PCB 3703 Exam 1 V1 | PCB 3703 Human
Physiology | Actual Q&A with Rationale (PCB3703
Exam 1) | University of Central Florida
1. Which of the following best describes the concept of homeostasis in human physiology?
A. The ability of the body to keep the internal environment exactly constant at all times.
B. A state of static equilibrium where no energy is required to maintain internal conditions.
C. The process by which the body ignores external changes to maintain metabolic rate.
D. The maintenance of a relatively stable internal environment despite external
fluctuations.
Correct Answer: D
Explanation: Homeostasis represents a dynamic state of equilibrium rather than a static
one. It involves complex regulatory mechanisms that adjust physiological processes to
maintain variables within a narrow, life-sustaining range. This process is essential for the
survival of complex organisms facing varying environmental stressors.
2. In a negative feedback loop, which component is responsible for comparing the current
value of a variable to the desired set point?
A. Sensor
B. Effector
C. Integrating center
,D. Afferent pathway
Correct Answer: C
Explanation: The integrating center, often located in the central nervous system or
endocrine glands, receives input from sensors. It evaluates this information against a
programmed set point to determine if a response is necessary. If a deviation is detected, it
sends instructions to effectors to correct the imbalance.
3. Which fluid compartment contains the majority of the total body water in a healthy adult?
A. Intracellular fluid (ICF)
B. Interstitial fluid (ISF)
C. Plasma
D. Extracellular fluid (ECF)
Correct Answer: A
Explanation: The intracellular fluid accounts for approximately two-thirds of the total
body water. The remaining one-third is found in the extracellular compartment, which is
further divided into interstitial fluid and plasma. Maintaining the distinct chemical
compositions of these compartments is a fundamental requirement for cellular function.
4. What is the primary function of the phospholipid bilayer in the cell membrane?
A. To provide structural rigidity to the cell.
B. To act as a primary site for ATP synthesis.
, C. To serve as a selective barrier against water-soluble molecules.
D. To facilitate the transport of large proteins via simple diffusion.
Correct Answer: C
Explanation: The amphipathic nature of phospholipids allows them to form a bilayer with
hydrophobic tails facing inward. This arrangement prevents the free passage of polar and
charged substances, requiring specialized proteins for their transport. This selectivity is
crucial for maintaining the unique environments of the ICF and ECF.
5. Which of the following statements regarding the Sodium-Potassium ATPase pump is
correct?
A. It moves 2 Sodium ions out and 3 Potassium ions in.
B. It facilitates the passive movement of ions down their concentration gradients.
C. It is an example of secondary active transport using a glucose gradient.
D. It moves 3 Sodium ions out and 2 Potassium ions in per ATP hydrolyzed.
Correct Answer: D
Explanation: The Na+/K+ ATPase is a primary active transporter that uses energy directly
from ATP hydrolysis. By moving more positive charges out than in, it contributes to the
electrogenic nature of the cell membrane. This pump is vital for maintaining the
concentration gradients necessary for action potentials and secondary active transport.
Physiology | Actual Q&A with Rationale (PCB3703
Exam 1) | University of Central Florida
1. Which of the following best describes the concept of homeostasis in human physiology?
A. The ability of the body to keep the internal environment exactly constant at all times.
B. A state of static equilibrium where no energy is required to maintain internal conditions.
C. The process by which the body ignores external changes to maintain metabolic rate.
D. The maintenance of a relatively stable internal environment despite external
fluctuations.
Correct Answer: D
Explanation: Homeostasis represents a dynamic state of equilibrium rather than a static
one. It involves complex regulatory mechanisms that adjust physiological processes to
maintain variables within a narrow, life-sustaining range. This process is essential for the
survival of complex organisms facing varying environmental stressors.
2. In a negative feedback loop, which component is responsible for comparing the current
value of a variable to the desired set point?
A. Sensor
B. Effector
C. Integrating center
,D. Afferent pathway
Correct Answer: C
Explanation: The integrating center, often located in the central nervous system or
endocrine glands, receives input from sensors. It evaluates this information against a
programmed set point to determine if a response is necessary. If a deviation is detected, it
sends instructions to effectors to correct the imbalance.
3. Which fluid compartment contains the majority of the total body water in a healthy adult?
A. Intracellular fluid (ICF)
B. Interstitial fluid (ISF)
C. Plasma
D. Extracellular fluid (ECF)
Correct Answer: A
Explanation: The intracellular fluid accounts for approximately two-thirds of the total
body water. The remaining one-third is found in the extracellular compartment, which is
further divided into interstitial fluid and plasma. Maintaining the distinct chemical
compositions of these compartments is a fundamental requirement for cellular function.
4. What is the primary function of the phospholipid bilayer in the cell membrane?
A. To provide structural rigidity to the cell.
B. To act as a primary site for ATP synthesis.
, C. To serve as a selective barrier against water-soluble molecules.
D. To facilitate the transport of large proteins via simple diffusion.
Correct Answer: C
Explanation: The amphipathic nature of phospholipids allows them to form a bilayer with
hydrophobic tails facing inward. This arrangement prevents the free passage of polar and
charged substances, requiring specialized proteins for their transport. This selectivity is
crucial for maintaining the unique environments of the ICF and ECF.
5. Which of the following statements regarding the Sodium-Potassium ATPase pump is
correct?
A. It moves 2 Sodium ions out and 3 Potassium ions in.
B. It facilitates the passive movement of ions down their concentration gradients.
C. It is an example of secondary active transport using a glucose gradient.
D. It moves 3 Sodium ions out and 2 Potassium ions in per ATP hydrolyzed.
Correct Answer: D
Explanation: The Na+/K+ ATPase is a primary active transporter that uses energy directly
from ATP hydrolysis. By moving more positive charges out than in, it contributes to the
electrogenic nature of the cell membrane. This pump is vital for maintaining the
concentration gradients necessary for action potentials and secondary active transport.
