,Nightingale SCI 221 Exam 1 | Human Physiology
(2026) Q&A
1. Which principle states that the function of a body part is determined by its
unique structure?
A) Principle of homeostasis
B) Principle of complementarity
C) Principle of negative feedback
D) Principle of anatomical position
Correct Answer: Principle of complementarity
Rationale: The principle of complementarity states that structure determines
function; the shape and form of a body part enable its specific job. Homeostasis
refers to maintaining internal stability, negative feedback is a regulatory
mechanism, and anatomical position is a reference posture. This principle is
foundational to understanding physiology.
2. What is the primary function of a receptor in a homeostatic control system?
A) To produce a response that alters the variable
B) To detect changes in the internal environment
C) To integrate sensory information and determine a set point
D) To serve as the communication link between the brain and spinal cord
Correct Answer: To detect changes in the internal environment
,Rationale: The receptor monitors the internal environment and responds to
stimuli, sending information to the control center via the afferent pathway. The
effector produces the response, the control center processes information, and the
communication link is the afferent or efferent pathway.
3. In a negative feedback loop, what is the specific role of the effector?
A) To process the signal and determine the set point
B) To carry out the response that restores the variable to its set point
C) To amplify the stimulus until a climax is reached
D) To detect the initial change in the variable
Correct Answer: To carry out the response that restores the variable to its set
point
Rationale: The effector receives output from the control center and produces a
response that opposes the initial stimulus, returning the internal environment to
its ideal physiological set point. Processing the signal and determining the set
point are functions of the control center, and amplifying the stimulus describes
positive feedback.
4. Which of the following best describes homeostasis?
A) A state of complete physiological stasis where no changes occur
B) A process that primarily uses positive feedback to prevent organ failure
C) The maintenance of a relatively stable internal environment despite external
changes
D) The body’s ability to maximize energy expenditure during periods of rest
, Correct Answer: The maintenance of a relatively stable internal environment
despite external changes
Rationale: Homeostasis is the body’s ability to maintain a stable internal
environment even when the external environment changes significantly. It
involves a dynamic state of equilibrium where internal conditions are kept within
narrow, healthy ranges, primarily through negative feedback loops. Complete
stasis is not compatible with life.
5. Which type of feedback mechanism amplifies a change until a specific event is
completed, such as during childbirth?
A) Negative feedback
B) Positive feedback
C) Feed-forward control
D) Neutral feedback
Correct Answer: Positive feedback
Rationale: Positive feedback mechanisms amplify or strengthen the original
change until a specific event, such as childbirth or blood clotting, is completed.
Negative feedback opposes a change, feed-forward control anticipates a change,
and neutral feedback is not a physiological regulatory mechanism.
6. Of the 11 major body systems, which is considered the least involved in
maintaining homeostasis?
A) Circulatory system
B) Endocrine system
C) Lymphatic system
(2026) Q&A
1. Which principle states that the function of a body part is determined by its
unique structure?
A) Principle of homeostasis
B) Principle of complementarity
C) Principle of negative feedback
D) Principle of anatomical position
Correct Answer: Principle of complementarity
Rationale: The principle of complementarity states that structure determines
function; the shape and form of a body part enable its specific job. Homeostasis
refers to maintaining internal stability, negative feedback is a regulatory
mechanism, and anatomical position is a reference posture. This principle is
foundational to understanding physiology.
2. What is the primary function of a receptor in a homeostatic control system?
A) To produce a response that alters the variable
B) To detect changes in the internal environment
C) To integrate sensory information and determine a set point
D) To serve as the communication link between the brain and spinal cord
Correct Answer: To detect changes in the internal environment
,Rationale: The receptor monitors the internal environment and responds to
stimuli, sending information to the control center via the afferent pathway. The
effector produces the response, the control center processes information, and the
communication link is the afferent or efferent pathway.
3. In a negative feedback loop, what is the specific role of the effector?
A) To process the signal and determine the set point
B) To carry out the response that restores the variable to its set point
C) To amplify the stimulus until a climax is reached
D) To detect the initial change in the variable
Correct Answer: To carry out the response that restores the variable to its set
point
Rationale: The effector receives output from the control center and produces a
response that opposes the initial stimulus, returning the internal environment to
its ideal physiological set point. Processing the signal and determining the set
point are functions of the control center, and amplifying the stimulus describes
positive feedback.
4. Which of the following best describes homeostasis?
A) A state of complete physiological stasis where no changes occur
B) A process that primarily uses positive feedback to prevent organ failure
C) The maintenance of a relatively stable internal environment despite external
changes
D) The body’s ability to maximize energy expenditure during periods of rest
, Correct Answer: The maintenance of a relatively stable internal environment
despite external changes
Rationale: Homeostasis is the body’s ability to maintain a stable internal
environment even when the external environment changes significantly. It
involves a dynamic state of equilibrium where internal conditions are kept within
narrow, healthy ranges, primarily through negative feedback loops. Complete
stasis is not compatible with life.
5. Which type of feedback mechanism amplifies a change until a specific event is
completed, such as during childbirth?
A) Negative feedback
B) Positive feedback
C) Feed-forward control
D) Neutral feedback
Correct Answer: Positive feedback
Rationale: Positive feedback mechanisms amplify or strengthen the original
change until a specific event, such as childbirth or blood clotting, is completed.
Negative feedback opposes a change, feed-forward control anticipates a change,
and neutral feedback is not a physiological regulatory mechanism.
6. Of the 11 major body systems, which is considered the least involved in
maintaining homeostasis?
A) Circulatory system
B) Endocrine system
C) Lymphatic system
