Midterm 2 - Respiratory Structure and Function Flashcards
what is the general respiratory function
gas transport for metabolism
what is the main function of the respiratory system
move oxygen from air into pulmonary blood
clearance of CO2
what do lungs receive and from where
receive 100% of the cardiac output from the right heart
what are non-respiratory functions of the respiratory system
filter blood
chemical processing
maintenance and defences
important to maintain blood pH
what does the respiratory system facilitate (non-respiratory)
venous return (respiratory pump)
what is respiration
the entire process = interchanges of gases between the atmosphere and the cells of the body
what are the 3 steps of respiration
- ventilation (breathing)
- gas exchange
- cellular respiration
what is ventilation
transport of air to and from lungs
what is gas exchange
O2/CO2 exchange between the air in the lungs and cells in the body (movement of gas across barrier)
what is cellular respiration
oxidation of cellular molecules that produces CO2, water and ATP (O2 uptake and metabolism)
what is occurring when air is transported through airways from the atmosphere to the respiratory zone of the lungs
ventilation
what are airways a system of
tubular structures
what are the airways in order
- nasal/oral cavities
- pharynx and larynx
- trachea
- bronchi
- bronchioles
what do bronchioles connect to
alveoli - gas exchange
what does the trachea split into
bronchi
what do the bronchi split into
bronchioles
main function of the airways
delivering gas to the respiratory zone (alveoli)
conditioning inhaled air
what are 3 types of conditioning inhaled air that the airways are responsible for
air warmed to core body temp
gas humidification
filtration, cleansing
why does the air have to be warmed to the core body temp
prevents temp choc in the alveoli
how do the airways humidify gas
saturate with vapour
why do the airways humidify gas
to prevent dehydration of the respiratory epithelium in alveoli
why do the airways filtrate and cleanse air
to prevent foreign objects and microorganisms to enter the lungs which reduces the risk of injury and infection
what is the inner surface of the nasal/oral cavities
mucous membrane that warms and humidifies air
what is the first spot for air conditioning
nasal/oral cavities
what do some species have that acts as the first filter
hair in nostrils
what do the epithelium in nasal/oral cavities contain
ciliated cells and mucus cells (goblet)
what do ciliated and goblet cells do
trap foreign objects and move the mucus towards the pharynx
what is the pharynx
connection between nasal/oral cavity and the larynx
what does the pharynx ensure
no food in airways
what does the larynx connect
pharynx and trachea
what does the larynx consist of
glottis and epiglottis
what are the glottis and epiglottis
cartilage that prevents food to enter the trachea
what is the trachea
a flexible tube that is kept open by cartilage rings
what keeps the trachea open
cartilage rings
what is the inner surface of the trachea lined with
ciliated and mucus cells
what does mucus do
`traps particles
that do the cilia movements do
push trash back towards the pharynx
what do the bronchi possess
cartilage plates
what do the cartilage plates in bronchi do
maintain the shape
what is the primary bronchi
where the bronchi start off - 1 tube per lung
what happens to the primary bronchi
they branch off to narrower tubes with less cartilage
where are bronchioles
inside lungs
what are the cartilage plates in bronchi not subject to
the same pressure because they are in the ribcage
what do bronchioles lack
cartilage
what do bronchioles depend on instead of cartilage
lung recoil to maintain potency
what do bronchioles possess
smooth muscle
what do both bronchi and bronchioles possess
ciliated and mucus producing epithelial cells
what is the general amount of bronchioles that branch from the trachea to the terminal alveoli
20-24
what do the muscle layers on bronchioles control
opening/closing of bronchioles
what is occurring when an airway is inflamed
the muscle layers on bronchioles are too tight due to obstructed lumen
what occurs to the airway’s cross sectional area when moving from trachea to respiratory zone
increases dramatically
where is there a geometric increase
in a number of small airways
what does the velocity of airflow reduce to as cross sectional area increases
reduces to virtually 0
how does gas move in the respiratory zone
by diffusion
how do you calculate the velocity of airflow
velocity (cm/sec) = flow (cm3/sec)/cross sectional area (cm2)
what is responsible for airway clearance
cilia and goblet cells
what do cilia and goblet cells work to do
move thin sheet of mucus from lower parts of the lungs to the throat region
what is defensin
the airway “lysol”
what does defensins do
destroy bacteria
what is the first line of defence for airway clearance
defensins
what is the second line of defence for airway clearance
immune system proper - immune cell microphages
what is associated with inflammation of the lower airways
accumulation of mucus and pus in the trachea
what is the involvement of the ciliated epithelium with inflammation of the lower airways
it cannot move mucus, which impacts airflow and enacts turbulence
what are alveoli
clusters around terminal bronchioles of functional units of sacs
how much space does the adult human’s alveoli cover
75-80 m2
what are alveoli formed by
a single layer of epithelial cells
what surrounds alveoli
a capillary network
how is air separated from blood in alveoli
2 layers of cells: endothelium and epithelium.
what type of epithelial cells produce fluid
type 2: surfactant which reduces surface tension
what keeps alveoli open
the surface tension - H- bonds between water molecules
what happens if small molecules reach alveoli
they are phagocytize by macrophages
what is responsible for the immune defence in alveoli
macrophages - digest any pathogen/debrise
what is the thoracic cavity
the space within the thoracic cage between thoracic vertebras, ribs and intercostal muscles, and sternum
what does the diaphragm separate
thoracic and abdominal cavity
what is the diaphragm
sheet of skeletal muscles and tendon
what is the mediastinum
sleeve of connective tissue that divides thoracic cage in 2 halves from spine to sternum
what does each lung fill
1 half of the mediastinum
what does the connective tissue of the mediastinum contain
vessels
nerves
trachea
esophagus
heart
pleural membranes
wet epithelial surfaces that cover the lungs
what is the intrapleural space filled with
small amount of liquid = lubrication for friction free movements
what does ventilation follow
the laws of physics - flow from high to low pressure
what does ventilation depend on
difference of pressure
in ventilation, what is resistance of flow due to
friction of air particles with each others and with the ducts
what happens if resistance increases
change in pressure must increase to maintain air flow
what happens change of pressure decreases
resistance must decrease to maintain air flow
what is air flow equal to
change in pressure/ resistance
what controls change of pressure
compression/expansion of the lungs by respiratory muscles: ventilation pump
what kind of mechanism is inspiration
active
what kind of mechanism is expiration
passive (at rest)
what is the most important muscle at rest
diaphragm
what is Boyle’s law of gases
for a gas at a set temperature, pressure and volume are linked: P1V1=P2V2
what happens if volume increases
pressure decreases
what happens if volume decreases
pressure increases
what is different about ventilation in horses
the end of expiration is active
the beginning of inspiration is passive (recoil)
what is different about horse locomotion
more than just the diaphragm and intercostal muscles involved - muscles take an active part in expiration (increase speed)
what is unique about horses galloping
galloping synchronizes with breathing
what is unique about diving mammals
voluntary apnea (up to 1 hour)
what do diving animals possess
strong conducting airways
what occurs underwater with diving animals
compresses gas pushed towards air ways (no gas exchange) to prevent entry of gas in blood
what is the general case with diving animals
do not dive with full lungs
what are factors influencing ventilation
air ways resistance
lung compliance
alveolar surface tension
what is the air flow concept similar to
blood flow
what is the major factor in airways
pressure
where is most air way resistance found
nasal cavities - diseases, obstruction
what do most animals use to reduce resistance during exercise
mouth
what do horses do to reduce resistance during exercise
flare nostrils
what is the degree of turbulence
more turbulence = more resistance
what happens to airway diameter
it is reduce with branching which increases resistance
what do parallel branches result in
increased cross section (surface area) which compensates for increased resistance
what does the autonomic nervous system control in ventilation
smooth muscle in bronchiole
what does the sympathetic nervous system do to bronchiole
relaxes cells which increases diameter
what does the parasympathetic nervous system do to bronchioles
contracts cells which reduced diameter
what is lung compliance directly linked to
the ability to create a change in pressure
what is lung compliance
the ability of the lung to distend followed by the ability to recoil
what contributes to lung compliance
elastic fibers in the lung
muscle tissue in the intercostal muscles
what does lung compliance depend on
elasticity of the tissues in the lung and the thoracic cage
surface tension in alveoli
what is alveolar surface tension due to
hydrogen bonds in water molecules when on contact with air
what does alveolar surface tension tend to reduce
reduce surface area
what occurs since alveoli are lined with moisture
it creates surface tension against distention
what does alveolar surface tension get reduce by
the presence of surfactant
what is surfactant
a mix of phospholipids, Ca2+, and proteins
what reduce surface tension between h-bonds
phospholipids
what is barker syndrome in piglets
inadequate production of surfactant which increases surface tension, resistance to distension, and decreases ventilation
what does a spirometer measure
volumes of air inhaled and exhaled
what is the tidal volume
volume flowing through airways
what else does a spirometer also measure
respirratory frequency
what is the inspiratory reserve volume
further force more air during inspiration by max contraction of respiratory muscles
what is the expiratory reserve volume
after normal expiration, it is possible to force more air out
what is the residual volume
after ERV forced out, there will always remain air in the lungs
what is the vital capacity
the max air that can be inhaled/exhaled
what is the total lung capacity equal to
RV+VT
