Chap22 PPT

Chapter 22: The Respiratory System

22.1 Anatomy of the Respiratory System

• Functions of the Respiratory System:

  • Gas Exchange: O2 and CO2 exchanged between blood and air.

  • Communication: Speech and other vocalizations.

  • Olfaction: Sense of smell.

  • Acid-base Balance: Influences pH of body fluids by eliminating CO2.

  • Blood Pressure Regulation: Assists with synthesis of angiotensin II, a hormone that regulates blood pressure.

  • Blood and Lymph Flow: Breathing creates pressure gradients that promote flow of lymph and blood.

  • Platelet Production: More than half of platelets are produced in lungs (not bone marrow).

  • Blood Filtration: Lungs filter small clots.

  • Expulsion of Abdominal Contents: Breath-holding assists in urination, defecation, and childbirth.

Major Organs

• Principal Organs of the Respiratory System:

  • Nose

  • Pharynx

  • Larynx

  • Trachea

  • Bronchi

  • Lungs

• Conducting Zone: Passages that serve only for airflow (no gas exchange) from the nostrils through major bronchioles.

• Respiratory Zone: Regions participating in gas exchange including alveoli and nearby structures.

• Upper Respiratory Tract: Airway from nose through larynx.

• Lower Respiratory Tract: Regions from trachea through lungs.

22.1a The Nose

• Functions of the Nose:

  • Warms, cleanses, and humidifies inhaled air.

  • Detects odors and serves as a resonating chamber for voice.

  • Anatomy of the Nose:

    • Extends from nostrils (nares) to posterior nasal apertures (choanae).

    • Facial part shaped by bone and hyaline cartilage.

    • Superior Half: Nasal bones and maxillae.

    • Inferior Half: Lateral and alar cartilages.

    • Ala Nasi: Flared portion at lower end of nose shaped by alar cartilages.

22.1b The Pharynx

• Structure:

  • Muscular funnel extending about 13 cm (5 in.) from nasal apertures to larynx.

  • Divided into three regions:

    • Nasopharynx: Receives auditory tubes and contains pharyngeal tonsil.

    • Oropharynx: Space between soft palate and epiglottis, contains palatine tonsils.

    • Laryngopharynx: Posterior to larynx, esophagus begins at this point.

22.1c The Larynx

• Structure:

  • Cartilaginous chamber about 4 cm (1.5 in.) long.

  • Functions: Keeps food and drink out of airway; produces sound (voice box).

  • Components:

    • Epiglottis: Guards superior opening of larynx.

    • Cartilage Structures: Nine cartilages, including epiglottic, thyroid, and cricoid cartilages.

22.1d The Trachea

• Function: Connects larynx to bronchi, commonly known as the windpipe.

• Structure:

  • Rigid tube, 12 cm long, 2.5 cm in diameter.

  • Supported by 16 to 20 C-shaped rings of hyaline cartilage.

• Histology: Lined by ciliated pseudostratified columnar epithelium.

22.1e The Lungs and Bronchial Tree

• Each lung has a conical shape with apex, base, costal surface, and mediastinal surface.

• Bronchial Tree: Branching system of air tubes from main bronchus to terminal bronchioles.

22.2 Pulmonary Ventilation

• Breathing Cycle: Repetitive cycle of inspiration (inhalation) and expiration (exhalation).

  • Quiet Respiration: Effortless and automatic; occurs at rest.

  • Forced Respiration: Deep or rapid breathing, as during exercise.

22.2b Neural Control of Breathing

• Brainstem Centers: Control automatic, unconscious breathing.

  • Ventral respiratory group (VRG): Primary generator of respiratory rhythm.

22.3 Gas Exchange and Transport

• Composition of Inspired and Alveolar Air: Differs due to humidification, gas exchange, and mixing with residual air.

  • Henry’s Law: Gas solubility in water is influenced by its partial pressure.

22.4 Respiratory Disorders

• Hypoxia: Deficiency of oxygen.

  • Chronic Obstructive Pulmonary Diseases (COPDs): Includes chronic bronchitis and emphysema; linked to smoking.

• Lung Cancer: Most common form due to smoking; major forms include squamous-cell carcinoma, adenocarcinoma, and small-cell carcinoma.

Key Terms

• Gas Exchange: The process by which oxygen and carbon dioxide are exchanged between lungs and blood.

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

• Hypoxia: A deficiency of oxygen in tissues.

• COPD: Chronic obstruction of airflow from the lungs.