2Functions of the Respiratory System Gas exchangerAir goes to bloodBlood goes to cellsAir distributorOther functionsHumidificationFilteringPhonationWarmingControl of pHOlfaction
3Respiratory SystemPrimary function – Gas exchange: to obtain oxygen and remove carbon dioxide.Cells require oxygen to break down nutrients to release energy and produce ATP = Cellular RespirationCells must excrete carbon dioxide that results from cellular respiration.
4Cellular Respiration - Review C6H12O6 (aq) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l)Without O2, a cell can only undergo fermentation, resulting in a net gain of only 2 ATP for the cell.Why would this be a problem?The result of cellular respiration is carbon dioxide and water. This carbon dioxide enters the blood stream and there it has various functions, including:Regulation of blood pHHaldane EffectBohr EffectAutoregulation of blood supply to tissues
5Cellular RespirationTherefore it is incredibly important that cellular respiration takes place, in a timely manner, throughout the body.When O2 levels are limited, cellular respiration activity slows down and the body reverts to fermentation.What are the results of fermentation?The respiratory system allows for gas exchange between the air and blood in the body to occur, resulting in an intake of oxygen from the atmosphere.
6Introduction to Respiration Respiration – gas exchange between atmosphere and cells.Ventilation – movement of air into and out of lungs.Gas exchange between blood and air in lungs = external respiration.Gas transport in blood between lungs and body cells.Gas exchange between blood and cells = internal respiration.Cellular respiration – process of oxygen utilization and carbon dioxide production at the cellular level.
9The Nose Protrudes from face Openings called nares Ala are cartilage rings or flares at naresFloor made of palatine and maxillaRoof formed by ethmoidSeptum made of cartilage and bone (perpendicular plate of ethmoid and vomer)Lined with mucosaMeatuses formed cavities
10Functions of the NosePassageway – filters, warms, moistens and chemically examines airSmellPhonationParanasal sinuses – air filled spaces that reduce weight of skull and affect quality of voice.
11The NoseNostrils (nares) – are where air enters and leaves nasal cavity.Nasal cavity – hollow space behind noseNasal conchae – bones that divide nasal passageway.These support the nasal cavity and increase surface area.Why is this important?Help in nasal congestion in response to climatic changes and needs of the body.Mucous membrane – epithelium rich in mucous-secreting goblet cells that trap dust and other particles.How would this aid the respiratory system?
12Pharynx (throat) Made of muscle and mucous lining into 3 divisions Nasopharynx – posterior nares to soft palateOropharynx – soft palate to hyoid bone; adenoid tonsilsLaryngopharynx – hyoid bone to esophagus; palatine and lingual tonsils
13The Larynx Enlargement in airway. Houses vocal cords. Upper end of trachea3-6th cervical vertebraeMade of 9 pieces of cartilage in shape of box.Thyroid muscle – called “Adam’s apple”Glottis – opening between vocal cords. Triangular slit. Present during normal breathing. Muscles close glottis when eating or drinking.Why would this be important?Prevent food and liquid from entering trachea.
14The Larynx Epiglottis – lid. Muscle that allows air into larynx. Closes during eating. Why?Arytenoids – hold vocal cordsVocal cords – fibroelastic bands stretched across hollow interiorMales is larger with less fatFunction to produce voice (pitch determined by length and tension in cords)Changing the shape of the pharynx and oral cavity and using the tongue and lips transform sounds waves to words.
15The Trachea“Windpipe” – flexible tube lined with ciliated mucous membrane tissue.Made of smooth muscleContains “C” shaped rings of cartilage4.5 inches longProvides passageway to and from lungsSplits into left and right bronchi.
16Bronchi Made similar to trachea but complete rings Branched into primary, secondary bronchi, bronchioles, alveolar ducts, alveoliProvide passageways and alveoli provide gas exchange surface
17Bronchial treeBranched airways leading from the trachea to the air sacs in the lungs.Left and right bronchi, divide into primary, secondary…Bronchioles – terminal bronchioles, smaller tubes. Lack cartilage.Alveoli – air sacs in lungs connected to the capillary network. Provide large surface area.Why is the large surface area important for alveoli?O2 diffuses through cell walls into bloodCo2 diffuses through blood into cell walls.
18AlveoliAlveolar ducts are very thin ducts that connect the terminal bronchioles to the alveolar sacs.Alveoli lie within the capillary network.Two adult lungs have about 300 million alveoli, providing a surface area nearly half the size of a tennis court.
19Lungs3 lobes in Rt. Lung and 2 in the left. Therefore R lung larger than the left.Root of lung consists of primary bronchus and pulmonary arteries and veinsFunction is to provide rapid exchange of gases.Lobes connected to lymphatic system, blood vessels, air passages, nerves, and connective tissue.
20Respiratory Mucosa Lining of entire respiratory system Makes mucous (sputum)Mucous will help clean and filterMake about 125 mL dailyMoves about 1 to 2 cm per minute from lower respiratory tract to oropharynxSwallow or spit out
21Quiz Time!Very short quiz over anatomy and some functions of the respiratory system.
22Breathing Mechanisms Inspiration – inhalation Atmospheric pressure, due to weight of air, is the force that moves air into lungs.At sea level, the atmospheric pressure is sufficient to support a column of mercury about 760 mm high in a tube. Therefore, normal air pressure = 760 mmHg.Normal, resting inspiration – if pressure inside lungs and alveoli decreases, atmospheric pressure will push outside air in.
23Normal, quiet Inspiration Diaphragm contraction (result of impulse from phrenic nerves) diaphragm moving down.Increase in vertical diameter of thoraxIncrease in transverse diameter of thoraxAlveoli air pressure decreases about 2-3 mmHg less than atmospheric pressure.Expansion of lungs – cohesion of visceral and parietal pleurasAir enters lungs = inspiration.
24Normal, quiet Expiration Expiration – exhalationForce comes from elastic recoil of tissues and surface tension (attraction of H2O molecules that make it difficult for alveoli to inflate)Passive processRelaxation of inspiratory musclesDecrease in size of thorax – elastic recoil of lung tissueIncrease in intrathoracic pressureDecrease in size of lungsIncrease in alveolar pressure from about -3mm of Hg to +3 or +4 mm Hg (Pressure and volume in inverse relationship)Air moves out of lungs – expiration
25Respiratory VolumesRespiratory Cycle – 1 inspiration and following expiration.Tidal Volume – volume that enters during 1 resp. cycleResting Tidal volume – about 500 mL of air.Inspiratory reserve volume (IRV) – During forced inspiration, air in addition to resting tidal volume can enter lungs. This maxes out at about 3,000 mL of air.Expiratory reserve volume (ERV) – lungs can forcefully expel about 1,100 mL more than resting tidal volume.Residual volume – amount always in lungs = 1,200 mL.
26Respiratory VolumesBecause of the residual volume, new air inhaled mixes with old air in the lungs.This is very important as it prevents the concentration of O2 and CO2 in the lungs from fluctuating much during respiration.Why would this be important?CH3CH2OH(g) + O2(g) -> HC2H3O2(g) + H2O(l)Ethyl alcohol and oxygen to acetic acid and water.The breathalyzer. No way around it!
27Respiratory Capacities When two or more volumes are combined.Vital Capacity – tidal volume + ERV + IRV = 4,600 mL. Maximum air during deepest breath possible.Inspiratory Capacity – Tidal volume + IRV = 3,500 mL. Maximum amount a person can inhale after resting expiration.Functional residual capacity – ERV + Residual volume = 2,300 mL. Volume of air in lungs after resting exp.Total lung capacity – vital capacity + residual volume = 5,800 mL. Varies with age, sex and body size.
28The didgeridooWind instrument developed by Aborigines in Australia over 1,500 years ago.Often considered world’s oldest wind instrument.Termite-bored branches are often used to make these instruments.Vibrations produced by the player’s lips and the strength of the vocal tract influence the timbre of the sound.The technique of circular breathing can help.
29Gas ExchangeRespiratory membrane – walls of alveoli exchange gas between blood and air.Gases diffuse from regions of high pressure to regions of low pressure.Air = 78% N, 21% O, 0.04% CO2Partial pressure – amount of pressure each gas contributes to its concentration.O2 = 160 mmHG (21% of 760 mmHg)Gas diffuses into liquid - O2 into blood.Another example: CO2 into coca cola.
30Gas Exchange Follow partial pressure gradients. Each gas diffuses between blood and its surroundings from areas of higher partial pressure to areas of lower partial pressure until the partial pressures in the two regions reach equilibrium.PO2is alveoli is 105 mm of Hg while in the blood it is only 40 mmHg. Thus O2 diffuses from the alveolar air into the blood.PCO2 is 45 mmHg in blood but only 40 mmHg in alveolar air. Therefore CO2 diffuses from the blood into the alveoli.
32Oxygen Transport98% of O2 binds with iron group of hemoglobin. 2% dissolves in plasma.In lungs, combines with hemoglobin oxyhemoglobin.This is an unstable bond and as PO2 decreases, oxygen releases and diffuses into cell to be used in cellular respiration.More O2 is released from oxyhemoglobin when [CO2] is high, when blood pH is low, and when blood temperature is high.When might these conditions occur?Exercise, when more O2 is released to the muscles.
33Carbon Dioxide Transport Tissues have relatively high PCO2 to blood, so CO2 rapidly diffuses into blood.Blood transports CO2 to lungs as CO2 in plasma, bonded to hemoglobin, or as bicarbonate ion (HCO3-)CO2 bonds with the amino group of hemoglobin forming carbaminohemoglobin, which decomposes in areas of low PCO2 releasing carbon dioxide.Do you think it’s possible for both O2 and CO2 to be bound to hemoglobin at the same time?Yes! CO2 binds to the amino group while O2 binds to the iron group of hemoglobin. Some exceptions…
34Bohr ShiftAt lower pH (more acidic environment), hemoglobin will bind to oxygen with less affinity = Bohr ShiftThat is, oxygen is more likely to be released from oxyhemoglobin in a more acidic environment.In RBCs carbonic acid (H2CO3) dissociates into protons (H+) and bicarbonate ions (HCO3-).Since CO2 is in direct equilibrium with the concentration of protons in the blood, increasing CO2 levels leads to a decreases in pH Bohr Shift.
35Haldane EffectRelated to the Bohr Shift is the Haldane Effect, which is the phenomenon in which oxygenated blood has a reduced capacity for hemoglobin to carry carbon dioxide and vice versa.
36Quiz Time!A short quiz over physiology and gas exchange in the respiratory system