Respiratory System Biol 105 Lecture 18 Chapter 14

Outline - Respiratory System Function of the respiratory system Parts of the respiratory system Mechanics of breathing Regulation of breathing Disorders of the respiratory system

Respiratory system Function The function of the respiratory system is to bring in oxygen to the body and remove carbon dioxide.

The Respiratory System Breathing moves air in and out of the lungs. External respiration is the exchange of oxygen and carbon dioxide between the lungs and the blood. Gas transport moves oxygen and carbon dioxide between the lungs and the body tissues. Internal respiration is the exchange of oxygen and carbon dioxide between blood and the body tissues. Oxygen transport Carbon dioxide transport Lungs Gas diffusion Gas diffusion Tissue Figure 14.1

This type of tissue covers and lines body parts Connective Epithelial Muscle Nervous

Cells lining respiratory tract Lined by pseudostratified ciliated columnar epithelial cells. The cilia sweeps mucus, germs and debris toward the throat. Mucas produced by goblet cells. Smoking damages the ciliated cells 8-4

The Respiratory System Figure 14.4a

Ciliated cells in respiratory tract

The Respiratory System Figure 14.3

The Respiratory System UPPER RESPIRATORY SYSTEM Sinuses • Cavities in skull • Lighten head • Warm and moisten air • Filters, warms, and moistens air Nasal cavity • Produces mucus • Filters, warms, and moistens air • Olfaction Pharynx • Passageway for air and food RESPIRATORY MUSCLES • Cause breathing Intercostal muscles Diaphragm • Muscle sheet between chest and abdominal cavities with a role in breathing • Move ribs during breathing Figure 14.2 (1 of 2)

The Respiratory System LOWER RESPIRATORY SYSTEM • Exchanges gases Epiglottis • Covers larynx during swallowing Larynx • Air passageway • Prevents food and drink from entering lower respiratory system • Produces voice Lungs • Structures that contain alveoli and air passageways • Allow exchange of oxygen and carbon dioxide between atmosphere and blood Bronchi • Two branches of trachea that conduct air from trachea to each lung Trachea • Connects larynx with bronchi leading to each lung • Conducts air to and from bronchi Bronchioles • Narrow passageways to conduct air from bronchi to alveoli Alveoli • Microscopic chambers for gas exchange Figure 14.2 (2 of 2)

moisten the air entering the lungs smell 1. Nasal cavity Functions: filter warm moisten the air entering the lungs smell 8-3

Mucus membranes - secrete sticky mucus to trap germs & debris. 1. Nasal cavity Parts of the nasal cavity: Mucus membranes - secrete sticky mucus to trap germs & debris. Contains olfactory receptor cells for the sense of smell Sinuses – air filled cavities, warm and moisten air 8-3

2. Pharynx Functions - is a passageway for air, liquids, and food. (swallowing begins here). Connects the nasal cavity to the esophagus and the larynx Tonsils are found here – lymphatic tissue that protects against infection 8-4

Functions Connects the pharynx to the trachea 3. Larynx Functions Connects the pharynx to the trachea Contains vocal cords used to generate sound Prevents food from entering lower respiratory tract 8-4

Structure made from cartilage 3. Larynx Structure made from cartilage Epiglottis closes the trachea when swallowing 8-4

FIGURE 14.5a The larynx, commonly called the voice box or Adam's apple, is an adjustable entryway to the trachea and the source of the voice. (a) The epiglottis is open during breathing but covers the opening to the larynx during swallowing to prevent food or drink from entering the trachea. (b) The vocal cords are the folds of connective tissue above the opening of the larynx (the glottis) that produce the voice.

FIGURE 14.5b The larynx, commonly called the voice box or Adam's apple, is an adjustable entryway to the trachea and the source of the voice. (a) The epiglottis is open during breathing but covers the opening to the larynx during swallowing to prevent food or drink from entering the trachea. (b) The vocal cords are the folds of connective tissue above the opening of the larynx (the glottis) that produce the voice.

Windpipe held open by concentric rings of cartilage 4. Trachea Windpipe held open by concentric rings of cartilage Function – Connects the larynx to the bronchi. 8-4

Trachea leads to the bronchial tree: Bronchi (bronchus) Bronchioles Alveoli (alveolus). 8-4

The Respiratory System Figure 14.7

7. Alveoli Sacs at the end of the bronchioles, they are surrounded by blood capillaries . Function: It is here that the oxygen diffuses across the membrane into the capillaries, and carbon dioxide goes from the capillaries to the inside of the lungs. 8-6

Alveoli Lungs - have about 300 million alveoli The structure of the alveoli increases surface area of lung For alveoli to function properly they are coated with phospholipid molecules called surfactant that keep them open

Alveoli Figure 14.8

The Respiratory System Table 14.1 (1 of 2)

The Respiratory System Table 14.1 (2 of 2)

What cells secrete mucus Cilliated columnar epi goblet Squamous epi osteocytes

The tube connecting the larynx to the primary bronchi is pharynx trachea bronchioles alveoli

Common passageway for air, food and drink pharynx trachea bronchioles alveoli

Conduct air from the trachea to the bronchioles pharynx trachea bronchi alveoli

Gas exchange takes place here pharynx trachea bronchioles alveoli

Which cavity is the lung located in? Abdominal Pericardial Pleural Dorsal

Inhalation Inhalation Air flow Rib cage moves up and out Intercostal muscles contract Diaphragm contracts and flattens Diaphragm contracts The chest cavity increases in size, and pressure within the lungs decreases. The lungs expand, and air moves in. (a) Figure 14.9a

Inhalation When the diaphragm and intercostal muscles contract, the volume of the thoracic cavity increases, causing the pressure in the lungs to decrease Inhalation is also called inspiration

Exhalation Exhalation Air flow Rib cage moves down and inward Intercostal muscles relax Diaphragm relaxes and moves upward Diaphragm relaxes The chest cavity decreases in size, and pressure within the lungs increases. The lungs recoil, and air moves out. (b) Figure 14.9b

Exhalation Exhalation = Expiration When the same muscles relax, volume of the thoracic cavity decreases, pressure in the lungs increase

Air Volumes The volume of air inhaled or exhaled during a normal breath is called the tidal volume Tidal volume is usually around 500 ml The volume of air moved into and out of the lungs is an indication of health

Air Volumes Inspiratory reserve volume = forced inhalation volume Expiratory reserve volume = forced exhalation volume Residual volume is the amount of air left in the lungs after forced exhalation Vital capacity is the amount of air brought in and out of the lungs during forced breathing

Air Volumes 6000 Inspiratory reserve (forced inhalation) volume Total lung capacity 5000 Vital capacity 4000 Tidal volume Lung Volume (ml) 3000 Expiratory reserve (forced exhalation) volume 2000 1000 Residual volume Figure 14.10 (1 of 2)

Gas Exchanges in the Body Remember that O2 enters and CO2 leaves the lungs = External respiration Then O2 and CO2 is exchanged between the blood vessels and tissues = Internal Respiration This gas exchange is due to diffusion 8-14

Oxygen Transport Oxygen is transported on Hemoglobin. When Oxygen is bound to hemoglobin, then it is called Oxyhemoglobin 8-15

Carbon Dioxide Transport CO2 is transported dissolved in the plasma (10%) CO2 is bound to hemoglobin (20%) CO2 is converted to bicarbonate ions (70%) 8-14

Bicarbonate ions CO2 + H2O H2CO3 H+ + HCO3- Carbonic anhydrase 8-14

Diffusion of Gasses: Alveoli and Capillaries Figure 14.11 (2 of 2)

Diffusion of Gasses: Capillaries and Tissues Figure 14.11 (1 of 2)

Regulation of Breathing Normally we breath 12 - 15 ventilations per minute. This rate is controlled by the medulla oblongata region of the brain. Nerves transmit signal to the diaphragm and muscles. Chemoreceptors in the medulla oblongata and arteries detect levels of CO2 and O2 in the blood, controlling the rate and depth of breathing. 8-12

Respiratory Disorders Common cold Flu Pneumonia Strep Throat Tuberculosis Bronchitis Asthma Emphysema Lung Cancer 8-16

Respiratory Disorders – Common Cold The common cold - Caused by several types of viruses. Symptoms: runny nose, sore throat, sneezing, nasal discharge Treatment: rest and plenty of fluids Prevention: wash your hands

Respiratory Disorders - Flu The flu is caused by the Influenza viruses but there are many variants of these viruses Symptoms: Similar to colds but appear suddenly and more severe. Usually have fever and chills, may have muscle aches, headache, and weakness. Treatment and prevention – same as cold Can take drugs to ease symptoms and antiviral medications may ease symptoms

Respiratory Disorders - Pneumonia Pneumonia is an inflammation of the lungs that causes fluid to accumulate in the alveoli, reducing gas exchange Usually caused by a viral or bacterial infection Symptoms: fever, chills, chest pain, cough, shortness of breath. Treatment depends on cause – bacteria can be treated with antibiotics.

Respiratory Disorders Strep throat Strep throat is caused by Streptococcus bacteria Can lead to rheumatic fever which can damage heart and kidney disease Symptoms: Sore throat accompanied by swollen glands and fever Treatment: antibiotics

Respiratory Disorders - Tuberculosis Tuberculosis is caused by a bacteria = mycobacterium tuberculosis. Bacteria spread through airborne transmission Our body encapsulates the bacteria with a fibrous capsule made of connective tissue to try to protect itself, capsule is called tubercles

Respiratory Disorders - Tuberculosis Symptoms: similar to flu, weight loss, tired, dry cough. Treatment: Antibiotics must be taken for 6 months to 2 years – some people to stop early – leads to antibiotic resistant strains of bacteria

Respiratory Disorders - Bronchitis Bronchitis is an inflammation of the mucous membrane of the bronchi Caused by viruses, bacteria, or chemical irritation Symptoms: Inflammation results in the production of excess mucus, which triggers a deep cough Treatment: Depends on cause

Respiratory Disorders - Asthma The smooth muscles surrounding the bronchi spasm – causing the bronchi to constrict, making it hard to breathe Causes and triggers: allergies, colds, exercise, stress

Respiratory Disorders - Emphysema Emphysema is caused by the destruction of alveoli, usually by smoking Reduction in the surface area available for gas exchange and the increased dead air space results in shortness of breath Treatment - no cure, can supplement with oxygen and drugs can dilate airways.

Respiratory Disorders - Emphysema Figure 14.14

Lung Cancer Lung Cancer is the result of uncontrolled cell division forms a tumor The smoke irritates the lining of the bronchi. The cilia that normally function to clear dust and particles from the lungs are destroyed. Often caused by inhaled carcinogens, including those found in tobacco smoke. Between 85 – 90% of lung cancer is from smoking.

Lung Cancer Lung cancer is more common in men, but as more women are smoking, the rate of lung cancer in women is rising. Women are more at risk Many compounds in the smoke are cancer promoters, they trigger the progression of cancer in cells. 8-16

Effects of Smoking The 5-year survival rate is 13%. Smoking can cause cancers of other parts of the respiratory system. 8-16

Effects of Smoking on Pregnancy Cigarette smoke contains CO, the fetal blood has a higher affinity for CO than the mothers blood, so CO builds up in the fetuses body. Nicotine is also passed into the fetus, stimulating the developing nervous system. Men smoking can damage the DNA in their sperm and pass genetic mutations to their offspring. 8-16

Figure 8.11

Lung Cancer Figure 14.15

Figure: 14A-01a Title: Cigarette smoking reduces life expectancy. Caption: (a) Smoking causes more than 400,000 deaths each year in the United States, more people each year than the combined number of deaths due to AIDS, alcohol, drugs, car accidents, murder, and suicide. These data are from a report from the Centers for Disease Control and Prevention in 2000. The number of deaths from cigarette smoking have increased since then, but the relative importance of each cause of death remains similar.

Figure: 14A-04 Title: Tobacco use and lung cancer. Caption: Lung cancer usually takes about 20 years to develop. Notice that the number of deaths from lung cancer increases and decreases with tobacco use with about a 20-year delay. The lung cancer death rate of females is lower than that of men because there are fewer female smokers than there are male smokers. Source: http:www.cancer.org/downloads/PRO/cancer%20statistics%202004.ppt. Death rates: U.S. Mortality Public Use Tapes, 1960-2000, U.S. Mortality Volumes, 1930-1959, National Center for Health Statistics, Centers for Disease Control and Prevention, 2002. Cigarette consumption: U.S. Department of Agriculture, 1900-2000.

Figure: 14A-07 Title: Death rate due to heart disease among nonsmokers and smokers. Caption: Notice that the death rate from heart disease increases with the number of cigarettes smoked per day. People who smoke over a pack per day have more than twice the risk of death due to heart disease than do people who have never smoked. In any case, a smoker who successfully quits is much less likely to die of heart disease than if the smoking habit continues.

What is the smoking policy on campus? You can smoke anywhere You can smoke anywhere outside You can smoke at designated spots No smoking on campus

Do you think smoking should be allowed on campus? Yes No

Do you smoke? Never Used to, but quit Smoke, but trying to quit Smoke

Important Concepts Read Ch 15 What is the function of the respiratory system? What is the location and function of the all the parts of the respiratory system? What are the parts of the nasal cavity and their functions? What are the parts of the larynx and their functions?

Important Concepts What cell types lines the trachea, what are their functions, be able to discus how smoking effects this tissue? Where does the exchange of gases occur in the lungs? What cavity contains the lungs? What controls the rate of breathing? Be able to discuss the mechanics of breathing?

Important Concepts How is oxygen carried in the blood? How is carbon dioxide carried in the blood, know all the ways, and the which is the predominate mode? (You don’t need to know the chemical equation of bicarbonate formation) What is the diaphragm and what is its function?

Important Concepts Be able to discuss the disorders of the respiratory system including the description, symptoms, cause, and treatments. How does smoking effect pregnancy?

Definitions Goblet cells, sinuses, epiglottis, surfactant, diaphragm, intercostal muscles, Inhalation/inspiration, exhalation/expiration tidal volume, inspiratory reserve volume, expiratory reserve volume, residual volume, vital capacity, hemoglobin, oxyhemoglobin, chemoreceptors, tubercles, antibiotic resistant