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Respiratory System Anatomy. NosePharynx = throatLarynx = voiceboxTrachea = windpipeBronchi = airwaysLungsLocations of infectionsupper respiratory tract is above vocal cordslower respiratory tract is below vocal cords. External Nasal Structures. Skin, nasal bones,
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1. Chapter 23The Respiratory System Cells continually use O2 & release CO2
Respiratory system designed for gas exchange
Cardiovascular system transports gases in blood
Failure of either system
rapid cell death from O2 starvation
2. Respiratory System Anatomy Nose
Pharynx = throat
Larynx = voicebox
Trachea = windpipe
Bronchi = airways
Lungs
Locations of infections
upper respiratory tract is above vocal cords
lower respiratory tract is below vocal cords
3. External Nasal Structures Skin, nasal bones, & cartilage lined with mucous membrane
Openings called external nares or nostrils
4. Nose -- Internal Structures Large chamber within the skull
Roof is made up of ethmoid and floor is hard palate
Internal nares (choanae) are openings to pharynx
Nasal septum is composed of bone & cartilage
Bony swelling or conchae on lateral walls
5. Functions of the Nasal Structures Olfactory epithelium for sense of smell
Pseudostratified ciliated columnar with goblet cells lines nasal cavity
warms air due to high vascularity
mucous moistens air & traps dust
cilia move mucous towards pharynx
Paranasal sinuses open into nasal cavity
found in ethmoid, sphenoid, frontal & maxillary
lighten skull & resonate voice
6. Tortora & Grabowski 9/e ?2000 JWS 23-6 Rhinoplasty Commonly called a “nose job”
Surgical procedure done for cosmetic reasons / fracture or septal repair
Procedure
local and general anesthetic
nasal cartilage is reshaped through nostrils
bones fractured and repositioned
internal packing & splint while healing
7. Pharynx Muscular tube (5 inch long) hanging from skull
skeletal muscle & mucous membrane
Extends from internal nares to cricoid cartilage
Functions
passageway for food and air
resonating chamber for speech production
tonsil (lymphatic tissue) in the walls protects entryway into body
Distinct regions -- nasopharynx, oropharynx and laryngopharynx
8. Nasopharynx From choanae to soft palate
openings of auditory (Eustachian) tubes from middle ear cavity
adenoids or pharyngeal tonsil in roof
Passageway for air only
pseudostratified ciliated columnar epithelium with goblet
9. Oropharynx From soft palate to epiglottis
fauces is opening from mouth into oropharynx
palatine tonsils found in side walls, lingual tonsil in tongue
Common passageway for food & air
stratified squamous epithelium
10. Laryngopharynx Extends from epiglottis to cricoid cartilage
Common passageway for food & air & ends as esophagus inferiorly
stratified squamous epithelium
11. Cartilages of the Larynx Thyroid cartilage forms Adam’s apple
Epiglottis---leaf-shaped piece of elastic cartilage
during swallowing, larynx moves upward
epiglottis bends to cover glottis
Cricoid cartilage---ring of cartilage attached to top of trachea
Pair of arytenoid cartilages sit upon cricoid
many muscles responsible for their movement
partially buried in vocal folds (true vocal cords)
12. Larynx Cartilage & connective tissue tube
Anterior to C4 to C6
Constructed of 3 single & 3 paired cartilages
13. Vocal Cords False vocal cords (ventricular folds) found above vocal folds (true vocal cords)
True vocal cords attach to arytenoid cartilages
14. The Structures of Voice Production True vocal cord contains both skeletal muscle and an elastic ligament (vocal ligament)
When 10 intrinsic muscles of the larynx contract, move cartilages & stretch vocal cord tight
When air is pushed past tight ligament, sound is produced (the longer & thicker vocal cord in male produces a lower pitch of sound)
The tighter the ligament, the higher the pitch
To increase volume of sound, push air harder
15. Movement of Vocal Cords Opening and closing of the vocal folds occurs during breathing and speech
16. Speech and Whispering Speech is modified sound made by the larynx.
Speech requires pharynx, mouth, nasal cavity & sinuses to resonate that sound
Tongue & lips form words
Pitch is controlled by tension on vocal folds
pulled tight produces higher pitch
male vocal folds are thicker & longer so vibrate more slowly producing a lower pitch
Whispering is forcing air through almost closed rima glottidis -- oral cavity alone forms speech
17. Trachea Size is 5 in long & 1in diameter
Extends from larynx to T5 anterior to the esophagus and then splits into bronchi
Layers
mucosa = pseudostratified columnar with cilia & goblet
submucosa = loose connective tissue & seromucous glands
hyaline cartilage = 16 to 20 incomplete rings
open side facing esophagus contains trachealis m. (smooth)
internal ridge on last ring called carina
adventitia binds it to other organs
18. Trachea and Bronchial Tree Full extent of airways is visible starting at the larynx and trachea
19. Histology of the Trachea Ciliated pseudostratified columnar epithelium
Hyaline cartilage as C-shaped structure closed by trachealis muscle
20. Airway Epithelium Ciliated pseudostratified columnar epithelium with goblet cells produce a moving mass of mucus.
21. Tortora & Grabowski 9/e ?2000 JWS 23-21 Tracheostomy and Intubation Reestablishing airflow past an airway obstruction
crushing injury to larynx or chest
swelling that closes airway
vomit or foreign object
Tracheostomy is incision in trachea below cricoid cartilage if larynx is obstructed
Intubation is passing a tube from mouth or nose through larynx and trachea
22. Bronchi and Bronchioles Primary bronchi supply each lung
Secondary bronchi supply each lobe of the lungs (3 right + 2 left)
Tertiary bronchi supply each bronchopulmonary segment
Repeated branchings called bronchioles form a bronchial tree
23. Histology of Bronchial Tree Epithelium changes from pseudostratified ciliated columnar to nonciliated simple cuboidal as pass deeper into lungs
Incomplete rings of cartilage replaced by rings of smooth muscle & then connective tissue
sympathetic NS & adrenal gland release epinephrine that relaxes smooth muscle & dilates airways
asthma attack or allergic reactions constrict distal bronchiole smooth muscle
nebulization therapy = inhale mist with chemicals that relax muscle & reduce thickness of mucus
24. Pleural Membranes & Pleural Cavity Visceral pleura covers lungs --- parietal pleura lines ribcage & covers upper surface of diaphragm
Pleural cavity is potential space between ribs & lungs
25. Gross Anatomy of Lungs Base, apex (cupula), costal surface, cardiac notch
Oblique & horizontal fissure in right lung results in 3 lobes
Oblique fissure only in left lung produces 2 lobes
26. Mediastinal Surface of Lungs Blood vessels & airways enter lungs at hilus
Forms root of lungs
Covered with pleura (parietal becomes visceral)
27. Structures within a Lobule of Lung Branchings of single arteriole, venule & bronchiole are wrapped by elastic CT
Respiratory bronchiole
simple squamous
Alveolar ducts surrounded by alveolar sacs & alveoli
sac is 2 or more alveoli sharing a common opening
28. Histology of Lung Tissue
29. Cells Types of the Alveoli Type I alveolar cells
simple squamous cells where gas exchange occurs
Type II alveolar cells (septal cells)
free surface has microvilli
secrete alveolar fluid containing surfactant
Alveolar dust cells
wandering macrophages remove debris
30. Alveolar-Capillary Membrane Respiratory membrane = 1/2 micron thick
Exchange of gas from alveoli to blood
4 Layers of membrane to cross
alveolar epithelial wall of type I cells
alveolar epithelial basement membrane
capillary basement membrane
endothelial cells of capillary
Vast surface area = handball court
31. Details of Respiratory Membrane Find the 4 layers that comprise the respiratory membrane
32. Double Blood Supply to the Lungs Deoxygenated blood arrives through pulmonary trunk from the right ventricle
Bronchial arteries branch off of the aorta to supply oxygenated blood to lung tissue
Venous drainage returns all blood to heart
Less pressure in venous system
Pulmonary blood vessels constrict in response to low O2 levels so as not to pick up CO2 on there way through the lungs
33. Breathing or Pulmonary Ventilation Air moves into lungs when pressure inside lungs is less than atmospheric pressure
How is this accomplished?
Air moves out of the lungs when pressure inside lungs is greater than atmospheric pressure
How is this accomplished?
Atmospheric pressure = 1 atm or 760mm Hg
34. Boyle’s Law As the size of closed container decreases, pressure inside is increased
The molecules have less wall area to strike so the pressure on each inch of area increases.
35. Dimensions of the Chest Cavity Breathing in requires muscular activity & chest size changes
Contraction of the diaphragm flattens the dome and increases the vertical dimension of the chest
36. Diaphragm moves 1 cm & ribs lifted by muscles
Intrathoracic pressure falls and 2-3 liters inhaled Quiet Inspiration
37. Passive process with no muscle action
Elastic recoil & surface tension in alveoli pulls inward
Alveolar pressure increases & air is pushed out Quiet Expiration
38. Labored Breathing Forced expiration
abdominal mm force diaphragm up
internal intercostals depress ribs
Forced inspiration
sternocleidomastoid, scalenes & pectoralis minor lift chest upwards as you gasp for air
39. IntrathoracicPressures Always subatmospheric (756 mm Hg)
As diaphragm contracts intrathoracic pressure decreases even more (754 mm Hg)
Helps keep parietal & visceral pleura stick together
40. Summary of Breathing Alveolar pressure decreases & air rushes in
Alveolar pressure increases & air rushes out
41. Alveolar Surface Tension Thin layer of fluid in alveoli causes inwardly directed force = surface tension
water molecules strongly attracted to each other
Causes alveoli to remain as small as possible
Detergent-like substance called surfactant produced by Type II alveolar cells
lowers alveolar surface tension
insufficient in premature babies so that alveoli collapse at end of each exhalation
42. Tortora & Grabowski 9/e ?2000 JWS 23-42 Pneumothorax Pleural cavities are sealed cavities not open to the outside
Injuries to the chest wall that let air enter the intrapleural space
causes a pneumothorax
collapsed lung on same side as injury
surface tension and recoil of elastic fibers causes the lung to collapse
43. Tortora & Grabowski 9/e ?2000 JWS 23-43 Compliance of the Lungs Ease with which lungs & chest wall expand depends upon elasticity of lungs & surface tension
Some diseases reduce compliance
tuberculosis forms scar tissue
pulmonary edema --- fluid in lungs & reduced surfactant
paralysis
44. Airway Resistance Resistance to airflow depends upon airway size
increase size of chest
airways increase in diameter
contract smooth muscles in airways
decreases in diameter
45. Breathing Patterns Eupnea = normal quiet breathing
Apnea = temporary cessation of breathing
Dyspnea =difficult or labored breathing
Tachypnea = rapid breathing
Diaphragmatic breathing = descent of diaphragm causes stomach to bulge during inspiration
Costal breathing = just rib activity involved
46. Modified Respiratory Movements Coughing
deep inspiration, closure of rima glottidis & strong expiration blasts air out to clear respiratory passages
Hiccuping
spasmodic contraction of diaphragm & quick closure of rima glottidis produce sharp inspiratory sound
Chart of others on page 794
47. Tidal volume = amount air moved during quiet breathing
MVR= minute ventilation is amount of air moved in a minute
Reserve volumes ---- amount you can breathe either in or out above that amount of tidal volume
Residual volume = 1200 mL permanently trapped air in system
Vital capacity & total lung capacity are sums of the other volumes Lung Volumes and Capacities
48. Dalton’s Law Each gas in a mixture of gases exerts its own pressure
as if all other gases were not present
partial pressures denoted as p
Total pressure is sum of all partial pressures
atmospheric pressure (760 mm Hg) = pO2 + pCO2 + pN2 + pH2O
to determine partial pressure of O2-- multiply 760 by % of air that is O2 (21%) = 160 mm Hg
49. What is Composition of Air? Air = 21% O2, 79% N2 and .04% CO2
Alveolar air = 14% O2, 79% N2 and 5.2% CO2
Expired air = 16% O2, 79% N2 and 4.5% CO2
Observations
alveolar air has less O2 since absorbed by blood
mystery-----expired air has more O2 & less CO2 than alveolar air?
Anatomical dead space = 150 ml of 500 ml of tidal volume
50. Henry’s Law Quantity of a gas that will dissolve in a liquid depends upon the amount of gas present and its solubility coefficient
explains why you can breathe compressed air while scuba diving despite 79% Nitrogen
N2 has very low solubility unlike CO2 (soda cans)
dive deep & increased pressure forces more N2 to dissolve in the blood (nitrogen narcosis)
decompression sickness if come back to surface too fast or stay deep too long
Breathing O2 under pressure dissolves more O2 in blood
51. Tortora & Grabowski 9/e ?2000 JWS 23-51 Hyperbaric Oxygenation Clinical application of Henry’s law
Use of pressure to dissolve more O2 in the blood
treatment for patients with anaerobic bacterial infections (tetanus and gangrene)
anaerobic bacteria die in the presence of O2
Hyperbaric chamber pressure raised to 3 to 4 atmospheres so that tissues absorb more O2
Used to treat heart disorders, carbon monoxide poisoning, cerebral edema, bone infections, gas embolisms & crush injuries
52. External Respiration Gases diffuse from areas of high partial pressure to areas of low partial pressure
Exchange of gas between air & blood
Deoxygenated blood becomes saturated
Compare gas movements in pulmonary capillaries to tissue capillaries
53. Rate of Diffusion of Gases Depends upon partial pressure of gases in air
p O2 at sea level is 160 mm Hg
10,000 feet is 110 mm Hg / 50,000 feet is 18 mm Hg
Large surface area of our alveoli
Diffusion distance is very small
Solubility & molecular weight of gases
O2 smaller molecule diffuses somewhat faster
CO2 dissolves 24X more easily in water so net outward diffusion of CO2 is much faster
disease produces hypoxia before hypercapnia
lack of O2 before too much CO2
54. Internal Respiration Exchange of gases between blood & tissues
Conversion of oxygenated blood into deoxygenated
Observe diffusion of O2 inward
at rest 25% of available O2 enters cells
during exercise more O2 is absorbed
Observe diffusion of CO2 outward
55. Oxygen Transport in the Blood Oxyhemoglobin contains 98.5% chemically combined oxygen and hemoglobin
inside red blood cells
Does not dissolve easily in water
only 1.5% transported dissolved in blood
Only the dissolved O2 can diffuse into tissues
Factors affecting dissociation of O2 from hemoglobin are important
Oxygen dissociation curve shows levels of saturation and oxygen partial pressures
56. Blood is almost fully saturated at pO2 of 60mm
people OK at high altitudes & with some disease
Between 40 & 20 mm Hg, large amounts of O2 are released as in areas of need like contracting muscle Hemoglobin and Oxygen Partial Pressure
57. Acidity & Oxygen Affinity for Hb As acidity increases, O2 affinity for Hb decreases
Bohr effect
H+ binds to hemoglobin & alters it
O2 left behind in needy tissues
58. pCO2 & Oxygen Release As pCO2 rises with exercise, O2 is released more easily
CO2 converts to carbonic acid & becomes H+ and bicarbonate ions & lowers pH.
59. Temperature & Oxygen Release As temperature increases, more O2 is released
Metabolic activity & heat
More BPG, more O2 released
RBC activity
hormones like thyroxine & growth hormone
60. Oxygen Affinity & Fetal Hemoglobin Differs from adult in structure & affinity for O2
When pO2 is low, can carry more O2
Maternal blood in placenta has less O2
61. Carbon Monoxide Poisoning CO from car exhaust & tobacco smoke
Binds to Hb heme group more successfully than O2
CO poisoning
Treat by administering pure O2
62. Carbon Dioxide Transport 100 ml of blood carries 55 ml of CO2
Is carried by the blood in 3 ways
dissolved in plasma
combined with the globin part of Hb molecule forming carbaminohemoglobin
as part of bicarbonate ion
CO2 + H2O combine to form carbonic acid that dissociates into H+ and bicarbonate ion
63. Summary of Gas Exchange & Transport
64. Role of the Respiratory Center Respiratory mm. controlled by neurons in pons & medulla
3 groups of neurons
medullary rhythmicity
pneumotaxic
apneustic centers
65. Medullary Rhythmicity Area Controls basic rhythm of respiration
Inspiration for 2 seconds, expiration for 3
Autorhythmic cells active for 2 seconds then inactive
Expiratory neurons inactive during most quiet breathing only active during high ventilation rates
66. Pneumotaxic & Apneustic Areas Pneumotaxic Area
constant inhibitory impulses to inspiratory area
neurons trying to turn off inspiration before lungs too expanded
Apneustic Area
stimulatory signals to inspiratory area to prolong inspiration
if pneumotaxic area is sick
67. Regulation of Respiratory Center Cortical Influences
voluntarily alter breathing patterns
limitations are buildup of CO2 & H+ in blood
inspiratory center is stimulated by increase in either
if you hold breathe until you faint----breathing will resume
68. Chemical Regulation of Respiration Central chemoreceptors in medulla
respond to changes in H+ or pCO2
hypercapnia = slight increase in pCO2 is noticed
Peripheral chemoreceptors
respond to changes in H+ , pO2 or PCO2
aortic body---in wall of aorta
nerves join vagus
carotid bodies--in walls of common carotid arteries
nerves join glossopharyngeal nerve
69. Negative feedback control of breathing
Increase in arterial pCO2
Stimulates receptors
Inspiratory center
Muscles of respiration contract more frequently & forcefully
pCO2 Decreases Negative Feedback Regulation of Breathing
70. Regulation of Ventilation Rate and Depth
71. Types of Hypoxia Deficiency of O2 at tissue level
Types of hypoxia
hypoxic hypoxia--low pO2 in arterial blood
high altitude, fluid in lungs & obstructions
anemic hypoxia--too little functioning Hb
hemorrhage or anemia
ischemic hypoxia--blood flow is too low
histotoxic hypoxia--cyanide poisoning
blocks metabolic stages & O2 usage
72. Tortora & Grabowski 9/e ?2000 JWS 23-72 Respiratory Influences & Reflex Behaviors Quick breathing rate response to exercise
input from proprioceptors
Inflation Reflex (Hering-Breurer reflex)
big deep breath stretching receptors produces urge to exhale
Factors increasing breathing rate
emotional anxiety, temperature increase or drop in blood pressure
Apnea or cessation of breathing
by sudden plunge into cold water, sudden pain, irritation of airway
73. Tortora & Grabowski 9/e ?2000 JWS 23-73 Exercise and the Respiratory System During exercise, muscles consume large amounts of O2 & produce large amounts CO2
Pulmonary ventilation must increase
moderate exercise increases depth of breathing,
strenuous exercise also increases rate of breathing
Abrupt changes at start of exercise are neural
anticipation & sensory signals from proprioceptors
impulses from motor cortex
Chemical & physical changes are important
decrease in pO2, increase in pCO2 & increased temperature
74. Tortora & Grabowski 9/e ?2000 JWS 23-74 Smokers Lowered Respiratory Efficiency Smoker is easily “winded” with moderate exercise
nicotine constricts terminal bronchioles
carbon monoxide in smoke binds to hemoglobin
irritants in smoke cause excess mucus secretion
irritants inhibit movements of cilia
in time destroys elastic fibers in lungs & leads to emphysema
trapping of air in alveoli & reduced gas exchange
75. Tortora & Grabowski 9/e ?2000 JWS 23-75 Developmental Anatomy of Respiratory System 4 weeks endoderm of foregut gives rise to lung bud
Differentiates into epithelial lining of airways
6 months closed-tubes swell into alveoli of lungs
76. Aging & the Respiratory System Respiratory tissues & chest wall become more rigid
Vital capacity decreases to 35% by age 70.
Decreases in macrophage activity
Diminished ciliary action
Decrease in blood levels of O2
Result is an age-related susceptibility to pneumonia or bronchitis
77. Tortora & Grabowski 9/e ?2000 JWS 23-77 Disorders of the Respiratory System Asthma
Chronic obstructive pulmonary disease
Emphysema
Chronic bronchitis
Lung cancer
Pneumonia
Tuberculosis
Coryza and Influenza
Pulmonary Edema
Cystic fibrosis