Respiratory system Flashcards
What is the major function of the respiratory system
the major function is to supply the body with oxygen and get rid of carbon dioxide
what side of the lungs have 3 lobes
right side
what is the dorsal respiratory group ? (DRG)
the DRG controls the basic rhythm of breathing by triggering inspiratiory impulses.
these neurons send impulses to the motor neurons of the diaphragm and external intercostal muscles
describe the process of expiration
1- inspiration muscles relax
2- the size of the thoratic cavity decreases
3- lungs recoil and intrapulmonary volume decreases
4- intrapulmonary pressure rises
5- air flows out of the lungs and down the pressure gradient until intrapulmonary pressure is 0
describe the process of inspiration
1- muscles contract
2- the size of the thoracic cavity increases
3- lungs stretch and intrapulmonary volume
4- intrapulmonary pressure drops
5- air flows into the lungs down the pressure gradient until the pressure is 0
what is the boyle’s law
the action of inspiration and expiration- the pressure of a set mass of gas is inversely proportional to its volume at a constant temperature
what are the two phases of pulmonary ventilation
inspiration (breathing in- active process)
expiration (breathing out- passive process)
describe the mechanism of breathing
completely mechanical process and depends on volume changes in the thoracic cavity
volume changes lead to pressure changes which leads to the flow of gases to equalises pressure
how have the lungs become adapted for immune support
hairs in nasal passage which traps debris
lymphoid tissues (tonsils)
cilia (hair like projections) beats towards the throat
mucus
additional defences- cough and sneezing to remove irritants
what does the alveoli have a good blood flow
optimum blood flow for gaseous exchange is obtained by ventilation/ perfusion matching
why does the alveoli have a thin membrane
allows rapid diffusion of gases
give 3 structures of the alveoli
thin membranes
large surface area
good blow flow
what is the parietal pleura
the portion of the protective tissues that lines the inner surface of the chest wall and covers the diaphragm
what is the visceral pleura
the portion of the protective tissues that is attached directly to the lungs
name the 2 layers of the pleura
visceral
parietal
how many layers does the pleura have
2
what is the pleura
it consist of a closed sac of serous membrane, one of each lung which contains a small amount of serous fluid
what side of the lungs have 2 lobes
left
what is the pontine respiratory group
control centres in the pons modify the rate and depth of breathing establisehd by the medulla
what are the three factors that affect o2 and co2 transport across the respiratory membrane
Partial pressure gradients
Ventilation-perfusion coupling
Structure of respiratory membrane
what is the henry’s law
“At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.”
what is diffusion
This is where gases diffuse down a concentration gradient (from an area of high gas concentration to an area of lower gas concentration) until they are equally distributed
what is the respiration components for cellular respiration
Oxygen + Glucose ENERGY (ATP) + Carbon Dioxide + Water
what is ventilation- perfusion coupling
Ventilation (V) refers to the flow of air into and out of the alveoli, while perfusion (Q) refers to the flow of blood to alveolar capillaries
how is oxygen transported around the body
Oxygen is carried to the tissues as oxyhaemoglobin in red blood cells
how does oxygen become oxyhaemoglobin
Once an O2 molecule has bound to iron, it changes Haemoglobin shape. Making it easier for other O2 molecules to bind. When 4 O2 molecules are bound Haemoglobin is fully saturated
how is carbon dioxide carried in the blood
Carbon dioxide is carried in blood to the lungs in 3 forms:
- ~ 10 % Dissolved in plasma
- 20 % Chemically bound to haemoglobin
- 70% as bicarbonate ions in plasma
how does a pulseoximeter work
measures the percentage of arterial haemoglobin saturated with oxygen
what is airway resistance
Airway resistance is the resistance of the respiratory tract to airflow during inhalation and exhalation.
A small change in diameter has a huge effect on the resistance of an airway e.g. halving the radius of an airway would cause a 16-fold increase in resistance.
what are the two autonomic nerves that control the diameter of the airway
parasympathetic system
sympathetic system
what is the parasympathetic system
causes the smooth muscle in the airway to contract (bronchoconstriction) Unstressed situations
what is the sympathetic system
causes the smooth muscle in the airway to relax (bronchodilation). Stressful situations require more air to meet increased oxygen consumption
what is a tidal volume
the volume of air that is inhaled or exhaled in only a single such breath.
what is a vital capacity
the maximum amount of air a person can expel from the lungs after a maximum inhalation, usually 4.5 - 5.5 L
what is a dead space volume
– air that remains in conducting zone and never reaches the alveoli
what is the total lung capacity
maximum amount the lungs can hold ~ 6L of air
what is residual volume of air
the air after exhalation
what is the minute volume of air
)- the total volume of gas entering (or leaving) the lung per minute. It is equal to the tidal volume (TV) multiplied by the respiratory rate (f).At rest, a normal person moves ~450 ml/breath x 10 breath/min = 4500 ml/min.
