T lymphocytes are responsible for:
Humoral immunity.
Cell-mediated immunity.
Programming macrophages.
Producing antibodies.
The Correct Answer is B
T lymphocytes, also known as T cells, are a type of white blood cell that is an essential part of the immune system.
T cells are one of two primary types of lymphocytes — B cells being the second type — that determine the specificity of immune response to antigens (foreign substances) in the body.
T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface.
T cells originate in the bone marrow and mature in the thymus.
After migration to the thymus, the precursor cells mature into several distinct types of T cells.
One of these types is the CD8+ T cell, also known as cytotoxic T cell, which is responsible for cell-mediated immunity.
Cell-mediated immunity is the type of immunity that involves the direct killing of infected cells and cancer cells by cytotoxic T cells.
Choice A is wrong because humoral immunity is the type of immunity that involves the production of antibodies by B cells and plasma cells.
Antibodies are proteins that bind to specific antigens and mark them for destruction by other immune cells.
Choice C is wrong because programming macrophages is not a function of T lymphocytes.
Macrophages are a type of phagocytic cell that can engulf and digest pathogens and cellular debris.
Macrophages can be activated by cytokines, which are chemical messengers secreted by helper T cells and other immune cells.
Choice D is wrong because producing antibodies is not a function of T lymphocytes.
As mentioned above, antibodies are produced by B cells and plasma cells, which are another type of lymphocyte.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
The radial artery is one of the major blood-supplying vessels to the forearm and hand.
It can be felt as a pulse near the thumb on the wrist by gently pressing the artery against the underlying bone.
This is the most commonly measured pulse by nurses to assess peripheral pulse characteristics.
Choice B.
Palmar arch arteries are wrong because these are branches of the radial and ulnar arteries that form anastomosis in the palm of the hand.
They are not palpable on the wrist.
Choice C.
The brachial artery is wrong because this is the main artery of the upper arm that bifurcates into the radial and ulnar arteries at the cubital fossa.
It can be felt as a pulse in the antecubital fossa, not near the thumb on the wrist.
Choice D
The Ulnar artery is wrong because this is another major blood-supplying vessel to the forearm and hand that runs along the medial aspect of the forearm.
It can be felt as a pulse on the little finger side of the wrist, not near the thumb.
Correct Answer is C
Explanation
This is because the external jugular vein drains blood from the face and scalp into the subclavian vein.
Some possible explanations for the other choices are:
Choice A. Superior vena cava.
This is wrong because the superior vena cava is a large vein that collects blood from the head, neck, chest, and upper limbs and returns it to the right atrium of the heart.
It does not drain blood from the face and scalp directly.
Choice B. Subclavian vein.
This is wrong because the subclavian vein is a vein that receives blood from the external jugular vein, the internal jugular vein, and the vertebral vein and joins with the internal thoracic vein to form the brachiocephalic vein.
It does not drain blood from the face and scalp directly.
Choice D. Cephalic vein.
This is wrong because the cephalic vein is a vein that runs along the lateral side of the arm from the hand to the shoulder and empties into the axillary vein.
It does not drain blood from the face and scalp at all.
Normal ranges for blood pressure vary depending on age, gender, health status, and other factors, but a general guideline is that systolic blood pressure (the pressure when the heart contracts) should be less than 120 mmHg and diastolic blood pressure (the pressure when the heart relaxes) should be less than 80 mmHg.
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