Biology 8 Unit 2: Respiratory System
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Questions and Answers

Which of the following functions is NOT performed by the nose?

  • Lightens the skull (correct)
  • Detects odors in the air stream
  • Provides an airway for respiration
  • Filters and cleans inspired air

    • What is the primary function of the epiglottis?

  • Expels mucus from the lungs
  • Routes food to the larynx and air toward the trachea (correct)
  • Supports the vocal cords
  • Vibrates to create sound

    • Which structure is known to connect the larynx with the bronchi?

  • Pharynx
  • Trachea (correct)
  • Diaphragm
  • Esophagus

    • What are the three regions of the pharynx?

    <p>Nasopharynx, oropharynx, laryngopharynx</p> Signup and view all the answers

    What characteristic distinguishes the right bronchus from the left bronchus?

    <p>It is wider, shorter, and straighter</p> Signup and view all the answers

    What is the primary function of the respiratory system?

    <p>To supply blood with oxygen and remove carbon dioxide</p> Signup and view all the answers

    Which of the following structures is part of the lower respiratory tract?

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

    What occurs during the process of inhalation?

    <p>Air is drawn into the lungs</p> Signup and view all the answers

    What role do the conchae serve in the nasal cavity?

    <p>They increase surface area and air turbulence</p> Signup and view all the answers

    How is the nasal cavity separated from the oral cavity?

    <p>By the palate</p> Signup and view all the answers

    What is the main function of the alveoli in the respiratory system?

    <p>To facilitate the exchange of oxygen and carbon dioxide</p> Signup and view all the answers

    Which of the following best describes the role of the diaphragm during inhalation?

    <p>It contracts and increases the volume of the thoracic cavity.</p> Signup and view all the answers

    Which structure covers the lung surface and is essential for allowing the lungs to move during breathing?

    <p>Pulmonary (visceral) pleura</p> Signup and view all the answers

    What characterizes the right lung compared to the left lung?

    <p>The right lung has three lobes while the left lung has two lobes.</p> Signup and view all the answers

    What triggers the movement of air during exhalation?

    <p>The lowering of the rib cage and relaxation of the diaphragm</p> Signup and view all the answers

    Study Notes

    Introduction to Biology 8

    • The theme for Biology 8 is the 5Cs: Competence, Character, Commitment, Collaboration, and Creativity.
    • These concepts are achieved through academic rigor, growth mindset, and grit.

    Unit 2: Life Processes of Living Things - Respiratory System

    • The respiratory system supplies oxygen to the blood, allowing it to deliver oxygen to the body's cells.
    • It also removes carbon dioxide waste produced by cells.
    • The system oversees gas exchange between the blood and the external environment.
    • Gas exchange primarily occurs within the alveoli and is aided by the passageways (purifying, warming, humidifying the incoming air).

    Upper Respiratory Tract

    • The upper respiratory tract includes the nasal cavity, pharynx, epiglottis, and larynx.
    • The nasal cavity and the nostrils are the airways where air enters the system.
    • The pharynx is the throat, a common passageway for air and food.
    • The epiglottis covers the trachea during swallowing, preventing food from entering the lungs.
    • The larynx contains the vocal cords responsible for voicing sounds (speech).

    Lower Respiratory Tract

    • The lower respiratory tract includes the trachea, bronchi, lungs, and diaphragm.
    • The trachea is the windpipe connecting the larynx to the bronchi.
    • The bronchi are branches of the trachea leading to the lungs.
    • Lungs contain the alveoli, crucial for gas exchange.
    • The diaphragm is a dome-shaped muscle vital in breathing, contracting to inhale and relaxing to exhale.

    Breathing Mechanism (Inhalation and Exhalation)

    • Breathing consists of two cyclic phases: inhalation (inspiration) and exhalation (expiration).
    • Inspiration draws air into the lungs.
    • The diaphragm contracts.
    • Rib cage rises.
    • The chest cavity expands.
    • Expiration forces air out of the lungs.
    • The diaphragm relaxes.
    • Rib cage lowers.
    • The chest cavity decreases in volume.

    Nose (Anatomical Details and Function)

    • The nose is the primary external entrance of the upper respiratory tract.
    • Air enters the nose via the nostrils/ external nares.
    • The nasal cavity has a septum that divides it and contains cilia.
    • The cilia filters and cleanses the air, preventing foreign bodies from reaching the lungs.
    • The nose warms and moistens the air before it enters the lower respiratory tract.
    • It contains smell receptors for olfaction.
    • Other structures in the nasal cavity include the sinuses.

    Nasal Cavity

    • Olfactory receptors are present on the superior surface, allowing smell recognition.
    • Respiratory mucosa lines the nasal cavity, moistening the inhaled air and trapping incoming foreign particles.
    • Lateral walls have conchae projections that increase surface area and air turbulence.
    • The nasal cavity is divided by a nasal septum and is separated from the oral cavity by the hard palate (anterior) and soft palate (posterior).
    • The function of the nasal cavity is to clean, humidify and warm air before reaching the lungs.

    Paranasal Sinuses

    • Cavities in bones surrounding the nasal cavity (frontal, sphenoid, ethmoid, and maxillary bones).
    • These act as resonating chambers for speech and lighten the skull.
    • Sinuses produce mucus that drains into the nasal cavity.

    Pharynx (Throat)

    • The pharynx is a muscular tube connecting the nasal cavity and oral cavity to the larynx and esophagus.
    • This tube has three sections:
      • Nasopharynx - located above the soft palate, and the common passageway for air.
      • Oropharynx - lies behind the mouth and is a common passageway for both air and food.
      • Laryngopharynx - an inferior part, connecting to the larynx and esophagus.
    • Tonsils are found in the pharynx, which are part of the lymphatic system, aiding in the fighting of infections in the throat.

    Epiglottis

    • A flap of elastic cartilage that covers the trachea when swallowing, preventing food from entering the lungs.
    • Its position changes, covering the trachea when food is in the esophagus and uncovering the airway when breathing or speaking.

    Larynx (Voice Box)

    • The larynx is a cartilaginous structure connecting the pharynx to the trachea.
    • Its role is crucial in speech and helps route air and food into suitable channels.
    • The larynx also houses the vocal cords that vibrate when air passes through, creating sound.
    • Eight rigid hyaline cartilages and an elastic cartilage (epiglottis) form the structure.

    Trachea (Windpipe)

    • The trachea is a tube-like structure connecting the larynx to the bronchi.
    • It's lined with ciliated mucosa whose movement expels mucus carrying dust and debris.
    • C-shaped cartilage reinforces the trachea to keep it open.

    Bronchus

    • Bronchi are extensions of the trachea, branching into the lungs.
    • The right bronchus is wider and shorter than the left bronchus.
    • Bronchi branch into progressively smaller tubes until reaching the alveoli.

    Bronchioles

    • Bronchioles are the smallest branches of the bronchi, lacking cartilaginous reinforcement.
    • Terminal bronchioles lead into alveoli where gas exchange takes place.

    Alveolus

    • Microscopic air sacs in the lungs where gas exchange occurs.
    • The alveolar walls are covered with pulmonary capillaries (small blood vessels) and epithelial cells.
    • The respiratory membrane separates the air from the blood, assisting in gas exchange.
    • Surfactant coats the alveoli to prevent collapse.

    Lungs

    • The lungs are vital organs that house alveoli and are responsible for gas exchange.
    • Lungs are divided into lobes by fissures to ease the process of expansion and contraction during breathing.
    • The right lung has three lobes, while the left has two.

    Pleura (Lung Cover)

    • The pleura is a double-layered membrane around the lungs.
    • It facilitates smooth movement of the lungs during respiration.
    • Pleural fluid reduces friction between the lung and rib cage.

    Diaphragm

    • A large, dome-shaped muscle located below the lungs.
    • It is responsible for the process of inhalation and exhalation.
    • It contracts during inhalation to pull air into the lungs.
    • It relaxes during exhalation to push air out of the lungs.

    Breathing

    • The act of taking in oxygen (inhalation) and releasing carbon dioxide (exhalation).
    • Breathing is driven by the diaphragm and rib muscles.
    • There is a pressure difference between the lungs and atmosphere causing air flow.

    Gas Exchange

    • Gases exchange between the air (alveoli) and blood (capillaries).
    • Oxygen enters the blood.
    • Carbon dioxide leaves the blood.
    • The process occurs by diffusion across the thin respiratory membrane.
    • Macrophages and surfactant also play key roles.

    Events of Respiration

    • Pulmonary ventilation.
    • External respiration.
    • Respiratory gas transport.
    • Internal respiration.
    • The process involves inhaling and exhaling air to exchange oxygen and carbon dioxide.
    • Diffusion of gases are also involved.

    External Respiration

    • The process of gas exchange between the alveoli and the pulmonary capillaries.
    • Oxygen from the alveoli moves into the blood.
    • Carbon dioxide from the blood moves into the alveoli.
    • Oxygen concentration is higher in the alveoli than in the blood.
    • Carbon dioxide concentration is higher in the blood than in the alveoli.
    • Diffusion allows the movement of gases based on concentration gradients.

    Respiratory Gas Transport

    • Transport of oxygen and carbon dioxide by the blood.
    • Oxygen attaches to hemoglobin in red blood cells (oxyhemoglobin).
    • Most carbon dioxide travels dissolved in the plasma as bicarbonate ions (HCO³⁻).

    Internal Respiration

    • Gas exchange between the blood and tissue cells.
    • Oxygen diffuses from the blood into the tissue cells.
    • Carbon dioxide diffuses from the tissue cells into the blood.
    • This process provides oxygen for cellular respiration and removes wastes.

    Mechanics of Breathing - Inspiration and Expiration

    • Inspiration (breathing in):
      • Diaphragm and intercostal muscles contract.
      • The thoracic cavity volume increases.
      • Intrapulmonary pressure decreases.
      • Air flows into the lungs.
    • Expiration (breathing out):
      • Diaphragm and intercostal muscles relax.
      • The thoracic cavity volume decreases.
      • Intrapulmonary pressure increases.
      • Air flows out of the lungs.

    Respiratory Volumes and Capacities

    • Measurements of air volumes in and out during respiration:
      • Tidal volume (TV): Amount of air inhaled or exhaled in a normal breath.
      • Inspiratory reserve volume (IRV): Maximum additional air inhaled beyond a normal breath.
      • Expiratory reserve volume (ERV): Maximum additional air exhaled beyond a normal breath.
      • Residual volume (RV): Volume of air remaining in the lungs after maximum exhalation.

    Respiratory Sounds

    • Sounds created during breathing, monitored with a stethoscope.
      • Bronchial sounds: Produced by air rushing through the trachea and bronchi.
      • Vesicular sounds: Soft sounds from air filling the alveoli.

    Respiratory Disorders

    • Diseases affecting the respiratory system.
      • Chronic Obstructive Pulmonary Disease (COPD): includes chronic bronchitis and emphysema
      • Lung Cancer: Associated with smoking, and has various types.
      • Sudden Infant Death Syndrome (SIDS): often from issues with respiratory control centers or heart rhythm.
      • Asthma: Inflammatory response causes breathing issues.

    Developmental Aspects of the Respiratory System

    • Fetal lungs are filled with fluid.
    • Surfactant is critical for later development and is important for premature babies.
    • Important birth defects for newborns include cystic fibrosis and cleft palate.

    Aging Effects

    • Respiratory system changes with age, leading to reduced elasticity, vital capacity, blood oxygen levels, and carbon dioxide stimulating responses.
    • Rates of respiration can be affected.

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    Description

    Dive into the intricacies of the respiratory system in Biology 8. This quiz covers the gas exchange process, the structure of the upper respiratory tract, and the vital functions it performs to supply oxygen to the body's cells. Test your understanding of these life processes!

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