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Respiratory System Flashcards

The Respiratory System

  • A typical human cannot survive without breathing for more than 3 minutes.

  • The respiratory system includes muscles, passageways, and gas exchange surfaces.

  • The circulatory system transports gases.

Organs and Structures of the Respiratory System

  • Major functions:

    • Provide oxygen.

    • Remove carbon dioxide.

    • Maintain acid-base balance.

  • Non-vital functions: sensing odors, speech, straining.

  • Divided into conducting and respiratory zones.

Conducting Zone

  • Major functions: route for air, remove debris, warm and humidify air.

  • Epithelium important for sensing odors and metabolizing carcinogens.

The Nose and its Adjacent Structures

  • Entrance and exit for the respiratory system.

  • Two sections: external nose and nasal cavity.

  • External Nose: Root, bridge, dorsum nasi, apex, ala, philtrum.

  • Skeletal features: Nasal bone, septal cartilage, alar cartilage.

  • Nasal Cavity: Separated by nasal septum, contains superior, middle, and inferior nasal conchae. Palate forms the floor. Air exits via internal nares.

  • Paranasal Sinuses: Warm and humidify air; frontal, maxillary, sphenoidal, and ethmoidal sinuses.

  • Linings: Mucous membranes with sebaceous glands and hair follicles, olfactory epithelium, and respiratory epithelium.

Pharynx

  • Tube of skeletal muscle lined by mucous membrane.

  • Three regions: nasopharynx, oropharynx, laryngopharynx.

Nasopharynx

  • Airway; contains pharyngeal tonsils and uvula. Auditory tubes connect to middle ear cavity.

Oropharynx

  • Air and food passageway. Contains palatine and lingual tonsils. Epithelium is stratified squamous.

Laryngopharynx

  • Route for material and air until digestive and respiratory systems diverge. Opens into larynx and esophagus.

Larynx

  • Cartilaginous structure connecting pharynx to trachea, regulates air volume.

  • Formed by thyroid, epiglottis, cricoid, arytenoids, corniculates, and cuneiforms cartilages.

  • Contains the glottis, vestibular folds, and true vocal cords for speech.

Trachea

  • Extends from larynx to lungs, formed by C-shaped cartilage pieces.

  • Contains trachealis muscle and fibroelastic membrane.

  • Lined with pseudostratified ciliated columnar epithelium.

Bronchial Tree

  • Trachea branches into primary bronchi at the carina.

  • Bronchi branch into a bronchial tree, leading to bronchioles and terminal bronchioles.

  • Bronchiole walls lack cartilage.

Respiratory Zone

  • Structures directly involved in gas exchange.

  • Includes respiratory bronchioles, alveolar ducts, and alveoli.

Alveoli

  • Grape-like sacs attached to alveolar ducts; alveolar sacs are clusters of alveoli.

  • Walls contain type I and type II alveolar cells, and alveolar macrophages.

  • Respiratory membrane: formed by alveoli and capillary membranes for gas exchange.

Respiratory System: Asthma

  • Chronic disease with inflammation and bronchospasms.

  • Triggers include environmental factors, infections, exercise, and stress.

  • Symptoms: coughing, shortness of breath, wheezing, chest tightness.

  • Treatments: inhalers, nebulizers, and medications targetting viruses and bacteria such as HRVC, Mycoplasma pneumoniae, and Chlamydia pneumoniae.

The Lungs

  • Exchange oxygen and carbon dioxide.

Gross Anatomy of the Lungs

  • Pyramid-shaped organs connected to the trachea by bronchi.

  • Right lung: 3 lobes; left lung: 2 lobes with cardiac notch.

  • Apex, base, costal surface, mediastinal surface.

Lobes and Segments

  • Right lung: superior, middle, inferior lobes.

  • Left lung: superior, inferior lobes.

  • Bronchopulmonary segments receive air from tertiary bronchus.

  • Pulmonary lobules are subdivisions, separated by interlobular septa.

Blood Supply and Nervous Innervation of the Lungs

  • Pulmonary artery carries deoxygenated blood to alveoli.

  • Pulmonary veins drain oxygenated blood from alveoli.

  • Parasympathetic system: bronchoconstriction; sympathetic: bronchodilation.

Pleura of the Lungs

  • Each lung enclosed by pleura: visceral and parietal layers.

  • Pleural cavity contains pleural fluid for lubrication and surface tension.

The Process of Breathing

  • Pulmonary ventilation: movement of air into and out of the lungs.

  • Dependent on atmospheric, intra-alveolar, and intrapleural pressures.

Mechanisms of Breathing

  • Dependent on air pressure and lung features.

Pressure Relationships

  • Inspiration and expiration depend on pressure differences.

  • Boyle’s law: pressure and volume are inversely related (P = k/V).

Pressures Involved in Pulmonary Ventilation

  • Atmospheric pressure (P {atm}): force exerted by gases.

  • Intra-alveolar pressure (P {alv}): pressure within alveoli.

  • Intrapleural pressure (P {ip}): pressure within pleural cavity.

  • Transpulmonary pressure: difference between intrapleural and intra-alveolar pressures.

Physical Factors Affecting Ventilation

  • Muscle contraction, resistance, surface tension, and thoracic wall compliance affect breathing.

  • Airway resistance: F = \frac{ΔP}{R}

Pulmonary Ventilation

  • Air flows from high to low pressure.

  • Inspiration: air enters lungs; expiration: air leaves lungs.

  • Respiratory cycle: one sequence of inspiration and expiration.

Inspiration

  • Diaphragm and external intercostal muscles contract.

Expiration

  • Passive process; lung tissue recoils.

Types of Breathing

  • Quiet breathing (eupnea): diaphragm and external intercostals contract.

  • Forced breathing (hyperpnea): muscle contractions during inspiration and expiration.

Respiratory Volumes and Capacities

  • Respiratory volume: air moved by lungs.

  • TV, ERV, IRV, RV.

  • Respiratory capacity: combination of volumes.

  • TLC, VC, IC, FRC.

  • Anatomical, alveolar, and total dead space.

Respiratory Rate and Control of Ventilation

  • Respiratory rate: breaths per minute; controlled by the medulla oblongata.

Ventilation Control Centers

  • Neurons in the medulla oblongata control ventilation.