Question 1

______ feedback is often referred to as a &#34;vicious cycle&#34; because it leads to _______ instability and sometimes death.&#10;A)Positive, progressive&#10;B)Positive, diminished&#10;C)Negative, progressive&#10;D)Negative, diminished&#10;E)Adaptive, progressive

Accepted Answer

Positive feedback loops amplify changes and can lead to progressive instability, often described as a "vicious cycle." This can sometimes result in conditions that lead to death if the feedback loop is not interrupted.

Question 2

Which of the following is an example of a &#34;feed forward&#34; control system?&#10;A)The arterial baroreceptor system&#10;B)The progressive nature of uterine contractions during childbirth&#10;C)Control of skeletal muscle movements by the brain&#10;D)Generation of an action potential

Accepted Answer

Feed forward control systems anticipate changes and initiate responses in advance. The control of skeletal muscle movements by the brain involves planning and initiating movements before they occur, fitting the definition of feed forward control.

Question 3

Which of the following is an example of positive feedback in the body?&#10;A)Clotting of blood&#10;B)Return of blood pressure toward normal after a hemorrhage&#10;C)Increased respiration rate caused by accumulation of carbon dioxide in the blood&#10;D)Decreased sympathetic nervous system activity that occurs in response to increased blood pressure

Accepted Answer

Positive feedback is a process where a change in a variable leads to an amplification of that change, leading to a greater response. Clotting of blood is an example of positive feedback because when a blood vessel is damaged, platelets form a clot that helps to stop the bleeding. The clotting process is a positive feedback loop because the more platelets that gather at the site of injury, the more chemicals they release to recruit more platelets, ultimately leading to the formation of a clot.

Question 4

When a person is at rest, how much time is required for the blood in the circulation to traverse the entire circulatory circuit?&#10;A)1 second&#10;B)1 minute&#10;C)3 minutes&#10;D)4 minutes&#10;E)5 minutes

Accepted Answer

At rest, it takes approximately one minute for the blood to travel through the entire circulatory circuit. This is also known as the cardiac output, which is the amount of blood pumped by the heart per minute. The average cardiac output for an adult at rest is 5 liters per minute, and the total blood volume in the circulatory system is approximately 5 liters. Therefore, it takes one minute for all the blood in the body to circulate once through the heart and the blood vessels.

Question 5

Which of the following statements about homeostasis is incorrect?&#10;A)It refers to the maintenance of a stable internal environment for the body&#10;B)Homeostatic mechanisms do not operate in diseases&#10;C)Homeostasis requires integrated actions of the cells, tissues, organs, and multiple nervous, hormonal, and local control systems&#10;D)Homeostatic compensations that begin after a major environmental challenge may contribute to abnormalities of body function

Accepted Answer

Homeostatic mechanisms can still operate in diseases, but they may be compromised or not functioning properly, leading to disruptions in the internal environment of the body.

Question 6

Which of the following is an example of negative feedback?&#10;A)Arterial baroreceptor control of blood pressure&#10;B)Excitation of the respiratory center by increased blood carbon dioxide concentration&#10;C)Hemorrhagic shock cause by severe blood loss&#10;D)A and B&#10;E)A, B, and C

Accepted Answer

Negative feedback mechanisms work to correct a deviation from a set point (return to homeostasis), and both arterial baroreceptor control of blood pressure and excitation of the respiratory center by increased blood carbon dioxide concentration are examples of this process.

Question 7

Which of the following substances has the highest extracellular fluid to intracellular fluid concentration ratio for most mammalian cells?&#10;A)Sodium ions&#10;B)Potassium ions&#10;C)Carbon dioxide&#10;D)Glucose&#10;E)Protein

Accepted Answer

Sodium ions have a higher extracellular concentration compared to intracellular concentration in most mammalian cells. Potassium ions, on the other hand, have a higher intracellular concentration compared to extracellular concentration. Carbon dioxide, glucose, and proteins are relatively evenly distributed between extracellular and intracellular fluids.

Question 8

Exchange of substances between the cardiovascular system and the interstitial fluid occurs mainly in which of the following?&#10;A)Arteries&#10;B)Arterioles&#10;C)Capillaries&#10;D)Venules&#10;E)Veins

Accepted Answer

Capillaries are the smallest and thinnest blood vessels in the body, and they are where the exchange of substances (such as oxygen, nutrients, and waste products) between the cardiovascular system and the interstitial fluid occurs. Arteries, arterioles, venules, and veins all transport blood to and from the capillaries, but they do not participate in the actual exchange process themselves.

Deck 1: Functional Organization of the Human Body and Control of the Internal Environment