What characteristics would be found in the tissue that forms the inner lining of the respiratory passages?
Mucus-secreting, ciliated, and pseudostratified
Mucus-secreting and transitional
Stratified, sputum-secreting, and non-ciliated
Simple squamous, keratinized, and dry
The Correct Answer is A
The respiratory tract is lined by a specialized epithelium designed to protect the airway and maintain efficient gas exchange. This lining must trap inhaled particles, prevent infection, and move debris out of the respiratory system. The epithelium of most of the conducting airways, such as the trachea and bronchi, is adapted for this protective function. It contains goblet cells and ciliated cells working together in a coordinated system known as the mucociliary escalator.
A. Mucus-secreting, ciliated, and pseudostratified: the respiratory passages are primarily lined by pseudostratified ciliated columnar epithelium. This tissue contains goblet cells that secrete mucus, which traps dust, pathogens, and debris inhaled into the airway. The cilia then beat in a coordinated motion to move this mucus upward toward the pharynx for removal. The pseudostratified arrangement allows multiple cell types at different heights while still forming a single epithelial layer essential for airway protection.
B. Mucus-secreting and transitional: transitional epithelium is found in the urinary system, particularly in the bladder and ureters. Its primary function is to allow stretching and recoil as urine volume changes, not airway protection. Although mucus secretion is present in respiratory tissues, transitional epithelium does not contain ciliated cells or form the mucociliary escalator.
C. Stratified, sputum-secreting, and non-ciliated: stratified epithelium is generally found in areas subject to high abrasion, such as the skin, esophagus, and oral cavity. The respiratory tract requires ciliated cells to move mucus, which this option lacks. Additionally, sputum production is a pathological term rather than a normal epithelial function. The absence of cilia makes this option inconsistent with respiratory physiology.
D. Simple squamous, keratinized, and dry: simple squamous epithelium is found in structures requiring rapid diffusion, such as alveoli, not the conducting airways. Keratinization and dryness are characteristics of the skin, not internal respiratory passages. The respiratory tract must remain moist to facilitate mucus movement and gas exchange.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
The wall of the eye is composed of three concentric layers (tunics), each with distinct anatomical and functional roles. The outer fibrous tunic includes the sclera and cornea and provides protection and structural support. The middle vascular tunic (uvea) includes the iris, ciliary body, and choroid and is responsible for vascular supply and light regulation. The inner neural tunic contains the retina, which is essential for converting light into neural impulses for vision.
A. Sclera: The sclera is the dense, fibrous outer layer of the eye that forms the “white” of the eyeball. It is composed mainly of collagen and provides structural integrity, maintaining the shape of the globe and protecting internal structures. It serves as an attachment site for extraocular muscles. Since it belongs to the outer fibrous tunic rather than the inner layer, it is not part of the inner tunic.
B. Cornea: The cornea is the transparent anterior continuation of the sclera and forms the outermost refractive surface of the eye. It is avascular and highly organized to allow light transmission and refraction. Its primary function is optical, contributing significantly to focusing light onto the retina. It is part of the outer fibrous tunic, not the inner neural layer.
C. Retina: The retina is the innermost layer (inner neural tunic) of the eye and is derived from neuroectoderm. It contains specialized photoreceptor cells (rods and cones) that convert light energy into electrical signals through phototransduction. These signals are processed by bipolar and ganglion cells, whose axons form the optic nerve. Because it is the sensory layer responsible for initiating vision, it is correctly classified as part of the inner tunic.
D. Iris: The iris is a pigmented muscular structure located in the middle vascular tunic (uvea) of the eye. It controls pupil size through contraction and relaxation of smooth muscle fibers, regulating the amount of light entering the eye. It plays a key role in light adaptation but is not part of the inner neural layer. Therefore, it belongs to the middle tunic, not the inner tunic.
Correct Answer is B
Explanation
The nervous system is a highly specialized communication network responsible for detecting internal and external stimuli, processing information, and coordinating appropriate responses. It is composed of the central nervous system (brain and spinal cord) and peripheral nervous system (nerves and ganglia). Its primary mode of communication is rapid electrical signaling via neurons, which allows precise control of bodily functions. This system works closely with the endocrine system to maintain homeostasis.
A. Contracts and generates a force to cause bodily motion: contraction and force generation are functions of the muscular system, not the nervous system. Skeletal muscles contract in response to neural stimulation, but they are the effectors rather than the controllers. The nervous system only initiates and regulates these contractions. This describes muscle function rather than neural function.
B. Controls and coordinates body activities by transmitting electrical signals: the nervous system regulates body functions through rapid transmission of electrical impulses along neurons. These signals allow communication between different parts of the body and enable coordination of movement, sensation, and autonomic processes. The brain and spinal cord integrate information and generate appropriate responses. This makes the nervous system the primary control and coordination system of the body.
C. Produces hormones that directly contract skeletal muscle: hormone production is primarily the role of the endocrine system, not the nervous system. While some endocrine glands are regulated by the nervous system (e.g., hypothalamus and pituitary), hormones themselves do not directly cause skeletal muscle contraction. Muscle contraction is triggered by motor neuron stimulation via neurotransmitters, not hormones.
D. Stores nutrients for energy use during muscle contraction: nutrient storage is primarily the function of tissues such as the liver, adipose tissue, and skeletal muscle. Glycogen and fat serve as energy reserves, but this is not a function of the nervous system. The nervous system may regulate metabolic activity but does not store energy substrates. This option describes metabolic storage functions rather than neural activity.
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