EM

Chapter 1: The Anatomy and Physiology of the Respiratory System

Upper Airway

  • Consists of nose, oral cavity, pharynx, larynx

  • Functions: conductor of air; humidify and warm or cool inspired air; prevent foreign materials entering tracheobronchial tree; important in speech and smell

Structure of the Nose

  • Functions: Filter; Humidify; Condition (warm or cool) inspired air

Oral Cavity

  • Vestibule

  • Tongue: intrinsic muscles; extrinsic muscles

  • Lingual frenulum

  • Hard palate

  • Soft palate

  • Palatine arches

Pharynx

  • Divided into 3 parts: nasopharynx; oropharynx; laryngopharynx

The Larynx

  • Vestibule: opening into trachea from pharynx

  • Functions: Passageway of air between pharynx and trachea; protection from aspiration of food and liquids; generates sounds for speech

Lower Airways: Tracheobronchial Tree

  • Cartilaginous airways: trachea, main stem bronchi, lobar bronchi, segmental bronchi and subsegmental bronchi; only conduct air between the external environment and sites of gas exchange

  • Noncartilaginous airways: bronchioles, terminal bronchioles; both conductors of air and as sites of gas exchange

Structures of the Lungs

  • Major structures and corresponding generations of the tracheobronchial tree

  • Note: precise number of generations between subsegmental bronchi and alveolar sacs is not known

  • These structures collectively are referred to as a primary lobule or lung parenchyma; also called terminal respiratory units and functional units

Sites of Gas Exchange

  • Primary lobule

  • Alveolar epithelium

  • Pores of Kohn

  • Alveolar macrophages

  • Interstitium

Pulmonary Vascular System

  • Arteries; Arterioles; Capillaries; Venules and veins

Lymphatic System

  • Lymphatic vessels of bronchial airways, pulmonary arteries, and veins

Neural Control of the Lungs

  • Balance of lungs controlled by autonomic nervous system

  • Sympathetic: accelerates heart rate, constricts blood vessels, relaxes bronchial smooth muscles, raises blood pressure

  • Parasympathetic: slows heart rate, constricts bronchial smooth muscles, increases peristalsis and gland activity

Some Effects of Autonomic Nervous System Activity (Table 1-2)

  • Heart: Sympathetic — increases rate; increases strength of contraction; Parasympathetic — decreases rate; decreases strength of contraction

  • Bronchial smooth muscle: Sympathetic — relaxation; Parasympathetic — constriction

  • Bronchial glands: Sympathetic — decreases secretions; Parasympathetic — increases secretions

  • Salivary glands: Sympathetic — decreases secretions; Parasympathetic — increases secretions

  • Stomach: Sympathetic — decreases motility; Parasympathetic — increases motility

  • Intestines: Sympathetic — decreases motility; Parasympathetic — increases motility

  • Eyes: Sympathetic — widens (dilates) pupils; Parasympathetic — constricts pupils

Mediastinum

  • Components of the mediastinum (as listed in the text)

Pleural Membranes

  • Visceral pleura; Parietal pleura; Pleural cavity with fluid

Thorax

  • Bony thorax forms the rib cage protecting the heart and lungs

Diaphragm

  • Dome-shaped muscle; major muscle of inspiration; separates thorax and abdomen

Accessory Muscles of Inspiration

  • External intercostal muscles

  • Scalenus muscles

  • Sternocleidomastoid muscles

  • Pectoralis major muscles

  • Trapezius muscles

Accessory Muscles of Expiration

  • Rectus abdominis muscles

  • External abdominal obliquus muscles

  • Internal abdominal obliquus muscles

  • Transversus abdominis muscles

  • Internal intercostal muscles