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biology chapter 23
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- 1respiration includes- air movement into and out of lungs
- gas exchange: air <~> blood
- gas transport in blood
- gas exchange: blood <~> tissues - 2the respiratory organs- nose and nasal cavity
- - 3nose and nasal cavity- most of anterior part of nose is cartlage
- lined insu=ide with mucous membrane
- 2 nostrils
- internal nares
- nasal cavity - 4nostrils (external nares, anterior nares)- openings into each half of nasal cavity from outside
- 5internal nares (posterior nares, choanae)- connect each half of nasal cavity into nasopharynx
- 6nasal cavity- partitioned into right and left half by nasal septum
- anterior part = vestibule
- nasal conchae
- olfactory receptors
- paranasal sinus
- nasolacrimal (tear) ducts
- hard palate
- soft palate
- rhinoplasty - 7nasal cavity: nasal conchae (turbinates)- bony projections ~> increased furface area
- covered by mucous membrane (pseudostratified ciliated columnar epithelium)
- filters, warms and humidifies air - 8nasal cavity: olfactory receptors- in mucous of inferior surface of cribriform plate and upper surfaces of superior nasal conchae (the olfactory epithelium)
- 9nasal cavity: paranasal sinus- air-filled spaces in maxillary, frontal, ethmoid and sphenoid bones
- mucous membrane lined
- sinusitis - 10nasal cavity: paranasal sinus: sinustis- inflammation of mucous membrane of paranasal sunuses
- 11nasal cavity: nasolacrimal (tear) ducts- open into each half of nasal cavity
- 12nasal cavity: hard plate- seperated oral nad nasal cavities
- 13nasal cavity: soft plate- seperates nasopharynx from rest of pharynx
- 14nasal cavity: path of incoming airexternal nares ~> vestibule ~> superior, middle and iferior meatuses ~> internal nares ~> nasopharynx
- 15functions of nose- air warming, moistenig, and filtering
- olfaction
- speech
~ structures ~> vocal resonance - 16pharynx- muscular tube lined by mucous membrane conecting nasal and oral cavities to larynx and esophagus
- subdivided into:
~ nasopharynx
~ oropharynx
~ laryngopharynx - 17naspharynx- connects throat to nasal cavity via internal nares
- site of openings to auditory (eustachian) tubes
- connects pharyngeal tonsil - 18oropharynx- middle portion of pharynx
- communicates with oral cavity via the fauces
- contains:
~ palatine tonsils in anterior lateral wall
~ lingual tonsils at base of tongue (part of immune system) - 19laryngopharynx (hypopharynx)- are between epiglottis/hyoid and mouth of esophagus
- connects to larynx and esophagus - 20functions of pharynx- common passage way for air na dfood/drink (oro- and laryngo-_
- routes these substances to either larynx/trachea or esophagus
- immune functions
- vocal resonance - 21larynx (voice box)- passagewa connecting pharynx to trachea its apex, thyroid cartilage (adams appple), located at anterior neck
- contains 3 unpaired cartilages:
- contains 3 paired cartilages
- reflex coughing expels foreign substances entering rima gottis - 223 unpaited cartilages of larynxa) thyroid cartilage - thyroid membrane
b) epiglottis - covers glottal opening of larynx during swallowing
c) circoid cartilage - connects larynx and trachea via crotracheal ligament - 233 paired cartilages of larynxa) 2 arytenoid cartilages
= sites of attachment of true vocal cords and intrinsic laryngeal muscle
b) 2 corniculate cartilages
c) 2 cuniform cartilages - 24glottis- true vocal cords (vocal folds) + rima glottis
- 25tracheotomy- incision of cricotracheal ligament
- 26true vocal cords (vocal folds)- mucous membrane flds supported by elastic ligaments and are strung across rima glottis
- contractio of lateral cricoarytenoid muscles ~> adduction
- contraction of posterior cricoarytenoid muscles ~> abduction
- during puberty, larynx and vocal crd growth is rapid in male ~< prominant thyroud cartilage and deeper voice
- vocal resonance from pharynx, oral and nasal cavities and paranasal sinus - 27- when air passes over true vocal cords~> vibration ~> sounds (phonation)
~ tightening cords ~> higher pitch
~ relaxing cords ~> lower pitch - 28pitch of voice depends upon- true vocal cord length
- vocal cord thickness
- vocal cord elasticity
- vocal cord tension - 29loudness/intensity of voice depends upon- amplitude of true vocal cord vibration
- amplitude of vibration corresponds to distance of travel of cords - 30pitch of voice depeds upon- speed of vocal cord vibration
- this corresponds to the transit time, which is regulated by tension at which the cords are held by intrinsic laryngeal muscles - 31vestibular folds (false vocal cords)- 2nd pare of folds, spanning the laryngeal cavity
- rima vestibule
- capable of adduction
- inelastic and less delicate - 32rima vestibule- space between vetibualr folds
- 33epithelial lining of larynx- non-keratinized stratified squamus epithelium above vocal cords and respiratory epithelium below
- 34types of laryngeal muscles1) intrinsic laryngeal muscles
2) extrinsic laryngeal muscles
- both prevent fod from entering glottis during swallowing - 35intrinsic laryngeal muscles- regulate tension on true vocal cords
- open adn close rima glottidis
- posterior cricoarytendoid muscles - abduction of true vocal cords
- lateral cricoarytenoid muscles - adduction of true vocla cords - 36entrinsic laryngeal muscles- raise and lower thyroid cartilage
- sternothyroid muscles ~> depression of thyroid cartilage
- thyrohyoids muscles ~> elevation of thyroid cartilage - 37heimlich maneuver (abdominal thrust)- first aid procedure for clearing obstructing objects from air passages
- 38laryngitis- inflamation of larynx
- 39trachea (windpipe)- rigid tube extending from C6 - T5, connecting larynx to primary bronchi at the carina
- composed of C-shaped hyaline cartilage rings ~~> stiffening tracheal walls to prevent collapse
- posterior tracheal wall contains 'trachealis muscle', and no cartilade
- if larynx obstructed, tracheotomy can be performed ~> tracheostomy - 40carina- last tracheal cartilage
- 41posterior tracheal wall- contains trachealis muscle, and no cartilage
~ during swallowing, allows posterior wall to bulge inward to assist movement of food bolus in esophagus - 42respiratory epithelium lining of trachea- pseudostratified ciliated columnar epithelium
- goblet cells ~> mucus
- cilia ~> mucociliary clearance of dirt, debris and microorganisms - 43bronchial tree- trachia ~> right and left main (1) bronchi ~> lobar (2) bronchi ~> segmental (3) bronchi ~> bronchioles (~20 generations) with the final generation = terminal bronchoiles
- as bronchoiles brance
1) amount of wall cartilage decreases
2) amount of smooth muscle increases
3) lumenal diameter decreases
4) epithelial type of mucosa changes
- 2 and 3 bronchi and all bronchioles = intrapulmonary
~ 1 branch = extrapulmonary
- each 1 bronchus entrs lung at hilum - 44bronchoilar smooth muscle ~>- broncho-constriction = contraction
~ parasympathetic effect
- bronchodilation = relaxation
~ sympathetic effect - 45epithelial type of mucosa changesa) trachia 1,2, and 3 bronchi -
~respiratory epithelium
b) larger bronchioles -
~ simple ciliated columnar epithelium with goblet cells
c) smaller bronchoiles -
~ simple ciliated cuboidal epithelium
d) terminla bronchioles -
~ simple coboidal epithelium - 46the lungs- organs of respiration seperated by mediastinal structures
- 1 bronch 1 form 2 bronchi which lead to each lobe of lung
- 2 bronchi forms 3 bronchi
- broncioles within each bronchiopulmonary segment branch ~> about 6500 terminal bronchioles (each ~> a single pulmonary lobule) - 47mediastinal structures that seperate respiration organs~ parietal and visceral pleurae
~ pneumothorax
~ hemothorax
~ pleuritis
~ plaural effusions
~ atelectasis
~ diaphragnatic, costal and mediastinal surfaces
~ thoracentesis - 481 bronchi ~> 2 bronchi- lobes seperated by fissures
- right lung: 3 lobes; seperated by 2 fissures
- left lung: 2 lobes; seperated by 1 fissure
~ cardiac notch seen - 492 bronchi ~> 3 bronchi- each 3 bronchus ~> air to a single bronchopulmonary segment
~ right lung: 10 bronchopulmonary segments
~ left lung: approx. 8-9 - 50bronchioles ~> terminal bronchioles- bronchioles within each bronchiopulmonary segment branch ~> about 6500 terminal bronchioles (each ~> a single pulmonary lobule)
=> about 124,000 terminal bronchioles => approx. 124,000 lubules/ 2 lungs
~ elastic CT trabeculae extend into lung parenchyma from hilium and from visceral pleura ~> branching ~> elastic interlobular septa ~> lobules - 51each lubule contains- a lymphatic vessel
- an arteriole
- a venule
- a terminal bronchiole and gas exchange airway connecte to it
~terminal bronchiole branches into respiratory bronchioles - 52terminal bronchiole ~> respiratory bronchioles- epithelium change (simple cuboidal ~> simple squamous)
- subdivide into up to 10 alveolar ducts
~ end at alveolar sacs
~ an alveolus - 53alveolar sacs- composed of several individual alveoli
- 54alveolus- a blind pocket
~ composed of simple squamous epithelium
~ surrounded by capillary network - 55exchange of respiratory gasses~> diffusion across alveolar-capilary (respiraory) membrane
- 56cell types associated with the alveolus1) type I alveolar cells (squamous pulmnary epithelial cells)
2)type 2 alveolar cels(septal cells;clara cells)
~ surfactant ~> increased surface tension, preventing alveolar colapse
~ respiratory distress syndrom of the newborn (RDSN)
3) alveolar macrophages
4) fibroblasts - 57components of the respiratory membrane- type 1 alveolar cells
- epithelial basement membrane
- capillary basement membrane
- endothelial cell layer
~ approx. 300 million alveoli in lungs (cross-sectional area of 50 - 70 m2) - 58blood supple to lungs- dual system: pulmonary arteries and bronchial arteries
~ pulmonary thromboemolism ~> hemoptysis (25% of cases only)
- tissue hypoxia ~> reflex vasoconstriction
i) not logical to perfuse alveoli that are not ventilated
ii) vertilation-perfusing coupling
iii) can be counterproductive
iv) lung hypoxia ~> reflex vasoconstrction, increasing afterload on right ventricle ~> possible congestive heart failure - 59pulmonary ventilation- air movement in and out of lungs
- note differences between pulmonary ventilation and:
~ pulmonary (external) respiration = exchane of O2, and CO2 between lungs and blood
~ tissue (internal) respiration = exchange of O2 and CO2 between capillary blood and tissue cells
~ cellular respiration:
O2+glucose or fatty acids~>CO2+H2O+ATP - 60mechanisms of pulmonary veltilation1) continuous column of air from nose/mouth to alveoli
2) sealed thoracic cavity
3) nervous controll
4) chemical controll - 61thoracic cavity composed of- ribs
- intercostal muscles
- diaphragm - 62pleural membranes- parietal pleura - adheres to walls of thoracic cavity and to diaphragm
- visceral pleura - fused to lungs - 63nervous control of pulmonary ventilation- respiratory controll center in brain stem's reticular formation
- 3 CNS nuclei
- cortical control of breathing - 643 CNS nuclei of respiratory controll centera) medullary respiratory center
i) dorsal respiratory group (DRG)
ii) ventral respiratory group (VRG)
b) pontine respiratory group (PRG) - 65dorsal respiratory group DRG)- stimulates inspiratory muscles: diaphragm, and external intercostal mm
- for 'quiet' breathing, active for 2 seconds; inactive for 3 seconds
DRG inactivity ~> passive expiration - 66ventral respiratory group (VRG)a) pre-botzinger complex of neurons = pacemaker
~ this area ditermines the rate of firing of DRG neurons ~> inspiratory muscles
b) some VRG neurons ~> forceful inhalation, causing accessor muscles of inhalation to contract - DRG drives these VRG neurons
c) other VRG neurons ~> forceful exhalation, causing accessory muscles of exhilation to contract - 67pontine respiratory group (PRG)- PRG neurons target DRG to alter basic rhythem of breathing
- 68cortical control of breathing- short-lived; overridden by chemical control of breathing
- 69chemical controls of pulmonary ventilationa) chemical chemoreceptors
b) peripheral chemoreceptors
- hyperventilaton
- breath-holding - 70chemical chemoreceptors- CO2 and H+ levels in CSF ~> breathing rate
- when [CO2] increases ~> [H+] increase ~> stimulation of medullary DRG ~> incresase depth and rate of respiration
- not sensitive to normal decreas in [O2] - 71peripheral chemoreceptors- carotid and aortic chemoreceptors detect:
a) hypoxemia
b) hypercapnia
c) acidosis
- any of above conditions => peripheral chemorecepters ~> stimulation of medullary DRG ~> increase rate and depth of respiration - 72hyperventilation- increase ventilation depth nad rate alkalosis
- often due to severe emotional destress
- *voluntary hyperventilation by swimmers is dangerous
~> low O2 stimulates DRG less than high CO2 - 73breath holding- is limited because central chemoreceptors' sensitivity to increased CSF [CO2] ~> involuntary inhalation
- 74proprioceptors affect ventilation- stimulate medullary DRG, increasing breathing rate and depth
- 75pulmonary ventilation => 2 processes- inspiration (inhilation)
- expiration (exhilation) - 76inspiration mechanics- medullaary DRG ~> nerve impulses to:
a) diaphragm ~> dome flattens
b) external intercostals - ribs move upward and outward
- forced inspiration invilves accessory muscles
- amount of diaphragm flattening => amount thoracic volume increases
- negative pressure ventilation - 77accessory muscles of forced inspiration- sternocleiodomastoid muscles
- scalene muscles
- pectoralis minor muscles
* their contraction elevates sternum nad ribs 1-5 - 78overall effect of inspiration- increased thoracic cavity dimensions ~> increased partial vacuum between pleurae ~> expansion of lungs
- boyle's law
- when alveolar pressure decreases below atmospheric pressure ~> inspiration
at rest, inspiration = active phase of breathing because ot requires muscle contraction - 79boyle's law- inverse relationship of gas volume and pressure
- 80expiration- passive expiration
- active expiration - 81passive expiration- quiet breathing: breif inactivit of medullary DRG
- inflation reflex: excessive expansion of lungs => bronchiolar baroreceptors send nerve impulses to inhibit the medullary DRG
- in either case: diaphragm and external intercostal muscles relax
- 2 forces help propel air outward
- when alveolar pressure > atmospheric pressure ~> expiration
- expiration is normally passive - 822 forces that help propel air outwards- elastic recoil of thoracic wall and lungs
- intra-alveolar fluid film surface tension:
~ water film surface tension decreases alveolar volumes
- decreased alveolar volumes ~> increased alveolar pressure ~> expiration - 83active expiration- deep rapid breathing => both inspiration and expiration active
- internal intercstal muscles ~> forced expiration
- abdominal wall muscles - 84collapse of the lungs- due to elastic recoil and intra-alveolar fluid film surface tension
- atelectasis - term for lung colapse - partial or complete colapse of previosly non-colapsed lung
- pneumothorax - air in intrapleural space => lung colapses - 85mechanisms that help prevent alveolar colapse1) surfactant - detergent made by alveolar tyoe ii cells
~ respiratory distress syndrome of the newborn (RDSN)
2) sub-atmospheric intrapleural pressure
~ intrapleural pressure normally < alveolar pressure => alveoli partially inflated at end of exporation - 86factors that affect the rate of inspiratory airflow in lungs1) intra-alveolar fluid film surface tension
2) lung and thoracic compliance
~ ease with which lungs and thoracic wall expand
~ decreased compliance => possible hypoxemia, hypercapnia, acidosis - 87airway resistance- sympathetic stimulation ~> bronchodilation
- parasympathetic stimulation ~> bronchoconstrction
- exhalation => increased intra-thoracic pressure ~> decreased diameter of bronchioles ~> increased airway resistance
- airway obstruction and bronchoconstriction ~> increased airway resistance
- COPD ( emphysema nad chronic bronchitis) ~> increased airway resistance - 88pulmonary air volumes and capacities- spirometric measurements
1) tidal volume (TV)
2) vital capacity (VC)
3) inspiratory reserve volume (IRV)
4) expiratory reserve volume (ERV)
5) forced expiratory volume in one second (FEV1)
6) residual volume
7) anatomic dead space
8) other lung capacities - 89tidal volume (TV)- normally about 500 ml (under resting conditions)
- 90vital capacity (VC)- sum of inspiratory reserve volume, tidal volume, adn exparatory reserve volume
- 91inspiratory reserve volume (IRV)-extra inspured air above tidal volume
- 92exparatory reserve volume (ERV)- extra volume of air beyond tidal volume that can be exhaled forcibly
- 93residual volume- volue of air still contained in lungs after a maximal expiration
- increased in emphysema - 94anatomic dead space- air that fils conducting airways
=> never fills lungs
- breathing through tube increases this - 95vital capacityIRV + TV + ERV
- 96inspiratory capacityIRV + TV
- 97total lung capacityIRV + TV + ERV +RV
- 98functional residual capacityRV + ERV
- 99external respiration- gas exchange across respiratory membranes in lungs
- 100internal respiration- gas exchange between capillary blood and peripheral tissue cells
- 101respiratory gases- move from area of higher pressure to lower presure
- prssure of gas determines rate of diffusion - 102partial pressure (P) of a gas- pressure exerted by that gas in a mixture of gases
- daltons law - 103dalton's law- each gas in a mixture of gases exerts its own pressure as if all of the other gases were not present
- atmospheric pressure = sum of all of the partial pressures of individual constitute gases
= 760 mm Hg at sea level = 1 atmosphere - 104henry's law- if temprature is constant, quantity of a gas that will dissolve in a liquid it is proportional to:
1) its partial pressure
2) solubility ceofficient - 105hyperbaric oxygen therepy (HBOT)- oxygen pressure > 1 atmosphere
- therefore can force increased oxygen into a patients blood - 106nitrogen narcrosis (rapture of the deep)- if SCUBA divers remain at depths > 100 ft, N2 gas forced into solution in blood
- concentrates in fatty tissues (eg. CNS) ~> narcotic effect - 107decompression sickness (caisson disease; aka, the 'bends')- a syndrom occuring in people working at great depths
- if ascent too rapid, nitrogen dissolved in blood ~> bubbles in tissues
~> painful bends and potentially lethal gas emboli, ect
- Tx: hyperbaric therapy - 108partial pressures of respiratory gases during internal and external respiration: in lungs: oxygen- 'external (pulmonary) respiration
1) PO2 of alveolar air = 105 mm Hg
2) PO2 of deoxygenated blood = 40 mm Hg
therefore => oxygen diffuses from laveolus into pulmonary capillary - 109partial pressures of respiratory gases during internal and external respiration: in lungs: carbon dioxide- external (pulmonary) respiration
1) PCO2 of deoxygenated blood=45 mm Hg
2) PCO2 of alveolar air = 40 mm Hg
=> carbon dioxide diffuses out of blood into alveoli - 110four factors influencing external respirationa) partial pressure of gases in alvolar air and pulmonary capillary bliid
~ influenced by:
i) ventilation rate
ii) lung perfusion
iii) metabolic activity of tissues
iv) altitude: as elevation increases, O2 gradient decreases
b) large surface area for gas exchange of respiratory membrane
c) thickness of respiratory membrane
d) molecular weight and solubbility of gases - CO2 diffusion rate = 20 O2 diffusion rate - 111partial pressures of respiratory gases during internal and external respiration: in peripheral tissues: oxygen- internal respiration
i) PO2 of oxygenated arteriol blood = 100 mm Hg (< PO2 of alveolar air = 105 mm Hg)
ii) PO2 of peripheral tissue cells = 40mm Hg
=> oxygen diffuses from cappillary inter peripheral tissues - 112partial pressures of respiratory gases during internal and external respiration: in peripheral tissues: carbon dioxidei) PCO2 of peripheral tissues = 45 mm Hg
ii) PCO2 of oxygenated arteriol blood = 40 mm Hg
=> carbon dioxide diffuses out of tissues into blood - 113oxygen transport: tansport modes1) 1.5% oxygen dissolved in plasma
2) 98.5% oxygen carried by heme of RBC hemoglobin (Hb) ~> oxyhemoglobin (HbO2)
~ Hb with decreased oxygen = deoxyhemoglobin (reduced hemoglobin) - 114oxygen transport : rule- the higher the PO2 the more O2 binds Hb
- at PO2 of alveolar air, Hb is approx 100% saturated with oxygen (SO2 = 100%)
- at PO2 of most peripheral tissues (40mm Hg), Hb releases some bound oxygen (SO2 = ~75%)
~ in actively metabolizing tissues (warmer and more acidic), Hb readily releases oxygen
~ also, when PO2 of arteriol blood = 60-100 mm Hg, SO2 = 90-100% - 115factors which affect association of oxygen and Hb- shift oxygen-Hb dissiciation curve to left or right
- include:
1) PO2 of alveolar air
2) acid pH (bohr effect)
3) PCO2 of arteriol blood
4) temprature
5) 2,3-bisphosphoglycerate (BPG,DPG) - 116factors which affect association of oxygen and Hb: PO2 of alveolar air- increased PO2 of alveolar air =(implies)> increased O2-Hb affinity (and vice versa)
- 117factors which affect association of oxygen and Hb: acid pH (bohr effect)- increased [H+] ~> shift-to-right => decreased O2-Hb affinity => increased O2 dilivery to tissues (and vice versa)
- aka. tissues producing more adic get more oxygen - 118factors which affect association of oxygen and Hb: PCO2 of arteriol blood- increased PCO2 of arterial blood ~> shift-to-right => decreased O2-Hb affinity => increased O2 delivery to tissues (and vice versa)
- 119factors which affect association of oxygen and Hb: temprature- increased temprature ~> shift-to-right => decreased O2-Hb affinity => increased O2 delivery (and vice versa)
- 120factors which affect association of oxygen and Hb: 2,3-bisphosphoglycerate (BPG,DPG)- a substance which decreases Hb's O2-affinity
- hormines ~> increased BPG
- increased BPG levels ~> shift-to-right => decreased O2-Hb affinity => increaed O2 delivery to tissue cells - 121fetal Hb (Hb-F)- has greater oxygen-affinity than adult Hb (Hb-A)
- when PO2 low, fetal Hb carries 20-30% more oxygen than maternal Hb
- allows maternal blood to transfer oxygen to fetal blood in the placenta - 122carbon monoxide (CO) poisoning- CO = by-product of incomplete oxidation of hydrocarbons
- problem: CO's affinity for Hb is >200X O2's Hb affinity
=> 0.1% CO can compete with atmospheric O2 (21%) - 123carbon dioxide transport- at PCO2, of peripheral tissues, carbon dioxide enters blood
1) 7% dissolves in plasma
2) 23% combines with Hb ~> carbaminohemoglobin (HbCO2)
~ haldane effect: amount of CO2 carried by Hb is inversly related to amount of Hb-O2
3) 70% transported as HCO3
~ HCO3 formation:
CO2+ H2O ~> H2CO3 ~> H+ + HCO3
~ RBC carbonic anhydrase (CA) speeds up this reaction
~ H+ ions released by this reaction are bufferes by globin part of Hb
~ underlies bohr effect which states that Hb's O2 binding affinity is inversely related to acidity - 124carbon dioxide transport: shloride shift in periphery1) HCO3 ions diffuse out of RBC's and caried into plasma
2) chloride (Cl-) ions from plasma enter RBCs
~ band III (spectrin)
* in lungs recerse of chloride shift *
1) HCO3 ions diffuse back into RBCs
2) Cl- diffuses out of RBCs and back into plasma
- RBC carbonic anhydrase catalyzes reactions: H + HCO3~>H2CO3~>CO2 + H2O
- carbon dioxide diffuses out of blood into alveoli for axpiration
- RBC Hb is again available to transport oxygen
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- Biology Flashcards on biology chapter 23, created by Jaimee Mc on 07/04/2018.
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