chapter 23: respiratory system Flashcards
what is the areolar CT of respiratory mucosa?
lamina propria
explain how mucus & cilia work together as a protective feature of the respiratory system?
mucus escalator: particulates from the inspired air get stuck in the mucus which is then swept out of the respiratory tract by the beating cilia
why do smokers tend to cough a lot?
cilia is destroyed by the chemicals in smoke, person is chronically drowning in their own mucus, cough is a mechanism to attempt to clear respiratory passages
the nasal cavity has three pairs of what in it to cause air to swirl as it passes through?
nasal conchea
the internal nares exit into what which is lined with pseudostratified columnar epithelium & contains the pharyngeal tonsils?
nasopharynx
why do neither the oropharynx or the laryngopharynx have cilia?
shared space with digestive system, has epithelium that resists abrasion from potentially sharp food
what is the elastic cartilage flap that cover the glottis during swallowing?
epiglottis
to produce wine-glass-shattering soprano sounds, vocal folds would need to be very what?
narrow and tight
what muscle is attached to the ends of hyaline cartilage, provides for constriction of the trachea in response to parasympathetic stimulation?
trachealis
the last branches of the conducting portion of the respiratory tree are what?
terminal bronchioles
all the alveoli serviced by one respiratory bronchiole is a what?
alveolar sac
what are the cells of the alveolar cells that produce surfactant?
type II
what happens when there’s a block occurs in a branch of the pulmonary artery which reduces blood flow & causes alveolar collapse?
pulmonary embolism
how many lobes does the right lung have?
3
what’s the serous membrane that covers the surface of the lung?
visceral pleura
what describes a lung that has elastic recoiled because it loss the surface tension that had been keeping it attached to the thoracic cavity wall and what’s the common cause of this?
atelectasis; pneumothorax
when the diaphragm contracts, the thoracic cavity what in size & air moves in or out?
increases, in
what occurs when there’s patient fails to produce enough surfactant to prevent alveoli from collapsing?
respiratory distress syndrome
what is the quiet breathing which only involves the diaphragm & external intercostal muscles?
eupnea
the amount of air you can force in behind the tidal volume (TV) is what?
inspiratory reserve volume (IRV)
what is the amount of air that actually reaches the alveoli for gas exchange per minute at rest?
alveolar ventilation
the earth’s atmosphere is 20% oxygen; at sea level or high at a mountain, still 20%, so what causes high altitude sickness then?
fewer overall molecules as elevation increases (20% of 1000 is 200 but 20% of 10 is only 2) resulting in lower partial pressure & thus less diffusion into the blood (above 25,000ft of elevation there are not enough oxygen molecules diffusing into the blood sustain cellular respiration)
in the tissues, the partial pressure (PP) of carbon dioxide is higher in the tissues than in the blood so the carbon dioxide diffuses from what to what? but at the lungs the partial pressure (PP) are reversed so the carbon dioxide diffuses from what?
tissues to blood; blood to alveoli
why does carbon monoxide poisoning occur even when oxygen is available?
CO binds to hemoglobin more strongly than O2
the Bohr effect is the observation that hemoglobin will what?
release O2 in acidic pH
what is the element essential to ability of hemoglobin to bind to oxygen?
iron
most of the carbon dioxide is carried in the blood as what?
carbonic acid
autoregulation of lung perfusion redirects blood flow to the alveoli with a higher what?
ppO2 (partial pressure O2)
what is the respiratory rhythmicity center serves as the pacesetting respiratory center by being active for 2 seconds & inactive for 3?
dorsal respiratory group/ DRG
when will you have more breaths per minute: when there’s more or when there’s less signaling from the pneumotaxic center?
more
respiratory system functions:
- external respiration
- pulmonary ventilation
- protection of respiratory surfaces (dehydration, temp. change, pathogens)
- produce sound
- produce olfactory sensation
upper respiratory system (anatomy of respiratory system)
-functions to warm & humidify air
-nose, nasal cavity, sinuses, pharynx
conducting portion (lower respiratory system -> anatomy of respiratory system)
-bring air to respiratory surfaces
-larynx, trachea, bronchi, bronchioles
respiratory portion (lower respiratory system -> anatomy of respiratory system)
-gas exchange
-alveoli
respiratory mucosa
-lines conducting portions
-pseudostratified columnar epithelium
lamina propria contains mucus glands & serous glands (lysozyme)
-usually ciliated
-scattered goblet cells (mucin production)
-cilia move mucus to pharynx to be swallowed
mucus (respiratory defense system)
from goblet cells & glands in lamina propria, traps foreign objects
cilia (respiratory defense system)
-“mucus escalator”
move carpet of mucus with trapped debris out of respiratory tract
alveolar macrophages (respiratory defense system)
phagocytes particles that reach alveoli
cystic fibrosis
-failure of cilia
produce thick mucus which blocks airways & encourages bacteria growth
what does smoking & inhaling of irritants result in?
-destroys cilia
-chronic inflammation -> cancer (squamous cell carcinoma)
nose functions (upper respiratory system)
-external feature
1. opening to airway for respiration
2. moisten & warm entering air
3. resonating chamber for speech
4. house olfactory receptors
nose features (upper respiratory system)
-external nares conduct air into vestibule
-vestibule leads to nasal cavity
vestibule (nose feature -> upper respiratiry system)
space in flexible part, lined with hairs to filter particles, leads to nasal cavity
nasal cavity (upper respiratory system
-divided into right & left by nasal septum
-superior portion has olfactory epithelium
-nasal conchae
-hard & soft palate form floor
-internal nares open to nasopharynx
-mucosa has large blood supply
-paranasal sinuses
nasal conchae (nasal cavity
-> upper respiratory system)
-superior, inferior, middle project into cavity on both sides
-cause air to swirl
1. increase likelihood of trapping foreign material in mucus
2. provide time for smell detection
3. provide time & contact to warm & humidify air
epistaxis
nosebleed
paranasal sinuses (nasal cavity -> upper respiratory system)
-in frontal, sphenoid, ethmoid & maxillary bones
-lined with respiratory mucosa, connected to nasal cavity, aids in warming/ moistening air
rhinitis
inflammation of nasal mucosa -> ↑ mucus production
what happens when there’s an infection in the nasal cavity?
blockage of sinuses: headache from negative pressure
pharynx (upper respiratory system)
-chamber between internal nares & entrances to larynx and esophagus
-three parts: nasopharynx, oropharynx, laryngopharynx
nasopharynx (pharynx -> upper respiratory system)
air only
-posterior to nasal cavity
-pseudostratified columnar epithelium
-closed off by soft palate & uvula during swallowing
-pharyngeal tonsil located on posterior wall (inflammation can block airway)
-auditory tubes open here
oropharynx (pharynx -> upper respiratory system)
food & air
-posterior to oral cavity
-stratified squamous epithelium
-palatine & lingual tonils in mucosa
laryngopharynx (pharynx -> upper respiratory system)
food & air
-lower portion
-stratified squamous epithelium
-continuous with esophagus
larynx (lower respiratory system)
-hyaline cartilage around glottis
-contains epiglottis
-folds epithelium over ligaments of elastic fibers create vocal fold/cords
-vocal cords project into glottis
-air passing through glottis vibrates folds producing sound
glottis
opening from laryngopharynx to trachea
epiglottis
elastic cartilage flap, cover glottis during swallowing
high pitch
pitch controlled by tensing/ relaxing cords: tense & narrow
-controlled by amount fo air
sound production (larynx)
phonation
speech
formation of sound using mouth & tongue with resonance in pharynx, mouth sinuses & nose
laryngitis
inflammation of vocal folds due to infection or overuse can inhibit phonation
trachea (lower respiratory system)
-attached inferior to larynx
-walls composed of 3 layers: mucosa, submucosa & adventitia
-branches into right & left primary bronchi
mucosa of trachea
pseudostratified columnar epithelium, goblet cell, lamina propria with smooth muscle & glands
submucosa of trachea
CT with additional mucus glands
adventitia of trachea
CT with hyaline cartilage rings (keeps airway open)
-15-20 C-shaped, has opening toward esophagus (allow expansion), ends connected by trachealis muscle
primary bronchi (lower respiratory system)
-similar structure as trachea (no trachealis muscle)
-right: steeper angle
-enter lungs at hilum (along with blood & lymphatic)
inside lungs bronchi branch, get smaller in diameter:
branch ~23 times creating the bronchial tree
as bronchi get smaller, structure changes:
- less cartilage in adventitia
- more smooth muscle in lamina propria
- epithelium thinner, less cilia, less mucus
terminal bronchi (lower respiratory system)
-smallest bronchi of respiratory tree
-no cartilage
-last part of conducting
-each delivers air to one pulmonary lobule (separated by CT)
-inside lobule, terminal bronchiole branches into respiratory bronchiols
-connect to alveolar sac
trachea, bronchi & bronchioles innervated by ANS to control airflow to lungs:
-sympathetic = bronchodilation
-parasympathetic = bronchoconstriction
asthma
strong bronchoconstriction activated by inflammatory chemicals (histamine) reduces airflow
-epinephrine inhaler mimics sympathetic (bronchodilation)
alveoli (lower respiratory system)
-wrapped in capillaries
-held in place by elastic fiber
-3 cell types: type I, II & alveolar macrophages
-connected to neighbors by alveolar pores (equalize pressure)
type I cells (alveoli -> lower respiratory system)
simple squamous epithelium, lines inside, gas exchange
type II cells (alveoli -> lower respiratory system)
cuboidal epithelial cells produce surfactant
surfactant (alveoli -> lower respiratory system)
phospholipids + proteins, prevent alveolar collapse
alveolar macrophages (alveoli -> lower respiratory system)
phagocytosis of particles
gas exchange occurs in the respiratory membrane (0.5μm thick):
- type I cells of alveolus
- thin basal lamina (fusion)
- endothelial cells of capillary
pneumonia
inflammation of lungs from infection or injury, fluid in alveoli prevents gas exchange
pulmonary embolism
block in branch of pulmonary artery, reduced blood flow causes alveolar collapse
gross anatomy of lungs
-concave base, rest on diaphragm
-right: 3 lobes
-left: 2 lobes & cardiac notch
-cavity lined with parietal pleura
-lungs covered by visceral pleura
-both pleura produce serous pleural fluid to reduce friction during expansion
pleurisy
inflammation of pleura, can restrict movement of lungs, causing breathing difficulty
pulmonary ventilation (step 1 of respiratory physiology)
-movement of air into/out of alveoli
-visceral pleura adheres to parietal pleura via surface tension: altering size of pleural cavity will alter size of lungs
pneumothorax
injury to thoracic cavity, air breaks surface tension, lungs recoil = atelectasis
atelectasis
collapsed lung
mechanics of breathing
-boyle’s law: gas pressure is inversely proportional to volume
-air flows from area of high pressure to low pressure
contraction of diaphragm pulls it toward abdomen:
- lung volume↑
-air pressure ↓
-air flows in
relaxation causes diaphragm to rise in dome shape:
- lung volume ↓
- air pressure ↑
-air flows out
air way resistance (factor influencing pulmonary ventilation)
- diameter of bronchi
-obstructions
alveolar surface tension (factor influencing pulmonary ventilation)
-surfactant (type II cells) reduces alveoli surface tension to allow inflation
-respiratory distress syndrome
respiratory distress syndrome
too little surfactant requires great force to open alveoli to inhale
-premature babies
compliance (factor influencing pulmonary ventilation)
effort required to expand lung & chest
-high compliance = expand easily
-low compliance = resist expanison
how is compliance affected by CT structure? (factor influencing pulmonary ventilation)
loss of elastin/ replacement by fibrous tissue =↓ compliance
emphysema
respiratory surface replaced by scars, ↓ elasticity ↓ compliance & have loss of surface for gas exchange
how is compliance affected by alveolar expandability vs collapse? (factor influencing pulmonary ventilation)
-↑ surface tension (↓ surfactant) = ↓ compliance
-fluid (edema) =↓ compliance
how is compliance affected by mobility of the thoracic cavity? (factor influencing pulmonary ventilation)
less mobility =↓ compliance
inspiration
inhalation involves contraction of muscles to increase thoracic volume
-eupnea & hypernea
eupnea (inspiration)
-quiet breathing
-diaphragm: moves 75% of air
-external intercostal: elevate ribs, 25% of air
hypernea (inspiration)
-forced breathing
-maximum rib elevation increases respiratory volume 6x: serrates anterior, pectoralis minor, scalenes & sternocleidomastoid
eupnea (expiration)
passive, muscle relax, thoracic volume decrease
hypernea (expiration)
abdominal muscles (obliques, transverses, rectus) contract, forcing diaphragm up, thoracic volume further decreases
a breath
one respiratory cycle
tidal volume (TV)
amount of air inhaled or exhaled with each breath under resting conditions
-500ml in males & females
inspiratory reserve volume (IRV)
amount of air that can be forcefully exhaled after a normal tidal volume inhalation
-3100ml in males & 1900ml in females
expiratory reserve volume (ERV)
amount of air that can be forcefully exhaled after a normal tidal volume exhalation
-1200ml in males & 700ml in females
residual volume (RV)
amount of air remaining in the lungs after a forced exhalation
-1200ml in males & 1100ml in females
total lung capacity (TLC)
maximum of air contained in lungs after a maximum inspiratory effort
-TV + IRV + ERV + RV
-6000ml in males & 4200ml in females
vital capacity (VC)
maximum amount of air that can expire after a maximum inspiratory effort
-TV + IRV + ERV (80% of TLC)
-4800ml in males & 3100ml in females
respiratory rate
breath/min
~18-20 at rest
respiratory minute volume (RMV/MRV)
respiratory rate multiplied by tidal volume
~6L
anatomic dead space
not all reaches alveoli, some remains in conducting portions
~1ml/Ib body weight
alveolar ventilation
air reaching alveoli/min at reast
~4.2L
air compoments (gas exchange -> step 2 of respiratory physiology)
79% N2, 21% O2, 0.5% H2O, 0.04% COs, trace inert gasses
partial pressure (PP) of gas (gas exchange -> step 2 of respiratory physiology)
concentration in air
gasses follow diffusion gradients to diffuse into liquid (gas exchange -> step 2 of respiratory physiology):
rate depends on partial pressure (PP) & temp.
high altitude sickness
↓ PP O2 at high altitude causes ↓ diffusion into blood
decompression sickness
PP of air gasses high underwater, hight amount of N2 diffuse into blood
-if pressure suddenly ↓ N2 leaves blood as gas causes bubbles (damage, pain)
what treats decompression sickness?
hyperbaric chambers
diffusion at respiratory membrane efficient (gas exchange -> step 2 of respiratory physiology):
- substantial differences in PP across membrane
- distance is small
- gases are lipid soluble
- large surface area for diffusion
- coordination of blood & airflow:↑ blood to alveoli with ↑ O2
diffusion at respiratory membrane in lungs (gas exchange -> step 2 of respiratory physiology):
-PP O2 ↑ in alveoli, ↓ capillary: diffuse into capillary
-PP CO2 ↓ in alveoli ↑ in capillary: diffuse into alveoli
diffusion at respiratory membrane in tissues (gas exchange -> step 2 of respiratory physiology):
-pressure & flow reserved
-O2 into tissues
-CO2 into capillary
transport of oxygen (gas transport -> step 3 of respiratory physiology)
-1.5% dissolved in plasma
-most bound to iron ions no heme of hemoglobin in erythrocytes: 4 O2/Hb
~280 million Hb/RBC = 1 billion O2/RBC
hemoglobin saturation (transport of oxygen -> gas transport -> step 3 of respiratory physiology)
% of hemes bound to O2
~97.5% at alveoli
@ ↑PP O2 hemoglobin binds O2
@ ↓ PP O2 hemoglobin drops O2
carbon monoxide poisoning
Co out-competes O2 for binding to Hb, even at low PP CO, causes suffocation (no O2)
Bohr effect (factor that affects Hb saturation -> transport of oxygen -> gas transport -> step 3 of respiratory physiology)
Hb releases O2 in acidic pH (high CO2 creates carbonic acid)
temperature (factor that affects Hb saturation -> transport of oxygen -> gas transport -> step 3 of respiratory physiology)
Hb releases O2 in ↑ temp.
BPG (2,3-diphosphoglycerate) (factor that affects Hb saturation -> transport of oxygen -> gas transport -> step 3 of respiratory physiology)
produced by healthy RBC during glycolysis
-↑ BPG = ↑ O2 release
pregnancy (factor that affects Hb saturation -> transport of oxygen -> gas transport -> step 3 of respiratory physiology
fetal Hb = ↑ O2 binding
hypoxia
inadequate O2 delivery to tissues
transport of carbon dioxide most common action (gas transport -> step 3 of respiratory physiology)
~70% as carbonic acid
-in RBCs & plasma
-carbonic anhydrase in RBCs catalyze reaction with water: CO2 + H2O <-> H2CO3 <-> H+ + HCO3-
-reaction reversed at lungs
transport of carbon dioxide second common action (gas transport -> step 3 of respiratory physiology)
~23% as carbaminohemoglobin
-CO2 bound to amino groups of Hb
transport of carbon dioxide least common action (gas transport -> step 3 of respiratory physiology)
~7% dissolved in plasma
age-related changes (respiratory system)
- elastic tissue deteriorates: ↓ compliance & ↓ VC
- arthritic changes in rib cage: ↓ mobility & ↓ RMV
- emphysema, some degree: ↓ gas exchange
regulation of respiration
respiratory homeostasis requires that diffusion rates at peripheral capillaries (O2 in CO2 out) & alveolar capillaries (CO2 out O2 in)
-if not respiration & cardiovascular functions will be altered
lung perfusion (autoregulation -> regulation of respiration)
blood flow in lungs is constantly redirected to alveoli with high partial pressure of O2
alveolar ventilation (autoregulation -> regulation of respiration)
alveoli with high partial pressure of CO2 receive increased airflow
respiratory rhythmicity centers (neural regulation -> regulation of respiration)
-located in medulla oblongata
-control basic pace & depth of respirations
-DRG & VRG
dorsal respiratory group (DRG) (respiratory rhythmicity centers -> neural regulation -> regulation of respiration)
-controls diaphragm & external intercostal muscles on every breath
-serves as pacesetting respiratory center (active 2 sec, inactive 3 sec)
ventral respiratory group (VRG) (respiratory rhythmicity centers -> neural regulation -> regulation of respiration)
controls accessory muscles during forced breathing
respiratory centers (neural regulation -> regulation of respiration)
-located in pons
-influence & modify activity of DRG & VRG to fine-tune breathing rhythm & prevent lung over inflation
-monitor input from sensory receptors to trigger appropriate reflexes to alter respiratory rate & depth of respiration to satisfy gas exchange needs
apneustic center (respiratory center ->neural regulation -> regulation of respiration)
-smaller
-stimulates DRG for inhalation: helps ↑ intensity of inhalation
-responds to lung inflation signals from sensory receptors
pneumotaxic center (respiratory center ->neural regulation -> regulation of respiration)
-bigger
-inhibits apneustic center to allow exhalation
-modifies pace set by DRG & VRG
- ↑ signaling will ↑ respiratory rate by ↓ duration of inhalation
- ↓ signaling will ↓ respiratory rate but ↑ depth by allowing apneustic center to signal DRG for greater inhalation
respiratory reflexes (neural regulation -> regulation of respiration)
respiratory center modify activity based in input from receptors
chemoreceptor (respiratory reflex ->neural regulation -> regulation of respiration)
monitor CO2, O2 & pH in blood & CSF (cerberal spinal fluid)
baroreceptors (respiratory reflex ->neural regulation -> regulation of respiration)
monitor blood blood pressure in aorta & carotid artery
stretch receptors (respiratory reflex ->neural regulation -> regulation of respiration)
monitor inhalation of the lungs (Hering-Breuer Reflex: don’t over inhale)
pulmonary irritant receptors (respiratory reflex ->neural regulation -> regulation of respiration)
monitor particles in respiratory tracts & trigger cough or sneeze
other receptors for respiratory reflexes (neural regulation -> regulation of respiration)
pain, temp. & other visceral sensations can trigger the reflexes
