Which structure is highlighted and indicated by the leader line?
Radial artery.
Superficial palmar arch.
Common digital arteries.
Brachial artery.
Ulnar artery.
The Correct Answer is B
Choice A rationale
The radial artery is a major artery in the forearm, running along the thumb side. It is a common site for pulse palpation and arterial blood gas sampling due to its superficial location. However, it typically terminates by contributing to the deep palmar arch, not forming the superficial palmar arch directly.
Choice B rationale
The superficial palmar arch is a vascular arcade formed primarily by the superficial branch of the ulnar artery, with a contribution from the radial artery. This arch is located just beneath the palmar aponeurosis and gives rise to the common digital arteries, supplying blood to the fingers.
Choice C rationale
Common digital arteries originate from the superficial palmar arch and run distally along the metacarpals. They then bifurcate into proper digital arteries, which supply the individual digits. These are branches of the arch, not the arch itself.
Choice D rationale
The brachial artery is a continuation of the axillary artery and is the main arterial supply to the arm. It typically bifurcates into the radial and ulnar arteries in the cubital fossa, well before reaching the hand to form palmar arches.
Choice E rationale
The ulnar artery is the larger terminal branch of the brachial artery, descending along the medial side of the forearm. Its superficial branch is the primary contributor to the superficial palmar arch, making it a key vessel in the hand's vascular supply.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Choice C rationale
Negative feedback inhibition is the most common mechanism by which target organs regulate pituitary hormone secretion. When the concentration of a hormone secreted by a target gland reaches a sufficient level, it inhibits the release of stimulating hormones from the pituitary and/or hypothalamus, thereby maintaining hormonal homeostasis and preventing overproduction.
Choice A rationale
Positive feedback is less common in endocrine regulation and typically leads to an amplification of the initial stimulus, rather than a return to homeostasis. An example is the surge of luteinizing hormone during ovulation, where estrogen stimulates more LH release.
Choice B rationale
Direct nervous stimulation occurs in some cases, such as the adrenal medulla's release of catecholamines in response to sympathetic preganglionic neurons. However, for target organ regulation of the pituitary, feedback loops involving hormones are the predominant mechanism, not direct nervous stimulation.
Choice D rationale
Reverberation refers to a type of neural circuit where neurons re-excite themselves or upstream neurons, leading to a sustained output. This concept is primarily relevant to neural networks and not a direct mechanism for endocrine feedback from target organs to the pituitary gland.
Correct Answer is D
Explanation
Choice A rationale
While the immune response originates in specific organs like the thymus, bone marrow, and lymph nodes, this statement describes the origin of immune cells and processes, not the fundamental characteristic of specificity, which relates to targeting particular antigens.
Choice B rationale
Similar to Choice A, the immune response involves specialized tissues throughout the body, such as lymphoid tissues. However, this describes the anatomical distribution of the immune system rather than the core principle of specificity in recognizing unique pathogens.
Choice C rationale
The immune response is indeed carried out by specific groups of cells, such as B lymphocytes and T lymphocytes, which have specialized functions. However, while these cells contribute to specificity, the most direct definition of specificity in immunity is the targeted response against a particular pathogen or antigen.
Choice D rationale
Specificity in immunity means that the immune system's response is highly targeted and precise. Each specific B and T lymphocyte is programmed to recognize and respond to a particular epitope (a specific molecular structure) on a pathogen, ensuring that the immune response is directed only against the invading microbe.
Choice E rationale
The immune response involves specialized tissues. However, this statement focuses on the location rather than the fundamental characteristic of specificity, which refers to the precise recognition and targeting of a particular pathogen or antigen by immune cells.
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