Function: to supply blood with, and to rid the body of

Transcription

1 Bio 1102 Lec. 7 (guided): Chapter 10 The Respiratory System Respiratory System Function: to supply blood with, and to rid the body of Oxygen: needed by cells to break down food in cellular respiration Carbon dioxide: a waste product generated in cellular respiration Four Processes of Respiration Breathing: the movement of air into and out of External respiration: the exchange of gases between inhaled air and Internal respiration: the exchange of gases between the blood and Cellular respiration: the process of using oxygen to produce within cells; this process also generates as a waste product The pathway of air Drawn into mouth or nose Pharynx ( ) Larynx ( ) Trachea ( ) Enters chest cavity Divides into two branches (left and right bronchus), one to each Bronchi branch inside lungs, forming smaller and smaller branches The smallest of these tubules branch to form ducts, called that lead to the (air sacs) Smooth muscles automatically control the opening and closing of bronchioles Lungs Located in cavity Contain millions of (air sacs) Surrounded by Where gas exchange occurs 9 What we breathe in Various airborne particles, such as dust, bacteria, pollen, and pollutants The trap Large particles become trapped in the mucus coating the epithelial linings of upper 1

2 respiratory tract (nasal passages, mouth cavity, pharynx, and trachea) Ciliated cells lining respiratory tract beat cilia, moving mucus upward toward mouth Mucus containing dust, bacteria, and other large particles may be swallowed or spit out Protects the lungs Smaller particles (fine particulates) may not become trapped in mucus, and make it all the way to the lungs Example: toxic metals such as mercury, and exhaust from diesel vehicles Can cause lung cancer When the mucus trap fails Doesn t always prevent all bacteria, viruses, and other particles from reaching lungs can decrease effectiveness of the ciliated cells lining the respiratory tract Sulfur dioxide gas in cigarette smoke May paralyze, or even kill, the ciliated cells Allows particles to enter lungs Smokers have more respiratory infections Interestingly, alcohol has same effect Getting Oxygen to the Cells Atmosphere is approximately % nitrogen and % oxygen gas Oxygen is generated by the of plants and other photosynthetic organisms When the air we breathe reaches the alveoli, gas exchange occurs Single-celled lining of the alveoli ( alveolar cells) Single-celled lining of the capillaries Mechanism: (movement of oxygen from an area of low high concentration to an area of low oxygen concentration) Oxygen then attaches to the molecules inside the red blood cells Is carried to the cells of the body via the arteries of the circulatory system Carbon dioxide: the opposite pathway Deoxygenated blood enters capillaries from the veins of the body Carbon dioxide diffuses from the capillaries into the Carbon dioxide is then expelled when we exhale Alveolar eat particles of dust, bacteria, and viruses that enter the alveoli Once they fill up, they embed themselves in the connective tissue of the lungs 2

3 Tobacco smoke contains so many particulates, causes MANY of these macrophages to fill up and embed in the lung tissue Gives a blackened appearance to lungs of smokers Similar effect may be seen in people who live in urban areas and breathe in large amounts of pollutants alveolar cells Secrete a lipid called Forms coating over thin layer of water over alveolar surface and prevents by reducing surface tension At air-water interface, water molecules stick to each other The surface tension of the water coating the alveolar epithelium could cause the thin walls of the alveoli to collapse Oily coating disrupts the pull of the water molecules toward each other Making Some Noise! Vocal cords are located in (voice box) Two Vibrate when air is released from lungs Sounds produced vary as tongue position and shape of oral cavity are changed Variation in length and thickness of vocal cords effects sound produced (different from person to person) Vocal cords in men usually longer and thicker, generating deeper voices Children have short, slender vocal cords higher pitched voices At puberty, a boy s voice changes: testosterone causes larynx to grow, and vocal cords to thicken Breathing Largely an involuntary action controlled by Inhalation: air is drawn into lungs Nerve impulses stimulate the to contract Sheet of muscle below the lungs Separates abdominal and chest cavities When diaphragm contracts, it flattens and lowers, causing Rib cage is also lifted upward and outward More space is available in chest cavity Exhalation: air is expelled from lungs Occurs after diaphragm and rib muscles Air is expelled 3

4 Breathing controlled by the breathing center of the brain Causes periodic impulses to be sent to diaphragm and rib muscles Contraction of these muscles results in When lungs fill, impulses stop being sent When muscles subsequently relax, you Diseases of Respiratory System Bronchitis: an infection of the Inflammation of lining of tubes Less air able to reach lungs Large amounts of mucus produced and coughed up Often associated with a cold bronchitis: when mucus-producing cough is present most days of the month for 3 months of the year for at least two years Can lead to scarring of bronchial tubes Excessive mucus is produced constantly Lungs can become scarred Infections more common #1 cause of chronic bronchitis: Other causes of bronchitis: bacterial and viral infections : walls of alveoli lose ability to stretch and recoil; sacs weaken and break Symptoms: shortness of breath and cough Usually caused by Effects of pollutants Asbestos Can cause lung cancer Can cause build up of scar tissue in lungs Asthma A type of, usually caused by dust, pollen, or pet dander Irritants stimulate increased production of mucus by bronchi and bronchioles Also cause bronchioles to Inflammation of respiratory tract occurs Breathing becomes more difficult 4

5 Lung Cancer Approximately 160,000 deaths from lung cancer each year #1 cause: (87% of cases due to smoking) Cigarette smoke contains >4,000 different chemicals, 69 of which are carcinogens After you stop smoking, normal cells gradually replace damaged cells, and risk of lung cancer drops Lung function increases 30% with 3 months After 10 years, risk of lung cancer approximately same as a non-smoker Second-hand smoke responsible for approximately 3,000 deaths each year A recent (2015) study has found that smoking causes even more diseases and deaths than previously thought 60,000 additional deaths Had already been linked to nearly half a million deaths due to 21 different diseases and 12 types of cancer Diseases newly linked to smoking include disease, diseases due to inadequate blood flow, increased risk for, and heart and lung ailments not previously linked to smoking Smoking weakens the immune system; causes diabetes and high blood pressure, which damages kidneys; artery disease from smoking can reduce blood supply to intestines, damaging the intestines Bonus Activity Ohio State University is just one of a growing number of institutions and businesses that is tobacco free. Discuss with your group the pro s and con s of such a policy, and list major arguments for/against going tobacco free. E-Cigarettes are gaining popularity as a healthier option to smoking. Are they safe? Read the article Vaping and Health. Then, pretend your group is a committee that has been tasked with making the decision as to whether or not to continue to make e- cigarettes part of the OSU no-tobacco policy. Write a consensus statement for your group. All for today 5