Introduction to Body Function Physiology Clinical Applications and Diagrams, Chapter 1 Part I. Clinical Applications

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1 Name: Lab Time: Introduction to Body Function Physiology Clinical Applications and Diagrams, Chapter 1 Part I. Clinical Applications 1 1. The hormone thyroxine is released in response to a pituitary hormone called thyroid stimulating hormone (TSH). As thyroxine levels increase in the blood, they exert negative feedback on the release of TSH by the pituitary gland. What effect will this have on the release of TSH? The release of TSH is decrease. Negative feedback causes the initial stimulus, TSH in this case, to decline. 2. During exercise, blood flow to skeletal muscles increases. The initial response that increases blood flow is due to changes that happen within the muscle and is independent of the nervous and endocrine systems. Which type of homeostatic regulation (intrinsic or extrinsic) is this and why? The initial increase in blood flow to active muscles is an example of autoregulation or intrinsic control. The increased demands for oxygen and for waste removal cause a local increase in blood flow even before responses from the nervous or endocrine system take place. Autoregulation is an immediate and automatic response to environmental change (in this case, low oxygen levels, CO2 buildup, decreased ph and increased wastes) that does not require the nervous or endocrine system. 3. Blood Pressure drops when a person goes from a lying to standing position. In order to correct the decreased drop in blood pressure the body uses mechanisms to increase blood pressure. Do these mechanisms use positive or negative feedback processes? Describe how the body responds to correct this situation. Correction of blood pressure in this situation is an example of a negative feedback process because the initial change (decreased blood pressure) is corrected by the response (increased blood pressure) which reveres the direction of the initial change. When you stand up, gravity causes blood to settle in the lower part of your body. Blood pressure receptors known as baroreceptors (sensors) detect the change in blood pressure. Baroreceptors are specialized sensory neurons in the walls of the aortic arch and the carotid sinuses that measure the degree of stretch in the vessel wall. Information is sent from the baroreceptors to the medulla oblongata via sensory nerves. The Medulla oblongata (control center) analyzes the change in blood pressure and sends a nerve impulse to the heart and blood vessels (mainly arterioles), both of which are effectors, to correct the decrease in blood pressure. Heart rate and amount of blood pumped are increased causing an increase in blood pressure Vasoconstriction of arterioles increases blood pressure. Thus if BP is too high or too low, a reflex change in cardiac output is initiated in order to correct it.

2 4. Are the events of child birth a positive or negative feedback process? Describe the events that support your answer. 2 Child birth is an example of a positive feedback process. When the baby is ready to be delivered, it drops lower in the uterus causing stretching of the uterus and cervix. Stretch receptors in the cervix and uterine wall are monitored by the hypothalamus of the brain. As the uterus stretches the hypothalamus releases oxytocin via the posterior pituitary gland, which causes the uterus to contract. This contraction further distorts and open the cervix resulting in more oxytocin to be released which increase uterine contractions. The cycle continues until the baby is delivered and the stretching stimulation is eliminated stopping the positive feedback loop. 5. Using insulin as an example, explain how the secretion of this hormone is stimulated and the mechanism by which its secretion is turned off. Hint: Think about feedback systems A rise in plasma glucose concentration stimulates insulin secretion from structures in the pancreas known as the pancreatic islets (islets of Langerhans). Insulin causes blood glucose to be taken into the body cells which results in a lowered amount of blood glucose. The lowering of blood glucose which due to insulin s action inhibits further insulin secretion. A fantastic example of a negative feedback mechanism. 6. Who are Claude Bernard and Walter Cannon? Why are the concepts they introduced so important in physiology and medicine? French physiologist Claude Bernard ( ) is considered the father of modern physiology because he observed that the milieu interieur (internal environment) remains remarkable constant despite changing conditions in the external environment. American physiologist Walter Cannon ( ) coined the term homeostasis to describe this internal constancy and suggested that many mechanisms of physiological regulation have but one purpose the maintenance of internal constancy. The body is healthy when homeostasis is maintained and thus is very important in the study of physiology and medicine. Homeostatic imbalance can result in a disorder, disease or death. 7. Monitoring fetal development may be dangerous for the fetus if improper diagnostic techniques are used. Why is ultrasound an effective means of monitoring fetal development? No adverse effects have been attributed to the sound waves, and fetal development can be monitored without a significant risk of birth defects. Ultrasound machines are relatively inexpensive and portable. 8. Gastroenterologists use X-rays to check for ulcers or other stomach and upper digestive tract disorders. Before the X-rays are taken why is it necessary for the patient to drink large quantities of a solution that contains barium ions? Barium is very radiodense, and the contours of the gastric and intestinal lining can be seen against the white of the barium solution.

3 9. The following are advanced imaging techniques have been discussed in lecture: CT, DSA, PET, ultrasound, and MRI. Which of these techniques uses X-rays? Which uses radio waves and magnetic fields? Which uses radioisotopes? Which displays body regions in sections? Your may have more than one answer for each question. Techniques that use - X-rays: CT and DSA Radiowaves and magnetic field: MRI Radioisotopes: PET Techniques that display body regions in sections: CT, MRI, and PET 10. You are studying for your first physiology exam and want to know which areas of your brain are working hardest as you study. Your classmate suggests that you could have a computed tomography (CT) scan done to assess your brain activity. Would this be the best way to determine brain activity? No. Computed tomography is used to look at differences in tissue density. To assess activity in an organ such as the brain, a positron emission tomography (PET) scan would provide a colorized visual assessment of brain activity. 11. Certain bacterial infections can cause a fever to develop. Describe the bases for fever formation and dissipation and how antipyretics such as aspirin work. The hypothalamus regulates body temperature. A fever is an elevation of core temperature caused by a resetting of the hypothalamic thermostat. Normal body temperature is at 98.6 F (37 C) Steps involved with fever formation caused by bacterial infection. 1. When macrophages and other phagocytes ingest certain bacteria, they are stimulated to secrete a pyrogen (pyro=fire, -gen=produce), a fever-producing substance. One pyrogen is interleukin -1 (IL-1). 2. IL-1 circulates to the hypothalamus and induces neurons to secrete prostaglandins that reset the hypothalamic thermostat at a higher temperature, lets say the hypothalamus thermostat is reset at 39 C (103 F). Prostaglandins are local chemical mediators which in this case, act directly on the hypothalamus. 3. Temperature regulating reflex mechanisms then act to bring the core body temperature up to this new setting. The heatpromoting mechanisms (vasoconstriction, increased metabolism, shivering) are operating at full force. Thus, even though core temperature is climbing higher than normal say, 38 C (101 F) the skin remains cold, and shivering occurs. This condition, called a chill, is a definite sign that core temperature is rising. After several hours, core temperature reaches the setting of the 3

4 thermostat, and the chills disappear. But now the body will continue to regulate temperature at 39 C (103 F). 4. When the pyrogens disappear, the thermostat is reset at normal 37 C (98.6 F). Because core temperature is high in the beginning, the heat-losing mechanisms (vasodilation and sweating) go into operation to decrease core temperature. The skin becomes warm, and the person begins to sweat. This phase of the fever indicates the core temperature is falling. Antipyretics and Fever Reduction Antipyretics such as aspirin are agents that relieve or reduce fever by inhibiting synthesis of certain prostaglandins within the hypothalamus and thus inhibit the effects of pyrogens to reset the hypothalamic thermostat. 4 Part II 1. receptor 2. control center 3. afferent 4. control center 5. effector 6. efferent 7. negative 8. positive 9. negative 10. cells 11. tissues 12. organs 13. organ systems 14. ventral 15. dorsal 16. dorsal 17. abdominopelvic 18. abdominopelvic 19. abdominopelvic 20. abdominopelvic 21. abdominopelvic 22. spinal 23. abdominopelvic 24. thoracic 25. thoracic 26. cranial 27. abdominopelvic 28. abdominopelvic 29. endocrine 30. urinary 31. reproductive 32. lymphatic/immune 33. skeletal 34. integumentary 35. digestive 36. same; stays 37. interstitial; internal 38. 1) gases (oxygen, carbon dioxide) 2) nutrients (proteins, glucose, etc.) 3) electrolytes (sodium, potassium, etc.) 4) fluids 5) temperature 6) pressure 39. lower; decreasing; stimulus; receptors; input; control 40. output; effectors; response 41. negative; increase; positive 42. negative; labor contractions or blood clotting 43. B

5 Part III 1. physiology 2. anatomy 3. homeostasis 4. metabolism 5. urinary 6. endocrine 7. skeletal 8. cardiovascular 9. integumentary 10. lymphatic/immune 11. digestive 12. respiratory 13. cardiovascular 14. muscular 15. urinary 16. reproductive 17. endocrine 18. integumentary 19. ventral cavity 20. thoracic cavity 21. diaphragm 22. abdominal cavity 23. pelvic cavity 24. cranial cavity 25. spinal cavity 26. dorsal cavity 27. Lt Pleural cavity 28. pericardial cavity 29. Rt pleural cavity 30. diaphragm 31. abdominal cavity 32. subatomic particles 33. atoms 34. molecules 35. protoplasm 36. organelles 37. cells 38. tissues 39. organs 40. systems 41. organism 5 Part IV 1. At #1 on the graph there will be increased blood flow to the skin and increased sweating if the body temperature rises above 99 F. Result will be a body surface that cools and the body temperature declines. At #2 on the graph, if the temperature falls below 98 F there is a decrease in blood flow to the skin and shivering occurs. These activities help to conserve body hear and the body temperature rises. 2. Calcitonin is released when calcium levels are elevated. This hormone should bring about a decrease in blood calcium levels, thus decreasing the stimulus for its own release. 3. cardiovascular 4. endocrine 5. urinary 6. reproductive 7. digestive 8. skeletal 9. nervous 10. B 11. A 12. D 13. D 14. D 15. C 16. D 17. A 18. D 19. C 20. D 21. B 22. A 23. C 24. C, E 25. D 26. B 27. B 28. A, B, C, D

6 Part V 1. DSA 2. PET 3. CR 4. US 5. CT 6. MRI A 12. D 13. A 14. C 6 Part VI Exercise A 1. Cranial cavity 2. Spinal cavity 3. Mediastinum 4. Pleural cavity 5. Pericardial cavity 6. Diaphragm 7. Abdominal cavity 8. Pelvic cavity 9. Abdominopelvic cavity 10. Ventral cavity Exercise B 1. Cranial cavity 2. Dorsal cavity 3. Spinal cavity 4. Thoracic cavity 5. Diaphragm 6. Abdominal cavity 7. Pelvic cavity Part VII Experimental Design For the following statements / hypothesis identify the variables, control group, and experimental group. 1. Cigarette smoking increases the risk of lung cancer. Hypothesis: If you smoke cigarettes, then your chances of getting cancer increases. Independent Variable: Smoking cigarettes; Dependent Variable: Whether you get cancer Control Group: People who do not smoke; Experimental Group: Smokers 2. Eating breakfast increases performance in school. Hypothesis: If you eat breakfast, then you will get better grades. Independent Variable: breakfast; Dependent Variable: Grades Control Group: students who do not eat breakfast; Experimental Group: students who eat breakfast 3. Hummingbirds are attracted to the color red. Hypothesis: If a bird feeder is red, then it will attract hummingbirds Independent Variable: color of feeder; Dependent Variable: number of hummingbirds present Control Group: feeder that is not red; Experimental Group: feeder that is red 4. ibook batteries last for 5 hours. Hypothesis: If you use ibook batteries, then your ibook will run for 5 hours. Independent Variable: battery type; Dependent Variable: time plays Control Group: different type of battery; Experimental Group: ibook battery 5. You conduct an experiment on twenty 18-year-old male subjects to see how various intensities of exercise influence heart rate. Which of the following is/are considered an independent variable? A) age of subjects B) sex of subjects C) intensity of exercise D) heart rate 6. You conduct an experiment on twenty 18-year-old male subjects to see how various intensities of exercise influence heart rate. Which of the following is/are considered a dependent variable? A) age of subjects B) sex of subjects C) intensity of exercise D) heart rate

7 7 7. Suzie wants to know the effect of different colors of light on the growth of plants. She believes that plants can survive best in white light. She buys 5 ferns of the same species, which are all approximately the same age and height. She places one in white light, one in blue light, one in green light, one in red light and one in the closet. All of the ferns are planted in Miracle-Grow and given 20 ml of water once a day for 2 weeks. After the two weeks, Suzie observes the plants and makes measurements. Hypothesis: If plants are grown in white light, then they will grow taller Independent Variable: type of light Dependent Variable: height of plant Control Group: plants in different colors of light; Experimental Group: plants in white light 8. Place these terms in the typical sequence in which they appear in the process of scientific inquiry: collect and analyze data, theory, model, question, hypothesis, replication, experiment, observation. Observation, question, hypothesis, experiment, collect and analyze data, model, theory Possible terms to use for the following questions: Blind Double-blind Crossover Retrospective Placebo Nocebo Control hypothesis Model Theory Double-blind crossover Independent variable Dependent variable 9. A study in which a participant acts as an experimental subject in part of the experiment and a control in another part of the experiment is called a _Crossover study. 10. An inactive drug or treatment that is expected to have no pharmacological or medical effect is called a _Placebo. 11. Term of an educated (logical) guess as to how that event happens: hypothesis 12. If a scientific model is supported or verified repeatedly by multiple investigators, it may become a Theory 13. It is an ill effect caused by the suggestion or belief that something is harmful. It is the phenomenon whereby a patient who has been informed of the side effects of a drug he is taking is more likely to experience some of the side effects than an otherwise similar patient receiving the same drug who has not been so informed. This is known as the Nocebo effect. 14. The independent variable is the variable that is controlled by the experimenter, it is the variable that is altered or removed. 15. _Double-blind study is when a third party, not involved in the experiment, is the only one who knows which group is receiving the experimental treatment and which group is receiving the control treatment. 16. Double-blind crossover study is when the control group is the first half of the experiment becomes the experimental group in the second half, and vice versa, but no one involved (except the third party) knows who is taking the active treatment. 17. The _placebo effect is where a patient taking an inactive substance thinks they are taking the actual medication and due to the power of their mind, there is a positive change in health not attributable to medication or treatment

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