Respiratory system Flashcards
what does the respiratory system consist of?
ventilation, external respiration, internal respiration + cellular respiration
what is ventilation?
breathing air in and out of the lungs
what is external respiration?
gaseous exchange between the lungs and blood
what is internal respiration?
gaseous exchange between the capillaries and body cells
what is cellular respiration?
metabolic reactions that take place in a cell to obtain energy from fuels (glucose)
what is diffusion?
the movement of gas molecules from an area of high partial pressure to an area of low partial pressure
what are the structures of the alveoli and their functions?
-walls are one cell thick= short diffusion pathway
-extensive capillary network= good blood supply to transport gases away
-huge surface area= allows greater uptake of O2
explain the mechanics of breathing, during inspiration at rest and during exercise.
-diaphragm= contracts and is pulled down/flat
-ribcage= moves up and out
-muscles at rest= diaphragm + external intercostals
-muscles during exercise= diaphragm, external intercostals, sternocleidomastoid, scalenes and pectoralis major
-volume= increases
-pressure- decreases
-air= rushes in
explain the mechanics of breathing during expiration at rest and during exercise.
-diaphragm= relaxes and rises to dome-shape
-ribcage- moves down and in
-muscles at rest= diaphragm and external intercostals passively
-muscles during exercise= internal intercostals + abdominals
-volume= decreases
-pressure= increases
-air=rushes out
what is tidal volume?
the volume of air inspired and expired per breath
what is minute ventilation?
the volume of air inspired or expired per minute
== number of breaths per minute X tidal volume
what is inspiratory reserve volume?
the volume of air that can be forcibly inspired after a normal breath
what is expiratory reserve volume?
the volume of air that can be forcibly expired after a normal breath
how does exercise affect lung volumes?
TV= increases as more O2 required so depth of breathing increases
IRV+ERV= decreases as more used up by TV
minute ventilation= increases as more air is inspired/expired per minute to meet O2 demand
residual volume= stays the same
what is a spirometer?
the measurement of volume of air breathing in + out
what is gaseous exchange?
the diffusion of O2 from the lungs/alveoli into the capillaries to be transported around the body + the removal of CO2 from the capillaries into the lungs
what occurs at the alveoli during gaseous exchange?
the partial pressure of O2 is higher in the alveoli than the capillaries so O2 diffuses into the capillaries down the concentration gradient until the pressure is equal in both
the partial pressure of CO2 is higher in the capillaries than the alveoli so it diffuses into the alveoli, down the concentration gradient
what is the diffusion pathway of O2?
alveoli->blood->muscles
what is the diffusion pathway of CO2?
muscles->blood->alveoli
explain gaseous exchange at the muscles.
the partial pressure of O2 is higher in the capillaries/blood than in the muscles so it diffuses into the muscles
-PO2 of capillaries/blood= 100mmHg
-PO2 of muscles capillaries=40mmHg
the partial pressure of CO2 is higher in the muscles than the capillaries/blood so it diffuses down the concentration gradient into the blood
PCO2 of muscles capillaries= 46mmHg
PCO2 of capillaries/blood= 40mmHg
what factors affect pulmonary ventilation during exercise?
-neutral control mechanism
-chemical control
-hormonal control
what increases and decreases breathing rate?
increases= sympathetic nervous system
decreases= parasympathetic nervous system
what is the neural and chemical regualtion of pulmonary ventilation controlled by?
the respiratory centre - in the medulla oblongata
how does PCO2 affect breathing rate?
increased CO2= respiratory centred stimulated-> triggers sympathetic nervous system-> increases breathing rate
decreases CO2= respiratory centre stimulated-> triggers parasympathetic nervous system -> decreases breathing rate
what is the inspiratory centre responsible for?
inspiration+ expiration
what is the expiratory centre responsible for?
stimulating expiratory muscles during exercise
how does the expiratory centre work?
receptors-> nerve impulses sent via the phrenic nerve-> to expiratory muscles -> so muscles contract
how do chemoreceptors aid pulmonary ventilation during exercise?
they detect increases in blood acidity due to increases in CO2+ lactic acid
-send impulses to respiratory control centre-> send impulses down phrenic nerve to stimulate more inspiratory muscles to contract–> so rate, depth and rhythm of breathing increases/ increases ventilation
how do proprioceptors aid pulmonary ventilation during exercise?
they detect increases in movement in joints muscles –> stimulates respiratory centre–> send impulse down phrenic nerve to increase breathing rate
how do baroreceptors aid pulmonary ventilation during exercise?
they detect decreases in blood pressure -> stimulates respiratory centre–> send impulse down phrenic nerve and causes breathing rate to increase
how do stretch receptors aid pulmonary ventilation during exercise?
they prevent over inflation of the lungs –
–> by sending impulses to the expiratory centre + down the intercostal nerve–> to the expiratory muscles to cause expiration to occur
how does the hormonal control mechanism aid pulmonary ventilation during exercise?
before exercise it send impulses to the renal glands–> so they pump adrenaline into the blood
–> so breathing rate increases to prepare for exercise
what are some poor lifestyle choices?
lack of exercise/poor diet + smoking
how does a lack of exercise/poor diet impact a person?
- it reduces cardiovascular endurance
-causes inefficient gas exchange
how does smoking impact a person?
–increases breathlessness
–nicotine constricts bronchioles
–damages cilia causing excess mucus to build up in the lung passages ==smokers cough
–damages alveoli by breaking down their walls==larger air sacs + reduces efficiency of gaseous exchange
–reduces number of alveoli
–CO bind to Hb more easily than O2- so reduces O2 carrying capacity of the blood
–decreases athletes ability to utilise O2 in energy production == less energy for activity + quicker fatigue due to working anaerobically
–increased risk of COPD(chronic obstructive pulmonary disease)
