Principles of Human Anatomy and Physiology, 11e1 Chapter 23 The Respiratory System Lecture Outline

2 INTRODUCTION Respiration is the exchange of gases between the atmosphere, blood, and cells. Respiration also helps adjust the pH of body fluids. It takes place in three basic steps: ventilation (breathing), external (pulmonary) respiration, and internal (tissue) respiration.

Principles of Human Anatomy and Physiology, 11e3 Respiratory System Anatomy Upper respiratory system: –Nose –Pharynx = throat Lower Respiratory system: –Larynx = voice box –Trachea = windpipe –Bronchi = airways –Lungs

Principles of Human Anatomy and Physiology, 11e4 External Anatomy The external portion of the nose is made of cartilage and skin and is lined with mucous membrane.

Principles of Human Anatomy and Physiology, 11e5 Internal Anatomy The interior structures of the nose are specialized for: – warming, moistening, and filtering incoming air – receiving olfactory stimuli – serving as large, hollow resonating chambers to modify speech sounds.

6 Nose -- Internal Structures Large chamber within the skull Roof is made up of bone and floor is hard palate Internal nares are openings to pharynx Nasal septum is composed of bone & cartilage

Principles of Human Anatomy and Physiology, 11e7 Rhinoplasty Rhinoplasty (“nose job”) is a surgical procedure in which the structure of the external nose is altered for cosmetic or functional reasons (fracture or septal repair) Procedure –local and general anesthetic –nasal cartilage is reshaped through nostrils –bones fractured and repositioned –internal packing & splint while healing

Principles of Human Anatomy and Physiology, 11e8 Pharynx Muscular tube (5 inch long) hanging from skull Extends from the nose to voice box (larynx) Functions –passageway for food and air –resonating chamber for speech production –Tonsils, found in the wall, participate in immunological reactions against foreign invaders Distinct regions -- nasopharynx, oropharynx and laryngopharynx

Principles of Human Anatomy and Physiology, 11e9 Nasopharynx Passageway for air only –Location of the tonsils –Equalizes pressure with the ears

Principles of Human Anatomy and Physiology, 11e10 Oropharynx Common passageway for food & air –Is open to the mouth

Principles of Human Anatomy and Physiology, 11e11 Laryngopharynx Common passageway for food & air –Begins at the hyoid bone –Ends at the esophagus and the larynx

Principles of Human Anatomy and Physiology, 11e12 Larynx - Overview The larynx (voice box) is a passageway that connects the pharynx with the trachea.

Principles of Human Anatomy and Physiology, 11e13 Cartilages of the Larynx Thyroid cartilage forms Adam’s apple Epiglottis---leaf-shaped piece of elastic cartilage that keeps food out of our lungs Glottis-location of vocal cords Cartilages-form the structure of the larynx

Principles of Human Anatomy and Physiology, 11e14 The Structures of Voice Production True vocal cord contains both skeletal muscle and an elastic ligament. Made of 10 small muscles and ligaments. The tighter the ligament, the higher the pitch To increase volume of sound, push air harder

Principles of Human Anatomy and Physiology, 11e15 Speech and Whispering Speech is modified sound made by the larynx. Speech requires pharynx, mouth, nasal cavity & sinuses to resonate that sound Tongue & lips form words Whispering is forcing air through almost closed glottis, vocal cords do not vibrate

Principles of Human Anatomy and Physiology, 11e16 Trachea The windpipe Size is 5 in long & 1 in diameter Extends from larynx down to the lungs where it splits into two bronchi

Principles of Human Anatomy and Physiology, 11e17 Bronchi The trachea divides into the right and left pulmonary bronchi. Made of rings of cartilage and lined with cilia (little hairs that move air along)

18 Bronchi and Bronchioles As the bronchi enter the lungs, they branch off into smaller tubes called bronchioles

Principles of Human Anatomy and Physiology, 11e19 Lungs - Overview Lungs are paired organs in the thoracic cavity; they are enclosed and protected by the pleural membrane. The parietal pleura is the outer layer which is attached to the wall of the thoracic cavity. The visceral pleura is the inner layer, covering the lungs themselves. Between the pleurae is a small potential space, the pleural cavity, which contains a lubricating fluid secreted by the membranes.

Principles of Human Anatomy and Physiology, 11e20 Lungs - Overview The lungs almost totally fill the thorax. The right lung has three lobes separated by two fissures; the left lung has two lobes separated by one fissure and a depression. Each lobe is divided into smaller sections called lobules.

21 Alveoli An alveolus (plural is alveoli) is a cup-shaped pouch filled with fluid called surfactant. This is where oxygen and carbon dioxide enter and leave the blood from the capillaries.

Principles of Human Anatomy and Physiology, 11e22 Photomicrograph of lung tissue showing bronchioles, alveoli and alveolar ducts. Histology of Lung Tissue

Principles of Human Anatomy and Physiology, 11e23

Principles of Human Anatomy and Physiology, 11e24 Blood Supply to the Lungs Deoxygenated blood enters the lungs through the pulmonary artery (from the heart) Oxygenated blood is returned to the heart through the pulmonary veins

Principles of Human Anatomy and Physiology, 11e25 Physiology of Respiration Respiration occurs in three basic steps: pulmonary ventilation, external respiration, and internal respiration.

Principles of Human Anatomy and Physiology, 11e26 Step 1 = Pulmonary Ventilation = Breathing Inhalation, or breathing in, is the first step. Lungs expand through muscle contraction, which increases lung volume and decreases pressure inside the lungs Lungs then fill with air

Principles of Human Anatomy and Physiology, 11e27 Expiration Expiration (exhalation) is the movement of air out of the lungs. No muscle contractions are involved, this is a passive process

Principles of Human Anatomy and Physiology, 11e28 Breathing Patterns Eupnea is normal variation in breathing rate and depth. Apnea refers to breath holding. Dyspnea relates to painful or difficult breathing. Tachypnea involves rapid breathing rate. Costal breathing is shallow breathing where the chest moves up and down. Diaphragmatic breathing is deep abdominal breathing. Modified respiratory movements are used to express emotions such as laughing, sighing, and sobbing; or coughing and hiccupping.

Principles of Human Anatomy and Physiology, 11e29 LUNG VOLUMES AND CAPACITIES At rest, a healthy adult averages 12 breaths a minute. Lower than normal indicates pulmonary malfunction. A spirometer or respirometer measures the volume of air exchanged during breathing.

Principles of Human Anatomy and Physiology, 11e30 Step 2: External (pulmonary) Respiration The exchange of O2 and CO2 between the alveoli and the blood occurs via passive diffusion. The gases flow from where they are MORE concentrated to where they are LESS concentrated.

Principles of Human Anatomy and Physiology, 11e31 Step 3 = Internal Respiration Exchange of gases between blood & tissues Conversion of oxygenated blood into deoxygenated Oxygen moves from the blood in capillaries to cells and tissues. CO2 leave cells and tissues and enters veins.

Principles of Human Anatomy and Physiology, 11e32 Oxygen Transport In each 100 ml of oxygenated blood, 1.5% of the O 2 is dissolved in the plasma and 98.5% is carried within red blood cells, which have hemoglobin. Hemoglobin consists of a protein portion called globin and a pigment called heme. The heme portion contains 4 atoms of iron, each capable of combining with a molecule of oxygen.

Principles of Human Anatomy and Physiology, 11e33 Carbon Dioxide Transport Is carried by the blood in 3 ways –dissolved in plasma (7%) –combined with the globin part of Hb molecule forming carbaminohemoglobin (23%) –As bicarbonate ions dissolved in plasma (70%), this is CO2 combined with hydrogen ions.

Principles of Human Anatomy and Physiology, 11e34 Respiratory Center The area of the brain from which nerve impulses are sent to respiratory muscles is located in the brain stem. –The medulla oblongata –The pons

Principles of Human Anatomy and Physiology, 11e35 EXERCISE AND THE RESPIRATORY SYSTEM As muscles contract, they use a lot of oxygen. Respiration and heart rate both increase.

Principles of Human Anatomy and Physiology, 11e36 Smokers Lowered Respiratory Efficiency Smoker is easily “winded” with moderate exercise –nicotine constricts terminal bronchioles –carbon monoxide in smoke binds to hemoglobin –irritants in smoke cause excess mucus secretion –irritants inhibit movements of cilia –in time destroys elastic fibers in lungs & leads to Emphysema: trapping of air in alveoli & reduced gas exchange

Principles of Human Anatomy and Physiology, 11e37 Aging & the Respiratory System Respiratory tissues & chest wall become more rigid Vital capacity decreases to 35% by age 70. Decreases in macrophage activity Diminished ciliary action Decrease in blood levels of O2 Result is an age-related susceptibility to pneumonia or bronchitis

Principles of Human Anatomy and Physiology, 11e38 Disorders of the Respiratory System Asthma Chronic obstructive pulmonary disease –Emphysema –Chronic bronchitis Lung Cancer Pneumonia Tuberculosis Coryza and Influenza Pulmonary Edema Cystic fibrosis Asbestos SIDS SARS

Principles of Human Anatomy and Physiology, 11e39 DISORDERS: HOMEOSTATIC IMBALANCES Asthma is chronic airway inflammation and obstruction, which causes difficult breathing. A common triggering factor is allergy, but other factors include emotional upset, aspirin, exercise, and breathing cold air or cigarette smoke.

Principles of Human Anatomy and Physiology, 11e40 DISORDERS: HOMEOSTATIC IMBALANCES Chronic obstructive pulmonary disease (COPD) is a type of respiratory disorder characterized by chronic and recurrent obstruction of air flow, which increases airway resistance. –Emphysema is caused by destruction of the alveoli, caused by smoking, pollution, exercise –Bronchitis is excessive secretion of bronchial mucus and a cough. It is caused by smoking, inhaled irritants, and bacterial infections.

Principles of Human Anatomy and Physiology, 11e41 DISORDERS: HOMEOSTATIC IMBALANCES In lung cancer, bronchial epithelial cells are replaced by cancer cells. Airways are often blocked and metastasis is very common. It is most commonly associated with smoking.

Principles of Human Anatomy and Physiology, 11e42 DISORDERS: HOMEOSTATIC IMBALANCES Pneumonia is an acute infection of the alveoli. The most common cause in the pneumococcal bacteria which can be treated with antibiotics. It is the most common cause of infectious death in the US. Tuberculosis (TB) is an inflammation of pleurae and lungs produced by the organism Mycobacterium tuberculosis. It is communicable and destroys lung tissue, may be treated with antibiotics. Coryza (common cold) is caused by viruses and usually is not accompanied by a fever, whereas influenza (flu) is usually accompanied by a fever greater than 101 o F.

Principles of Human Anatomy and Physiology, 11e43 DISORDERS: HOMEOSTATIC IMBALANCES Pulmonary edema refers to an abnormal accumulation of interstitial fluid in the alveoli of the lungs. It can be caused by the diet drug Phen-fen. Cystic fibrosis is an inherited disease of secretory epithelia that affects the respiratory passageways, pancreas, salivary glands, and sweat glands. 5% of white people are carriers.

Principles of Human Anatomy and Physiology, 11e44 DISORDERS: HOMEOSTATIC IMBALANCES Asbestos related diseases develop as a result of inhaling asbestos particles. Diseases such as asbestosis, diffuse pleural thickening, and mesothelioma (cancer) may result. Sudden infant death syndrome (SIDS) is the sudden unexpected death of an apparently healthy infant due to cessation of breathing. Peak incidence is ages two to four months. The exact cause is unknown. Severe acute respiratory syndrome (SARS) is an emerging infectious disease. It is viral and there is no vaccine or treatment. Death rate is 10%.