reparatory system Flashcards
work of respiratory system
compliance- lungs are very stretchy to ensure the least amount of work to breathe
driven by pressure differences
work is required to stretch the tissue and increase the surface area of water molecules
surface tension
a measure of work required to increase the surface area of the liquid
surfactant (produced by type II alveolar cells decreases the surface tension by decreasing the attraction between water molecules
resistance
impacted mostly by radius of airway
resistance in healthy lungs is low
large surface area also helps combat resistance
factors impaction- passive forces, smooth muscle contraction, and mucus production
obstructive respiratory diseases
an increase in airway resistance
emphysema and chronic bronchitis (inflammation of airways)
COPD - chronic (enlarged alveoli)
asthma- acute (contraction of smooth muscle in airway, inflammation, excess mucus)
restrictive respiratory diseases
decreased Lung compliance
caused by scarring in airways, additional weight on pulmonary cavity, deformations of the thoracic cavity
pulmonary fibrosis, scoliosis, obesity
reduced lung volumes, difficult to get air in
how to calculate FVC (forced vital capacity) or VC (vital capacity)
tidal volume (Vt)+inspiratory reserve vol (IRV)+ expiratory reserve volume (ERV)= FVC
how to calculate TLC (total lung capacity)
tidal volume (Vt)+IRV+ERV+residual vol (RV)= TLC
how to calculate inspiratory capacity (IC)
tidal volume + IRV= IC
how to calculate minute ventilation
tidal volume x respiration rate
how to calculate alveolar ventialtion
(tidal volume x RR) - (dead space volume x RR)= Alveolar ventilation
partial pressure
gasses follow their own partial pressure
depends on total concentration and total pressure
arterial blood O2 and CO2 relatively constant
O2 moves from alveoli to blood at the same rate as its consumed by cells
Co2 moves at the same rate from blood to alveoli as it is produced by cells
Pressure depends on metabolic activity, greater metabolic activity means lower pressure and greater diffusion
diffusion at the lungs
oxygen loading of the hemoglobin occurs at the alveoli
diffusion occurs at the lungs capillaries within the first 1/3.
saturates to 98%
takes 0.25 of a second
May be a limitation in elite athletes (most commonly males)
- Due to higher CO
transport of O2 and CO2
law of mass action state the more oxygen present the more will bind to hemoglobin
oxygen is transported by hemoglobin
carbonic anhydrase converts CO2 to water and carbonic acid
chloride shift is when bicarbonate gets exchanged for chloride at the rbc.
carbamino effect
effects of the offloading of CO2 on O2, the less CO2 that can be removed from hemoglobin the less oxygen can load on
2,3 DPG effect
at altitude more red blood cells are produced because of low O2
decreases hemoglobins affinity for O2 which enhances O2 unloading
carbon monoxide effect
prevents O2 from binding to hemoglobin because it has a greater affinity for CO
oxyhemoglobin curve
O2-carrying capacity in blood
helps get oxygen to where it is needed the most by releasing it in the areas that require it for more energy
when O2 affinity increases the curve goes up and left
when O2 affinity decreases the curve goes right and down
bohr effect
a change in pH causing the affinity of O2 to change
chemoreceptors and pH
peripheral chemoreceptors in carotid bodies- detect levels of O2 and CO2 in the blood, this will cause change in pH due to a change on PCO2 or H+ ions
Low PO2 increases chemoreceptor sensitivity to PO2
central chemoreceptors in medulla oblongata- H+ ions directly and PCO2 indirectly, cannot respond to H+ in the blood because of blood brain barrier, increased CO2 decreases pH
control/regulation of breathing
spinal cord and medulla, pons, and central pattern generator responsible for breathing mechanism and control.
phrenic nerve in the diaphragm and external intercostal nerve responsible for inspiration
internal intercostal nerve for expiration
mixed neurons for both expiration and inspiration
respiratory motor neurons
firing stops at expiration
passive at rest
during active ventilation, greater firing rate and force generation at inspiratory motor neurons
expiratory motor neurons only become active during active expiration- exercise, hyper ventilation, limbic system
peripheral input to respiratory centres
chemoreceptors
pulmonary stretch receptors
irritant receptors
muscle anf joint proprioceptors
baroreceptors
thermoreceptors
nociceptors
limbic system, hypothalamus, cerebellum
exercise and the respiratory system
bronchoconstriction and bronchodilation- smooth muscle innervated by ANS
at rest only 33% of pulmonary capacity
those not participating in gas exchange considered dead space
EIAH or EIH- exercise induced arterial hypoxemia
desaturation at maximal exercise
O2 diffusion decreased from alveoli to blood
right shift go O2-Hb curve due to increased temperature
respiratory muscle training
results are mixed, reduces the reflex response that redistributes blood away from exercising muscle to respiratory muscle
