Respiratory System Overview
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Questions and Answers

What replaces cartilage in the airway walls at the bronchiolar level?

  • Elastic fibers
  • Non-ciliated epithelium
  • Connective tissue
  • Smooth muscle (correct)
  • Which system is responsible for bronchoconstriction?

  • Sympathetic system
  • Parasympathetic system (correct)
  • Somatic nervous system
  • Central nervous system
  • What is the primary function of bronchial contractility?

  • Maintain lung volume
  • Control gas exchange
  • Change airway diameter (correct)
  • Produce mucus
  • What type of epithelium primarily composes the alveolar wall?

    <p>Squamous epithelial cells</p> Signup and view all the answers

    How many alveoli are approximately present in the adult lung?

    <p>150 million</p> Signup and view all the answers

    What is the primary mechanism of expiration at rest?

    <p>Relaxation of the external intercostal muscles and diaphragm</p> Signup and view all the answers

    What does compliance refer to in pulmonary physiology?

    <p>The stretchability of the lungs</p> Signup and view all the answers

    What volume of air does tidal volume (TV) approximately represent at rest?

    <p>500 mL</p> Signup and view all the answers

    What effect does increased airway resistance have on the respiratory effort?

    <p>Increases the effort needed to inflate the lungs</p> Signup and view all the answers

    Which lung volume remains in the lungs after a normal expiration to prevent total collapse?

    <p>Residual volume (RV)</p> Signup and view all the answers

    What type of epithelium is found in the nasopharynx?

    <p>Ciliated columnar epithelium</p> Signup and view all the answers

    What is the main function of the constrictor muscles in the pharynx?

    <p>To push food and fluid into the esophagus during swallowing</p> Signup and view all the answers

    How does the pharynx contribute to warming and humidifying air?

    <p>By allowing air to pass through the nasal and oral sections</p> Signup and view all the answers

    What role does the pharyngeal tonsils play in the immune system?

    <p>They produce antibodies in response to pathogens</p> Signup and view all the answers

    What is the primary purpose of the auditory tube in the pharynx?

    <p>To equalize pressure in the middle ear</p> Signup and view all the answers

    What can cause obstruction of the pharyngeal opening during sleep?

    <p>Sedative drugs or alcohol reducing muscle tone</p> Signup and view all the answers

    What type of epithelium is predominantly found in the oropharynx and laryngopharynx?

    <p>Stratified squamous epithelium</p> Signup and view all the answers

    Which function is NOT associated with the pharynx?

    <p>Regulating blood pressure</p> Signup and view all the answers

    What is the primary function of the respiratory system?

    <p>To bring atmospheric oxygen to the blood and remove carbon dioxide</p> Signup and view all the answers

    Which structure is responsible for dividing the nasal cavity into two passages?

    <p>Septum</p> Signup and view all the answers

    What type of epithelium lines the nasal cavity?

    <p>Ciliated columnar epithelium</p> Signup and view all the answers

    Which of the following bones forms part of the bony septum in the nasal cavity?

    <p>Vomer</p> Signup and view all the answers

    The paranasal sinuses serve which of the following purposes?

    <p>Producing vocal sounds and lightening the skull</p> Signup and view all the answers

    What characterizes the anterior nares of the nasal cavity?

    <p>They are the openings from outside into the nasal cavity</p> Signup and view all the answers

    Which muscles are primarily involved in the process of breathing?

    <p>Intercostal muscles and diaphragm</p> Signup and view all the answers

    What does the hard palate in the nasal cavity consist of?

    <p>Only bone</p> Signup and view all the answers

    What is the primary function of the pleural fluid?

    <p>To enable lung inflation during breathing</p> Signup and view all the answers

    What distinguishes the right bronchus from the left bronchus?

    <p>It divides into three branches instead of two</p> Signup and view all the answers

    Which of the following structures is part of the mediastinum?

    <p>The heart</p> Signup and view all the answers

    What happens if either layer of the pleura is punctured?

    <p>Air enters the pleural space causing lung collapse</p> Signup and view all the answers

    How many lobes does the left lung have compared to the right lung?

    <p>Left lung: 2, Right lung: 3</p> Signup and view all the answers

    What is the structural characteristic of the bronchi as they become smaller?

    <p>Diminishing bronchial walls</p> Signup and view all the answers

    What is the costal surface of the lungs?

    <p>The broad outer surface of the lung</p> Signup and view all the answers

    What is the role of the diaphragm concerning the lungs?

    <p>To aid in lung inflation and deflation</p> Signup and view all the answers

    Which anatomical feature allows the lungs to remain inflated?

    <p>Superficial tension between pleura layers</p> Signup and view all the answers

    What are lobules within the lungs?

    <p>Functional units made up of alveoli</p> Signup and view all the answers

    What does the Functional Residual Capacity (FRC) represent?

    <p>The amount of air remaining in the lungs after quiet expiration</p> Signup and view all the answers

    Which equation accurately represents the calculation for Total Lung Capacity (TLC)?

    <p>TLC = VC + RV</p> Signup and view all the answers

    During external respiration, what happens to the blood as it passes through the alveoli?

    <p>It becomes enriched in O2 and rejects CO2</p> Signup and view all the answers

    How is oxygen primarily transported in the bloodstream?

    <p>98.5% bound to hemoglobin and 1.5% dissolved in plasma</p> Signup and view all the answers

    What is the primary way carbon dioxide is transported in the bloodstream?

    <p>70% as bicarbonate ion</p> Signup and view all the answers

    What is the purpose of internal respiration?

    <p>To facilitate gas exchange between blood and body tissues</p> Signup and view all the answers

    Which statement is true about the factors affecting dissociation of oxyhemoglobin?

    <p>Low O2 levels enhance the release of oxygen</p> Signup and view all the answers

    Which lung capacity is defined as the maximum volume of air that can be moved into and out of the lungs?

    <p>Vital Capacity (VC)</p> Signup and view all the answers

    Study Notes

    Respiratory System Overview

    • All organs constantly use oxygen (O2) and release carbon dioxide (CO2).
    • Gas exchange increases when organs are active.
    • The respiratory system delivers atmospheric oxygen to the blood for distribution throughout the body, and removes carbon dioxide.

    Respiratory System Organs

    • Nose
    • Pharynx
    • Larynx
    • Trachea
    • Bronchi
    • Bronchioles
    • Lungs
    • Pleura (covering the lungs)
    • Muscles of breathing (intercostal muscles and diaphragm)

    Nose and Nasal Cavity

    • The nasal cavity is the primary air entry point.
    • It's a large, irregular cavity divided into two passages by a septum.
    • The posterior septum is bony (perpendicular plate of the ethmoid bone and vomer).
    • The anterior septum is made of hyaline cartilage.
    • The roof includes the cribriform plate of the ethmoid bone, as well as the sphenoid, frontal, and nasal bones.
    • The floor is formed by the hard palate (maxilla and palatine bones) and soft palate (muscles).

    Lining of the Nasal Cavity

    • Ciliated columnar epithelium lines the nasal cavity.
    • It has mucus-producing goblet cells.
    • The epithelium blends with the skin at the nostrils and extends posteriorly into the nasopharynx.

    Openings into the Nasal Cavity

    • Anterior nares (nostrils): external openings to the nasal cavity.
    • Posterior nares: openings from the nasal cavity to the pharynx.
    • Paranasal sinuses: air-filled cavities in facial and cranial bones.
    • Important sinuses include maxillary, frontal, sphenoid, and ethmoidal sinuses.
    • Sinuses aid speech and lighten the skull; the nasolacrimal ducts drain tears from the eyes into the nose.

    Functions of the Nose

    • Warms, moistens, and filters inhaled air.
    • The three conchae (scroll-shaped structures) increase surface area and create turbulence.
    • This promotes better mixing of inspired air with the nasal mucosa, facilitating warming, humidification, and filtration.
    • Olfaction (smell) occurs due to specialized receptors in the roof of the nose and superior conchae.

    Pharynx (Throat)

    • The pharynx is a 12-14 cm passageway behind the nasal cavity, mouth, and larynx, leading to the esophagus.
    • It's divided into three regions: nasopharynx, oropharynx, and laryngopharynx.
    • Nasopharynx: superior; communicates with nasal cavities.
    • Oropharynx: middle; connects to oral cavity and laryngopharynx.
    • Laryngopharynx: inferior; connects to the larynx and narrows into the esophagus.

    Nasopharynx

    • Lies behind the nose above the soft palate.
    • Contains openings for auditory tubes.
    • The pharynx contains pharyngeal tonsils (adenoids) on its posterior wall.

    Oropharynx

    • Lies behind the mouth, from the soft palate to the upper part of the third cervical vertebra.
    • Lateral walls blend with the soft palate to form folds.
    • Palatine tonsils are located between the folds.
    • Prevents food or fluids from entering the nasal cavity during swallowing.

    Laryngopharynx

    • Connects oropharynx to esophagus and larynx.
    • Air and food pass through.

    Larynx (Voice Box)

    • Connects the laryngopharynx and trachea.
    • Located in front of the 3rd-6th cervical vertebrae.
    • Composed of cartilage, ligaments, and muscles.
    • Important components include hyoid bone, thyroid cartilage, cricoid cartilage, arytenoid cartilages, and epiglottis.

    Larynx Structure (Cartilages)

    • Thyroid cartilage (largest): forms anterior and lateral walls (Adam's apple).
    • Cricoid cartilage (ring-shaped): located below the thyroid cartilage.
    • Arytenoid cartilages (paired): top of the cricoid cartilage, responsible for vocal cord movement.
    • Epiglottis (leaf-shaped): covers the larynx during swallowing.

    Larynx Structure (Interior)

    • The vocal cords are folds of mucous membranes, extending between the thyroid and arytenoid cartilages.
    • The space between vocal cords is called the glottis.

    Larynx (Functions)

    • Production of sound: pitch and volume are dependent on cord length and tension/force of air passed.
    • Resonance: depends on shape of the mouth, tongue position, and paranasal sinuses.
    • Protection of the lower respiratory tract: epiglottis closes the larynx during swallowing, preventing food from entering the trachea.
    • Passageway for air: links pharynx and trachea

    Trachea (Windpipe)

    • Lies in front of the esophagus.
    • About 10-11 cm long
    • Extends from the larynx to the 5th thoracic vertebra.
    • Divides into right and left primary bronchi.
    • Structures associated with the trachea: larynx superiorly and inferiorly (right and left bronchi), isthmus of the thyroid gland anteriorly (upper part), arch of the aorta and sternum (lower portion), the esophagus posteriorly, and lungs and thyroid gland laterally.
    • Composed of C-shaped cartilage rings, smooth muscle, and connective tissue.

    Trachea (Structure/Functions)

    • Flexible air duct with C-shaped cartilage rings to provide support and flexibility.

    • Cartilages are incomplete posteriorly to allow esophagus expansion during swallowing.

    • The smooth muscle in the posterior wall regulates the trachea's diameter.

    • Ciliated mucus membrane captures and removes dust and debris.

    • Cartilages held together by a connective tissue band (allows flexibility), posteriorly lacks cartilage to allow esophageal expansion in swallowing.

    Bronchi

    • Formed when trachea divides into two primary bronchi (right and left).
    • The right is wider, shorter, and more vertical than the left.
    • Enters the lung at the hilum (splits into smaller ones).
    • Bronchi branch into lobar and segmental bronchi, which further branch into bronchioles.

    Bronchial Passages (Changes)

    • As bronchi divide, they become smaller, their cartilage structure changes to allow for greater airflow flexibility.
    • Cartilage is not present in bronchioles, smooth muscles replace it.

    Bronchial Contractility

    • Smooth musculature in the bronchioles controls airflow by constriction or dilation.
    • Under autonomic nervous system; parasympathetic input causes constriction and sympathetic input causes dilation.
    • Important for regulating airflow and responding to environmental stimuli.

    Alveoli

    • Tiny air sacs in the lungs where gas exchange occurs.
    • Composed of a single layer of squamous epithelial cells and a dense network of capillaries.
    • The layer around the alveoli is called the respiratory membrane
    • Gas exchange depends on diffusion driven by pressure differences in oxygen and carbon dioxide concentrations in air and blood.

    Lungs

    • Two spongy masses in the thorax, separated by the mediastinum.
    • Right lung has three lobes; left lung has two lobes.
    • Enclosed and separated by the pleura (thin tissue layers).
    • Supported by the rib cage and separated from the abdomen by the diaphragm.

    Pleural Cavity and Pleura

    • Pleura: two layers (visceral and parietal) surrounding each lung forming a cavity.
    • Pleural fluid lubricates the two layers to reduce friction during breathing.
    • The space between the layers is the pleural cavity and contains no air.
    • Surrounding a serosa.

    External Respiration

    • Oxygen diffuses from alveoli into pulmonary capillaries and CO2 diffuses from capillaries into alveoli.
    • This exchange results in blood oxygen enrichment and CO2 removal.

    Internal Respiration

    • Blood (carrying oxygen) passes from capillaries to tissues, releasing oxygen in exchange for carbon dioxide.

    Gas Transport in Bloodstream

    • Oxygen (98.5%) is transported bound to hemoglobin, (1.5% dissolved in plasma).
    • Carbon dioxide (70%) is transported as bicarbonate ions, (23% bound to hemoglobin, 7% as dissolved gas).

    Respiration and the Lungs

    • Breathing in (inspiration): muscles contract to increase thoracic volume, reducing pressure and drawing air into the lungs. – Active, energy required.
    • Breathing out (expiration): muscles relax and thoracic volume decreases; increasing pressure expels air. – Passive, little energy required.

    Variables Affecting Breathing

    • Elasticity - lung ability to recoil to normal shape after inflation, important for breathing out
    • Compliance - lung stretchability, important for breathing in, determined by the effort to create the necessary pressure.
    • Airway Resistance - resistance caused by the airways during breathing, important for airflow. High resistance in conditions like bronchoconstriction necessitates higher effort.

    Lung Volumes and Capacities

    • Several measures are used to quantify the amount of air the lungs hold. This includes: Tidal Volume (TV): volume of air moved in and out during normal breathing. Inspiratory Reserve Volume (IRV): maximum extra air inhaled after a normal breath. Expiratory Reserve Volume (ERV): maximum extra air that can be exhaled after a normal breath. Residual Volume (RV): air remaining in lungs after maximum exhalation. Inspiratory Capacity (IC): Maximum volume that can be inhaled. Functional Residual Capacity (FRC): volume remaining in lungs after a normal breath. Vital Capacity (VC): maximum volume of air that can be moved in and out of the lungs during one respiratory cycle. Total Lung Capacity (TLC): total volume of air that the lungs can contain.

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    Description

    Explore the intricacies of the respiratory system, including its essential organs and their functions. This quiz will cover gas exchange, the structure of the nasal cavity, and the anatomy involved in the process of breathing. Prepare to test your knowledge on how the body utilizes oxygen and expels carbon dioxide.

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