Respiratory System

1. Respiratory System Chapter 8

2. Respiratory System Functions • To get oxygen into the red blood cells • To release carbon dioxide from the blood • “pulmonary”- refers to the lungs

4. Respiration • Inhalation- air enters nose and mouth • gains heat and moisture as it enters the lungs • filtered by nose hairs and cilia within the trachea to remove contaminants • exhalation- warm air cools as it leaves the body- condenses on a cold day and looks like smoke

5. Pathway of air • Nose- has odor receptors, hairs filter air, tear ducts and sinuses drain here • nasopharynx- just above the back of throat • pharynx- connects mouth and nasal passages • tonsils- right behind tongue- part of the immune system

7. Into the windpipe • Glottis- opening from pharynx to trachea • epiglottis- flap of tissue that covers the glottis when you swallow so you don’t choke • larynx- just below glottis- has vocal cords • trachea- windpipe- has cartilage rings- prevents collapse • bronchi- forks of trachea that leads to the lungs

8. The lungs • Bronchi fork into smaller bronchioles • bronchi and bronchioles are surrounded by smooth muscles- they can contract and cause asthma- difficulty breathing • end in tiny air sacs called alveoli • Located in the thoracic cavity of the upper chest

10. Alveoli • Made of simple squamous epithelium surrounded by tiny capillaries • gas exchange takes place here • All these tiny sacs increase surface area for gas exchange- lungs have 60m2 of area • lined with surfactant that prevents them from sticking closed by h-bonding of water

11. Mechanics of breathing • The thoracic cavity is sealed so when the diaphragm muscle on the bottom contracts, the cavity gets bigger • the vacuum that this creates pulls the lungs open and air rushes is • diaphragm relaxes- lungs expel the air because they are elastic • damage to this cavity= lung collapse

14. Other muscles • External intercostal muscles- expands rib cage to help with inhalation • internal intercostal muscles- cause rib cage to get smaller= forced exhalation • contraction of abdominal muscles can also force more air out of the lungs by pushing up against the diaphragm

15. Control of breathing • Medulla- control center- generates continuous impulses to stimulate diaphragm • chemoreceptors sensing carbon dioxide and acidity in the carotid (neck) arteries and the aorta can increase rate

16. Gas exchange • Carbon dioxide is carried in blood plasma as bicarbonate • hemoglobin in red blood cells picks up oxygen and changes to oxyhemoglobin

17. In tissues • The oxyhemoglobin drops off oxygen • carbon dioxide enters red blood cells and is then converted into bicarbonate and enters the plasma

18. Upper Respiratory Infections • Sinusitis- infection of the sinuses- hollow areas of the skull • clogged drains • pain increases as you lean forward • Treated with spray decongestants, hot shower

19. Otitis media • Bacterial infection of middle ear • bacteria get in through auditory tube • Treatment= antibiotics • tubes sometimes are inserted to drain fluid

20. Tonsilitus • Tonsils become inflamed and enlarged • Tonsils normally fight pathogens • If severely swollen, they can interfere with breathing so they are sometimes removed • immune system is impaired if removed

21. laryngitis • Infection of larynx • Causes hoarseness

23. Lower respiratory diseases • Acute bronchitus- a bacterial infection of the bronchi after a viral Upper respiratory infection • dry cough becomes a deep cough that expectorates mucus and pus • pneumonia- viral or bacterial infection of part of the lungs- alveoli fill with fluid • usually occurs after the flu • fever, headache, chest pain

24. More Lower Resp. Infections • Pulmonary tuberculosis- bacterial • Bacteria are encased by lung cells- called tubercules • skin test reveals exposure • some people can recover naturally • sanatoriums- quarantine areas • Treatment= antibiotics- but now some strains are partially resistant

25. Other lung disorders • Pulmonary fibrosis- the inhalation of dust and fibers such as asbestos causes fibrous connective tissue to build up in the alveoli • the elasticity of the lungs is reduced and they cannot inflate properly • poor respiration

26. Chronic bronchitus • Airways are inflamed and filled with mucus • cilia have been lost • more prone to infection • caused by smoking and exposure to pollutants

27. Emphysema • Alveoli are stretched out and damaged so that less surface area is available for gas exchange • chronic • lungs aren’t as elastic and don’t exhale all the air present- inefficient because lots of stale air remains in the lungs • supplemental oxygen is sometimes needed

28. Asthma • Wheezing, breathlessness and coughing • affects bronchi and bronchioles • when airways are exposed to an irritant, the smooth muscle spasms and constricts them • triggered by immune system • Treatment- inhalers to stop spasms and dilate airways

29. Lung cancer • Steps- caused by smoking and other chemicals- 1. thickening of cells in airway, 2. cilia are lost, 3. nucleus becomes abnormal (damaged DNA), 3. cancerous cells break free and spread to other parts of the body • surgery can remove the affected part of the lung if it the cancer hasn’t spread • also caused by second hand smoke