Capillary walls consist of a single layer of epithelial cells, and they exchange substances in the blood for substances in the tissue fluid surrounding body cells.
True
False
The Correct Answer is A
Capillary walls consist of a single layer of epithelial cells, and they exchange substances in the blood for substances in the tissue fluid surrounding body cells.
This single layer of cells is called the endothelium and it forms the barrier between the blood and the interstitial fluid.
The endothelium can be either continuous or fenestrated, depending on the tissue type and function.
The capillaries are very thin and allow red blood cells to flow through them single file.
The capillaries also have a layer of a glycoprotein called the glycocalyx that covers their luminal surface.
Choice B. False is wrong because it contradicts the definition and structure of capillaries.
Capillaries are not made of multiple layers of cells, nor do they prevent the exchange of substances between the blood and the tissue fluid.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
This type of blood cell is a granulocyte that has a bi-lobed nucleus and red granules in the cytoplasm.
Eosinophils are involved in allergic reactions and parasitic infections.
Choice A is wrong because basophils are granulocytes that have a lobed nucleus and dark blue or purple granules in the cytoplasm.
Basophils are involved in inflammatory responses and histamine release.
Choice B is wrong because lymphocytes are agranulocytes that have a large round nucleus and a thin rim of cytoplasm.
Lymphocytes are involved in immune responses and produce antibodies.
Choice D is wrong because monocytes are agranulocytes that have a kidney-shaped nucleus and a pale blue cytoplasm.
Monocytes are involved in phagocytosis and tissue repair.
Choice E is wrong because neutrophils are granulocytes that have a multi-lobed nucleus and pale pink granules in the cytoplasm.
Neutrophils are involved in bacterial infections and inflammation.
Correct Answer is D
Explanation
Paracrine secretions are chemical signals that affect only nearby cells.
They are released by the sending cell and diffuse through the extracellular space to the target cell, which has a specific receptor for the signal.
Paracrine signaling is a form of local signaling that occurs in multicellular organisms.
Choice A is wrong because autocrine secretions are chemical signals that act on the same cell that produced them.
Autocrine signaling is also a form of local signaling, but it involves cell signaling itself.
Choice B is wrong because endocrine secretions are chemical signals that are secreted into the blood and act at long distances.
Endocrine signaling is a form of long-range signaling that involves ductless glands that secrete hormones.
Choice C is wrong because exocrine secretions are non-hormonal substances that are secreted into ducts to the external environment.
Exocrine signaling is not a form of cell-cell communication, but rather a way of releasing substances such as sweat, saliva, or digestive enzymes.
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