Respiration And the Pulmonary System Types of Respiration

Respiration And the Pulmonary System

Types of Respiration l Pulmonary respiration (ventilation) – Breathing – Inspiration – Expiration External respiration – between lungs and blood l Internal respiration – Between blood and cells l Cellular respiration Glucose + Oxygen Carbon Dioxide and water and energy. l

Organization of Respiratory Organs l By location – Upper respiratory system l l Nose Pharynx and associated structure – Lower respiratory system l l l Larynx Bronchial tree Lungs l By function – Conducting portion l Nasal passageways l Pharynx l Larynx – Respiratory portion l Bronchial tree – Bronchi terminal bronchiole l Respiratory bronchioles l Alveolar ducts l Alveoli

Nose l Components l – – – External l l Nasal bones Alar cartilage External nares – Nostils Nasal septum – Internal l l Choanae Internal nares – Mucous membrane Paranasal sinuses l Frontal Sphenoidal Ethmoidal Maxillary Functions – Incoming air l Warmed l Moistened l Filtered – Olfactory stimuli received – Sound l Resonate l Modification

Pharynx (throat) l Extent l – Internal nares – Cricoid cartilage – Oropharynx l Opening – Fauces l Tonsils (larynx) l – Palatine – Lingual – Common Path • Air • Drink • Food Regions – Nasopharynx l Openings – Internal nares – Auditory (Eustachian) tubes Pharyngeal tonsil (adenoid) – Laryngopharynx (hypopharynx) – Connected inferiorly l l Esophagus Larynx

Larynx (Part 1) Joins pharynx to trachea l Cartilages l – 3 unpaired l Epiglottis – Protects airway – Covers glottis l l Thyroid – Adam’s apple Cricoid – Tracheostomy landmark – 3 paired l Arytenoid l Corniculate l Cuneiform l Voice production – Laryngeal mucous membranes l l Ventricular folds (false vocal chords)– Superior Vocal folds (true vocal chords) – Inferior – Bring folds together l l Hold breath against pressure Vibrate in response to pressure

Larynx (Part 2) – Control l l Loudness – Air pressure Pitch – vocal fold tension – Resonance l l Upper respiratory tract Paranasal sinuses – Modifications – Muscles l l Pharynx Face Tongue Cheeks

Anatomy of the Larynx

Trachea Windpipe l Leads from larynx into bronchial tree l – Sternal angle – T 5 – Carina – Cough reflex l C-shaped cartilage – Holds trachea open – Allows esophageal expansion l Clinical applications – Tracheostomy – Intubation

Bronchi (Part 1) Begin at sternal angle (T 5) l Diameter decreases as branching increases l l l – Left l Smaller diameter l Longer l More horizontal – Amount of cartilage decreases as diameter decreases – Amount of smooth muscle increases as diameter increases l l Secondary (serve a lobe) – 3 on right – 2 on left Primary (serve a lung) – Right l Wider diameter Shorter More vertical l Tertiary – Segmental or lobular

Bronchi (Part 2) Tertiary – Segmental or lobular l Bronchioles l – Small branches of bronchial area – Terminal – Extend into alveolar clusters – Respiratory – Extend directly into alveoli l ANS effects – Sympathetic -- Bronchodilate – Parasympathetic -Bronchoconstrict

Lungs (Part 1) l Enclosed by pleurae – Parietal l l – Visceral – Blood vessels – Bronchi – Nerves – Pleural cavity l Gross anatomy – Base – fits over diagragm – Apex – extends into root of neck – Costal surface – Lies against ribs – Mediastinal surface Faces heart Hilus (hilum) – Entrance/Exit l Right lung – 3 lobes • Superior • Middle • Inferior – 2 fissures

Lungs (Part 2) • Oblique • Horizontal l Left lung – 2 lobes • Superior • Inferior – 1 fissure – Oblique – Cardiac notch

Pulmonary Ventilation - Respiration (Part 1) 1 respiration = 1 inspiration + 1 expiration l Exchange of gases between atmosphere and lungs l Normal inspiration (inhalation) – Air rushes into lungs l – Increase thoracic cavity volume – Contract l l Diaphragm External intercostals – Reduction in intrapleural pressure l Forced inspiration – Body needs more air exchange – Need more change in thoracic cavity volume – Use additional muscles to raise thoracic cage l l l Sterrocleidomastoid Scalenes Pectoralis minor

Pulmonary Ventilation - Respiration (Part 2) l Normal expiration (exhalation) l l – Decrease thoracic cavity volume – Diaphragm relaxes – Intrapleural pressure increases – Air pushed out of lungs l Forced expiration – Body needs more air exchange – Active process using l Abdominal muscles Internal intercostals Factors affecting ease of respiration – Compliance l Elasticity – Surface tension – Surfactant l l Airway resistance Modified respirations – – Cough Sneeze Sigh Yawn

Pulmonary Ventilation - Respiration (Part 3) – Laugh – Hiccuping l Related terminology – Hyperventilation – Hypoventilation – Eupnea – Dyspnea – Apnea – Shortness of Breath (SOB) – Atelectasis

Lung Histology Lung – Lobe – Segment – Lobule – Alveoli l Alveolus – Respiratory membrane – Components l Alveolar wall l Epithelial basement membrane l Capillary endothelial – Thickness – 0. 5 microns – Allows fast exchange of l – Epithelial “bubble” l Type I cells – lining l Type II cells – surfactant – Alveolar macrophages – Monocytes – Fibroblasts l Alveolar capillary membrane respiratory gases l Total surface area – 70 square meters (750 square feet)

Lung Blood Supply l Bronchial – Arteries l Bring blood to supply lung cells – Veins l Drain blood from lung cells l Drain into azygous system l Pulmonary – Arteries l Carry oxygen poor blood from. R. Ventricle for perfusion – Veins l Carry oxygen rich blood back to L. ventricle for systemic circulation

Respiratory Gases in the Blood l Oxygen – Very little dissolved in plasma – Most bound to hemoglobin (Hb) l l 1 O 2/heme 4 hemes/Hb – Hb+O 2 Hb. O 2 l Carbon dioxide – Small amount dissolves in plasma – More soluble than oxygen – Carbaminohemoglobin – Hb + CO 2 Hb. CO 2 – As bicarbonate ions l l CO 2+H 2 O H 2 CO 3 H+HCO 3

Transport and Exchange of Carbon Dioxide and Oxygen

Pulmonary Function Measurements 1 respiration = 1 inspiration + 1 expiration l Should be – Inspiratory reserve volume l (IRV) – Expiratory reserve volume (ERV) – Residual volume (RV) – Minimal volume (MV) – About 12 per minute – About 6 L per minute Measure with spirometer l Pulmonary volumes (specific conditions) l – Tidal volume (TV) – Minute respiratory volume (MVR) – TV x respiration rate l Pulmonary capacities (combined conditions) – Inspiratory capacity – TV +IRV – Function residual capacity – RV+ERV – Vital capacity – IRV+TV +ERV – Total capacity – TV+IRV+ERV+RV+MV

Control of Respiration (Part 1) l Respiratory centers – Medullary rhythmicity l Areas – Inspiration – Expiratory l Sets basic rhythm – 2 sec inspiration – 3 sec expiration l Communicate with diaphragm – Phrenic n. – Intercostal n. – Pons l Helps switch between inspiration/expiration l Areas – Pneumotaxic • Limits inspiration • Overrides apneuistic area – Apneuistic – Limits expiration • Stimulates inspiration • Works when pneumotaxis area is inactive

Control of Respiration (Part 2) l Influencing factors l – Aortic body – Carotid body – Vagus n. l l Bronchial stretch receptors – Inflation reflex Anal sphincter receptors – Chemical stimuli l Medulla oblongata – Central chemoceptors – H ions – Peripheral chemoceptors Where l What – H ions – CO 2 – Proprioceptors – Increased body temperature – Pain l Acute l Chronic – Upper respiratory irritation – Emotional stimuli – Cortical influences