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RESPIRATORY EXAM QUESTIONS

1.Exercise results in an increase in the volume of gas exchanged in the

lungs

Define Tidal Volume and describe how a performer is able to increase lung volumes during exercise using neural control.

1. Definition: ‘The amount of air breathed in/out of the lungs in one

breath’.

Description:• Movement detected by proprioreceptors• Changes in blood pressure via baroreceptors • Emotional influences/lung stretch receptors• Change in blood pH via chemoreceptors/ drop in

oxygen.• Respiratory Centre (in medulla) controls breathing.• Inspiratory/Expiratory centre initiate impulses

(apneunistic/pneumotaxic)• Impulses sent via phrenic nerves• Impulses received by respiratory muscles• This leads to increased rate and depth of breathing.

2. How is oxygen transported in the blood to the working

muscles?

• Attached to haemoglobin

• Forms oxyhaemoglobin

• Dissolved in plasma

3. Describe how more oxygen is diffused into the muscles during

exercise.

• Gas diffuses from an area of high pressure to an area of low pressure

• There is a high partial pressure of oxygen in blood, low P02 in muscle.

• There is a decreased partial pressure of oxygen in the muscle during exercise.

• Therefore there is an increased diffusion gradient.

• Increase in temperature encourages greater release of oxygen (from haemoglobin)

4. At rest and during physical activity the performer varies the volume of gas exchanged in the lungs.

Give typical minute ventilation values for a fit 20 year old at rest & during maximal exercise.

ANSWER

AT REST = 4 – 15 LITRES/MIN

MAXIMAL = 100 – 180 LITRES/MIN

5.

DESCRIBE HOW NEURAL CONTROL ENABLES AN ATHLETE TO INCREASE LUNG VOLUMES.

WHY IS THIS BENEFICIAL TO PERFORMANCE?

HOW CONTROL IS EXERTED:• INFORMATION RECEIVED BY RESPIRATORY

CONTROL CENTRE (RCC) IN MEDULLA OBLONGATA

• RATE & DEPTH OF BREATHING REGULATED BY RESPIRATORY CONTROL CENTRE

• THESE SEND NERVE IMPULSE TO THE RESPIRATORY MUSCLES

• THESE INCREASE THE RATE & DEPTH OF BREATHING

WHY: • LARGER VOLUMES OF AIR EXPIRED MORE RAPIDLY,

THEREFORE MORE CO2 EXPELLED

• LARGER VOLUMES OF AIR INSPIRED, THEREFORE GREATER AMOUNTS OF OXYGEN AVAILABLE

6. DESCRIBE THE EFFECT OF ALTITUDE ON THE EXCHANGE OF GASES AT THE ALVEOLI AND WHY

THIS MAY BE BENEFICIAL.

EFFECTS:• HAEMOGLOBIN SATURATION DEPENDS UPON PARTIAL PRESSURE

OF O2 IN ALVEOLAR AIR/THE LUNGS.

• AT ALTITUDE THE PARTIAL PRESSURE/CONCENTRATION OF O2 IS REDUCED

• THEREFORE THERE IS A REDUCTION IN THE DIFFUSION GRADIENT

• HAEMOGLOBIN IS NOT FULLY STATURATED

• WHICH RESULTS IN A LOWER O2 CARRYING CAPACITY.

INFLUENCE:• THEREFORE LESS O2 DELIVERED TO WORKING MUSCLES• SO EARLIER ONSET OF FATIQUE

• RESULTING IN DECREASE IN PERFORMANCE (OF AEROBIC ACTIVITIES)

7. EXPLAIN HOW THE RESPIRATORY CONTROL CENTRE IN THE MEDULLA

OBLONGATA RESPONDS TO THE INCREASED DEMAND FOR OXYGEN

DURING EXERCISE.

• Drop in pH/more acidity, 02 and increase in C02 detected by chemoreceptors

• Changes in blood pressure detected by baroreceptors

• Increase in motor movement detected by proprioreceptors

Which all stimulate the Respiratory Control Centre:• RCC controls/regulated breathing• Stimulates inspiratory/expiratory muscles• Results in stronger contractions and increased

rate of stimulus/increased rate & depth of breathing.

8. Why does an increase in C02 during exercise increase

heart rate?

How does this happen?

Why?• Increase in C02 changes ph/acidity

How?• This is detected by chemoreceptors• Information sent to Cardiac Control Centre• Under autonomic control• Impulses sent via cardiac accelerator nerve• SA node is stimulated• Known as sympathetic

9. Describe how the mechanics of breathing after during

exercise to expire greater volumes of C02.

• This process becomes active• Due to intercostals contracting• Abdominal muscles contracting• Diaphram pushed up harder/rib

cage pulled in & down• Decrease in volume of thoracic

cavity• Causing an increased pressure

within thoracic cavity.

10. Identify two ways in which C02 is carried in the blood during

aerobic performance.

• Dissolves in plasma

• Combines with haemoglobin

• Forms carbaminohaemoglobin

• Dissolves in water/forms carbonic acid

11. How is C02 diffused from the muscle tissue into the

blood during exercise?

• C02 flows from an area of high pressure to low pressure

• Partial pressure of C02 is lower in the blood

• During exercise there is a greater concentration/diffusion gradient so faster diffusion will occur

• Haemoglobin is able to pick up C02 more easily when 02 is released

12.Describe the mechanics of inspiration and expiration

during exercise.

INSPIRATION• External intercostals contract with more force• Diaphragm contracts/flattens• More muscles involved, trapezius / sternocleidomastoid /

pectorals• Lift thoracic cavity further up and out/ribs up and out• Increases volume of cavity

EXPIRATION• Process becomes active• Internal intercostals contract• This pulls ribs down and in• Abdominals contract (pushes diaphragm up)• Decreases volume of cavity