2Intended Learning Outcomes PagesIdentify and give the functions for each of the following:Larynx,Trachea, Bronchi, Bronchioles, Alveoli, Diaphragm & ribs, Pleural membranes, and Thoracic cavity.Compare and contrast the mechanics of the processes of inhalation and exhalation .Explain the relationship between the structure and function of the alveoli.Explain the roles of the cilia and mucous in the respiratory tract.Describe the interaction of the lungs, pleural membranes, ribs, and diaphragm in the breathing process.Explain the roles of carbon dioxide and hydrogen ions in stimulating the breathing centre in the medulla oblongata.Describe the exchange of carbon dioxide and oxygen during internal and external respiration.Distinguish between the transport of carbon dioxide and oxygen in the blood by explaining the roles of oxyhemoglobin, carboxyhemoglobin, reduced hemoglobin, and bicarbonate ions.
4Interesting Facts The right lung is slightly larger than the left. Hairs in the nose help to clean the air we breathe, as well as warming it.The highest recorded "sneeze speed" is 165 km per hour.The surface area of the lungs is roughly the same size as a tennis court.Each red blood cell has about million Hemoglobin molecules.
5More Interesting Facts The capillaries in the lungs would extend 1,600 km if placed end to end.We lose half a litre of water a day through breathing. This is the water vapour we see when we breathe onto glass.A person at rest usually breathes between 12 and 15 times a minute.The breathing rate is faster in children and women than in men.Lung breathing probably evolved about 400 million years ago.
10The Nasal SinusThe Nasal Sinus is surrounded by a lot of capillary beds and mucous glands. Because it is one of the major entry ways into the body it has many things to help keep us safeNose hairs: with the aid of mucous, these hairs filter and trap debris. The debris that is trapped in this manner is discharged through the nose.There are many white blood cells here to recognize and destroy foreign objects.Histamines are released here as an allergic response when foreign irritants are encountered. This causes runny nose.
15LarynxWhen the epiglottis is opened, the air is able to pass through the larynx (voice box) and into the trachea.The larynx contains the vocal cords (two tendons that adjust the pitch of sounds according to how taut they are).
17When a guy goes through puberty, his vocal chords and voice box (larynx) grow larger, and begins to stick out at the front of the throat. This lump is called the Adam's Apple.Male vocal cords: 17 mm & 25 mm in length.Female vocal cords: mm & 17.5 mm in length.[1
18Trachea This is the windpipe. This passageway is held open by the presence of C-shaped rings of cartilage.This is a protective adaptation.The trachea conducts air into the bronchi.
19Cilia and mucus filter the air as it moves through the trachea. The mucous traps the dirt and other particles, and the cilia push it to the back of the throat so we swallow it into our digestive systemCilia with pollen trapped by mucous.
20Conditioning of the Air Several things happen to the air on its way to the alveoli. It is:Adjusted to Body Temperature: By the time it arrives at the alveoli the air has been in contact with many tissues and is 37o C.Adjusted to 100% humidity. As inhaled air passes over the mucous passageways, it becomes saturated with water.Cleansed of debris in a 2 part process.Nose hairs and mucous in the nasal passageways.Mucous and Cilia in Trachea and bronchi. *Note: cilia do not filter!
21BronchiThe trachea splits into two bronchi and takes the air into each lung.These branches also have cartilage around them, for the same reason.The bronchi conducts air into smaller branching passageways called bronchioles.
22BronchiolesThe bronchioles are branching passageways that carry air to its ultimate destination, the alveoli.
24AlveoliThese are the blind sac-like endings at the end of the bronchioles.There are approx. 700,000 alveoli in the human lung.This is the site of gas exchange.O2 leaves the alveoli and moves into the blood to be taken around the body.CO2 does the opposite and is breathed out.
25Why are they so special?NUMEROUS: Each adult lung contains millions of alveoli. This provides lots of surface area for the gases to be exchanged.THIN WALLS: The walls of alveoli are only one cell thick.STRETCH RECEPTORS: They have stretch receptors that signal when the alveoli are full enough (stretched). They send a message to the brain to start exhalation.
27Why are they so special?MOIST: They are very moist and this helps gas exchange.VERY RICH BLOOD SUPPLY: They have a close association with many blood capillaries so oxygen and carbon dioxide can be exchanged efficiently.LINED WITH A LAYER OF LIPOPROTEINS (surfactant) on their inner surface. This helps to maintain surface tension, thus preventing them from collapsing and sticking together during exhalation.
30DiaphragmThis is a sheet of muscle that separates the chest cavity from the abdominal cavity.When you inhale it moves down.When you exhale it moves up.
31Ribs and MusclesThese are the bones that are connected to the vertebral column and sternum.These are INTERCOSTAL muscles between the ribs, which help to move the ribs…Up and out when we inhale.Down and in when we exhale.
32MEDULLA OBLONGATAOur control of the breathing process is only voluntary to a point.The medulla oblongata of the brain is sensitive to the concentration of carbon dioxide and hydrogen ions in the blood.When the concentrations of H+ and CO2 reach a critical level, the breathing center in the medulla oblongata is stimulated and sends nerve impulses to the diaphragm and the intercostal muscles.
33TO INHALEWhen the brain realizes there is too much CO2 in our blood, it sends a message to the rib muscles and diaphragm to contract.The ribs move up and out, the diaphragm moves down.This creates more space in the lungs (negative air pressure) and air rushes in to fill that space.This is called inhalation.
34TO EXHALEWhen the alveoli get too stretched (full of air), they send a message to the brain to stop inhaling.The brain tells the muscles to relax and the ribs move back down and in, while the diaphragm moves back up.This decreases the amount of space in the lungs and the air is pushed out.This is called exhalation.
36See a Working Respiratory System: http://www. smm
37Pleural MembranesThese are membranes that enclose the lungs.The outer pleural membrane sticks closely to the walls of the chest & the diaphragm.The inner pleural membrane is stuck to the lungs. The two lie very close to each other.The pleura allows the surface of the lungs to slide over the body wall easily, without abrasion.
38Pleural MembranesThe pleura seals off the thoracic cavity so when the lungs inflate, a negative air pressure is created and this causes air to rush in.These membranes also stick the lungs to the chest cavity walls, so when the ribs move out, so do the lungs.
39PneumothoraxA puncture to the chest wall, piercing the pleural membrane (even without damaging the lung itself), will result in a pneumothorax, or collapse of the lung.In a situation like this, the negative pressure effectively draws air in through the puncture wound, putting pressure on the surface of the lung instead of inside it and the lung collapses.
40Respiratory SystemRespiration is the set of processes involved with the conduction of oxygen to the tissues and the removal of the waste product CO2.There are four aspects to respiration: 1. Breathing: the inspiration and expiration of air. 2. External Respiration: gas exchange at the alveoli.Internal Respiration: gas exchange at the tissues.Cellular Respiration: mitochondria turn O2 and glucose into CO2 and H2O and ATP energy.
41External Respiration Happens at the lungs. Happens at the lungs.It is the diffusion of O2 into the pulmonary capillaries (blood) and the diffusion of CO2 and water into the alveoli to be exhaled with the air.
42External RespirationBecause there is a lot of CO2 returning to the lungs, and not very much in the alveoli, the CO2 diffuses from [H] to [L] down its concentration gradient and moves into the alveoli to be breathed out.Because there is a lot of O2 in the fresh air in the alveoli, and not much in the deO2 blood, the oxygen diffuses from [H] to [L] down its concentration gradient and into the blood.
43External Respiration Conditions in the blood at the alveoli are: Conditions in the blood at the alveoli are:Under these conditions, hemoglobin lets go of CO2 and starts to love oxygen.As it leaves the lungs, 99% of hemoglobin is occupied with oxygen it is called oxyhemoglobin.Hemoglobin transports oxygen to the tissue cells.Basic: pH of ~7.4Cool: ~37o CLow (negative) pressureO2 + Hb HbO2
44Internal Respiration Happens at the tissues. Happens at the tissues.It is the diffusion of O2 into the tissue cells, and the diffusion of CO2 and water into the blood capillaries.The CO2 is then returned to the heart and sent to the lungs to be removed during exhalation.
46Internal Respiration Conditions in the blood at the tissues are: Conditions in the blood at the tissues are:Under these conditions, hemoglobin lets go of O2 and starts to love CO2 and H+.The oxygen diffuses into the tissue spaces along with the water that is forced from the plasma due to blood pressure.Acidic: pH of ~7.3Warm: ~38o CHigh pressureHbO Hb + O2
48Internal Respiration (con’t) At the venule end of the capillary bed, when water is drawn back into the blood by osmotic pressure, CO2 enters the blood.Carbon dioxide can be transported in three ways:1. Dissolved gas, 2. Carboxyhemoglobin (HbCO2), 3. Bicarbonate ion (HCO3-)
49Internal Respiration (con’t) Because the hemoglobin now loves the CO2, they join to form carboxyhemoglobin.CO2 also joins with water to make the bicarbonate ion. There is an enzyme in the red blood cells called CARBONIC ANHYDRASE which catalyzes this reaction.CO2 + Hb HbCO2CO2 + H2O H2CO HCO H+Carbonic anhydrase Carbonic anhydrase
50Internal Respiration (con’t) CO2 + H2O H2CO HCO H+Carbonic anhydrase Carbonic anhydraseThe extra hydrogen ion from the water is now free. This is BAD as it is ACIDIC and can eat through the blood vessel walls.So, hemoglobin acts as a buffer and joins with the hydrogen ion to make reduced hemoglobin.H+ + Hb HHb
52External RespirationWhen the blood returns to the lungs, the conditions change again, and hemoglobin dumps CO2 and H+ & wants to pick up O2 again.So all of the reactions happen in reverse.HbCO CO2 + HbHHb H+ + HbH HCO H2CO CO2 + H2OCarbonic anhydrase Carbonic anhydrase
53External Respiration H2O + CO2 At this point, all that is left to be excreted at the lungs is water and CO2.So the CO2 diffuses into the alveoli and is exhaled.The water will either:1. Be exhaled in the air 2. Enter the alveoli to keep them moist3. Remain in the plasmaH2O + CO2
56REVIEW OF RESPIRATION: Transport of Carbon Dioxide:
57Problems With the Lungs Smoking causes lung cancer and emphysemaEmphysema causes the alveoli to lose their elasticityPeople who have respiratory disease often have heart diseaseThere are over 4000 chemicals in cigarettesSmoking also destroys the cilia lining in your respiratory system so that dirt and particles can’t be removed
62What Else Can Go Wrong?ASTHMA: Over 20 million people have asthma in the US, and it's the number-one reason that kids and teens chronically miss school.Asthma is a long-term, inflammatory lung disease that causes airways to tighten and narrow when a person with the condition comes into contact with irritants such as cigarette smoke, dust, or pet dander.
63What Else Can Go Wrong?BRONCHITIS: Although bronchitis doesn't affect most teens, it can affect those who smoke.In bronchitis, the membranes lining the bronchial tubes become inflamed and an excessive amount of mucus is produced.The person with bronchitis develops a bad cough to get rid of the mucus.
64What Else Can Go Wrong?COMMON COLD: Colds are caused by over 200 different viruses that cause inflammation in the upper respiratory tract.The common cold is the most common respiratory infection.Symptoms may include a mild fever, cough, headache, runny nose, sneezing, and sore throat.
65What Else Can Go Wrong?CYSTIC FIBROSIS (CF): CF is an inherited disease affecting the lungs. CF causes mucus in the body to be abnormally thick and sticky. The mucus can clog the airways in the lungs and make a person more likely to get bacterial infections.
66PNEMONIA is an inflammation of the lungs, which usually occurs because of infection (bacteria or virus).Pneumonia causes fever, inflammation of lung tissue, and makes breathing difficult because the lungs have to work harder to transfer oxygen into the bloodstream and remove carbon dioxide from the blood.
67You can prevent many chronic lung and respiratory illnesses by avoiding smoking, staying away from pollutants and irritants, washing your hands often to avoid infection, and getting regular medical checkups.
68SLEEP APNEA: Although the automatic breathing regulation system allows you to breathe while you sleep, it sometimes malfunctions.Apnea involves stoppage of breathing for as long as 10 seconds, in some individuals as often as 300 times per night.This failure to respond to elevated blood levels of carbon dioxide may result from viral infections of the brain, tumors, or it may develop spontaneously.A malfunction of the breathing centers in newborns may result in SIDS (sudden infant death syndrome).
69ALTITUDE SICKNESS: As altitude increases, atmospheric pressure decreases. Above 10,000 feet decreased oxygen pressures causes loading of oxygen into hemoglobin to drop off, leading to lowered oxygen levels in the blood.The result can be mountain sickness (nausea and loss of appetite).Mountain sickness does not result from oxygen starvation but rather from the loss of carbon dioxide due to increased breathing in order to obtain more oxygen.