2. [5 pts] Contrast agents are substances used to enhance the radiodensity of a targeted tissue by altering the way that electromagnetic radiation or ultrasound waves pass through the body. A patient is administered contrast agent intravenously. The contrast agent first gets distributed in the plasma. The contrast agent can diffuse from the plasma into the targeted tissue as well as diffuse from the targeted tissue back into plasma. The contrast agent is eliminated by glomerular filtration in the kidneys and leaves the body with urine. Draw a flow diagram to show how the contrast agent travels through the body (from when it enters the body to when it leaves the body). Use arrows to represent the flow. Make sure that you capture all the main components of the described process. [Continues on next page] 3. [Total: 19 pts] Blood glucose and insulin regulation The equations that characterize the steady state regulation of glucose and insulin can be derived by taking into account the main factors that affect the appearance and disappearance of each of these substances in the body. The mass balance for blood glucose (x) is given by: QL = Ax + vxy (Eqn. 1) where QL represents the flow-rate (assume to be constant) at which glucose enters the blood through absorption from the gastrointestinal tract or through production from the liver, Ax represents the rate at which the body tissues utilize glucose without help from insulin, and vxy is the rate at which glucose is metabolized with facilitation from insulin. The blood concentration of insulin is represented by y, and 1 and v are constant parameters. Thus, Eqn. 1 represents the "glucose response to insulin". By applying similar mass-balance considerations to the production of insulin from the pancreas and the subsequent destruction of insulin, we can derive the following expression for the "insulin response to glucose": y = 0, x≤ Q (Eqn. 2a) y = {(x-(), x> (Eqn. 2b) where { and o are constant parameters. Insulin is not produced when glucose is lower than the threshold parameter q (Eqn.2a). Note that the insulin production and destruction rates are combined into one parameter, { (zeta). By using empirically derived values for the model parameters (QL, 2, v, {, () in Eqns. 1 and 2a/b, these equations allow us to predict the blood concentrations of glucose (x) and insulin (y) under various conditions. The figure below displays the plots corresponding to these responses in normal and diabetic subjects. Point N is the operating point of a normal subject. A B C D 0.2 Insulin concentration (mU.mL-1) 0.15 E 0.1 N 0.05 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Glucose concentration (mg.mL-1) [Continues on next page] a) [2 pts] Estimate from the figure the operating values of glucose and insulin in the blood of a normal subject. b) [3 pts] Suppose this person eats junk food everyday and does not exercise, and after many years, develops "insulin resistance" (i.e., the body requires more and more insulin to metabolize the same amount of glucose). Assuming his pancreas still functions normally. Which parameter(s) need to change to simulate this condition? Determine his new operating values of glucose and insulin. Label the new operating point "b". Briefly explain how you arrived at your answers. c) [3 pts] After many years of untreated insulin resistance, this subject's pancreas can now operate at half of its full capacity. Which parameter(s) need to change to simulate this condition? Determine his new operating values of glucose and insulin. Label the new operating point "c". Briefly explain how you arrived at your answers. [Continues on next page] d) [5 pts] The subject does nothing to change his lifestyle and the pancreas eventually fails. Suppose that his pancreas is removed and replaced by a machine that continuously infuses insulin into his body independent of the glucose level. The machine is adjusted such that it infuses the appropriate amount of insulin, restoring the plasma glucose concentration to the normal level. Sketch as accurately as possible in the provided figure to reflect the described condition. Label the curve(s) "d". Briefly explain how you arrived at your answer. e) [3 pts] From the provided figure, is it possible for you to estimate the parameter ( of a normal healthy person? If so, provide your best estimate of (. Briefly explain how you arrived at your answer. f) [3 pts] From the provided figure, is it possible for you to estimate the parameter { (Eqn. 2b) of a normal healthy person? If so, provide your best estimate of { and from which graph. Briefly explain how you arrived at your answer. [Continues on next page] 4. [Total: 23 pts] Cardiac output and venous return The figure below displays the cardiac output (Qc) and venous return (QR) curves that represent the steady state characteristics of the heart and the rest of the circulation of a subject who is bleeding badly from a knife wound in the abdomen. Point N shows the steady state operating point of the system under normal circumstances prior to the stabbing and subsequent bleeding. 2800 T A B T Venous return and cardiac output (mL/min) 2400 C 2000 1600 E N 1200 800 T F 400 G 0 -8 -4 0 4 8 12 Right atrial pressure (mmHg) a) [3 pts] Bleeding reduces blood volume and increases circulatory resistance. Which curve (A, B, C, D, E, F or G) best represents these changes from the normal case? Briefly explain the reason for your selection. [Continues on next page] D b) [5 pts] From the information displayed in the figure, provide a rough estimate of the total volume of blood lost, assuming that the sum of arterial and venous compliances is 0.53 L.mmHg-1. Briefly explain how you arrived at your answer. c) [4 pts] In the compensated stage of shock from the bleeding, the heart becomes hypereffective (i.e., it generates a higher cardiac output for the same Pra). Label on the figure "c", the new steady state equilibrium values of Pra and cardiac output in the compensated stage of shock following blood loss. Briefly explain your answer. d) [3 pts] If this subject remains in this state without medical care, the irreversible stage of shock sets in. The heart is no longer able to sustain its hypereffective performance and deteriorates progressively. Which curve (A, B, C, D, E, F or G) best represents this situation? Briefly explain your selection. Label on the figure "d", the new steady state equilibrium values of Pra and cardiac output in the irreversible stage of shock. [Continues on next page] e) [4 pts] Assuming arterial pressure (PA) to be 40 mmHg and pleural pressure (Ppl) to be -4 mmHg, provide your best estimate of what the ratio of systolic to diastolic compliance (Cs/CD) of the heart would be in the irreversible stage of shock from the bleeding, based the information displayed in the figure. f) [4 pts] If the subject were to receive blood transfusion at the irreversible stage of shock, can the blood transfusion restore the cardiac output to the normal level? Assume that the body has not yet adjusted to the replenished blood volume. Explain your answer. [Continues on next page] 5. [Total: 8 pts] Muscle stretch reflex The figure below shows a simplified model of muscle stretch reflex in an experimental anesthetized animal. The model describes how the muscle stretch reflex regulates the muscle length. All variables shown have been linearized and represent fluctuations around its mean value under normal resting condition. Z represents external neural frequency stimulating the spinal cord. fa represents the total change in afferent neural frequency. The spinal cord, represented by the gain Gc, converts the incoming neural input to the neural output fe. The changes in the efferent neural frequency, fe, are relayed through motor neurons to the muscle. The muscle converts the efferent neural frequency to changes in muscle length L. The gain of this conversion is -GM. Note that the gain is negative because increases in efferent neural frequency lead to decreases in muscle length. The change in the muscle length is sensed by the muscle spindle. The muscle spindle relays the neural output, fs, to the spinal cord through sensory neurons. This process is represented by the gain Gs. fa fe + Z Gc + -GM Gs fs L a) [4 pts] Suppose that animal A is injected with a drug that disrupts neurotransmission, blocking the sensory neurons. Under such condition, is the system operating as a negative feedback system? Explain your answer. Please also state which gain(s) is affected by the sensory nerve blockade. b) [4 pts] Under which condition between normal and sensory nerve blockade would result in stronger muscle contraction for the same level of the external stimulation Z? Explain your answer. [Continues on next page] 6. [Total: 9 pts] Chemical regulation of ventilation Measures ventilation An investigator wants to investigate the effect of exercise on ventilation and Paco2 in a healthy volunteer. Assume that the baseline ventilatory response to CO2 and the subject's metabolic hyperbola prior to participating in the study yields an operating point labeled "BL" in the figure below. In order to measure ventilation during the exercise study, when the volunteer has to be on a treadmill, she has to wear a face mask connected to a long breathing tube which is then connected to a device used to measure ventilation. This device does not provide any ventilation support, but it can provide different levels of inhaled oxygen. The graph below shows metabolic hyperbolas and ventilatory response to CO2 under different conditions. A B C VdotE or VdotC (L/min) D E BL F P or P (mmHg) ACO2 aCO2 a) [3 pts] First, the subject's ventilation and Paco2 are measured while she is standing at rest on the treadmill and she breathes in air (21% O2). Considering the long tube in this experimental setup, which curve (A, B, C, D, E or F) best represents this situation? Briefly explain your selection. Label on the figure "a", the new steady state equilibrium values of PACO2 and ventilation for the volunteer at rest. [Continues on next page] b) [3 pts] The investigator then turns on the treadmill and so the volunteer runs on the treadmill while breathing air (21% O2). During exercise, the metabolic production of CO2 increases. Which curve (A, B, C, D, E or F) best represents this situation? Briefly explain your selection. Label on the figure "b", the new steady state equilibrium values of PACO2 and ventilation for a healthy volunteer during exercise. c) [3 pts] In the second part of the study, after the volunteer has rested, she uses the same face mask and long tubing arrangement. She runs on the treadmill at the same speed as in the first part of the study so that her metabolic production rate of CO2 matches what it was previously. But now she is given 100% O2 to breathe. Which curve (A, B, C, D, E or F) best represents this situation? Briefly explain your selection. Label on the figure "c", the new steady state equilibrium values of PACO2 and ventilation for a healthy volunteer during exercise. End of Exam 1/nAnswer based on the project on EEG attached 1. Identify engineering design requirements and define design strategy. 2. Identify design constraints considering public health, safety, and welfare, as well as global, cultural, social, environmental, and economic factors. 3. Use a methodical process to develop and evaluate feasible solutions against specifications/requirements with consideration of public health, safety, and welfare, as well as global, cultural, social, environmental, and economic factors 4. Detail the below points: A- List and analyze the different tradeoffs/compromises in each of your solutions. B- Select a solution by considering risks and making appropriate trade-offs. Instructions: Word limit: min 500 words Plagiarism free Solutions generated from any AI platform is strictly Prohibited Referencing and formatting Style APA Need Typed Solutions only.

Solved: 2. [5 pts] Contrast agents are substances used to enhance the radioden

Home
questions and answers
2 5 pts contrast agents are substances used to enhance the radiodensit

Question

2. [5 pts] Contrast agents are substances used to enhance the radiodensity of a targeted tissue by altering the way that electromagnetic radiation or ultrasound waves pass through the body. A patient is administered contrast agent intravenously. The contrast agent first gets distributed in the plasma. The contrast agen