AS level PEAS level PE

Respiratory systemRespiratory system

Discus mechanics of breathingDiscus mechanics of breathing

InspirationInspiration

ExpirationExpiration

Air is distributed to the lungs by way of the Air is distributed to the lungs by way of the – TracheaTrachea– Primary bronchi (Also secondary/tertiary)Primary bronchi (Also secondary/tertiary)– BronchiolesBronchioles– alveolialveoli

Respiratory system – 3 main Respiratory system – 3 main processesprocesses

Pulmonary respirationPulmonary respiration– The breathing of air into and out of the lungsThe breathing of air into and out of the lungs

External respirationExternal respiration– Exchange of O2 and CO2 between the lungs Exchange of O2 and CO2 between the lungs

and the bloodand the blood

Internal respirationInternal respiration– Exchange of O2 and CO2 between the blood Exchange of O2 and CO2 between the blood

and muscle tissues and muscle tissues

RESPIRATORY VOLUMES AT RESPIRATORY VOLUMES AT RESTREST

Tidal volumeTidal volume– Amount of air inhaled and exhaled with each Amount of air inhaled and exhaled with each

breath (approx 500ml)breath (approx 500ml)

Frequency (f) Frequency (f) – Rate of breathingRate of breathing

Minute VentilationMinute Ventilation– VE = TV X fVE = TV X f

Residual volumeResidual volume– Volume of air remaining in the lungs (1200ml)Volume of air remaining in the lungs (1200ml)

RESPIRATORY VOLUMES AT RESPIRATORY VOLUMES AT REST (Cont’d)REST (Cont’d)

Inspiratory reserve volInspiratory reserve vol

Expiratory reserve volumeExpiratory reserve volume

LUNG CAPACITIESLUNG CAPACITIES

Inspiratory capacity = IRV + TVInspiratory capacity = IRV + TVExpiratory capacity = ERV + TVExpiratory capacity = ERV + TVVital capacity Vital capacity – Maximal vol of air that can be expired after Maximal vol of air that can be expired after

maximal inspirationmaximal inspiration

Total lung capacityTotal lung capacity– Maximal volume of air contained in the lungs Maximal volume of air contained in the lungs

after a maximal inspirationafter a maximal inspiration– TLC = TV + IRV + ERV + RVTLC = TV + IRV + ERV + RV

ALVEOLIALVEOLI

Gaseous ExchangeGaseous Exchange

Gaseous exchange refers to the exchange Gaseous exchange refers to the exchange of gases, namely O2 and CO2 and relies of gases, namely O2 and CO2 and relies on a process called diffusionon a process called diffusion

What is Diffusion??What is Diffusion??

PP – partial pressure of a gas is the PP – partial pressure of a gas is the pressure it exerts within a mixture of gasespressure it exerts within a mixture of gases– Gases always move from an area of high Gases always move from an area of high

pressure to an area of low pressurepressure to an area of low pressure

Inspired air – PO2 -159 , PCO2 -0.3Inspired air – PO2 -159 , PCO2 -0.3– Trachea – PO2 – 149, PCO2 – 0.3Trachea – PO2 – 149, PCO2 – 0.3– Pulmonary veins – PO2-100, PCO2 -40Pulmonary veins – PO2-100, PCO2 -40– HeartHeart– Body tissues – PO2 – 40, PCO2 - 46Body tissues – PO2 – 40, PCO2 - 46

MYOGLOBIN – RED PIGMENT IN MYOGLOBIN – RED PIGMENT IN MUSCLES THAT STORES O2 AND MUSCLES THAT STORES O2 AND TRANSPORTS O2 TO THE TRANSPORTS O2 TO THE MITOCHONDRIAMITOCHONDRIA

02 – muscle cells (hb – myoglobin)02 – muscle cells (hb – myoglobin)

-- by product – CO2-- by product – CO2

CO2 travels in blood as carbonic acid (70%),CO2 travels in blood as carbonic acid (70%),

Carbaminohaemoglobin(20%) & 7% plasmaCarbaminohaemoglobin(20%) & 7% plasma

TASKTASK

IN GROUPS OF 3-4 YOU HAVE 5-IN GROUPS OF 3-4 YOU HAVE 5-10MINS TO DISCUSS AND PRESENT 10MINS TO DISCUSS AND PRESENT THE MECHANICS OF RESPIRATION THE MECHANICS OF RESPIRATION DURING EXERCISEDURING EXERCISE

1.1. MECHANICSMECHANICS

2.2. LUNG VOLUME CHANGES DURING LUNG VOLUME CHANGES DURING EXERCISEEXERCISE

SKIPPING ROPESSKIPPING ROPES

CONES & PAPERCONES & PAPER

MECHANICS OF RESPIRATION MECHANICS OF RESPIRATION DURING EXERCISEDURING EXERCISE

What muscles are involved?What muscles are involved?

Inspiration – SCOM(sternocleidomastoid), Inspiration – SCOM(sternocleidomastoid), scalenes & pec minorscalenes & pec minor

Expiration – internal intercostals & rectus Expiration – internal intercostals & rectus abdominals / obliquesabdominals / obliques

See p.96See p.96

Discuss the ventilatory response to light, Discuss the ventilatory response to light, moderate and heavy exercisemoderate and heavy exercise

LUNG VOLUME & EXERCISELUNG VOLUME & EXERCISE

Tidal volume – 500ml Tidal volume – 500ml 3-4litres3-4litres

Frequency – 12-15 Frequency – 12-15 40-6040-60

VE – 6-7.5l VE – 6-7.5l 120-180l120-180l

IRV – 3100ml IRV – 3100ml decreases decreases

ERV – 1200ml ERV – 1200ml slightly decreases slightly decreases

Vital capacity – 4800ml Vital capacity – 4800ml slight decrease slight decrease

Residual volume – 1200ml Residual volume – 1200ml slight increase slight increase

Total lung capacity – 6000ml Total lung capacity – 6000ml slight decrease slight decrease

EXERCISE CHANGES TO EXERCISE CHANGES TO GASEOUS EXCHANGEGASEOUS EXCHANGE

BOTH EXTERNAL & INTERNAL BOTH EXTERNAL & INTERNAL RESPIRATION INCREASE DURING RESPIRATION INCREASE DURING EXERCISE IN ORDER TO INCREASE EXERCISE IN ORDER TO INCREASE THE SUPPLY OF O2 TO THE WORKING THE SUPPLY OF O2 TO THE WORKING MUSCLESMUSCLES

OXYGEN-HAEMOGLOBIN OXYGEN-HAEMOGLOBIN DISSOCIATION CURVEDISSOCIATION CURVE