The heart is enfolded within a space called the:
Pericardial cavity.
Mediastinum.
Abdominal cavity.
Pleural cavity.
Myocardium.
The Correct Answer is B
Choice A rationale
The pericardial cavity is the potential space between the parietal and visceral layers of the serous pericardium, containing pericardial fluid. While the heart resides within this cavity, the pericardial cavity itself is a component *within* the larger mediastinum.
Choice B rationale
The mediastinum is the central compartment of the thoracic cavity, located between the two pleural cavities. It extends from the sternum to the vertebral column and contains the heart, great vessels, trachea, esophagus, and thymus. The heart is indeed enfolded within this space.
Choice C rationale
The abdominal cavity is a large body cavity in the abdominopelvic region, containing major digestive, urinary, and reproductive organs. The heart is located in the thoracic cavity, superior to the diaphragm, and thus is not found in the abdominal cavity.
Choice D rationale
The pleural cavity refers to the potential space between the parietal and visceral pleura, surrounding each lung. There are two pleural cavities, one for each lung. The heart is situated *between* these two cavities, not within them.
Choice E rationale
The myocardium is the muscular layer of the heart wall responsible for pumping blood. It is a part of the heart itself, not a space that encloses the heart. The myocardium is covered externally by the epicardium and internally by the endocardium.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Choice A rationale
During exercise, local accumulation of metabolic byproducts like lactic acid, carbon dioxide, and adenosine in active muscles causes vasodilation, not constriction, of precapillary sphincters and arterioles. This vasodilation increases blood flow to meet the increased metabolic demand.
Choice B rationale
During exercise, the adrenal medulla releases epinephrine and norepinephrine, and sympathetic nerves release norepinephrine. These catecholamines cause widespread vasoconstriction in inactive tissues but induce vasodilation in skeletal muscles through specific receptor activation (beta-2 adrenergic receptors), increasing blood flow to working muscles.
Choice C rationale
Muscle contraction does compress blood vessels, aiding venous return (skeletal muscle pump). However, this is a mechanical action aiding circulation, not the direct effect of adrenal medulla and sympathetic nerves on arteriolar diameter in response to exercise, which primarily involves neurochemical regulation.
Choice D rationale
During exercise, the sympathetic nervous system is highly activated, leading to a "fight or flight" response. Conversely, the parasympathetic nervous system, which promotes "rest and digest" functions, is generally inhibited or its activity is decreased, not activated, to allow for increased cardiac output and blood flow to muscles.
Correct Answer is B
Explanation
Choice A rationale
Antidiuretic hormone (ADH), also known as vasopressin, is synthesized in the hypothalamus and subsequently released from the posterior pituitary gland. Its primary function involves regulating water balance by increasing water reabsorption in the renal collecting ducts, thereby concentrating urine and preventing dehydration.
Choice B rationale
Luteinizing hormone (LH) is a gonadotropic hormone produced and secreted by the anterior pituitary gland. In females, it triggers ovulation and corpus luteum formation, while in males, it stimulates testosterone production by the Leydig cells. It is not synthesized in the hypothalamus.
Choice C rationale
Thyrotropin-releasing hormone (TRH) is a hypothalamic hormone that stimulates the anterior pituitary to release thyroid-stimulating hormone (TSH) and prolactin. This tripeptide hormone plays a crucial role in regulating thyroid function and lactation through its signaling pathways.
Choice D rationale
Somatostatin, also known as growth hormone-inhibiting hormone (GHIH), is a peptide hormone produced in the hypothalamus. It inhibits the release of growth hormone (GH) and thyroid-stimulating hormone (TSH) from the anterior pituitary, playing a vital role in neuroendocrine regulation and metabolism.
Choice E rationale
Prolactin-inhibiting hormone (PIH), primarily dopamine, is synthesized in the hypothalamus. It continuously inhibits the secretion of prolactin from the anterior pituitary gland, thus regulating lactation. A decrease in PIH allows for increased prolactin release, promoting milk synthesis.
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.