Essentials of Human Anatomy & Physiology Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 37-3 The Respiratory System

Human Respiratory System Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Human Respiratory System Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Functions: –Works closely with circulatory system, exchanging gases between air and blood: Takes up oxygen from air and supplies it to blood (for cellular respiration). Removal and disposal of carbon dioxide from blood (waste product from cellular respiration). Homeostatic Role: –Regulates blood pH. –Regulates blood oxygen and carbon dioxide levels.

Components: Upper Respiratory Tract Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Upper Respiratory Tract Functions Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Passageway for respiration Receptors for smell Filters incoming air to filter larger foreign material Moistens and warms incoming air Resonating chambers for voice

Components:Lower Respiratory Tract Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Upper Respiratory Tract Functions Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Larynx: maintains an open airway, routes food and air appropriately, assists in sound production Trachea: transports air to and from lungs Bronchi: branch into lungs Lungs: transport air to alveoli for gas exchange

Organs of the Respiratory system Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Nasal Cavity  Pharynx (throat)  Larynx (voice box)  Trachea (windpipe)  Bronchi  Bronchioles  Lungs (alveoli)

Organs of the Respiratory system

Anatomy of the Nasal Cavity Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Olfactory receptors are located in the mucosa on the superior surface  The rest of the cavity is lined with respiratory mucosa  Moistens air  Traps incoming foreign particles

Anatomy of the Nasal Cavity Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The nasal cavity is separated from the oral cavity by the palate  Anterior hard palate (bone)  Posterior soft palate (muscle)

Structures of the Pharynx Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Auditory tubes enter the nasopharynx  Tonsils of the pharynx  Pharyngeal tonsil (adenoids) in the nasopharynx  Palatine tonsils in the oropharynx  Lingual tonsils at the base of the tongue

Larynx (Voice Box) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Routes air and food into proper channels  Plays a role in speech  Made of eight rigid hyaline cartilages and a spoon-shaped flap of elastic cartilage (epiglottis)

Structures of the Larynx Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Thyroid cartilage  Largest hyaline cartilage  Protrudes anteriorly (Adam’s apple)  Epiglottis  Superior opening of the larynx  Routes food to the larynx and air toward the trachea

Structures of the Larynx Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Vocal cords (laryngoscope video)(laryngoscope video)  Vibrate with expelled air to create sound (speech)  Glottis – opening between vocal cords

Trachea (Windpipe) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Connects larynx with bronchi  Lined with ciliated mucosa  Beat continuously in the opposite direction of incoming air  Expel mucus loaded with dust and other debris away from lungs  Walls are reinforced with C-shaped hyaline cartilage

Primary Bronchi Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Formed by division of the trachea  Enters the lung at the hilus (medial depression)  Right bronchus is wider, shorter, and straighter than left  Bronchi subdivide into smaller and smaller branches

Lungs Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Occupy most of the thoracic cavity  Apex is near the clavicle (superior portion)  Base rests on the diaphragm (inferior portion)  Each lung is divided into lobes by fissures  Left lung – two lobes  Right lung – three lobes

Lungs Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 13.4b

Coverings of the Lungs Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Pulmonary (visceral) pleura covers the lung surface  Parietal pleura lines the walls of the thoracic cavity  Pleural fluid fills the area between layers of pleura to allow gliding

Respiratory Tree Divisions Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Primary bronchi  Secondary bronchi  Tertiary bronchi  Bronchioli  Terminal bronchioli

Bronchioles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Smallest branches of the bronchi

Bronchioles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  All but the smallest branches have reinforcing cartilage

Bronchioles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Terminal bronchioles end in alveoli

Alveoli Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Structure of alveoli  Alveolar duct  Alveolar sac  Alveolus  Gas exchange

Respiratory Membrane (Air-Blood Barrier) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Gas Exchange Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Gas crosses the respiratory membrane by diffusion  Oxygen enters the blood  Carbon dioxide enters the alveoli  Macrophages add protection  Surfactant coats gas-exposed alveolar surfaces

Gas Exchange: Blood and Alveoli Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Regulation of Breathing Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Mechanics of Breathing (Pulmonary Ventilation) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Two phases  Inspiration – flow of air into lung  Expiration – air leaving lung

Inspiration Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Diaphragm and intercostal muscles contract  The size of the thoracic cavity increases  External air is pulled into the lungs due to an increase in intrapulmonary volume

Exhalation Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Largely a passive process which depends on natural lung elasticity  As muscles relax, air is pushed out of the lungs  Forced expiration can occur mostly by contracting internal intercostal muscles to depress the rib cage

Inspiration Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Exhalation

Gas Transport in the Blood Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Oxygen transport in the blood  Inside red blood cells attached to hemoglobin (oxyhemoglobin [HbO 2 ])  A small amount is carried dissolved in the plasma

Hemoglobin Loading/Unloading O 2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Respiratory Acidosis Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Hypoventilation. Accumulation of CO 2 in the tissues. pH decreases. Plasma HCO 3 - increases. P c02 increases.

Respiratory Alkalosis Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Hyperventilation. Excessive loss of CO 2. pH increases. Plasma HCO 3 - decreases. P c02 decreases.

Factors Influencing Respiratory Rate and Depth Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Physical factors  Increased body temperature  Exercise  Talking  Coughing  Volition (conscious control)  Emotional factors

Factors Influencing Respiratory Rate and Depth Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Chemical factors  Carbon dioxide levels  Oxygen levels

Respiratory Rate Changes Throughout Life Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Newborns – 40 to 80 respirations per minute  Infants – 30 respirations per minute  Age 5 – 25 respirations per minute  Adults – 12 to 18 respirations per minute  Rate often increases somewhat with age

Lung Cancer Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Accounts for 1/3 of all cancer deaths in the United States  Increased incidence associated with smoking  Three common types  Squamous cell carcinoma  Adenocarcinoma  Small cell carcinoma

Asthma Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Chronic inflamed hypersensitive bronchiole passages  Response to irritants, coughing, and wheezing

Developmental Aspects of the Respiratory System Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Lungs are filled with fluid in the fetus  Lungs are not fully inflated with air until two weeks after birth  Surfactant that lowers alveolar surface tension is not present until late in fetal development and may not be present in premature babies

Fetus Exchanges Gases With Mother’s Blood Through Placenta Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings