The Respiratory System Involves the exchange of gases between cells, blood and the atmosphere

Types of Respiration Pulmonary ventilation External respiration inspiration expiration External respiration occurs in the lungs Internal respiration occurs in the tissues

Nose, Pharynx,Larynx,Trachea, Bronchial Tree, Lungs Organs of Respiration Nose, Pharynx,Larynx,Trachea, Bronchial Tree, Lungs

NOSE Moistens, warms, and filters air Houses olfactory receptors Serves as resonating chamber for speech Nasal septum divides nasal cavity

PALATE Serves to separate the nasal cavity from the oral cavity Hard palate Soft palate Uvula

PHARYNX Nasopharynx - upper portion, region above the soft palate Oropharynx - middle portion, area behind the oral cavity Laryngopharynx - lower portion, area below the epiglottis

LARYNX Functions to prevent food or fluid from entering the respiratory system during swallowing and allows air flow during breathing Production of sound is secondary function

Larynx Unpaired cartilages - thyroid, cricoid, epiglottis Paired cartilage - arytenoid, corniculate, cuneiform Vocal folds Glottis

TRACHEA Tubelike structure leading from the larynx to bronchial tree Consists of smooth muscle and “C” shaped hyaline cartilage rings Lined with psuedostratified ciliated columnar epithelium Mucociliary escalator

BRONCHIAL TREE Includes a right and left primary bronchus which divides to produce secondary bronchi, tertiary bronchi and bronchioles Terminal bronchioles branch into respiratory bronchioles which divide into alveolar ducts that connect to alveoli

ALVEOLI Functional unit of the lungs where gas exchange occurs (300 million) Thin walls made of simple squamous epithelium Type I and type II alveolar cells Diffusion of gases takes place across an alveolar-capillary respiratory membrane

LUNGS Paired organs in the thoracic cavity Right lung : 3 lobes horizontal/oblique fissure Left lung : 2 lobes oblique fissure Apex/Base Hilus

PLEURAL MEMBRANES Parietal pleura Visceral pleura Pleural cavity Pleurisy Pneumothorax

Physiology of Respiration

Pressures Atmospheric pressure - 760mm Hg Intrapleural pressure - is always less than atmospheric and alveolar pressure Alveolar (intrapulmonary) pressure - changes with phases of breathing Pressure changes in lungs are produced by variations in lung volume

BOYLE’S LAW The pressure of a gas is inversely proportional to its volume More volume-less pressure Less volume - more pressure

Inspiration Expiration Alveolar pressure is below atmospheric pressure due to increased volume Air flows into lungs 760 vs 758 mm Hg Alveolar pressure is above atmospheric pressure due to decreased volume Air flows out of lung 762 vs 760 mm Hg

Respiratory Air Volumes Tidal volume Inspiratory reserve volume Expiratory reserve volume Vital capacity Residual volume Spirometer

Regulation of Respiration Medullary rhythmicity center - medulla oblongata controls basic rhythm of respiration Control centers in the pons pneumotaxic center inhibits inspiration apneustic area stimulates inspiration

Gas Transport

Oxygen Transport 98% of oxygen is bound to hemoglobin as oxyhemoglobin Each hemoglobin molecule has the capacity to bind with four oxygen molecules Hypoxia

Factors Affecting Hemoglobin Saturation Partial pressure of oxygen increase pO2, the greater the % saturation pH - in an acid environment, O2 splits more readily from hemoglobin Temperature - the higher the temperature, the more oxygen released from hemoglobin

Carbon dioxide tranport 70% of CO2 is transported in the plasma as bicarbonate ion 23% of CO2 is bound to the globin part of hemoglobin as carbominohemoglobin 7% is dissolved in the plasma

RESPIRATORY DISORDERS COPD (Chronic Obstructive Pulmonary Disease) Asthma Bronchitis Emphysema Lung Cancer Tuberculosis Cystic Fibrosis Cheyne-Stokes Respiration Pneumonia Sleep Apnea SIDS