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Respiratory System Anatomy & Physiology

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  • Primary functions of the respiratory system

    Provides extensive gas exchange surface area, moves air to/from lungs, protects respiratory surfaces, produces sounds, and participates in olfaction.

  • Divisions of the respiratory system

    Upper respiratory system (above larynx) and lower respiratory system (below larynx).

  • Conducting vs respiratory portions of respiratory tract

    Conducting portion: nasal cavity to terminal bronchioles; respiratory portion: respiratory bronchioles and alveoli where gas exchange occurs.

  • Structure of respiratory epithelium

    Pseudostratified ciliated columnar epithelium with mucous cells in nasal cavity and upper respiratory tract; stratified squamous epithelium in inferior pharynx; cuboidal epithelium in smaller bronchioles.

  • Role of respiratory mucosa and lamina propria

    Mucosa lines conducting portion; lamina propria supports epithelium, contains mucous glands in upper tract and smooth muscle in lower bronchioles.

  • Components of the respiratory defense system

    Mucous cells/glands produce mucus, cilia move mucus to pharynx, nasal cavity filters large particles, alveolar macrophages engulf small particles.

  • Functions of the nose in respiration

    Air enters through nostrils, nasal hairs filter particles, nasal cavity warms, humidifies, and traps particles via mucosa and meatuses.

  • Pharynx divisions and functions

    Nasopharynx (upper, contains pharyngeal tonsils), oropharynx (middle, communicates with oral cavity), laryngopharynx (lower, leads to larynx and esophagus).

  • Cartilages of the larynx

    Three large unpaired: thyroid, cricoid, epiglottis; three pairs of smaller hyaline cartilages: arytenoid, corniculate, cuneiform.

  • Functions of thyroid and cricoid cartilages

    Support and protect glottis and trachea entrance; during swallowing, larynx elevates and epiglottis folds to prevent food entry.

  • Sound production in the larynx

    Air passing through glottis vibrates vocal folds (vocal cords); sound varies by tension on vocal folds controlled by intrinsic muscles.

  • Structure and function of the trachea

    Windpipe extending from cricoid cartilage to bronchi; supported by 15-20 C-shaped tracheal cartilages; submucosa contains mucous glands.

  • Primary bronchi characteristics

    Right bronchus is larger and steeper; primary bronchi branch into secondary (lobar) bronchi, then tertiary (segmental) bronchi supplying bronchopulmonary segments.

  • Bronchioles and their control

    Bronchioles lack cartilage, dominated by smooth muscle; diameter controlled by autonomic nervous system affecting airflow and resistance.

  • Pulmonary lobules and alveoli

    Each terminal bronchiole supplies a pulmonary lobule containing respiratory bronchioles and alveoli where gas exchange occurs.

  • Alveolar epithelium cell types

    Type I pneumocytes: thin squamous cells for gas exchange; Type II pneumocytes: produce surfactant to reduce surface tension; alveolar macrophages patrol alveoli.

  • Respiratory membrane composition

    Consists of alveolar epithelium, fused basement membranes, and capillary endothelium; thin for rapid gas diffusion.

  • Mechanics of pulmonary ventilation

    Air moves due to pressure differences; inhalation increases thoracic volume via diaphragm and external intercostals; exhalation decreases volume, can be passive or active.

  • Muscles involved in breathing

    Primary: diaphragm and external intercostals; accessory muscles assist during forced breathing; internal intercostals and abdominal muscles aid forced exhalation.

  • Control centers of respiration in the brain

    Medulla oblongata contains dorsal (DRG) and ventral (VRG) respiratory groups; pons contains apneustic and pneumotaxic centers regulating rate and depth.

  • Chemoreceptor reflexes in respiration

    Peripheral chemoreceptors in carotid and aortic bodies respond to blood pH, PO2; central chemoreceptors in medulla respond to CSF pH and PCO2 to adjust breathing.

  • Gas transport in blood

    Oxygen transported bound to hemoglobin; carbon dioxide transported as bicarbonate, bound to hemoglobin, or dissolved in plasma.

  • Factors affecting hemoglobin oxygen binding

    PO2, blood pH (Bohr effect), temperature, and 2,3-BPG levels influence hemoglobin's oxygen affinity and release.

  • Pulmonary volumes and capacities

    Includes tidal volume, inspiratory/expiratory reserve volumes, residual volume; capacities include vital capacity, inspiratory capacity, functional residual capacity, and total lung capacity.

  • Compliance in pulmonary ventilation

    Compliance is lung expandability; affected by connective tissue, surfactant levels, and thoracic cage mobility; low compliance requires more force to breathe.

  • Protective respiratory reflexes

    Triggered by irritants causing sneezing, coughing, laryngeal spasm to protect airways from harmful substances.

  • Effects of aging on respiratory system

    Elastic tissue deterioration, arthritic changes limiting chest movement, and emphysema reduce lung function and respiratory capacity.