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