As a result of the allergen-antibody reaction, mast cells release histamine:
False
True
The Correct Answer is B
As a result of the allergen-antibody reaction, mast cells release histamine.
This is because when mast cells are exposed to an allergen that binds to IgE antibodies attached to their FcɛRI receptors, they release histamine and other inflammatory mediators.
Histamine causes vasodilation, increased capillary permeability, mucus secretion, and smooth muscle contraction, which result in allergic symptoms such as itching, swelling, sneezing, and wheezing.
Mast cells do release histamine in response to allergen-antibody reactions. Some additional sentences are:
Normal ranges of histamine levels vary depending on the tissue and the method of measurement, but they are usually low in healthy individuals and elevated in allergic conditions.
Histamine can be degraded by enzymes such as diamine oxidase and histamine N- methyltransferase, or inhibited by drugs such as antihistamines.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Excretion is the process of removing metabolic wastes or excrements from the body.
Metabolic wastes are substances left over from metabolic processes (such as cellular respiration) which cannot be used by the organism and must therefore be excreted.
These include nitrogen compounds, water, CO2, phosphates, sulphates, etc.
Choice B. Absorption is wrong because absorption is the process of taking in substances into the body or cells.
It is not related to the removal of waste.
Choice C. Metabolism is wrong because metabolism is the sum of all the chemical reactions that occur in an organism.
It is not a process of removing wastes, but rather producing them.
Choice D. Assimilation is wrong because assimilation is the process of incorporating substances into the body or cells.
It is also not related to the removal of waste.
Normal ranges for metabolic wastes vary depending on the type and concentration of the waste, as well as the organism and its environment.
For example, ammonia is a very toxic waste that requires a lot of water for its excretion, while uric acid is a less toxic waste that can be concentrated into a small volume.
Some normal ranges for human metabolic wastes are:
Urea: 2.5 to 6.4 mmol/L in blood serum Uric acid: 3.4 to 7.2 mg/dL in blood serum Creatinine: 0.6 to 1.2 mg/dL in blood serum CO2: 35 to 45 mmHg in arterial blood gas
Correct Answer is B
Explanation
Epinephrine, also known as adrenaline, is a hormone that the adrenal medulla secretes in response to stress or low blood sugar levels.
It helps the body react to stress by increasing blood pressure, heart rate, oxygen delivery to muscles, and blood sugar levels.
Choice A is wrong because mineralocorticoids are hormones that the adrenal cortex secretes, not the adrenal medulla.
They help regulate the balance of sodium and potassium in the body.
Choice C is wrong because glucocorticoids are also hormones that the adrenal cortex secretes, not the adrenal medulla.
They help control the body’s use of fats, proteins, and carbohydrates, suppress inflammation, and regulate blood pressure and blood sugar.
Choice D is wrong because aldosterone is a specific type of mineralocorticoid that the adrenal cortex secretes, not the adrenal medulla.
It helps regulate the balance of sodium and water in the body.
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