Exam 2: Respiratory System Flashcards
respiration
transportation of oxygen and carbon dioxide across tissues
breathing
alternation of inspiration and expiration of air into and out of the lungs
- measured in the number of breaths per minute
external respiration
between air and blood in the lungs
internal respiration
between blood and tissue cells
gas exchange
exchange of oxygen and carbon dioxide
diffusion down a pressure/concentration gradient
ventilation
RATE at which air flows into or out of the lungs
- flow of gas measured in liters/min
extrathorasic (conduction zone)
outside of the thoracic cavity (getting air down so gas exchange can occur)
- anatomic DEAD SPACE (just a pathway, nothing occurring)
- nose, pharynx, larynx, trachea, bronchi
- deliver air
intrathoracic (respiratory zone)
- gas exchange between air and blood
- respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli
the pharynx
the throat
- connects nose and mouth to the esophagus
- passages of air
nasopharynx (part of pharynx)
- contains pharyngeal tonsil
- passes only air lined by pseudostratified columnar epithelium!
oropharynx (part of pharynx)
- space between soft palate and epiglottis
- contains palatine tonsils
- passes air, food, and drink lined with stratified squamous epithelium (thicker to handle more friction from the food)
laryngopharynx (part of pharynx)
- epiglottis to larynx cartilage
- esophagus begins ar this point
- lined with stratified squamous epithelium
what are each layer of the pharynx covered with?
- nasopharynx = pseudostratified columnar epithelium
- oropharynx = stratified squamous epithelium
- laryngopharynx = stratified squamous epithelium
the larynx (voice box)
keep food out of the airway
- comprised of 9 cartilages and 3 ligaments
epiglottis ( part of the larynx)
superior opening of the larynx, aids in directing food to the esophagus when swallowing
vestibular folds ( part of the larynx)
closes the larynx when swallowing
glottis ( part of the larynx)
produce sound when air passes between them - vibrates with air molecules - vocal cords and area between them more tight = higher pitch longer, looser = lower pitch
the trachea (windpipe)
mucus-secreting cells, ciliated cells, and stem cells
- lined by ciliated pseudostratified columnar epithelium
cilia moves material up and out of the airway (dust)
mucociliary escalator
- removes debris
- mucus traps inhaled particles and upward beating cilia moves mucus to pharynx to be swallowed
surfaces of the lung
costal - pressed against the rib cage
mediastinal - faces medially toward the heart
hilum of the lungs
main bronchus, blood vessels, lymphatics, and nerves join
right lung
- shorter than left lung because liver rises higher on right side
- has THREE lobes (superior, middle, and inferior)
- lobes separated by the horizontal and oblique fissure
left lung
- tall and narrow because the heart tilts toward the left and occupies more space
- has indentation/ cardiac impression
- has TWO lobes (superior and inferior) separated by a single oblique fissure
Bronchi
- lined with ciliated pseudostratified columnar epithelium
- mucous gland and lymphocyte nodules (MALT)
- intercepts inhaled pathogens
- bronchial tree has elastic connective tissue (contributes to recoil that expels air from lungs)
bronchioles
- ciliated cuboidal epithelium
- developed smooth muscle layer
- final branches of conducting zone (before gas exchange)
- no mucus glands or goblet cells
- have cilia that move mucus
- each terminal bronchiole gives off to TWO OR MORE smaller respiratory bronchioles
alveolus vs alveolar sac
alveolus is one singular grape
alveolar sac is a bundle of grapes
respiratory bronchioles
- alveoli budding from their walls
- beginning of the respiratory zone
- divides into ducts and end in alveolar sacs
steps in respiratory zone
- respiratory terminal bronchioles
- alveolar ducts
- alveolar sacs
- alveoli
alveoli
sacs in the lungs that allow for rapid gas exchange
respiratory membrane
- epithelial cells of the alveoli (single epithelial cell)
- capillary endothelium ( single capillary cell)
- shared basement membrane (in between the 2 cells where has exchange occurs)
- rapid diffusion, membrane is extremely thin
macrophages
aid in innate defense
- phagocytize, pathogen, transported out via mucociliary escalator (cilia)
type 1 pneumocytes
create very thin diffusion barrier for gases
- simple squamous epithelial cells (95% alveolar area)
- connected by tight junctions
type 2 pneumocytes
secrete surfactant between alveolar walls
- cuboidal (5% alveolar area, 60% total number of cells)
- stops alveoli from collapsing during breathing
- connected to epithelium and other constituent cells by tight junctions
surfactant
decreases surface tension
- specifically between alveolar walls and stop alveoli from collapsing when breathing
bronchial circulation
provides a blood supply to the lung tissue
- high pressure
two types of lung circulation
bronchial and pulmonary
autonomic regulation of the lungs
innervated by autonomic nervous system
- sympathetic bronchodilation
- parasympathetic bronchoconstriction
pulmonary ventilation
amount of air moving in and out of the lungs DOWN pressure gradients
- pressure and volume are inversely proportional
- pressure changes in lungs by increasing or decreasing lung volume
pulmonary pleura
serous membranes that separate the lungs and the wall of the thoracic cavity
- visceral pleura - organs
- pleural cavity (in-between the 2 membranes)
- parietal pleura - body cavity walls
intrapulmonary pressure
pressure in the alveoli equalizes to atmospheric pressure
- (0 mmHg)
- pressure inside lung decreases as lung volume increases during inspiration
- pressure increases during expiration
intrapleural pressure
pressure in pleural cavity is LOWER (negative)
- (-4 mmHg)
- pressure becomes more negative as chest wall expands during inspiration
- returns to initial value as chest wall recoils
atelectasis
collapse of lungs
- negative intrapleural pressure is equalized with pulmonary pressure
pulmonary pressure
- volume of chest increases during inhilation
- increase in volume causes a decrease in pressure (change in pressure draws air into lungs)
inhalation effect
increases volume of thoracic cavity
diaphragm
- contraction = flattens, increasing chest volume and lowering pressure (inhalation)
- relaxation = domes up, increases pressure and decreases volume (exhalation)
innervation by phrenic nerve (C3-C5)
injury where you can no longer breathe on your own
- any injury below C5 you can still breathe on your own
inspiration
increasing air volume in lungs
- P decreases to less than atmospheric pressure, air moves IN to equalize
expiration
decreasing air volume in lungs
- P increases to more than atmospheric pressure, air moves OUT to equalize
external intercostals
elevate ribs
assist in inspiration
increase volume for air flow in
internal intercostals
depress ribs
assist in exhalation (abdominal muscles assist too)
decrease volume to exhale
active inspiratory
diaphragm and external intercostals actively contract
-normal quiet inhalation
inactive inspiratory
diaphragm and external intercostals relax, followed by elastic recoil of chest wall and lungs
- normal quiet exhalation
spirometry
measuring inputs and outputs
functional residual capacity equation
RV + ERV
residual volume + expiratory reserve volume
inspiratory capacity equation
TV + IRV
tidal volume + inspiratory residual volume
total lung capacity/volume equation
RV + ERV + TV + IRV
anatomic dead space
last part of each volume of inspired air still remains in the conducting airways
- no gaseous exchange is possible in the conducting airways
alveolar dead space
alveolar air ventilated but not perfused
physiological dead space
sum of anatomical and alveolar dead space
alveolar ventilation
alveolar ventilation rate assesses respiratory efficiency
- AVR changes when breath pattern changes (ex. slow, deep breathing and rapid, shallow breathing)
AVR = frequency x (TV - dead space)
dead space volume
is a constant
= 150 ml roughly
factors that affect pulmonary ventilation
- alveolar surface tension - surfactant
- compliance - how easy can heart open and expand
- airway resistance or obstruction - what resists air from moving (diaphragm)
alveolar surface tension
- alveolar fluid contains lots of water, which has high surface tension which can try to collapse alveoli
- surfactant reduces surface tension, less energy needed to expand lungs and prevent alveolar from collapsing
- surfactant improves compliance
lung compliance
- ease with which lungs can expand
- compliance is reduced by degenerative lung diseases in which the lungs stiffen from scar tissue
- limits expansion and many times the lung can inflate
airway resistance
ease with which air can move through the airway
- airway diameter has greatest affect
- as branching increases, resistance decreases
- not a big factor in healthy lungs
diameter of bronchiols
biggest effect on airways and ventillation
obstructive disorders
DECREASE airflow by narrowing/blocking the airway
- makes it more difficult into inhale or exhale
ex = asthma
bronchoconstriction
decrease in diameter
- histamine, parasympathetic nerves, cold air
- suffocation can occir from anaphylactic shock and asthma
bronchodilation
- sympathetic
- epinepherine (adrenal)
- norepinephrine (nerves)
list the factors that affect gas exchange (respiration/movement of gases across the membrane)
- solubility
- surface area - area available for gas exchange
- diffusion distance - how thin the membranes are
example of a disease that can affect gas exchange in respiration
scaring or fibrosis
- hickening of the membrane occurs and this make it more difficult for gases to diffuse across it
big issue with lung damage
injury and shunt can alter the amount of alveoli available for gas exchange
solubility in gas exchange
- air in alveolus is in contact film of water covering the alveolar epithelium
- for O2 to get into blood, it must dissolve in water and pass through respiratory membrane which separates air from bloodstream
- for CO2 to leave blood, it must pass the other way and diffuse out of the water film into alveolar air
what do gases need to be in order to diffuse across a membrane
- diffusion occurs until pressure equilibrium in the membranes is reached
gases need to be soluble to diffuse and get into the water and bloodstream
partial pressure in gas
greater the partial pressure of gas, the greater the number of gas molecules that will go into the solution
- CO2 is 24 times more soluble than O2
hemoglobin
280 million Hb in one RBC -> 4 molecules of oxygen per 1 Hb
- makes blood red
- binds easily and reversibly with O2
3 ways hemoglobin can exist
- oxyhemoglobin = fully saturated
- deoxyhemoglobin = no O2
- carbaminohemoglobin = bound to CO2 and globin
what do oxygen and carbon dioxide bind to
oxygen binds to heme
carbon dioxide binds to globin
in the lungs, when Po2 is high
Hb is almost fully saturated with O2
in tissues and other organs, when Po2 is low
Hb is less saturated with O2
myoglobin
higher affinity for oxygen compared to hemoglobin
- myoglobin steals away oxygen from hemoglobin
ways lung volume changes with exercise
- respiration becomes more active
- more O2 needed by muscle
- more muscle needed in inspiration and expiration
- increases in tidal volume to accommodate demand
hypoxia
inadequate oxygen delivery to body and tissues
hypoxia can be due to …
- few/faulty RBCs (anemica hypoxia)
- impaired circulation (ischemic hypoxia)
- body cells cant use provided O2 (histotoxic hypoxia)
- low arterial pressure (hypoxemix hypoxia)
hypoxia and carbon monoxide poisoning
hemoglobin has a higher affinity for CO2 than O2, so Hb will bind to carbon dioxide if it is given the chance
carbon dioxide transport
- dissolved CO2
- carbamino compounds
- bicarbonate ions
respiratory centers in the brain
- monitor CO2 and pH
- control motor neurons in intercostal muscles and diaphragm
chemoreceptors on aorta and carotid sinus
send information about chemical changes in blood to respiratory centers in the brain stem
motor neurons
to intercostal muscles and diaphragm
