the paper, list four different populations that should consider exercising caution when consuming energy drinks. d) Explain briefly what the research found. 2 MRU Lab Safety Chemical Materials Some lab exercises involve the use of chemicals; therefore, you must be familiar with the WHMIS labelling system. WHMIS stands for Workplace Hazardous Materials Information System, and the WHMIS symbols are standard for all labs. WHMIS is a national system designed to ensure that all employers obtain the information they need to inform and train their employees about the safe handling and use of hazardous materials. The goal is to reduce the incidence of illnesses and injuries resulting from the use of hazardous materials. You must complete the WHMIS training provided by your lab instructor in order to identify and understand the hazardous controlled products utilized in our activities. Science labs generate high amounts of hazardous and biohazardous waste that must be disposed of properly to protect ourselves and the environment, therefore MRU has established appropriate hazardous waste disposal procedures that must be adhered to by all members of the university. To protect yourself, others, and the environment, a variety of chemical and biohazard waste disposal containers are provided throughout the lab space. All solid and liquid chemical waste are collected in waste disposal containers with their appropriate hazard symbols. Regardless of how non-toxic a chemical may be, the disposal of hazardous waste down the drain or in general landfill is strictly prohibited. Waste containers are clearly labelled with a list of their desired contents and WHMIS pictograms (where applicable). It is important you understand why chemicals must be segregated into different containers. A summary table of chemical and biological waste procedures is found on the instructor’s desk. Always ask the instructor if you are unsure where to dispose materials. 1 Activity 1 - WHMIS labelling Complete the following by filling in the name and a brief explanation of each symbol. 2 Watch the Biology Laboratory Orientation video, filmed by the MRU Biology technologists, which summarizes the rules and regulations that help keep you and the environment safe. This video is posted on your Blackboard site, and will help you complete the activities below: Activity 2 - Identifying chemical disposal containers Using the resources available to you, answer the following questions based on proper chemical waste disposal procedures. Your answers should reflect MRU’s policies and procedures. a. Match the following examples of chemically contaminated materials with their proper waste container. A. B. C. D. Corrosive: Corrosive: Bases Acids ___- You accidentally knocked over a glass cylinder while reaching for a beaker in the cabinet. ___- Test tubes contaminated with glucose. ___- You need to empty a beaker of sodium hydroxide before you clean it with soap and water. ___- A solution of hydrochloric acid, water, and pH 7 buffer. ___- Paper towels used to clean your work area at the end of the lab. ___- Gloves used to handle sodium chloride, glucose, and starch. ___- Broken test tubes found at the bottom of the product box. ___- Microscope slides with the letter ‘e’ printed on them. ___- You poured 75 mL sucrose into your beaker, but you only need 50 mL. b. Draw the maximum fill line on the following liquid waste containers. 10 L 4L 2L 3 Activity 3 - Identifying biohazard disposal containers Read the Safety Practices in the Laboratory document and answer the following questions based on proper biohazard waste disposal procedures. Your answers should reflect MRU’s policies and procedures. a. Where would you dispose of the following items? ____________ - Prepared microscope slides with blood and saline solution. ____________ - Capped syringe needle contaminated with human blood. ____________ - Gloves soiled with traces of blood. ____________ - Chicken eggs soaked in 30% sucrose. ____________ - Bench coat with human urine spilled upon it. ____________ - Razor blade used to dissect a preserved sheep brain. ____________ - Expired bottle of sheep blood. ____________ - Microcapillary tubes used to separate blood into its formed elements. ____________ - Specimen cups filled with human urine. ____________ - Plastic bottles filled with blood mixed with saline and sugars. ____________ - Preserved sheep kidneys. ____________ - Cotton balls and alcohol swabs contaminated with human blood b. Provide an example of waste (not listed above) that could be disposed of as: i) Biohazardous anatomical waste - __________________________________________. ii) Biohazardous materials waste - ___________________________________________. iii) Sharps container - _____________________________________________________. 4 Safety Equipment and Procedures There are several safety items in the laboratory. It is extremely unlikely that you will ever need to use any of them, but please note the locations of the following: First aid kit Telephone Fire exits Fire extinguisher Nearest pull-station fire alarm Emergency shower Fire blanket Eye wash station Read the guidelines for Emergency Procedures, Spill Response and Accidents or Incidents that are posted in the lab. The phone numbers for Campus Security are posted by the telephone. o Emergency: 403-440-5900; Non-emergency: 403-440-6897 Note that an incident report is required not only for accidents or incidents, but also for near misses. Please make sure to report these to your instructor, so that a report can be made that may help to improve lab safety in the future. Remember it is always your job to ensure that the lab is clean BEFORE you leave. The lab instructors will guide you in this process. Activity 4 - The scientific method The systematic process of acquiring knowledge of the natural world is known as the scientific method, which typically consists of four steps. 1. Making an observation: May occur during experimentation or it may be garnered from researching scientific literature. Questions naturally arise from observations. 2. Formulate a hypothesis: A possible explanation for the observation but isn’t formulated as a question you are trying to answer. A simple hypothesis is often described as an “if…then…” statement. “If “you change _______ (independent variable) “then” this will happen______ (dependent variable). The hypothesis must also be testable. 5  3. Design an experiment to test the hypothesis. The experiment needs to include: Independent variable, which is set by the experimenter. Dependent variable, which is changed by the independent variable and measured by the experimenter. A vital component of any experiment is the control or control group, which is part of the experiment in which the independent variable is not altered. In other words, a set of experimental samples or subjects aren’t exposed to the independent variable. This allows the scientists to know that the changes in the experiment are due to changes in the independent variable and no other factors. It is also important to limit these potential other factors that could affect the outcome of the experimental group(s). The idea is to keep all the conditions as similar and constant as possible throughout the experiment. An experimenter can set particular value(s) or parameters for the duration of the experiment to keep that variable the same or controlled. Such controlled variables in a plant experiment might be the humidity, amount of water or light intensity exposure for the duration of the experiment. 4. Interpret the data: Data are often displayed on graphs and in tables. When plotting graphs your independent variable goes on the x-axis (horizontal axis) and the dependent variable is along the y-axis (vertical axis). Interpretation of data involves the use of statistics to examine the reliability of the results to determine if the data is based on real phenomena. After much repetition and acceptance of the hypothesis a scientific theory is formed. Scientific literature is used as a research tool to investigate current studies in the field. The main sources of scientific information are journals, books, and the internet. A scientific journal is a collection of science-based articles including original research, reviews, and editorials. Original research articles present methods, data, results and conclusions about scientific questions that have never been answered before (i.e., it is "original" research). The authors of an original research paper actually designed and conducted the experiments and formed the conclusions, and so, we describe these types of articles as primary research. Since original research articles are presenting new, never-before-published information, these publications must undergo rigorous fact-checking by other experts in the particular field of research (a process known as peer review). Once many original research articles have been published on a similar topic, other experts (who may not have actually performed any experiments) will summarize the results of previously published works into a larger, more broadly themed article that reviews the current state of knowledge on a topic. These review articles are secondary sources of information and must also undergo the peer review process to ensure the information presented is accurate. Scientific journals can also publish editorials, or opinions, in short, easily read articles. These are NOT peer reviewed as they represent someone's opinion not empirical facts (even if the opinion is that of a well-known scientist and expert). 6 Books can also be a source of scientific information. A science textbook summarizes the main concepts in a particular scientific field. A drawback to the use of textbooks is they don’t always carry the most current scientific findings as they often take years to write and publish. Internet searches can provide literature, but information may not always be reliable. It’s important to recognize that information found in books and on the internet has typically not been peer-reviewed. Consider both scenarios. Be prepared to discuss these in your group and with the class. The Strange Case of BeriBeri In 1887 a strange nerve disease attacked the people in the Dutch East Indies. The disease was beriberi. Symptoms of the disease included weakness and loss of appetite; victims often died of heart failure. Scientists thought the disease might be caused by bacteria. They injected chickens with bacteria from the blood of patients with beriberi. The injected chickens became sick. However, so did a group of chickens that were not injected with bacteria. One of the scientists, Dr. Eijkman, noticed something. Before the experiment, all the chickens had eaten whole-grain rice, but during the experiment, the chickens were fed polished rice. Dr. Eijkman researched this interesting case. He found that polished rice lacked thiamine, a vitamin necessary for good health. 1. State the problem 2. What was the hypothesis? 3. How was the hypothesis tested? 4. Should the hypothesis be supported or rejected based on the experiment? 5. What should be the new hypothesis? 7 How Penicillin Was Discovered In 1928, Sir Alexander Fleming was studying Staphylococcus bacteria growing in culture dishes. He noticed that a mold called Penicillium was also growing in some of the dishes. A clear area existed around the mold because all the bacteria that had grown in this area had died. In the culture dishes without the mold, no clear areas were present. Fleming hypothesized that the mold must be producing a chemical that killed the bacteria. He decided to isolate this substance and test it to see if it would kill bacteria. Fleming transferred the mold to a nutrient broth solution. This solution contained all the materials the mold needed to grow. After the mold grew, he removed it from the nutrient broth. Fleming then added the nutrient broth in which the mold had grown to a culture of bacteria. He observed that the bacteria died. 1. Identify the problem. 2. What was Fleming's hypothesis? 3. How was the hypothesis tested? 4. Should the hypothesis be supported or rejected based on the experiment? 5. This experiment led to the development of what major medical advancement? 8 Activity 5 - The gummi bear experiment Questions (choose ONE): Will changing the water temperatures affect how a gummi bear dissolves in water? Will a dismembered gummi bear dissolve more? Does the color of gummi bear affect how a gummi bear dissolves? Once you have discussed the experiment (in your groups and with the broader class), rethink the experiment. How would you have designed the experiment to factor in everything you discussed? Use the following flow chart (on the next page), and remember to be as complete as possible, including a list of materials, a complete method (someone should be able to read your method and perform your experiment). Finally, watch this example of a ‘good’ experiment. Is there anything else you would have done differently? 9 10 Activity 6 - Reading a scientific paper Randomized Controlled Trial of High-Volume Energy Drink Versus Caffeine Consumption on ECG and Hemodynamic Parameters The lab instructor will “walk you through” the process of reading a scientific paper and discuss all the sections found in a typical paper. This will be very beneficial to you as your Podcast Project later in the semester requires you to search for and use scientific papers. 1. Is this paper designed for a “layman”? Why or why not? 2. Based on the science presented would you use a high-volume energy drink to boost your physical and mental alertness? Why or why not? 3. Name 3 abnormal heart rhythms that were listed in a review of energy drink associated adverse cardiovascular events. Briefly define each of the terms. 4. There were several terms used in the study to describe the methods used in this paper, can you briefly describe the following? Double-blind study Random order/randomized Crossover design 5. Name one limitation of this study. What future considerations were mentioned in the conclusions to the study? 11 6. Is this paper a secondary or a primary source paper? 7. What are the distinct sections of the paper? 12 Review Questions for Gummi Bear Experiment Choose one of the 4 topics listed above to answer the following questions: 1. State a concise hypothesis in one sentence. Keep in mind that a hypothesis is a statement and not a question. Use an “if – then” statement when composing your hypothesis. Remember to keep in mind what your variables are and to be clear and concise. 2. Identify all the variables in this experiment: independent, dependent and controlled variables. 3. Identify your control group(s) chosen for this experiment. Explain why you chose this to be your control group. 4. List all the materials used in your experiment; be specific. 13  5. Describe the detailed method that you would use for this experiment. Please use written sentences in paragraph format with appropriate punctuation. The methods of your experiment must test your hypothesis. When answering this question ask yourself if a peer were to repeat this experiment using your methods, are they clear and concise enough for them to get the same results as you. Sources used in writing this lab include Derrickson, B. (2019). Human Physiology (2nd ed.). Hoboken, NJ: John Wiley& Sons, Inc. 14 Lab 2 – Plasma Membranes: Cell Transport Mechanisms In order to complete the lab in the required time, you must come to the lab well prepared, and with all lab reading done. Please note that spelling counts – a mistake will be half value deduction and zero if unrecognizable. Read the entire lab before coming to lab. Come prepared with questions you have regarding the material presented in the lab manual. Prepare for Quiz 1 (material from lab 1) which will take place at the beginning of the lab. Key terms: Brownian movement, kinetic energy, solute, solvent, concentration, concentration gradient, diffusion, rate of diffusion, osmosis, passive transport, plasma membrane, agar, potassium permanganate, methylene blue, selectively permeable membrane, dialysis tubing, non-living membranes, living membranes, isotonic, hypertonic, hypotonic, tonicity, hemolysis, crenation, transparent, opaque, saline, percentage of change, figure caption, APA formatting Objectives for Lab 2 1. To look at the properties of the cell membrane and to investigate transport mechanisms used in cells 2. To look at how transport rates can be influenced 3. Look at transport across a variety of different types of membranes 4. To set up an experiment and collect data 5. To analyze and graph results in APA format Topics: Demonstration of Brownian movement Observing diffusion through a solid Observing diffusion and osmosis through a non-living membrane (dialysis tubing) Demonstration of osmosis through a living membrane (red blood cells) Data collection on osmosis through a living membrane (egg) Design a graph from collected data (APA format) Remember it is always your job to ensure that the lab is clean BEFORE you leave. The lab instructors will guide you in this process. 1 Activity 1- Brownian movement Watch the following videos (What is Brownian motion? and Diffusion Animation) and answer the following questions. Brownian movement is the random drifting of particles suspended in a fluid (a liquid or a gas). It occurs because molecules are in constant motion. It is dependent on the media (liquid /gas/solid) and on temperature (the higher the temperature the ____________________ the motion). Understanding the random movement of particles is important to understanding the concepts of diffusion and osmosis. Questions: 1. What process do you observe on this slide? (watch until 7:12) 2. What is the physiological significance of Brownian movement in Biological systems? The exercise on Brownian motion showed that all molecules are in constant motion and that movement is random. When a difference in concentration exists (a concentration gradient) molecules will tend to move from an area of high concentration to an area of low concentration passively. The rate of this movement is dependent on: a) b) c) 2 Activity 2 - Observing diffusion through a solid – agar gel This activity was filmed in MRU labs to demonstrate how different sized molecules will diffuse at different rates. Watch this video, which follows these instructions: Procedure 1. Make two wells in the agar plate with a straw. 2. Carefully put one drop of Dye Molecule #1 in one well, and one drop of Dye Molecule #2 in the other well. Try to get the solutions only in the well, and equal amounts in each well. 3. Record the start time. Use a ruler to measure the diameter of each ring after 5 minutes, and again after 30 minutes. From these measurements, calculate the rate of diffusion for each dye. Complete the table below with your results. Diffusion (mm) Calculated Rate Molecular Diffusion (mm) after 30 of Diffusion Weight after 5 minutes minutes (mm/min) Dye Molecule #1 “___________” Dye Molecule #2 “___________” Questions: 1. Which molecule diffuses more quickly? 2. What do these results tell you about the molecular weight of the methylene blue and potassium permanganate? 3  3. How would performing this experiment in a liquid affect the rate of diffusion? 4. What is the relationship between molecular weight of the molecule and rate of diffusion? How would you calculate the rate of diffusion? Activity 3 - Observing diffusion and osmosis through a nonliving membrane From the previous activities we observed that diffusion is random and dependent on several physical factors. Now we want to observe how a selectively permeable membrane affects diffusion. In this activity, the dialysis membrane/tubing has predetermined sized pores, and therefore is selectively permeable. Only small molecules will pass through the pores. This activity was filmed in MRU biology labs. Watch this video, which follows these instructions: Procedure 1. Half fill the beakers as follows: Beaker 1: Water Beaker 2: 40 % glucose Beaker 3: Water Beaker 4: Water 2. Fill the dialysis tubing as follows: 10 ml of 40 % glucose 10 ml of 40 % glucose 10 ml of 10 % NaCl 10 ml of starch solution 3. Dry off the filled sac and record the weight of each one in the chart below, then place each sac in the appropriate beakers (1-4) and record start time ______. Leave the sacs in the solutions for 1 hour. 4  Change in % Change in Initial Mass (g) Final Mass (g) Mass (g) Mass Sac 1 (40% glucose) in beaker 1 (water) Sac 2 (40% glucose) in beaker 2 (40% glucose) Sac 3 (10% NaCl) in beaker 3 (water) Sac 4 (1% starch) in beaker 4 (water) 4. For each sac calculate if the mass went up, down or stayed the same. Record this on the above chart. Calculate the percentage change in mass and record. How will you calculate the percentage change in mass? Questions: 1. What does it mean when a membrane is described as being selectively permeable and why is it important to the body? 2. Identify the solutes and solvents in this experiment. 5 3. For each of the 4 sacs, which direction was of net movement of osmosis? How do you know? 4. How might you test to see if the solute moved across the membrane? 5. If solutes cross through a membrane, is it considered osmosis? 6. What might limit the movement of a solute crossing the membrane? 7. How can you relate this exercise to the human body in terms of intracellular fluid, extracellular fluid and plasma membrane? 8. Does the concentration gradient have a role in diffusion/osmosis? 9. When does the net movement of solutes and solvent stop? 6 Activity 4 - Demonstration of osmosis through a living membrane (red blood cells) When water movement (osmosis) occurs across a living selectively permeable cell membrane, cell volume is altered and cell functions can be disrupted. Tonicity is a term used to describe the effect that a solution of a certain concentration will have on cell volume. For activity 4, you will place erythrocytes into solutions that will be isotonic, hypotonic and hypertonic to the red blood cells (RBCs) to observe the effect on the cell. Can you describe what those terms mean? Isotonic: Hypotonic: Hypertonic: The following video shows RBCs suspended in a test tube containing physiological saline. This demonstration was filmed in MRU biology labs. Watch the video here, which follows the instructions below: Procedure Be careful not to cross contaminate solution bottles 1. Mark 3 clean test tubes with numbers 1 – 3 and add solutions to them as follows: Tube # Add 1 2 ml of 0.9% NaCl (saline) + 2 drops of sheep blood 2 2 ml of distilled water + 2 drops of sheep blood 3 2 ml of 10% NaCl + 2 drops of sheep blood 2. Check each tube for evidence of hemolysis. If the cells have burst, the test tube contents will be transparent. Record your observation in the table below. 7  3. Watch this video, using the following timestamps: 0.9% NaCl, water, 10% NaCl (if remote), or prepare a wet mount from each of the 3 test tubes and examine the cells under a compound microscope, and record your observations in the table below. Ask your instructor for assistance with usage of the microscope at this station. 4. For any of the tubes where there have been changes in the appearance of the cells, record the name of the process that occurred in the table below. Use scientific terms where applicable. 5. Use appropriate disposal containers for the contents of the test tubes, disposable pipette, slides, test tubes and gloves. Tube Contents Appearance Microscopic Name of Tonicity of # of test tubes appearance process the solution (transparent of cells (if a change to the cell or opaque) has occurred) 1 0.9%NaCl and red blood cells 2 Distilled water and red blood cells 3 10% NaCl and red blood cells Questions: 1. Describe how extracellular solute concentration of different solutions (tonicity) can impact water movement across the plasma membrane. 2. How does this movement of water affect the shape of the cell? 3. A solution of 9% NaCl would be ________________________ (tonicity) to a red blood cell and the cell would________________________ (scientific term).A solution of 0.5% NaCl would be _________________________(tonicity) to a red blood cell and the cell would_____________________________ (scientific term). 8 Activity 5 - Demonstration of osmosis through a living membrane (egg) In this activity, you will observe and measure how water moves through the membrane of an egg exposed to distilled water and a sucrose solution (30%). This demonstration was filmed in MRU biology labs. Watch the video here, which follows the instructions below: Procedure Wear gloves if you are participating in the data collection for this activity! Your instructor will provide you with specific instructions. 1. The deshelled eggs (2) will initially be dried GENTLY and weighed. The value will be recorded in the chart provided for the time of 0 minutes. One egg will be gently placed in the beaker containing distilled water and the other will be gently placed in the sucrose solution (Note the time______). 2. From the start time each egg will be removed, dried, weighed and the value recorded on the chart at 20, 40 and 60-minute marks. Be sure to put the egg back gently in the appropriate solution as to not mix them up or break the egg, this will impact your data. Calculate the change in weight of each time point compared to the weight of the eggs before submersion. Egg 1 in 30% sucrose solution Egg 2 in distilled water solution Weight Weight % Change % Change Time Weight Change Weight Change ** ** * * 0 min No change 0 No change 0 20 min 40 min 60 min 𝑊𝑒𝑖𝑔ℎ𝑡 𝑐ℎ𝑎𝑛𝑔𝑒 * Weight Change = Weight’x’min – Weight0min || ** % Change = [ 𝑊𝑒𝑖𝑔ℎ𝑡0𝑚𝑖𝑛 ] x 100 9 Review questions to be done in lab and discussed with Instructor before you leave 1. Describe how the weight of the egg soaked in distilled water changed over time? Which direction did osmosis occur? Is distilled water a hypotonic, isotonic or hypertonic solution to the egg? 2. Describe how the weight of the egg soaked in sucrose solution changed over time? Which direction did osmosis occur? Is a sucrose solution a hypotonic, isotonic or hypertonic solution to the egg? 3. Fill in the above table with the data collected for each egg. Calculate the weight change in mass (grams) for each egg and then calculate the percentage (%) of change measured in the weight of each egg at each time interval compared to initial weight of egg. 4. Identify all the variables in this experiment: independent, dependent and controlled variables. 5. Identify your control group for this experiment and explain why this is the control. 10 6. In this course we will use APA formatting, which you will find posted on your D2L site. Next, you will make a figure and will use APA formatting when constructing your graph You can make a computer-generated graph or draw one out (graph paper provided below). a. With the calculated percentage of change in weight, make a line graph showing the effect of distilled water and sucrose on the weight of each egg. Indicate the independent and dependent variables with their respective axis (X and Y) and include the appropriate units. Your scale on each axis should be consistent and fit your data, typically you add one more increment on the scale past your last data point. Be sure to clearly label or indicate which line represents which egg. This can be done in the figure caption or in a legend on the top right-hand corner of the graph. b. Your graph will also need a detailed figure caption. A proper figure caption gives the reader all the important information needed to understand the graph. The first sentence acts like a title and write it to show the relationship between the variables displayed and the results can be included as well. The reader should not have to consult the methods or results section to understand the figure. It should contain comprehensive but concise details about the variables, how they were measured, when they were measured and for how long if applicable. It is also important to include information about the subject/organism used in the experiment and conditions under which the measurements were taken. For example: Figure 1 DrugX inhibits the enzymatic reaction on protein digestion in the stomach of 210 male rats. 10mg of Drug X was ingested and measured through a blood draw, to measure level of SubstanceY, every hour for 12hours. 11 12 Activity 6 - General principles for designing a graph Graphs are tools that allow you to see relationships between two or more variables. Variables are factors that can have different values in different circumstances. Graphs help scientists to quickly evaluate and understand data. In some cases, they can help interpret complex trends in data. A graph consists of two straight lines set at right angles. The vertical line is the y-axis, or ordinate. The horizontal line is the x-axis, or abscissa. The intersection of these two lines is the origin of the graph, and the origin is usually set at zero. Generally, one variable (the dependent variable on the y-axis) will change as a result of a change in another variable (the independent variable, on the x-axis). The independent variable may have different values on the graph, not as a result of a change in the dependent variable, but rather as a factor that is manipulated by the experimenter. For example, the height and age of children are variables. Height is the dependent variable because it changes due to a change in age. Age is the independent variable because although it changes, this change is not due to a change in a child's height. If the relationship between the x values and the y values (i.e., between the independent and the dependent variables) is such that as one increases, the other also increases, there is a direct relationship between the variables. For example, imagine that you perform an experiment to find out how the size of the concentration gradient influences the rate of diffusion of a substance across a membrane. You would measure the rates of diffusion in different concentration gradients. Because the rate of diffusion in the experiment depends on the concentration gradient, rate of diffusion is the dependent variable. The data points from the experiments can be plotted on a graph as shown in Fig. 1, and a line of best fit can be drawn to connect the points as closely as possible. A quick glance at the graph then gives you an easy way to see that the relationship between the two variables is not only a direct relationship, but in this case, it is also a linear relationship, because the line of best fit is a straight line. The line of best is placed on the graph by performing linear regression, which can be done easily using Microsoft Excel. You can also determine the slope of the line and the “goodness of fit” by examining the R2 value. 13 Figure 1 The direct relationship between rate of diffusion of particles of dye as a function of the concentration gradient of these particles in water at 200C. The line of best fit is not always a straight line. For example, imagine that you want to investigate the effect of concentration of substrate (e.g., sucrose) on the rate of activity of an enzyme (e.g., sucrase). You are given a solution containing the enzyme sucrase, which you add to tubes containing different concentrations of sucrose. You perform tests to see how quickly the sucrose is broken down to the monosaccharides glucose and fructose. The graph of the experimental data would resemble Figure 2. The relationship in this graph is not linear, but rather is curvilinear. Note that the first part of the line is linear, but it then curves and levels off. Figure 2 The relationship between the rate of an enzyme reaction as a function of substrate concentration at 200 C. 14 Question: 1. What could explain the appearance of the graph in Figure 2? Why doesn’t the line continue upward indefinitely? Note: The two graphs in Figures 1 and 2 above are to show the principles of graphing, and do not represent real data. Therefore, there are no units on the axes. In your graphs for lab reports, make sure you always include both what you are measuring as well as the appropriate units on the x and y axes. Sources used in writing this lab include Derrickson B., (2019). Human Physiology (2nd ed.). Hoboken, NJ: John Wiley& Sons, Inc. 15 Lab 3 - Blood and the Immune System In order to complete the lab in the required time, you must come to the lab well prepared, and with all lab reading done. Please note that spelling counts – a mistake will be half value deduction and zero if unrecognizable. Read the entire lab before coming to lab. Come prepared with questions you have regarding the material presented in the lab manual. Prepare for Quiz 2 (material from lab 2) which will take place at the beginning of the lab. Key terms: Blood connective tissue, plasma, pH, formed elements, erythrocyte, biconcave, leukocyte, neutrophil, lymphocyte, monocyte, eosinophil, basophil, platelet, hematocrit, buffy coat, anemia, iron-deficiency anemia, hemoglobin, hemoglobinometer, antigens, antibodies, agglutination, transfusion reaction, antigen-antibody complex, universal donor, universal recipient, pathogens Objectives for Lab 3 1. To identify important components of blood and to understand their physiological properties. 2. To perform a hematocrit and hemoglobin test and understand the purpose of testing. 3. Understand differences among ABO blood types with Rh factor. 4. Determine blood type with simulated blood types. 5. An overview of the immune system and start to develop an understanding of human immunity. Please review the Safety Practices in the Laboratory document, and the Biology Laboratory Orientation video both found in the Lab Safety tab on D2L. In this lab you must wear gloves and eye protection! Topics: Characteristics of plasma Examining the formed elements of blood Blood tests – hematocrit and hemoglobin content Blood typing Spread of a pathogen activity Remember it is always your job to ensure that the lab is clean BEFORE you leave. The lab instructors will guide you in this process. This is especially important this week because of the use of blood in the lab. 1 Composition of Blood Activity 1 - Characteristics of plasma Blood is a _____________________________ tissue with a liquid matrix called ____________. Blood also has 3 kinds of formed elements (use scientific names) which are: 1. 2. 3. In this activity, you will observe the pH, colour and clarity of pH. Wearing gloves, follow the instructions and answer the questions below: 1. The pH of the plasma measures ________________________. Is this what you expected? 2. The color of the plasma is _______________________. Is this what you expected? 3. With gloves on, put your fingers into the plasma. How would you describe the consistency of the plasma? Thick, watery, sticky, granular? For virtual labs, predict what you think this plasma might feel like. 4. Use the appropriate waste disposal containers upon completion of this exercise. Plasma contaminated pH paper, gloves, and paper towels would go in __________________________________. 2 Activity 2 - Examining the formed elements of blood 1. Watch this video, which provides a good overall description of a blood smear and describes the microscopic details of the formed elements of blood. 2. Study the formed elements of blood models provided. 3. Fill out the table below, based on the video and blood models. Draw what this What is the Formed Describe Does it have formed element general Element nucleus granules? looks like function? 1. Erythrocyte 2. Platelet 3. Leukocytes: a. Neutrophil b. Lymphocyte c. Monocyte d. Eosinophil e. Basophil Activity 3. Blood tests 3 There are many clinical tests that can be done on blood. A common blood test is to check for anemia in a patient. Anemia is a condition in which the oxygen-carry capacity of the blood is reduced. It can result from reduced numbers of erythrocytes, and is observed with a decrease in the patient’s hematocrit. Iron-deficiency anemia presents with a decrease in amount of hemoglobin (iron is a component of hemoglobin) in the blood. This will be measured in our lab with a hemoglobinometer. Perform the following 2 tests, in groups of 4, on the sheep blood provided. Make sure you understand the physiological significance of each of these tests. If you have any questions ask your instructor for clarification. A. Hematocrit – Measures the percentage of whole blood that is occupied by packed cells (formed elements). If the patient has less than the normal values this could indicate anemia as there are fewer erythrocytes available to carry oxygen. Together in your group, complete the activity below. If working remotely, refer to this link. 1. Fill the tube with blood (about ¾ full). 2. Seal the ends of the tube with tube sealer. 3. Place the tube in the hematocrit centrifuge on opposite sides (check with your instructor about balancing these tubes). 4. The centrifuge will spin the tubes to separate the plasma from the formed elements. 5. Measure the height of the formed elements (erythrocytes) and the total height of the column (included both the clear plasma and the erythrocytes) with the ruler provided. 6. Calculate the percentage of formed elements (RBC, WBC and platelets), using the following formula: Length of the element column (mm) x 100 = _______________% Length of the total column (mm) Normal hematocrit for sheep blood is: 27-45% Normal hematocrit for human blood is: 40-54% for males and 38-46% for females. 7. Use appropriate waste disposal containers upon completion of exercise. Where do used capillary tubes and gloves go? Refer to the Safety Practices in the Laboratory document. 4 Questions: 1. What is your calculated hematocrit for the sheep blood? Show your work. Does the sheep sample exhibit anemia? 2. Can you see the pale buffy coat layer? This layer is occupied by the leukocytes and platelets which make up about 1% of the formed elements. This layer is more dense and sits under the plasma but less dense the erythrocytes, therefore sits between the plasma and erythrocytes. 3. What are normal ranges for a male and a female hematocrit? Draw a capillary tube and add the percentage values for formed elements and plasma for a male. 4. What can the hematocrit tell us? What if the values are higher or lower than the normal, what might that indicate? B. Hemoglobin using the hemoglobinometer – Hemoglobin is found inside the erythrocyte and is an oxygen-carrying protein. Therefore, if there is less hemoglobin in the erythrocyte then less oxygen can be transported throughout the body. Together in your group of 4, complete the activity below. 1. Fill the microcuvette with sheep blood. 2. Be sure to put the blood into the slot between the plastic edges not on top. 3. Wipe any excess blood off the surface of the microcuvette. 5  4. Turn the hemoglobinometer (hemocue) on. 5. When three dashes are observed place the microcuvette in the slot and close drawer. 6. The value will come up after 10-15 seconds. Normal hemoglobin level for sheep blood is: 90-150g/L Normal hemoglobin level for human blood is: 130-180g/L for males and 120-160g/L for females 7. Use appropriate waste disposal containers upon completion of exercise. The used microcuvette goes in ___________________ and gloves would go in ___________________________________. Refer to the Safety Practices in the Laboratory document. Questions: 1. Do the hematocrit and hemoglobin content of blood measure the same thing? Explain. 2. What were your measured results for the hemoglobin content in the sheep sample? 3. Did it fall within the normal range? Why or why not? 4. What is hemoglobin and why is it important? 5. Notice the yellow substance on the tip of the microcuvette, it causes the erythrocytes to hemolyze prior to measuring the hemoglobin content. Would the results be different if this didn’t take place? 6 Activity 4. Blood typing ABO blood typing designates the presence or absence of two antigens (agglutinogens), type A and type B. People whose erythrocytes have A antigens on their erythrocyte membrane surfaces are designated blood type A, and those whose erythrocytes have B antigens are blood type B. People can also have both A and B antigens on their erythrocytes, in which case they are blood type AB. People with neither A nor B antigens are designated blood type O and are considered universal donors. Individuals with type A blood have naturally preformed antibodies (agglutinins) to the B antigen circulating in their blood plasma. These antibodies, referred to as anti-B antibodies, will cause agglutination and hemolysis if they ever encounter erythrocytes with B antigens, resulting in a transfusion reaction. When this happens antigen-antibody complexes are produced causing erythrocytes to hemolyze which releases hemoglobin into the plasma causing damage to the kidneys. Similarly, an individual with type B blood has pre- formed anti-A antibodies. Individuals with type AB blood, which has both antigens, do not have preformed antibodies to either of these, therefore, are considered as universal recipients. People with type O blood lack antigens A and B on their erythrocytes, but both anti-A and anti-B antibodies circulate in their blood plasma (Figure 3.1). The Rh blood group is classified according to the presence or absence of a second erythrocyte antigen identified as Rh. Those who have the Rh antigen present on their erythrocytes are described as Rh positive (Rh+) and those who lack it are Rh negative (Rh−). Normally, plasma doesn’t contain anti-Rh antibodies however if a patient with Rh- blood receives Rh+ blood the recipient will develop anti-Rh antibodies to the Rh antigen which will remain in the blood. If that same patient receives a second transfusion with Rh+ blood, the previously formed anti-Rh antibodies will cause agglutination and the erythrocytes will hemolyze. 7  (O- is the universal donor) Figure 3.1 ABO Blood Groups. Images and text found in the above section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and- physiology/pages/1-introduction Your Instructor will direct you on how to use the blood typing kits to determine the ABO and Rh blood type for each hypothetical person. Fill out the chart below to record the reactions of the plasma antibodies to identify which surface antigens are present for each blood type. Sample Reaction with Reaction with Reaction with Blood Type Anti-A (+/-) Anti-B (+/-) Anti-Rh (+/-) Smith Jones Brown Green 8 Questions: 1. Which blood type is considered to be the universal donor and which type is considered to be the universal recipient and explain why? 2. Jenny has antibody A in her blood with no Rh antigen. What blood type does she have? 3. Which antigen(s) and antibodies are present with a person with type ARh+ blood? 4. Leonard’s blood type is ABRh-, could he receive a transfusion from Sheldon whose blood type is BRh-? Yes or no, explain your answer. 5. Could Leonard receive Howard’s BRh+ blood? Yes or no, explain your answer. 6. Penny has O+ blood and received O- blood through a transfusion. Could receiving this blood type be life threatening for Penny, why or why not? 9  7. If Joanne has blood type ORh- and her husband has blood type ABRh+, what possible effect could this have on their future pregnancy? 8. Which of the following statements is true regarding the ABO blood system? a. People who have the A antigen normally would not produce the anti-A antibody. b. People who are type AB normally produce both anti-A and anti-B antibodies. c. The only ABO blood type that normally does not have either A or B antigen is AB. Activity 5 - Spread of a pathogen Pathogens have various routes allowing entrance to our body that can make us ill. Pathogens can enter directly through contact of infected skin and/or fluid exchange, such as with HIV, genital herpes and syphilis. Also, if an infected person touches a surface like a phone the microbes can be transferred indirectly to a healthy person if they then touch their eyes, nose or mouth. In addition, you can also ingest microbes through contaminated food or be punctured by mishandling infected needles. Several creatures such as mosquitos, flies and ticks can carry such diseases as malaria, West Nile virus and Zika that can infect a human host. Lastly, airborne pathogens such as the flu, tuberculosis can be easily spread with coughing and sneezing as these droplets can remain suspended in the air for a period of time. Your instructor will guide the class through this group activity. 1. Your stock solution number is _____________. 2. Number of first contact_____ Number of second contact_____ Number of third contact______ 3. Complete the table below with data generated during this activity (if working remotely, view this link). Can you figure out which stock number the pathogen originated in? 10  # of # of # of Final “Infected” Stock # First Contact Second Contact Third Contact (Y/N) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Questions: 1. What different ways can pathogens be passed on or transmitted? 2. Which way was the pathogen passed in the lab activity? 11  3. What are some preventative measures that each of us can take to avoid coming into direct contact with a pathogen? 4. Use appropriate waste disposal containers upon completion of exercise. All chemical solutions go in labelled waste containers. Any paper towels, gloves or plastic transfer pipettes go in the ____________. Empty used test tubes go in __________________. Refer to the Safety Practices in the Laboratory document. Sources used in writing this lab include Derrickson, B. (2019). Human Physiology (2nd ed.). Hoboken, NJ: John Wiley& Sons, Inc. 12 Lab 4 – Nervous System and Sensory Systems In order to complete the lab in the required time, you must come to the lab well prepared, and with all lab reading done. Please note that spelling counts – a mistake will be half value deduction and zero if unrecognizable. Read the entire lab before coming to lab. Come prepared with questions you have regarding the material presented in the lab manual. Prepare for Quiz 3 (material from lab 3) it will take place at the beginning of the lab. Prepare for lab exam 1. Key terms: Dendrites, axon terminal, Schwann cell, nucleus of Schwann cell, Nodes of Ranvier, axon, myelin sheath, cell body, nucleus of cell body, axon hillock (trigger zone), synaptic end bulbs, neuron, reflex, sensory receptor (sensory neuron), stimulus, afferent pathway, integration center, efferent pathway(motor neuron), effector, stretch reflex, muscle spindle, patellar reflex, Achilles reflex, crossed extensor reflex, plantar reflex, Babinski sign, corneal reflex, pupillary reflex, ciliospinal reflex, monosynaptic reflex, polysynaptic reflex, ipsilateral reflex, contralateral reflex, reciprocal innervation, somatic reflex, autonomic reflex, general senses, special senses, adaptation (phasic receptors), two point discrimination threshold, calipers, touch receptors, thermoreceptors, referred pain, visual acuity, Snellen chart, emmetropic, myopia, hyperopia, accommodation, astigmatism, blind spot, near point accommodation, presbyopia, color vision, cones, rods Objectives for Lab 4 1. Understand the structure and function of the neuron 2. Define a simple reflex 3. Examine the pathways for several simple reflexes 4. Perform several tests to look at general sensations 5. Perform several tests for ocular function 1 Overview of Activities: 1. Neuron Structure 2. Reflexes 3. General Sensation 4. Special Senses Neuron model Patellar (knee jerk Two-point threshold Visual acuity reflex) Structure and Adaptation to touch Blind spot function Achilles reflex receptors and Near point of temperature receptors Crossed extensor accommodation reflex Referred Pain Astigmatism test Plantar reflex Blind spot test Corneal reflex Testing for color Pupillary reflex blindness Ciliospinal reflex Remember it is always your job to ensure that the lab is clean BEFORE you leave. The lab instructors will guide you in this process 2 Activity 1 - The neuron A nerve cell or neuron has three regions with specialized functions (Figure 4.1). I. Dendrites: are short, branched projections that carry signals towards the cell body. II. Cell body: contains the nucleus and organelles and acts as a metabolic center for the cell. III. Axon: is a single, elongated tube-like extension of the neuron that carries the nerve impulse or action potential, away from the cell body to other neurons or to effector organs such as muscles and glands. 1. Locate the following on the model of the neuron. A. Cell body 1. Axon hillock 2. Nucleus 5. Axon terminal 14. Dendrite B. Axon 7. Schwann cell nucleus 8. Schwann cell 9. Node of Ranvier 11. Myelin sheath 3 2. Label the following structure on the neuron below. Be sure to include these structures: axon, axon terminal, dendrites, cell body, nucleus of cell body, myelin sheath, Nodes of Ranvier, Schwann cells, nucleus of Schwann cell, axon hillock (trigger zone), and synaptic end bulb. Figure 4.1 Generic Neuron. From: Tortora, G. J. & Nielsen, M. T. (2017). Principles of Human Anatomy (14th ed.). Hoboken, NJ: John Wiley & Sons, Inc. 3. Order the following parts of a neuron in the correct order of receiving and sending (1-8). ____ incoming impulses ____axon ____axon terminal ____axon hillock (trigger zone) ____cell body ____dendrite ____synapse ____synaptic end bulb 4 Activity 2 - Reflexes A reflex is a response that occurs independently of conscious effort. It is a fast, automatic, involuntary response to stimulus. Some reflexes are used for clinical purposes in the assessment of neurological damage or disorders. Such tests may reveal diminished, absent, exaggerated, or altered reflexes so that the new “pathological reflexes” appear. Know the reflex arc (reflex pathway): 1. A sensory receptor (sensory neuron) that responds to the stimulus by producing an action potential. 2. A sensory neuron that relays sensory stimulus along the afferent pathway to the integration center in the CNS. 3. An integration center in the central nervous system (brain or spinal cord) that processes incoming sensory information and synapses with a motor neuron. The reflex could be monosynaptic or polysynaptic, depending on how many synapses are involved. 4. A motor neuron that carries instructions from the integration center along the efferent pathway and propagates out of CNS along the axon of motor neuron to effector. 5. An effector is the target that responds to the motor neuron. Effectors can be skeletal (somatic), cardiac or smooth muscle as well as glands (autonomic). If steps 1-5 (sensory receptor and effector) happen on the same side of the body it is referred to an ipsilateral reflex, whereas, if the stimulus (sensory receptor) happens on one side of the body and the response (effector) happens on the opposite side than it is a contralateral reflex. Simultaneous contraction of one muscle and relaxation of another is called reciprocal innervation (inhibition). This prevents conflict between opposing muscles and is vital to coordination with body movements. For each of the following activities and tests you must understand: How the test was performed The purpose of the test (what was it testing for) The expected results Do these tests in pairs. Each person should act as both researcher and subject for each test. When you complete each activity, use a sanitizing wipe to disinfect all materials. Stretch reflexes (i.e., patellar and Achilles’s reflex) are initiated by stretching and activating the sensory neurons of muscle spindles within the muscle which causes the muscle to contract, preventing further stretching. During muscle contraction the antagonistic muscle will be inhibited causing relaxation; as in reciprocal innervation; to allow the muscle stimulated to contract. The integration center for a stretch reflex is the spinal cord and are both monosynaptic and ipsilateral. How do you suppose the muscle is stretched during these reflexes? 5 A. Patellar reflex – Have your partner sit on the edge of the table or with legs crossed so that leg swings freely. Locate the tibial tuberosity (a hard point below the patella) and the lower edge of patella (kneecap). With a percussion hammer, strike in the center of the soft space between these two hard landmarks. Experiment with striking in various locations to see where the most pronounced reaction is elicited. Repeat for the other leg. If you are having trouble visualizing this test, watch this video. Questions: 1. When the quadriceps muscle group contracts in this reflex what happens to the antagonistic muscle group? 2. Is this reflex ipsilateral or contralateral? Is this a monosynaptic or polysynaptic reflex? 3. Draw what a patellar reflex arc would look like? Be specific to this reflex (Refer to textbook, pg. 429, Figure 12.4). 6 B. Achilles reflex – Have your lab partner remove his/her shoe. Dorsiflex the foot slightly (flex at the ankle so the toes go up slightly, it may help to kneel on a chair or have your partner support the foot with one hand). At the back of the foot tap the area just above the ankle with the broad side of the hammer observe what happens. If you are having trouble visualizing this test, watch this video. Questions: 1. Make sure you can relate this to the components of the reflex arc. For example, specifically where is the integration center for this reflex and is the effector somatic or autonomic? 2. Which antagonistic muscle would you think is inhibited by reciprocal innervation? 3. Is this a monosynaptic or polysynaptic reflex? C. Crossed extensor reflex – This is a polysynaptic reflex that involves flexors contracting to withdraw (ipsilateral reflex) from the stimulus on one side and extensors contracting on the other side (contralateral reflex). Have your partner sit with eyes closed with the back of one hand resting on the lab bench. Obtain a sharp pencil and suddenly prick the subject’s index finger, please do not draw blood! A gentle poke will be enough. Observe the reactions (hint: there should be more than one). If you are having trouble visualizing this test, watch this video. Questions: 1. Is this reflex a somatic or autonomic reflex? 2. Is this a monosynaptic or polysynaptic reflex? 7 D. Plantar flexion reflex – Have your lab partner remove his/her shoe and lie on the lab bench. With the handle of the reflex hammer draw along the bottom (sole) of the foot with slight pressure. Start at the medial side of the heel and then move towards the baby toe and finish across the ball of the foot at the base of the big toe. Observe slight flexion of the toes (curl in). If you are having trouble visualizing this test, watch this video. Questions: 1. The Babinski sign is abnormal in an adult. What would an abnormal reflex look like? Which population would a Babinski sign not be worrisome? 2. Is this reflex a somatic or autonomic reflex? E. Corneal reflex – A specialized reflex to protect the surface of the eye is the corneal reflex. Stand beside your lab partner and ask him/her to look at the wall ahead. Gently and quickly touch the cornea with a wisp of absorbent cotton. Observe and note what happens. If you are having trouble visualizing this test, watch this video. Questions: 1. Why is this reflex important? 2. Is this reflex a somatic or autonomic reflex? 8 F. Pupillary reflex – Shining light in one eye will elicit constriction of both pupils. Observe your lab partner’s pupils under normal lighting conditions. Estimate their approximate diameter. Get him/her to cover one eye. Shine a flashlight in the eye that is not covered. Observe what happens in this eye. If you are having trouble visualizing this test, watch this video. Questions: 1. Then do the reflex again and quickly observe the covered eye. Does the same thing happen? Is the pupillary light reflex ipsilateral, contralateral or both? 2. Is this reflex a somatic or autonomic reflex? 3. Is the integration center in the spinal cord or brain for this reflex? 4. Why do we have this reflex? G. Ciliospinal reflex – This is an autonomic reflex that can be used to investigate brainstem integrity often more prominent during sleep, coma and cluster headaches. Your lab partner should be seated. While observing the subject’s pupils gently pinch the left side of the back of the neck close to the hairline. Look for dilation of the ipsilateral pupil in response to painful or startling stimuli. If you are having trouble visualizing this test, watch this video. Question: 1. Does the response happen in both eyes? 9 An overview of the covered reflexes Reflex name Integration center: Synapses involved: Effector: Which side of the body does it occur: (ipsilateral or a (spinal cord or brain) (monosynaptic or (somatic or autonomic) contralateral reflex) polysynaptic) Patellar reflex Spinal cord Monosynaptic Somatic ipsilateral Achilles reflex Spinal cord Monosynaptic Somatic ipsilateral Withdraw from pain- ipsilateral Crossed Spinal cord Polysynaptic Somatic extensor reflex Extensor- contralateral spinal cord (but influenced by higher Plantar flexion centers) Polysynaptic Somatic ipsilateral reflex 10 Corneal reflex Brain Polysynaptic Somatic Usually both eyes close - bilaterally Ipsilateral is the eye receiving the light. Pupillary reflex Brain Polysynaptic autonomic Contralateral response in the eye that doesn’t receive the light as it will constrict too (sometimes referred to as consensual reflex) Ciliospinal reflex Brain Polysynaptic autonomic ipsilateral 11 Activity 3- General sensation For each of the following activities and tests you must understand: The name of test The purpose of the test (what was it testing for) The expected results The physiological significance of the results When you complete each activity, use a sanitizing wipe to disinfect all materials. A. Two-point discrimination threshold – Two-point discrimination threshold uses two caliper points to measure the minimum distance at which the two caliper points are perceived as separate points, which reflects the size of the receptive field in that region. You will be using an indirect measure to investigate the density of touch receptors in certain body regions. The higher number of touch receptors correlates to the higher sensitivity of that area as well as a larger size represented in the somatosensory cortex. Refer to sensory homunculus in your textbook (p. 306). Watch this video for a quick demonstration of the two-point discrimination. 1. With the subject’s eyes closed start with the two points of the caliper close together. Place both caliper points on the area at the same time and record if the subject feels 1 or 2 points. Systematically, increase the distance between the points until the subject can feel 2 points and record the distance for the two-point discrimination threshold. 2. When 2 points stimulate the same receptive field then only 1 point of touch is perceived. If 2 points stimulate different receptive fields the input is conveyed into the CNS along separate pathways and 2 points of touch are perceived. 3. Repeat the procedure for the locations below. Always clean caliper tips with alcohol swabs in between each body location. Body location Record distance Body location Record distance Lips Cheek Back of hand Forearm Palm of hand Back of leg Fingertip Back of neck Questions: 1. Which has the smallest 2-point threshold? Can you suggest a reason why? 12  2. Which has the largest 2-point threshold? Can you suggest a reason why? 3. Which area of the body that you tested would be represented by the smallest area of the cerebral cortex? B. Adaptation of sensory receptors with touch and temperature (phasic receptors) – If the stimulus has been applied for a prolonged period certain sensory receptor will exhibit adaptation. Adaptation is a decrease in response of a sensory receptor during a maintained, constant stimulus and the perception of sensation may fade or disappear even though the stimulus persists Touch: 1. The subject should do the test with eyes closed. You will need 5 pennies. Place one penny on the forearm. Time how long it takes for the sensation to disappear. Leaving the first penny in place, put a coin in another region. How long does it take for the sensation to disappear? 2. Stack 3 more coins on the first coin. Questions: 1. Which takes longer to adapt, the area with 1 penny or area with 4? 2. How long does it last? 3. Do you think you are stimulating the same receptors with 4 coins? 13 Temperature -- Thermoreceptors are sensitive to either an increase or decrease in temperature. Temperature receptors adapt between 20°C and 40°C. Temperatures below 10°C and above 45°C primarily stimulates pain receptors. Feeling of “cold” and “hot” may be relative to the previous temperature our skin was exposed to. This video follows the instructions below: 1. Obtain 3 trays and fill them as follows: Water at 45°C (warm) Room temperature water Ice water 2. After washing your hands with soap and water, immerse the left hand in the 45°C water for 1 minute. After a minute add the right hand into the same beaker. What do you initially feel? Does the sensation change over the minute? When the right hand is added to the water does it feel the same as the left one? Have the receptors adapted? 3. Next, immerse the left hand in 45°C warm water, and the right hand in ice water for 2 minutes. What do you immediately feel in each hand? What do you feel in 2 minutes? Which hand adapts more quickly? 4. After 2 minutes, place both hands in the room temperature water at the same time. What do you feel in the left hand? What do you feel in the right hand? 5. Immediately following this activity, wash hands thoroughly. 14 Questions 1. When sensory receptors adapt, does the cerebral cortex (CNS) receive an increased or decreased number of sensory impulses? 2. Which thermoreceptors seemed to adapt the quickest? C. Referred pain – The impulses for visceral (deep tissue and organ) pain seems to travel along the same pathways as the somatic (from skin, muscles and joints) pain impulses. This accounts for a phenomenon called referred pain, which often has a perceived location that is somatic in origin, rather than being perceived as arising from the actual location of visceral stimuli. This video, filmed in MRU biology labs, follows these instructions: 1. Wash your elbow with soap and water before you immerse your elbow in a bowl containing ice water. 2. Record the sensation felt after immediate immersion, after 1 minute, after 2 minutes, after 3 minutes and after your elbow was removed. 3. Wash your elbow again after completing this activity. 15  Time since immersion Sensation felt 0 min 1 min 2 min 3 min Questions: 1. What did you feel? 2. Did the sensation move over time and if so where? 3. Did the sensation change over time and if so, how? 4. What are some symptoms felt by most people suffering from a heart attack? Sources used in the writing of this section include Marieb, et al (2014). Human Anatomy & Physiology Laboratory Manual (10th ed). Glenview, IL: Pearson Education, Inc. Text found in this section are also a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction 16 Activity 4 - Special senses For each of the following activities and tests you must understand: The name of test The purpose of the test (what was it testing for) What the results illustrate The physiological significance of the results When you complete each activity, use a sanitizing wipe to disinfect all materials. A. Visual acuity – Use your textbook (Chapter 9) to write the definitions for the following terms: Accommodation: Astigmatism: Emmetropia: Hyperopia: Myopia: Presbyopia: Working eye model Watch this video for a summary of how light refracts and how the shape of the eyeball affects your vision. Your instructor will set up the working model of the eye and demonstrate how vision is affected by the shape of your eyeball. With this model, the retina of the eye is represented by a white screen, on which the macula lutea is the center, as shown by a circle, and the blind spot is represented by an off centered hole. The retina screen can be moved to three different settings for eyeball shape to mimic: emmetropia (middle slot), myopia (last slot), and hyperopia (first slot position). 17 The visual acuity test (sharpness of vision) is used to determine the smallest letters a person can read on a standardized chart (Snellen chart) or a card held 14 - 20 feet away. Stand at about 20 paces from the chart. Read the smallest line that you are able. Make note the smallest sized letter the subject can distinguish correctly. If the ratio is 20/20 then it indicates the subject’s vision is normal. Whereas a value of 20/40 indicates that the subject sees at 20 feet what the normal eye sees at 40 feet, this exhibits less than normal vision acuity. A subject with better than normal vision might measure a ratio of 20/15, indicating the subject can see at 20 feet what the normal eye sees at 15 feet. Questions: 1. Your measured visual acuity: _______________ 2. What does 20/20 vision mean? 3. What does 20/30 vision mean? 4. What does 20/15 vision mean? B. Near point of accommodation – The near point of accommodation measures the ability of the eye to focus for near vision. When the eye is focusing on a close object, the lens must go through the process of accommodation and becomes more curved and rounded. This causes refraction of light ray and increases the refractive power by shortening the focal length. Loss of this ability happens with age and is called presbyopia. Watch this video to gain an understanding of how the test works. 1. Hold the near point apparatus underneath your eye and slowly slide the printed text closer to your eye until it goes blurry. Repeat this process for the other eye. Age Distance (cm) 8 7 15 8 20 9 25 10 30 ~11.2 35 ~13.8 40 ~17.2 42 20 44 25 46 ~33.1 48 ~44.1 50 >50 2. Record the distance (cm): __________________ 3. What is the “physiological age” of your eyes? 18 C. Astigmatism – An astigmatism can cause visual problems due to irregular curvatures to the cornea that changes the way light travels to your retina. This can cause blurriness and distorted vision. Cover one eye and look at the center of the astigmatism chart provided and note if the lines look dark and sharp. If the lines aren’t uniform in color, are lighter or blurry you may have a measure of astigmatism in that eye. Record findings and repeat with your other eye. 1. Record the subject’s findings for the left eye_______________________________ 2. Record the subject’s findings for the right eye_______________________________ D. Detecting the Blind Spot – Use the card that has a cross and circle on it. Hold the card so the cross is on the left and the circle is on the right. Hold the card a foot away, close your left eye and look steadily at the circle with your right eye. Doing this, move the card slowly towards and away from your open eye, until at some point the cross disappears completely from the background. When the shape disappears, it has landed on the blind spot. Watch this video to find your blind spot at home. Questions: 1. Why does the cross disappear? 2. Does that impact our day-to-day vision? E. Color Vision Test – Color vision depends on the stimulation of three types of cones: red, blue and green. If one of the cone types is lacking or not functioning optimally, then this will manifest as color-blindness. The most common kind of color-blindness is red-green color- blindness. You will be using Ishihara color plates to see if you are color blind. If you have normal vision the numerals and pathways are fairly easy to distinguish. Look at each plate and report what you see to your lab partner. Use can also use this video to test yourself. Question: 1. Is there any indication of color blindness? Sources used in the writing of this section include Marieb, et al (2014). Human Anatomy & Physiology Laboratory Manual (10th ed). Glenview, IL: Pearson Education, Inc., and Derrickson, B. (2019). Human Physiology (2nd ed.). Hoboken, NJ: John Wiley& Sons, Inc. Text found in this section are also a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction 19