respiratory system Flashcards
what are the functional divisions of the respiratory system? which parts of the lung mark the boundary?
conducting zone from the nasal cavity to the terminal bronchioles
respiratory zone: respiratory bronchioles and alveoli
what is the main cell found in the alveoli?
type I pneumocyte (squamous epithelial cell)
what is atmospheric pressure at sea level?
760mm Hg
what part of the lungs is regulated by the autonomic nervous system?
the bronchioles
what is RV?
residual volume = amount of air left in passageways and lungs after maximal exhalation
about 1200ml men//1100ml women
what is normal tidal volume at rest?
200-500ml
what is VC?
vital capacity - the amount of air you can move through the lungs
IRV+TV+ERV
about 4.8L men // 3.3L women
define the respiratory defence system
a series of filtration mechanisms the prevent airway contamination by debris and pathogens
includes mucociliary escalator
what physical changes affect the total volume of the lungs?
movement of the diaphragm and ribs
why is the lining of the nasopharynx different from that of the oropharynx and the laryngopharynx?
nasopharynx and nasal cavity - psuedostratified ciliated columnar epithelium - this area only receives air through the nose.
oropharynx and laryngopharynx need more protection as they also have contact with food, so have stratified squamous epithelium
define internal respiration and external respiration
internal - absorption of oxygen and release of carbon dioxide by body’s cells
external - all processes involved in exchange of oxygen and carbon dioxide between body’s interstitial fluids and external environment
what is ERV?
expiratory reserve volume - the amount you can force out beyond tidal volume
about 1000ml male//700ml female
which muscles are involved in forced expiration?
internal intercostals
abdominal muscles
what are the accessory muscles for forced inspiration?
scalenes
sternocleidomastoids
what are the five basic functions of the respiratory system?
- provide extensive surface area for gas exchange
- move air to and from gas exchange area
- protect respiratory surfaces against dehydration and defend against pathogens
- producing sounds
- facilitating the detection of odours
what kind of membrane are the pleura?
serous membrane
trace the pathway of air as it enters the upper respiratory system
external nares nasal vestibule meatuses internal nares nasopharynx oropharynx laryngopharynx larynx
what are the superior/middle/inferior meatuses also know as
the (superior/middle/inferior) conchae
what structures make up the nasal cavity?
the nasal vestibule, guarded by hairs, and the meatuses
which arteries supply blood to the gas exchange surfaces and the conducting portions of the respiratory system
the pulmonary arteries supple the gas exchange surfaces
the external carotid arteries, the thyrocervical trunks and the bronchial arteries supply the conducting portions
identify the paired and unpaired cartilages that compose the larynx
unpaired:
thyroid cartilage
cricoid cartilage
epiglottis
paired:
arytenoid cartilage
corniculate cartilage
cuneiform cartilage
if food accidentally enters the bronchi, which bronchus is it more likely to lodge in?
the right bronchus because it is larger in diameter and slopes more steeply into the lung
list the defenses of the respiratory system
- hairs in nose
- mucociliary escalator
- cough and sneeze reflexes
- alveolar macrophages
- normal flora
- antibodies in mucosal membrane
what are the partial pressures of oxygen and carbon dioxide in the alveoli?
PO2 = 100 PCO2 = 40
give five reasons for efficiency of gas exchange
- substantial differences in partial pressure across the membrane
- very short distance across the membrane
- oxygen and carbon dioxide are lipid soluble
- total surface area is large
- blood flow and airflow are co-ordinated
when the diaphragm and external intercostals contract, what happens to intrapleural pressure?
it decreases
what does the respiratory mucosa consist of?
an epithelium and a layer of areolar tissue called the lamina propria
what are the partial pressures of oxygen and carbon dioxide in the alveolar capillaries?
leading in (before respiration): PO2 = 40 PCO2 = 45
leading out (after exchange) PO2 = 100 PCO2 = 40 (same as alveoli)
what are the partial pressures involved in internal respiration?
in cell:
PO2 = 40
PCO2 = 45
in capillaries:
before:
PO2 = 95
PCO2 = 40
after:
PO2 = 40
PCO2 = 45
(same as in alveolar capillaries before exchange
what does intrapulmonary pressure decrease to during inhalation?
758 mm Hg
what three factors affect the ease with which haemoglobin binds or releases oxygen?
partial pressure of oxygen in blood (PO2)
temperature
blood pH
what does intrapulmonary pressure increase to during exhalation?
762 mm HG
list the functions of the trachea
transports air between larynx and primary bronchi
cilia and mucous secretions
protect respiratory tree by trapping inhaled debris and sweeping it towards pharynx
what is Poiseuille’s law?
airway resistance is proportional to viscosity and length (ie tubes add dead space)
airflow is proportional to pressure gradient and radius (ie. bronchoconstriction = increased resistance (in asthma, pneumonia etc)
why is the vascularisation of the nasal cavity important?
what provides this vascularisation?
vascularisation of nasal cavity warms and humidifies air
abundant capillaries, veins and arteries in lamina propria of nasal cavity and nasal conchae
what are the highly elastic vocal folds of the epiglottis also known as?
the vocal cords
what function do the c-shaped tracheal cartilages allow?
allow room for oesophagus to expand when food or liquid is swallowed
describe the mechanism of a cough
glottis closes partway through an exhalation
abs and internal intercostals contract suddenly, creating pressure that blasts air out of the respiratory passages
name the integrated steps involved in external respiration
pulmonary ventilation (breathing)
gas diffusion
transport of oxygen and carbon dioxide
which alveolar cell produces surfectant?
type II pneumocyte
what would happen to the alveoli if surfectant was not produced?
the alveoli would collapse as a result of surface tension in the water layer on alveolar surfaces
name the various measurable pulmonary volumes
tidal volume (VT)
expiratory reserve volume (ERV)
inspiratory reserve volume (IRV)
what are the four main structures of the upper respiratory system? (not including larynx)
nose
nasal cavity
sinuses (paranasal sinues)
pharynx
what pressure determine the direction of airflow within the respiratory tract?
- intrapulmonary pressure - pressure inside the respiratory tract
- atmospheric pressure - pressure outside the respiratory tract
air moves from an area of high pressure to area of low pressure
what is IRV?
inspiratory reserve volume = the amount of extra air you’re able to inhale on top of tidal volume
about 3.3L men//1.9L women
where would you expect to find normal flora in the respiratory system?
upper respiratory system
describe the epithelium of the trachea
continuous with the epithelium of the larynx, and like that of the nasal cavity:
pseudostratified ciliated columnar epithelium
describe the location of the lungs within the thoracic cavity
left lung in left pleural cavity; right in right pleural cavity
apex of each lung extends superior to the first rib
base of lung rests on the diaphragm
where does the trachea begin and end?
the trachea begins anterior to vertebra C6 (attached by ligament to the cricoid cartilage) and ends in the mediastinum
trace the pathway of airflow along the passages of the lower respiratory tract
larynx -> trachea -> primary bronchus -> (lung) -> secondary bronchi -> tertiary bronchi -> bronchioles -> terminal bronchioles -> respiratory bronchiole -> alveolar duct -> alveolar sac -> alveolus -> respiratory membrane
what makes air move into the lungs?
gas pressure in the lungs is less than atmospheric pressure
distinguish between phonation and articulation
phonation is the production of sound
articulation is the clarity of the sound, produced by involvement of tongue, teeth and lips
what does the hard palate separate?
nasal cavity and oral cavity
what are the two anatomical divisions of the respiratory system?
upper respiratory system and the lower respiratory system
the larynx is in both
function of the pleura?
secretes pleural fluid, lubricating the parietal and visceral surfaces to prevent friction during breathing
how would blockage of the trachea affect blood pH?
blockage in trachea = carbon dioxide trapped in bloodstream = decreased blood pH
name the lobes and fissures of each lung
left: superior and inferior lobes, separated by oblique fissure
right: superior and middle lobe are separated by horizontal fissure. inferior lobe is separated by oblique fissure
what is the respiratory mucosa?
a mucous membrane that lines the conducting portion of the respiratory system
it consists of an epithelium and a layer of areolar tissue called the lamina propria
what are the two types of dead space?
anatomical dead space (volume of the airways) = about 150mls
physiological dead space is the alveoli which are ventilated but not perfused ( insignificant amount)
what are the two types of breathing that may take place in quiet breathing, and what muscles do they use?
deep breathing - uses diaphragm
shallow breathing - uses the external intercostals
what is TCL?
total lung capacity - the total amount of air in respiratory system
VC + RV = TCL (about 6000ml in men)
what is compliance, and what are three factors which affect it?
the ease with which the lungs expand
affected by
1. connective tissue structure of the lungs
- levels of surfactant production
- mobility of the thoracic cage
what gases make up air?
nitrogen
oxygen
carbon dioxide
water vapour
what are the two types of bronchioles?
terminal
respiratory
in pneumonia, fluid accumulates in the alveoli. how would this affect vital capacity?
vital capacity would decrease because the fluid takes up space that would usually be occupied by air
define Boyle’s law
the pressure of a gas is inversely proportional to its volume*
(double a container’s volume and its pressure will decrease by half, and vice versa)
*only at a constant temperature
