1. The Respiratory System
Chapter 23
The Respiratory System

2. Functions of Respiratory System
O2 and CO2 exchange between blood and air
Speech and other vocalizations
Smell
pH – regulates CO2
blood pressure –vasoconstrictor (increases blood flow rate), angiotensin II
pressure gradients -flow of lymph and venous blood (action of the diaphragm = respiratory pump).
Expulsion: expel abdominal contents during urination, defecation, and childbirth
Valsalva maneuver - done by closing one's mouth, pinching the nose shut while pressing out as if blowing up a balloon; equalizes pressure between ears and sinuses; test cardiac function
22-2

3. Respiration
Respiration exchange of gases between the atmosphere, blood, and cells.
3 step process
VENTILATION (bringing air into the body): inhalation (inflow) and exhalation (outflow) between atmosphere and alveoli of the lungs.
EXTERNAL (PULMONARY) RESPIRATION: exchange of gases between alveoli of lungs and blood in pulmonary capillaries across the respiratory membrane.
INTERNAL (TISSUE) RESPIRATION: exchange of gases between blood in systemic capillaries and tissue cells. Blood loses O2 and gains CO2.

4. Respiratory system is made up of nose, pharynx, larynx, trachea, bronchi & lungs
Structural divisions
Upper respiratory tract
above the larynx
Lower respiratory tract
below the larynx
Functional divisions
Conducting portion: cavities and tubes = passageways for air
Nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles.
Respiratory portion: gas exchange:
Respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
System Anatomy

5. Respiratory System – Illnesses
If microbes overwhelm respiratory system  disease.
Strep throat: Pharyngeal infection by Streptococcus bacteria  inflammation and fever  treated by antibiotics.
Coryza: Common cold by a variety of viruses  coughing, sneezing and excessive mucus secretion  no fever and antibiotics are not effective.
Influenza/Flu: Viral infection  chills, body ache, cold symptoms with fever.- Treated with Flu shots and antiviral drugs.
Whooping cough: Pertussis bacterial infection  cilia are destroyed  severe coughing to move the mucus. Part of DPT/Tdap vaccine.
Cystic fibrosis: Genetic disorder of certain exocrine glands  excessive secretion  thick mucus build-up  disabled mucus escalator  severe coughing and respiratory infections.

6. Nose Functions of the nose:
Opens to the outside by two external nares or nostrils
Made up of skin and cartilage, lined with mucous membrane.
Epithelial mucus membranes prevent drying of respiratory tract inhibiting infection
The Lamina Propria
Underlying CT areolar tissue supports respiratory epithelium
Functions of the nose:
Warms, moisturizes, and filters incoming air
Olfactory (smell) stimuli
Paranasal sinuses resonating chambers in bone modifies speech

7. Nasal Internal Structures
Bony framework: frontal, nasal, and maxillary bones
Hard Palate separates nasal cavity from oral cavity. Allows you to breathe while chewing food.
Connected to the to nasopharynx by 2 (posterior nares)/(internal nares)/(choanae)
Conchae: 3 folds of tissue overlay the inferior, middle and inferior bony swellings increases surface area for warming and moisturizing air.
Below each conchae is a narrow passageway (meatus) ensures air contact with mucus membranes
Nasal cavity - 2 chambers separated by nasal septum (vomer and ethmoid bones).
Begins in vestibule lined with stratified squamous epithelium w/ stiff guard hairs block insect / debris

8. How the Nasal Cycle Operates
Throughout the day, your nostrils ALTERNATE air flow in a process of congestion and decongestion called the nasal cycle.
While breathing through your nose, the majority of the air is moving in/out of one nostril; causing less air movement thru the other.
The conchae or turbinates have a thick epithelium with a vascularized lamina propria (erectile tissue) layer. The venous plexuses of the mucosa engorge with blood, restricting airflow and causing air to be directed to the other side of the nose, which acts in concert by shunting blood out of its turbinates.
The opening and closing of the two passages is done by swelling and deflating erectile tissue. This cycle occurs approximately every two and a half hours.

9. Nasal Structures

10. Movement of substances from one nasal cavity to the other
As fluid fills one side of the nasal cavity it moves into the opposite side via the internal nares located in the nasopharynx. The mouth remains open allowing air to continue to move into the lungs while the nasal cavity is not operating to pull air into the lungs.

11. Pharynx-throat
Extends from internal nares to cricoid cartilage of the larynx
Functions
passageway for air, food and drink
resonating chamber for speech production
tonsil (lymphatic tissue) in the walls protects entryway into body
Divided into distinct regions
Nasopharynx
Oropharynx
Laryngopharynx

12. Posterior to the posterior nasal apertures above the soft palate (skeletal muscle and glandular tissue)
Passageway for AIR ONLY
There are five openings in its wall
2 internal nares
2 openings that connect with Eustachian tube - equilibrate pressure between the middle ear and atmosphere
1 that connects to oropharynx.
Contains Adenoids or pharyngeal tonsil.
Lined by pseudostratified ciliated columnar epithelium with goblet cells. Cilia helps in movement of mucous.
90° turn forces air and debris to collide with mucosa near tonsil
Nasopharynx

13. Internal nares

14. Oropharynx Soft palate to epiglottis
Opening in back of throat to epiglottis is the fauces
Palatine tonsils found in side walls, lingual tonsil on back of the tongue
Common passageway for food and air
lined by non keratinized stratified squamous epithelium for contact with abrasive substances
Fauces

15. Laryngopharynx Extends inferiorly from hyoid bone
Common passageway for food/drink and air
Lined with non-keratinized stratified squamous epithelium
Has 2 openings at the inferior end
Opens into esophagus
Opens into larynx

16. pharyngeal tonsil.
lingual tonsil
Palatine tonsils

17. Larynx (Voice Box)
A slit-like opening into the larynx, positioned between the true vocal cords called the glottis connects the pharynx with the trachea. It is as an air passageway
Primary function is to keep food and drink out of the airway
epiglottis – flap of tissue that guards the superior opening of the larynx
stands almost vertical at rest
during swallowing, extrinsic muscles pull larynx upward tongue pushes epiglottis down to meet it closes airway and directs food to the esophagus behind it
Contains the vocal folds used for voice production
Larynx lined mainly with pseudostratified ciliated columnar epithelium, moves the mucus backwards, toward the pharynx
Contains multiple cartilages and the thyrohyoid membrane which connects the hyoid bone and thyroid cartilage

18. Larynx Cartilages
Thyroid cartilage: or “Adam’s apple”. Largest cartilage.
Laryngeal prominence- testosterone stimulates growth
Epiglottic cartilage: leaf shaped cartilage. Stem attached, leaf portion unattached-moves up and down.
Entry of food, dust, smoke or liquids into larynx, cough reflex initiated.
Cricoid cartilage: a complete ring of cartilage at the base connects larynx to trachea
In addition, the larynx consists of three paired cartilages that assist in speech production and the opening and closing of the glottis
arytenoids shaped like pyramids; point of attachment for the vocal cords, allow the opening and closing movement of the vocal cords necessary for respiration and voice
corniculate support arytenoids
cuneiform support the vocal folds and lateral aspects of the epiglottis

19. epiglottis

21. Grey’s Anatomy Textbook
Diagram from
Grey’s Anatomy Textbook

22. Mucus membrane of the larynx has two pairs of folds
Voice Production
Mucus membrane of the larynx has two pairs of folds
Ventricular/vestibular folds (false vocal cords):
Close the glottis if holding breath; when lifting weight; used for screaming, produce deep sonorous tones in Tibetan chant and the death growl vocal style, keeping food and drink out of the airway; if surgically removed can REGENERATE COMPLETELY!!
TRUE Vocal folds: for VOICE PRODUCTION
Sound is produced by the vibrations of true vocal cords

23. Action of Vocal Cords
Walls of trachea very muscular; Intrinsic muscles control the vocal cords via the Vagus nerve. The true cords are white due to scant blood circulation.
pull on the corniculate and arytenoid cartilages- causing the cartilages to pivot
abduct or adduct vocal cords, depending on direction of rotation
air forced between adducted vocal cords vibrates them
producing high pitched sound when cords are taut/tight
produce lower-pitched sound when cords are more slack
The difference in vocal fold size between men and women produces differently pitched voices. Genetics also causes variances amongst the same sex.
Frequency (# of vibrations ) of the sound generated by the larynx affects the pitch of a person's voice (deep /high ). In adult male, frequency averages about 125 Hz, adult females 210 Hz, children frequency is over 300 Hz. Frequency is influenced by the size, length, tension, and thickness of the vocal folds.
loudness – determined by the force of air passing between the vocal cords

24. Vocal Cords Animations:
Vocal cords produce crude unintelligible sounds that are formed into intelligible words by actions of pharynx, oral cavity, tongue, and lips
Laryngitis: is an inflammation of larynx which causes vocal cords to swell. Can be caused by respiratory infection or irritants like cigarette smoke.
Animations:
(tutorial)
(cough)
Singing:
Snoring animation (1.45 min)

25. Trachea (Windpipe) Trachea – a 4-6 inch TUBE
Made of fibrous and elastic tissues and smooth muscle lined with pseudostratified ciliated columnar epithelium cells; goblet cells produce mucus to trap inhaled foreign particles.
Circular bands of fibrous CT, annular ligaments, join the tracheal rings together
Connects pharynx and larynx to lungs; allows for passage of air.
Trachea (Windpipe)
Supported by incomplete C shaped cartilage rings that reinforce trachea to prevent collapsing inward during inhalation.
“C” shape allows esophagus to expand during swallowing
Posterior side, smooth muscle band, trachealis, stabilizes the open ends of the cartilage rings.
Epithelium cilia sweep debris from lungs and back to the throat to be swallowed via mucociliary escalator; smoking destroys the cilia

26. annular ligaments

28. Bronchial Tree CONDUCTING ZONE:
Primary Bronchi – rings of hyaline cartilage
 CARINA - where primary bronchi branch - most sensitive area of larynx/trachea; triggers cough reflex
Secondary bronchi (lobar): 1 to each lobe of the lung; 3 on right, 2 on left. Overlapping cartilage plates
Tertiary (segmental) bronchi: respiratory epithelium lining lumen surrounded by a layer of smooth muscle surrounded by irregular plates of hyaline cartilage that help to maintain the patency (openness) of the airway. ONE tertiary bronchus forms about 6,500 TERMINAL bronchioles.
Each lung is separated by connective tissue into independent compartmental units called bronchopulmonary segments. Segments are supplied by a tertiary bronchi and an artery.
10 SEGMENTS IN THE RIGHT LUNG, 8 IN THE LEFT.
One segment can be surgically removed without affecting the function of the other segments. Each segment is subdivided into approximately 130,000 lobules which receive air via the bronchioles.

29. Bronchial Tree

30. Bronchopulmonary Segments
Each segment is subdivided into approximately 130,000 lobules

31. Bronchioles RESPIRATORY ZONE CONDUCTING ZONE
Tertiary (Segmental) bronchi  primary bronchioles  terminal bronchioles 
RESPIRATORY ZONE
respiratory bronchioles  2 to 11 alveolar ducts.
Alveolar ducts have 5 or 6 alveolar sacs. The alveolus is basic anatomical unit of gas exchange in the lung.
Terminal bronchioles are the smallest bronchioles; contain no cartilage, no mucus or goblet cells; cilia eliminate any mucus drainage
RESPIRATORY ZONE area of gas exchange. Extends from respiratory bronchioles to air chambers (alveolar sacs).

32. Structural Components of Bronchial Tree
Epithelium gradually changes from pseudostratified ciliated columnar to non-ciliated simple cuboidal epithelium.
Cartilage: As bronchial tree descends:
First incomplete cartilage C- rings (trachea & primary bronchi)
These are replaced with plates of hyaline cartilage (secondary & tertiary bronchi)
all supportive cartilage disappears by the bronchiole.
Muscle: Bronchiole walls contain smooth muscle and no cartilage. Allows contraction and relaxation, regulating air flow to the alveoli.
During exercising, sympathetic ANS causes relaxation of smooth muscles thus dilating the air passageways, increasing airflow improving lung ventilation.
Parasympathetic activity of ANS causes constriction of passageways;
Allergic reactions cause the release of histamine dilating blood vessels increasing fluid accumulation which can constrict airways. These actions can account for an asthma attack.

33. Muscle Layer

34. Alveoli
Air filled sacs- kept dry to allow quicker diffusion of gases. Exchange occurs much slower thru FLUID.
Alveoli contain some collagen and elastic fibers which allow the alveoli to stretch
Epithelial surface cells:
Type I alveolar cells: simple squamous epithelial, form continuous layer, main site of gas exchange
Type II alveolar (Great) cells:
-- Secrete surfactant (mixture of phospholipids and protein); lowers surface tension; reduces tendency of alveoli to collapse; absence of surfactant would be similar to the inside of a wet plastic bag.
Respiratory Distress Syndrome: deficiency of surfactant in premature infants
700 million alveoli
40x the surface area of the skin.
Alveolar macrophages (dust cells): remove dust particles; found in the lumen; 100 million perish each day going up the “escalator”

35. Exchange of O2 and CO2 between lungs and blood occurs by diffusion across the respiratory membrane made of alveolar and capillary walls.
0.5 μm (ex: RBC 7.5μm) allows rapid gas diffusion
More extensive lymphatic drainage than any other organ. Important to prevent fluid buildup. Fluid slows gas exchange!
Respiratory Membrane
Alveolar I cell
Layers of the respiratory membrane
Each alveoli is lined with a THIN layer of tissue fluid essential for the diffusion of gases (a gas must first dissolve in a fluid in order to leave or enter a cell) EXCESS fluid retards gas exchange.
Squamous cells of the alveolar wall
Epithelial and capillary shared basement membrane
Capillary endothelium

36. A gas must first dissolve in a fluid in order to leave or enter a cell
A gas must first dissolve in a fluid in order to leave or enter a cell

37. Lungs
Two lungs - Left and right, cone shaped in thoracic cavity separated by mediastinum.
Enclosed and protected by the pleural membrane.
Parietal pleura: line the inside of the thoracic cavity
Visceral pleura: cover the lungs
Pleural cavity: space between visceral and parietal pleural filled with lubricating, serous pleural fluid
Reduces friction
Creates pressure gradient-lung inflation
Compartmentalizes-prevents spread of infection
The broad inferior portion is the base fits over the diaphragm.
The narrow superior portion of is the apex.
NON RESPIRATORY FUNCTION
Filter out small blood clots formed in veins
Convert angiotensin I to angiotensin II by the action of angiotensin- converting enzyme
The lungs serve as a blood reservoir. Blood volume of the lungs averages 450 ml, about 9% of the total blood volume

38. Lungs
the bronchi, pulmonary vessels, lymphatic vessels and nerves enter and exit at hilum.
right lung has 3 lobes separated by 2 fissures (Oblique & horizontal)
left lung has 2 lobes separated by the Oblique fissure
depression, the cardiac impression (notch) accommodates the heart

39. Respiration REGULATION: Respiratory Center
Located in Medulla oblongata of brain stem: Medullary rhythmicity
Dorsal Respiratory group- DRG -posterior – INSPIRATION
establishes the rhythm of normal quiet inspiratory breathing
neurons in DRG stimulates nerves to innervate the diaphragm and external intercostal muscles; the thorax to expands - air rushes in.
If DRG completely suppressed breathing stops (overdose sleeping pills, alcohol, etc.)
Ventral Respiratory group - VRG- anterior - EXPIRATION
Inspiratory and expiratory area inactive majority of the time; becomes active to controls voluntary forced exhalation such as during exercise
Located in The Pons of the brain stem:
Apneustic Center- provides continuous stimulation to its DRG center; increases the inhalation process. APC DRG
Controls intensity of breathing
Pneumotaxic Centers INHIBIT the apneustic centers; directly inhibits inhalation PC APC
limits action potentials in the phrenic nerve, effectively decreasing the tidal volume (inhaled + exhaled breath); regulating the respiratory rate
Promote passive or active exhalation by regulating the amount of air a person can take into the body in each breath

40. Respiratory Centers

41. Respiratory center is especially sensitive during infancy, and the neurons can be destroyed if the infant is dropped and/or shaken violently. The result can be death due to "SHAKEN BABY SYNDROME"
Ruptured blood vessels precipitate large blood clots which cause swelling within the brain
Inability of vertebrae to resist shaken can result in spinal cord injury
Ultimate outcome: retardation, blindness, paralysis, deafness, death

42. Yawning
A yawn is a reflex of simultaneous inhalation of air and stretching of the eardrums, followed by exhalation of breath.
Yawning is a reflex that tends to disrupt the normal breathing rhythm and is believed to be contagious.
The reason why we yawn is unknown, but some think we yawn as a way to regulate the body’s levels of O2 and CO2. Although there isn’t a concrete explanation as to why we yawn, others think people exhale as a cooling for our brains.
Yawning ventilate “ALL” the alveoli in the lungs.

43. Breathing Patterns
Eupnea [Eu-true, good / pnea - air, lung] = normal pattern of quiet breathing Apnea: [A –without / pnea - air, lung] = breath holding Dyspnea: [Dys- pain, difficulty/ pnea - air, lung] = painful or difficult breathing Tachypnea: [Tachy- fast, irregular / pnea - air, lung] = rapid breathing Costal breathing: combinations of various patterns of external intercostal muscles; during need for increased ventilation; e.g., exercise Diaphragmatic breathing: move air by contracting and relaxing the diaphragm to change the lung volume. “push stomach out”

44. REGULATION of Respiratory Center
Limbic system anticipation of activity and anxiety which in turn can increase rate of respiration.
Chemical regulation:
Chemoreceptors: monitor pH levels: monitor O2/CO2.
high concentrations of CO2 and H+ increase the rate and depth of breathing.
Blood pressure (BP):
Baroreceptors monitor BP
When BP rises, stimulates decrease in respiration rate. If BP drops respiration increases to maintain circulatory efficiency.
After heavy exercise BP rises; respiration rate drops to resume normal BP.
Temperature: increase in temperature, increases rate of respiration. Skeletal muscle produces most of the heat in the body. If temperature rising, muscles more active, in need of increased amounts of oxygen delivered by the respiratory cells.

45. Lung Volumes and Capacities
Spirometer or respirometer: instrument used to measure volume of air exchanged during breathing.
Respiratory rate: is the frequency of breaths per minute.
Average 12 breaths / minute (bm)
Range between per/min
20,000 per day
LUNG CAPACITIES
Tidal volume (TV): is the volume of air that moves in or moves out with each inspiration or expiration. This volume is close to 500ml.

46. Inspiratory reserve volume (IRV): During deep breathing, the excess of air inhaled over the normal amounts is termed inspiratory reserve volume. (3000 ml)
Inspiratory capacity: the SUM of IRV and Tidal Volume
Expiratory reserve volume: is the excess air exhaled out, over the normal amounts during FORCED exhalation. (1100ml)
Residual volume: is the air still left in the lungs after forced exhalation. (1200 ml in males and 1100 ml in females) Lungs never completely empty; cannot exhale residual volume. Volume can be estimated through gas dilution techniques and the use of helium in inspired air (we do not metabolize helium).

47. Vital capacity: is the maximum volume of air that can be inhaled and exhaled during forced breathing. This is approximately 4800 ml in males and 3100 ml in females. IRV+ERV+TV
Total lung capacity: is the sum of vital capacity and the residual volume ( = 6000 ml in males). IRV+ERV+TV+RV
Minimal volume- if the lungs fall below this volume value ( ml) they will collapse; effect of surfactant. Important in biopsy analysis.
Ex: determine if baby is stillborn or died after birth. No air in fetal lungs- will sink in water; if floats, baby inhaled at birth – lungs contained air. Baby not stillborn or dead at birth

48. Pulmonary Ventilation
Breathing - exchange of air between the atmosphere and the lungs
Inspiration (inhalation): air into the lungs
Expiration (exhalation): air exits the lungs.
REVIEW: WHY do we breathe?**
To receive NEW O2 to replenish O2 that has been used by body processes
To remove CO2 , a waste product of metabolism which increases the amount of acidity in the body.
The brain respiratory centers (in particular the DRG) set a breathing pattern rhythm to insure we receive adequate intake of O2 and the removal of CO2
HOW do we breathe?**
Air flow occurs due to pressure differences created by contraction and relaxation of respiratory muscles.
Based on BOYLE’S LAW - pressure exerted by a given mass of an gas is inversely proportional to the volume it occupies
When volume a gas occupies increases; pressure decreases
When volume a gas occupies decreases; pressure increases
Air flows from area of higher pressure to area of lower pressure

49. Respiratory Pump
Those abdominal and thoracic structures that contribute to the expansion and contraction of the lungs. Movement of the chest and abdomen alters central pressures during inspiration and expiration. During inspiration, decreases in intrathoracic pressure draw air into the trachea, bronchi, and lungs and draw blood into the vena cava and right atrium of the heart. During expiration, intrathoracic pressures rise, and air is forced out of the lungs.

51. Molecules are in constant, random motion
Molecules are in constant, random motion. As the molecules move around, the amount that they bang against each other and against any container that they are in is their pressure. Smaller the container; higher the pressure
To decrease pressure within respiratory tract, have to expand the “container”. Anatomical container is the thorax. Expanding the thorax, the air pressure within thoracic cavity will fall, and air will rush into respiratory tract.
Copy/Paste to Google- good information

52. Initiating Lung Expansion
Involves the two pleural layers and the diaphragm
When the ribs swing upward and outward during inspiration, the parietal pleura is attached to the thoracic (rib) cage and pulls it outward as the external intercostal muscles contract.
The visceral pleura is attached to the lung.
The space separating the two pleura (pleural cavity) contains a thin film of fluid which creates a POWERFUL SUCTION action due to a strong surface tension between the visceral and parietal pleura and prevents separation and friction.
As the rib cage expands, it pulls the parietal pleura with it. The suction action in the pleural cavity draws the visceral pleura. The visceral pleura is directly attached to the lung and pulls it outward. Elastic lung fibers unable to overpower the surface tension and lungs expand.
As the lung volume increases, its internal pressure drops, more volume; fewer air molecules collisions; the lung equalizes this pressure drop by drawing more air molecules into the lungs to increase the pressure. “INHALATION”

53. Animation-Good Lung Overview: https://www. youtube. com/watch

54. Inspiration Muscles
Animation:
Diaphragm - prime mover of respiration attached to inferior surface of the lungs
As the diaphragm contracts it flattens and pulls the bottom of the lungs downward expanding them and enlarging the volume of the thoracic cavity..
Controlled by the DRG respiratory center via the phrenic nerve.
External intercostal muscles between ribs contract raise the ribs and elevate the sternum stiffen the thoracic cage during respiration prevents it from caving inward when diaphragm descends contribute to enlargement and contraction of thoracic cage

55. Pressure Gradients- LUNGS****
Atmospheric pressure (the weight of the air above us)
drives respiration 760 mm Hg at sea level - 1 atmosphere (atm) lower at higher elevations
INTRAPULMONIC/alveolar pressure (pressure inside the lungs) equal to atmospheric pressure (760mm Hg at sea level)
“THE BODY NEEDS O2” . To insure an adequate O2 supply, the brain innervates the muscles to enlarge pulmonary space changing the pressure gradients forcing air (O2) to move into the lungs.
HOW? If the lung volume increases, intrapulmonary pressure falls. SAME AMOUNT OF AIR IN A LARGER VOLUME EXERTS LESS PRESSURE. if the pressure falls below atmospheric pressure (usually 759 mm Hg) the air moves passively into the lungs (inhalation) because the lungs will always attempt to equalize internal pressures with atmospheric pressures. Air is not forced into the lungs but moves based on pressure gradients!!
if the lung volume decreases, intrapulmonary pressure rises (usually 761 mm Hg). MORE AIR IN SMALLER VOLUME EXERTS MORE PRESSURE.
if the pressure rises above atmospheric pressure the air moves passively out of the lungs (exhalation); exhale CO2

56. Pressure Gradients- LUNGS
INTRAPLEURAL pressure
Pressure (756 mmHg) in space BETWEEN parietal and visceral pleura (pleural cavity) is always less (negative pressure) than atmospheric pressure. This produces a SUCTION ACTION to prevent the intrapulmonary and intrapleural pressures from equalizing.
Lack of a pressure gradient between the two layers would result in the collapse of the lungs!!
Good Animation: e9e/pages/49/ html

57. Expiration (Passive process)
Exhalation (movement of air out of lungs) occurs when alveolar pressure (inside lungs) is higher than atmospheric pressure.
Intrapulmonary pressure [inside lungs] increases (761mm Hg)
To reestablish equilibrium with atmospheric pressure (760 mmHg) the diaphragm and external intercostal muscles relax allowing diaphragm to bulge upward again and the elastic recoil of the thoracic cage to compresses the lungs. This enables the body to excrete waste substances.
Volume of thoracic cavity decreases
Air moves from the lungs reducing intrapulmonary pressure
Labored/Forced Breathing- Labored, deep, rapid or forced breathing occurs during exercising, singing, coughing, sneezing, playing an wind instrument, blowing a balloon enlists contraction of several other muscles
Can raise intrapulmonary pressure (in lungs) as high as mmHg - massive amounts of air then move out of the lungs

58. Factors Affecting Pulmonary Ventilation
Surface Tension - A thin layer of fluid lies next to the air in the alveoli. The attraction of H2O molecules for one another creates a force called surface tension. These H2O molecules come closer together during exhalation and this increases surface tension. Surface tension could cause alveoli to collapse making it more difficult to 're-expand' the lungs during inhalation.
Surfactant, detergent like substance reduces surface tension of alveolar cells and limits alveolus collapse.
A deficiency of surfactant in premature infants greatly increases surface tension and hence alveoli collapse at the end of exhalation (respiratory distress syndrome).
Compliance An indicator of EXPANDABILITY
Higher compliance value – less force to expand the lungs and thoracic wall; surfactant increases compliances
Lower compliance requires greater force
Compliance is decreased by:
Scarred lung tissue: tuberculosis and emphysema
Lung tissue filled with FLUID: pulmonary edema, pneumonia

59. Factors Affecting Pulmonary Ventilation:
Airway Resistance produced by the walls of the airways
Larger the diameter of the passageway, lower the resistance
If smooth muscle contracts due to irritants or chemicals, the airways decrease in diameter, increasing resistance
Obstruction or collapse of airways, increases resistance.
Causes: Asthma, emphysema, chronic bronchitis, and chronic obstructive pulmonary disease (COPD)

60. Respiratory Disorders
Chronic obstructive pulmonary disease (COPD): chronic and recurring obstruction of air passageways, increasing air resistance.
Asthma: partial or complete closure of airways, inflammation and excess production of mucous. Constriction of bronchial muscles
Bronchitis: inflammation of the bronchi caused by irritants. Causes constriction and breathing difficulty. Generally acute
Emphysema: destruction of the alveolar walls- elastin in the alveoli walls broken down- less membrane available for gas exchange
Cystic fibrosis: inherited disorder affecting secretory cells lining the lungs; results in the buildup of mucous in the passageways.
Tuberculosis: inflammation of pleurae and lungs produced by the bacterial organism Mycobacterium tuberculosis.
Pulmonary edema: abnormal accumulation of fluid in the interstitial spaces and alveoli of the lungs.
Lung cancer: ACCOUNTS FOR MORE DEATHS THAN ANY OTHER FORM OF CANCER. Each year, more people die of lung cancer than of breast, colon, and prostate cancers COMBINED.
Lung cancer is more common in older adults; rare under age 45
most prominent cause is smoking (15 carcinogens)
90% originate in primary bronchi; cancer of the respiratory epithelium

61. Nose  Pharynx  Larynx  Trachea  Bronchus  Lungs
Pneumothorax: when air fills pleural cavity  difficulty expanding.
Hemothorax: when blood fills pleural cavity.
Pleurisy: inflammation of pleural membranes.
Respiratory Distress Syndrome (RDS): Surfactant production begins in 7 month fetus  if insufficient  collapsed lungs (atelectasis). Cortisol shot to the mother during pre-mature delivery or surfactant spray to newborn lungs.
Pulmonary embolism: thrombus in legs  embolus to lungs  reduced blood flow to lungs and difficulty breathing  heparin/TPA to dissolve the clot.

62. Effect of Smoking Tumors (a) Healthy lung, mediastinal surface
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Tumors
(a) Healthy lung, mediastinal surface
(b) Smoker's lung with carcinoma
a: © The McGraw-Hill Companies/Dennis Strete, photographer; b: Biophoto Associates/Photo Researchers, Inc.

63. Respiratory Distress Treatment
The blockage of the trachea can be lethal if not fixed, and in severe cases where coughing is not enough to remove a blockage.
The Heimlich maneuver must be performed in order to remove the debris.
In very extreme cases, a tracheotomy may be performed, where the trachea is opened surgically to allow another way for air to reach the lungs.
Intubation: inserting a tube through mouth or nose, directly into the lungs  allow breathing.
Nebulization: administration of medication through fine mist spray of drugs  dilation of bronchioles  breathing resumes.

64. Alveolar Ventilation
Only air that enters the alveoli is available for gas exchange
not all inhaled air gets there - most of the air remains in nose, pharynx, trachea, bronchi, etc.
Anatomic dead space
conducting division of airway / no gas exchange
a person inhales 500 mL of air, and 150 mL (30%) stays in anatomical dead space, then 350 mL (70%) reaches alveoli
Physiologic (total) dead space
sum of anatomic dead space and any pathological alveolar dead space
in pulmonary diseases, some alveoli may be unable to exchange gases due to lack of blood flow or the respiratory membrane has been thickened by edema or fibrosis
22-64

65. Gas Exchange
Exchange of gases in external and internal respiration is based on passive diffusion. More surface area available-greater diffusion
Two main laws (Dalton’s / Henry’s) govern passive movement
Dalton’s law:
Air is a mixture of gases; each gas exerts its own pressure
Termed partial pressure (Px). Partial pressure related to the concentration of that particular gas in the total mixture.
Total pressure is always the sum of individual partial pressure. Atmospheric air: mixture of 78.6% N2, 20.9% O2, variable amount of water vapor (H2O), 0.4% CO2, and .06% other gases.
Atmospheric pressure
(760 mm Hg) = PO2 + PCO2 + PN2 + PH2O + Pother gases
To determine partial pressures. – convert % to decimal x 1 atm
O2 = X 760 mmHg = 152 mmHg
CO2 = X 760 = 0.3 mmHg

66. Henry’s Law
When temperature remains constant, the QUANTITY of a gas that will DISSOLVE in a liquid is proportional to the partial pressure (concentration) of the gas and ability of that gas to dissolve (SOLUBILITY) in water. When a gas is in contact with the surface of a liquid, the amount of the gas which will move into solution is proportional to the partial pressure of that gas.
More O2 in atmosphere, more O2 will dissolve in fluids
Less O2 in the atmosphere, lesser O2 will dissolved in fluids
Solubility of the gas - physical or chemical attraction for H20
OXYGEN moves from alveoli into RBC. Because O2 is distributed BETWEEN water molecules without reacting with it; little of the O2 that enters the RBC moves into the plasma.
CARBON DIOXIDE moves from tissues into RBC. More CO2 than O2 dissolves in blood plasma due to the solubility of CO2 which is 24x greater than that of O2.
1) Some CO2 goes directly into plasma. 2) 93% of CO2 moves into the RBC where it binds to water producing H2CO3 - carbonic acid. 3) Most of this carbonic acid is converted to bicarbonate and 4) moves into the plasma.

67. A gas must first dissolve in a fluid in order to leave or enter a cell
A gas must first dissolve in a fluid in order to leave or enter a cell

68. Oxygen
Carbon Dioxide

69. Most of the oxygen that enters the RBC stays within the RBC.
CO2 binds with H2O and 70% of it is released into the plasma as bicarbonate.

70. Respiration External Respiration
Exchange between the LUNGS and the BLOOD (RBCs)
Internal Respiration
Exchange of gases between BLOOD & TISSUES

71. External Respiration Exchange between the LUNGS and the BLOOD (RBCs)
During this exchange, each gas diffuses from where its partial pressure (Dalton’s Law) is high to where its partial pressure is low.
In lung of a resting person:
Oxygen moves from alveoli (PO2 =105 mmHg) into capillaries (PO2 =40 mmHg) [high to low]
Carbon dioxide (PC02 alveoli = 40 mmHg; PCO2 blood = 46 mmHG) moves in the opposite direction to the lungs. HCO3- (carbonic acid) moves from plasma to RBC where it is combines with H2O to form H2CO3. It then converts to H2O and CO2
During this exchange blood vessels pick up oxygen and deoxygenated blood becomes oxygenated.

73. External Respiration

74. Internal Respiration Exchange of gases between BLOOD & TISSUES
Oxygen moves from blood capillaries (PO2 =100 mmHg) into tissues (PO2 =40 mmHg)
Carbon dioxide moves from tissues (PCO2 =45 mmHg) into blood capillaries (PCO2 =40 mmHg). Most of CO2 is transported in the blood as HCO3-
Conversion of oxygenated blood into deoxygenated
At rest approximately 25% of available O2 enters cells, whereas during exercising more O2 is absorbed.

76. Internal Respiration
Animation:

77. Factors Effecting Rate of Diffusion of Gases
The greater the difference between partial pressures of alveoli and blood, the greater the rate of diffusion (Ex: Blood PO2=30; alveoli PO2 = 90)
At high altitude, oxygen molecules are more dispersed, each breath delivers less oxygen to the body (lower alveoli PO2).
Low diffusion rate can result in high altitude sickness
Body compensates by producing 1) more red blood cells, 2) more capillaries, and 3) increasing heart rate and respiration to bring additional oxygen into the lungs.
Surface area available for gas exchange: alveolar damage would decrease rate of exchange
Respiratory membrane thickness: Thicker membranes slow down diffusion. Fluid build up due to edema can also slow down diffusion.
Solubility and molecular weight of the gases: overall diffusion of carbon dioxide is faster that oxygen. Net movement of CO2 diffusion is 20x greater than inward diffusion movement of O2

78. TRANSPORT OF OXYGEN IN THE BLOOD
Oxyhemoglobin transports 98.5% of O2 on hemoglobin in RBCs; 1.5% of O2 dissolved in blood plasma.
Hemoglobin (Hb) made of protein globin and pigment, heme. After 1st heme group binds to an O2 molecules, Hb changes shape to facilitate its attraction (affinity) and uptake of subsequent O2 molecules.
Heme iron (Fe), binding sights can carry 4 O2 molecules; when all four heme groups are bound to O2 the Hb molecule is said to be saturated.
Several factors influence Hb saturation and release of O2.
increased acidity (pH) BPG, temperature, Pco2
NOTE: 1 oxygen bound to Hb it is 25% saturated; 2 O2 bound is 50% etc.

79. Factors affecting BINDING of O2 to hemoglobin
Partial pressure of oxygen: most important factor that determines how much O2 combines with hemoglobin
The greater the PO2 in the blood, (more available for uptake) the more O2 will bind with hemoglobin.
Relationship between the % saturation of hemoglobin and PO2 is described by the oxygen-hemoglobin dissociation curve.
Normal blood O2 levels is %. If the level is below 90%, is considered low resulting in hypoxemia
In the blood

80. Factors affecting the binding and “RELEASE” of O2 (Hb)
2. Acidity (pH): As pH decreases, the affinity of hemoglobin for O2 decreases. Causes a shift in curve to the right- enhances O2 RELEASE from Hb to the cells (muscles produce lactic acid indication of higher activity need more oxygen).
3. Partial pressure of CO2 - as the partial pressure of CO2 rises, Hb releases O2. In tissues higher levels of CO2 / O2 offloaded
Effects of acidity and CO2 concentration essentially the same.
> CO2 converted to carbonic acid > conversion to bicarbonate releases H+ ions increasing acidity which weakens Hb-O2 bond; known as the Bohr Effect = increase in CO2 or decrease in pH increases acidity and causes Hb to release O2 - accelerating O2 unloading
More O2 released
in the blood

82. Factors affecting the binding and RELEASE of O2 to hemoglobin (Hb)
4. Temperature:
temperature increases, hemoglobin releases O2
Metabolic cells release large amounts of heat and acids (lactic acid); promotes release of O2 from Hb needed to provide energy the for various metabolic activities of the cell.
During hypothermia (lowered body temperature), body needs less O2 and O2 remains bound to Hb
43° C = 109.4°F 20° C= 68°F
38° C= 100.4°F 10°C =50° F
37°C= 98.6°F

83. Factors affecting the binding of O2 to hemoglobin
BPG: is a compound found in RBCs during glycolysis, the breakdown of glucose.
When BPG binds to Hb, Hb’s bond with O2 WEAKENS promoting greater O2 RELEASE to tissues
Thyroxine, hGH, testosterone, and living at high altitude increase BPG formation
Animation: /watch?v=NdNTWt0DIPw
Fetal hemoglobin: Has greater capacity to bind and carry O2 than adult Hb. Fetal Hb must be able to bind O2 with greater affinity to compensate for the lower oxygen tension of the maternal blood. This higher affinity enables fetus to remove O2 from the mother’s blood.
Does not react to BPG

84. Oxygen Reading
A pulse oximeter is a medical device that indirectly monitors the O2 saturation of a patient's blood.
A pulse oximeter utilizes an electronic processor and a pair of small light-emitting diodes (LEDs) facing a photodiode through a translucent part of the patient's body (fingertip or an earlobe).
One LED is red, with wavelength of 660 nm, and the other is infrared with a wavelength of 940 nm. Absorption of light at these wavelengths differs significantly between blood loaded with O2 and blood lacking O2.
Oxygenated Hb ABSORBS more infrared light and allows more red light to pass through. While deoxygenated Hb ABSORBS more red light and allows more infrared light to pass through.
The amount of light that is transmitted and not absorbed is measured. The ratio of the red light to the infrared light measurement represents ratio of oxygenated hemoglobin to deoxygenated hemoglobin.
Pulse oximetry measures solely hemoglobin saturation, not ventilation and is not a complete measure of respiratory sufficiency

85. pulse oximeter

86. Carbon Monoxide Poisoning
Carbon monoxide is colorless, odorless gas in cigarette smoke, engine exhaust, fumes from furnaces and space heaters and toxic to all aerobic forms of life and competes for O2 binding sites on the Hb molecule resulting in less hemoglobin available to bind and deliver oxygen, leading to gradual suffocation
In the presence of CO, the affinity of Hb for O2 is enhanced = stronger bond harder to release. This shifts the dissociation curve to the left, which further prevents the unloading and delivery of O2 to tissues.
Carboxyhemoglobin (complex of CO and Hb bound together)
binds 210x as tightly as O2 for considerable time
non-smokers < than 1.5% of Hb bound to CO / smokers 10%
atmospheric concentrations of 0.1% (enclosed space such as garage/tent) enough CO to bind 50% of Hb; 0.16% (1600 ppm) dead within 2 hours; 0.2% CO is quickly lethal
O2 = 209,460 ppm; CO2= 392 ppm; CO = 9-35 ppm; (0.0035%)
The initial symptoms of acute carbon monoxide poisoning include headache, nausea, malaise, and fatigue

88. Carbon Monoxide Poisoning
Treatment: Hyperbaric O2 therapy. COHb has a half-life in the blood of 4 to 6 hours. This time can be reduced to 70 to 35 minutes with administration of pure oxygen in a hyperbaric chamber.
Patient placed into a full-body chamber that FORCES O2 UNDER PRESSURE AT HIGHER THAN 1 ATM into patient’s blood to remove the CO. The air pressure inside a hyperbaric oxygen chamber is approximately 2½ times greater than normal pressure in the atmosphere. Lungs draw in more O2 to equalize intrapulmonary pressure with increased atmospheric pressure.
When a patient receives 100% O2 under pressure, Hb becomes saturated. Increased oxygen intake allows the plasma to absorb, transport, and release more O2 to hypoxic tissues instead of having to utilize the crippled Hb bound to CO.
Same method is used for divers’ decompression.

89. Forms of Carbon Dioxide Transport
7% dissolved/remains in plasma / 93% diffuses into RBC
23 % combined with the globin part of Hb molecule forming carbaminohemoglobin
70% transported as bicarbonate ion
90% of CO2 combines w/ water to form carbonic acid, H2CO3
H2CO3 dissociates into H+ and bicarbonate ion (H+ + HCO3-)
HCO3- moves out of RBC in exchange for Cl- = chloride shift.
Aerobic respiration produces a molecule of CO2 for every molecule of O2 it consumes
HALDANE EFFECT
The less oxyhemoglobin (binding of Hb–O2), the higher the CO2 carrying capacity of Hb in the blood.
Hemoglobin with no oxygen bound to it (dexoyhemoglobin) binds to and transports more CO2

91. Respiratory acidosis and Respiratory alkalosis
Pulmonary ventilation maintains pH
CO2 diffuses easily; reacts with water to produces carbonic acid
It then dissociates into bicarbonate and hydrogen ions
Increased levels of carbon dioxide induce an acidic condition
Respiratory acidosis and Respiratory alkalosis – pH imbalances resulting from a mismatch between the rate of pulmonary ventilation and the rate of CO2 production
Acidosis decreased ventilation (hypoventilation) causes increased blood carbon dioxide concentration and decreased pH; due to neuromuscular disease, COPD
Corrective mechanism- Hyperventilation “blowing off ” CO2 faster than the body produces it is a corrective homeostatic response to acidosis
Alkalosis causes: hyperventilation. pneumonia, fever, anxiety, hysteria; stress. higher altitude, poor kidney function **
Main consequence: over-excitability of the central nervous system
Corrective homeostatic response- Hypoventilation (holding breath)
allows CO2 to accumulate in body fluids faster than can exhale it.
** correction to slide
22-91