Projections from the cell that move materials and mucus are called:
cilia.
flagella.
microvilli
microtubules.
The Correct Answer is A
A. Cilia: These are hair-like, motile projections composed of a specialized microtubule arrangement known as the 9+2 axoneme. In the respiratory tract, their coordinated, rhythmic beating creates a "mucociliary escalator" that effectively propels mucus, trapped pathogens, and particulate matter upward toward the pharynx to be cleared from the airway.
B. Flagella: While these are also motile projections with an internal microtubule structure similar to cilia, they are significantly longer and typically occur singly, such as the tail of a spermatozoon. Their primary physiological function is the locomotion of the entire cell through a fluid medium rather than the movement of extracellular materials or mucus.
C. Microvilli: These are non-motile, finger-like extensions of the plasma membrane that contain a core of actin filaments rather than microtubules. Their primary purpose is to increase the surface area of the cell membrane to facilitate efficient absorption and secretion, which is why they are found in high density on the brush border of intestinal and renal tubular epithelium.
D. Microtubules: These are intracellular hollow cylinders made of tubulin dimers that serve as a major component of the cytoskeleton and the structural framework for cilia and flagella. While they are essential for the movement of organelles and vesicles within the cytoplasm via motor proteins, they are internal structural elements rather than external projections.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is E
Explanation
A. Astrocyte: This is the most abundant neuroglial cell in the central nervous system, characterized by its star-shaped morphology and perivascular feet. These cells are essential for maintaining the blood-brain barrier, regulating the chemical environment of the interstitial fluid, and providing structural support to neurons. Their primary role is homeostatic and metabolic.
B. Schwann Cells: Schwann cells are glial cells of the peripheral nervous system that form the myelin sheath around axons. This myelination increases the speed of electrical impulse conduction along the nerve fiber. Schwann cells also aid in the regeneration of damaged peripheral nerves by guiding axonal growth.
C. Microglial cell: This cell functions as the resident macrophage and primary immune defense within the central nervous system. These small, mobile cells constantly scavenge for plaque, damaged neurons, and infectious agents to maintain neural health through phagocytosis.
D. Ependymal cells: Ependymal cells line the ventricles of the brain and the central canal of the spinal cord. These ciliated epithelial-like cells are responsible for the production, circulation, and monitoring of cerebrospinal fluid (CSF), creating a permeable barrier between the CSF and the nervous tissue. Their specialization is related to fluid dynamics and ventricular lining.
E. Oligodendrocyte: This is a specialized glial cell that extends multiple cytoplasmic processes to wrap around axons in the central nervous system. These wraps form the myelin sheath, a lipid-rich insulating layer that significantly increases the velocity of action potential conduction through saltatory conduction.
Correct Answer is D
Explanation
A. Flat: Flat bones are thin, flattened, and often slightly curved, providing broad surfaces for muscle attachment and protection of vital organs. Examples include the sternum, ribs, scapulae, and cranial bones, which protect the brain and thoracic organs. Their structure consists of two layers of compact bone enclosing spongy bone (diploë).
B. Irregular: Irregular bones have complex shapes that do not fit into other bone categories. They often provide protection of nervous tissue and serve as multiple muscle attachment sites, such as the vertebrae, sphenoid, and facial bones. Their anatomy reflects specialized functions rather than uniform shape.
C. Short: Short bones are roughly cube-shaped and consist primarily of spongy bone with a thin outer layer of compact bone. They provide stability and support with limited movement, as seen in the carpals and tarsals of the wrist and ankle.
D. Regular: “Regular” is not a recognized anatomical classification of bone. Standard bone classifications include long, short, flat, irregular, and sesamoid bones.
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