Which of the following physiologic principles would be considered a function of the somatic nervous system?
the patella reflex "knee jerk" activated by tapping the patella tendon
abdominal viscera the beginning of depolarization in the cardiac conduction of impulses
the act of typing a report using a computer keyboard
withdrawing the hand after touching a hot surface
The Correct Answer is C
A) The patella reflex ("knee jerk") activated by tapping the patella tendon: The patellar reflex is a monosynaptic spinal reflex that involves the somatic nervous system but is a reflex action rather than a voluntary motor function. The somatic nervous system governs voluntary movements, but reflex actions like the patellar reflex are involuntary responses that do not require higher brain input, though they involve somatic motor pathways.
B) Abdominal viscera the beginning of depolarization in the cardiac conduction of impulses: This process is primarily under the control of the autonomic nervous system (ANS), not the somatic nervous system. The ANS regulates involuntary processes like heart rate and digestion, while the somatic nervous system controls voluntary movements and somatic sensation.
C) The act of typing a report using a computer keyboard: Typing is a voluntary motor activity, controlled by the somatic nervous system. The somatic system is responsible for conscious, voluntary actions such as moving muscles in the arms, hands, and fingers to type. This is the most accurate example of a somatic function.
D) Withdrawing the hand after touching a hot surface: This is a reflex action known as the "withdrawal reflex," which involves the somatic nervous system. However, it is an involuntary action triggered by a sensory stimulus. While it does involve the somatic system, it is not a voluntary action like typing, and reflexes are considered part of the automatic response mechanisms.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
A) Norepinephrine: Norepinephrine is a neurotransmitter primarily involved in the sympathetic nervous system. It is not involved in terminating the stimulation caused by acetylcholine. Norepinephrine acts on adrenergic receptors, whereas acetylcholine primarily acts on cholinergic receptors.
B) Decarboxylase: Decarboxylase is an enzyme that plays a role in the synthesis of certain neurotransmitters, including dopamine, but it does not have a role in terminating the action of acetylcholine at the effector cell. It is unrelated to the termination of acetylcholine signaling.
C) Catecholamine: Catecholamines (such as dopamine, norepinephrine, and epinephrine) are a group of neurotransmitters involved in the sympathetic nervous system. While they play a role in synaptic transmission, they are not responsible for breaking down acetylcholine or terminating its effects. Their primary function is in adrenergic signaling.
D) Acetylcholinesterase: Acetylcholinesterase is the correct enzyme. It is responsible for breaking down acetylcholine (ACh) in the synaptic cleft after it has stimulated the effector cell. By hydrolyzing acetylcholine into acetate and choline, acetylcholinesterase effectively terminates the signal and allows the effector cell's membrane to repolarize. This action prevents continuous stimulation and ensures proper function of the cholinergic system.
Correct Answer is C
Explanation
A) Proteins:
Proteins are generally too large to diffuse freely across the cell membrane. They require specific transport mechanisms, such as endocytosis or transport proteins, to move in and out of cells. The hydrophilic nature of most proteins further complicates their passage across the lipid bilayer.
B) Enzymes:
Like proteins, enzymes are large molecules that do not freely diffuse across cell membranes. Enzymes, being proteins, also need specialized transport mechanisms or need to be secreted or endocytosed to enter or exit cells.
C) Hormones:
Many hormones, particularly lipid-soluble ones like steroid hormones, can diffuse freely across the cell membrane. These hormones pass through the lipid bilayer due to their hydrophobic nature and bind to intracellular receptors, initiating cellular responses. However, water-soluble hormones (e.g., insulin) typically do not diffuse freely but interact with receptors on the cell surface.
D) Electrolytes:
Electrolytes (such as sodium, potassium, calcium, and chloride ions) are charged particles that cannot pass freely through the lipid bilayer due to the hydrophobic interior of the cell membrane. They require specific ion channels or transporters to move in and out of the cell. Diffusion of electrolytes is facilitated through these channels, but it is not a simple diffusion process as seen with small, uncharged molecules.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.