😀 EASY
This MCQ relates to the learning outcomes set out in the homeostasis lecture. Good luck!
Reviewed by Jonathan Loomes-Vrdoljak
Homeostasis
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Question 1 |
Define homeostasis
Staying home | |
Maintenance of a stable state in the body, resisting change | |
Maintenance of stable equilibrium through physiological processes | |
Altering the baseline to new levels as the environment changes |
Question 1 Explanation:
Homeostasis is not about maintaining physiological processes in a stable state (this occurs at death), but about altering physiological processes dynamically in order to carry out physiological processes (ex. Moving ions against their concentration gradient in order to facilitate secondary active transport)
Question 2 |
What 3 components are needed for homeostasis?
Sensor, control centre and effector | |
Sensor and effector | |
Sensor, control centre and feedback centre | |
Control centre, feedback centre and effector |
Question 3 |
What is the term for a cycle of events in which the status of a body condition is continuously monitored, evaluated, changed and re-monitored?
Negative feedback
| |
Feedback control | |
Positive feedback | |
Homeostasis |
Question 4 |
What is the difference between negative and positive feedback?
In positive feedback, the output of the control system turns on a stimulus that had been switched off and negative feedback keeps a stimulus that has been turned on by positive feedback on | |
In positive feedback, the output of the control system reduces the original output stimulus and in negative feedback it increases the output stimulus | |
In negative feedback, the output of the control system reduces the original output stimulus and in positive feedback it shuts off the feedback temporarily | |
In negative feedback, the output of the control system reduces the original output stimulus and in positive feedback it increases the output stimulus |
Question 5 |
TSH levels in the bloodstream are rising, causing T3 and T4 levels to keep increasing proportionally, exceeding the normal range of T3 and T4 blood levels. What is this a failure of?
Positive feedback | |
Negative feedback | |
Tubular feedback | |
Thyroidal feedback |
Question 5 Explanation:
Normally a rise in T3 and T4 should be sufficient to cause negative feedback in the pituitary gland and hypothalamus, resulting in a decrease release of TRH and TSH. This has failed to happen in this case
Question 6 |
What is an example of a negative feedback loop with regards to glucose metabolism?
Insulin is released when glucose is low and when glucose levels increase, insulin release comes to a halt | |
Insulin is released when glucose is high and when glucose levels drop, insulin release comes to a halt | |
Glucagon is released when glucose is high and when glucose levels drop, glucagon release comes to a halt |
Question 7 |
What is an example of a negative feedback loop with regards to blood pressure?
Antidiuretic hormone (ADH) is released when blood pressure is low and when blood pressure increases, ADH levels drop | |
Antidiuretic hormone (ADH) is released when blood pressure is high and when blood pressure decreases, ADH levels drop | |
Adenosine is released when blood pressure is low and when blood pressure increases, adenosine levels drop | |
Atrial natriuretic peptide (ANP) is released when blood pressure is low and when blood pressure increases, ANP levels drop |
Question 8 |
What is an example of a negative feedback loop with regards to erythropoiesis (red blood cell formation)?
High levels of oxygen in the blood are detected by the kidney, releasing EPO. EPO enters the blood marrow where it promotes red blood cell progenitors to halt the differentiation process. | |
High levels of carbon dioxide are detected by the kidney, releasing EPO. EPO enters the blood marrow where it promotes red blood cell progenitors to halt the differentiation. | |
Low carbon dioxide levels in the blood are detected by the kidney, releasing EPO. EPO promotes the formation of new red blood cells. EPO levels decrease as blood oxygen levels increase. | |
Low oxygen levels in the blood are detected by the kidney, releasing EPO. EPO promotes the formation of new red blood cells. EPO levels decrease as blood oxygen levels increase. |
Question 8 Explanation:
EPO is erythropoietin
Question 9 |
What is the result of a failure in homeostasis?
Disease | |
Adaptation to the environment | |
Evolution | |
You cannot deviate from homeostasis because the body will always adjust |
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