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LEARNING LEARNING OUTCOMESOUTCOMES

To describe the change in the rate of To describe the change in the rate of respiration after completing a vigorous respiration after completing a vigorous activity;activity;

To correlate the rate of respiration with the To correlate the rate of respiration with the oxygen & carbon dioxide content in the body;oxygen & carbon dioxide content in the body;

To explain the regulatory mechanism of To explain the regulatory mechanism of oxygen & carbon dioxide content in the body;oxygen & carbon dioxide content in the body;

To explain the human respiratory response & To explain the human respiratory response & rate of respiration in different situations;rate of respiration in different situations;

To correlate the respiration with the rate of To correlate the respiration with the rate of heart beat.heart beat.

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At restAt rest : breathing rate of man : breathing rate of man – – 15 to 18 times15 to 18 times a minute. a minute.

At work @ vigorous activityAt work @ vigorous activity : : increasesincreases more O2 is needed more O2 is needed to supply enough energy, more to supply enough energy, more CO2 is produced from cell CO2 is produced from cell respiratory in the musclesrespiratory in the muscles

The The increased conc. of CO2increased conc. of CO2 in in the blood the blood the regulatory the regulatory mechanism mechanism rate of breathing rate of breathing increaseincrease O2 is supplied O2 is supplied quickly to the body cells, CO2 is quickly to the body cells, CO2 is removed rapidly from the lungsremoved rapidly from the lungs

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Regulatory Mechanism of O2 & Regulatory Mechanism of O2 & CO2 Content in the BodyCO2 Content in the Body

The The breathing centre of humansbreathing centre of humans is is locatedlocated in the in the medulla oblongatamedulla oblongata of the brain. Consist of a special of the brain. Consist of a special group cells called group cells called central central chemoreceptorschemoreceptors regulate the O2 & CO2 content in the body in the body

Vigorous activityVigorous activity (swimming & (swimming & aerobic exercises) – the [CO2] in aerobic exercises) – the [CO2] in the blood increases because of the blood increases because of the increased rate of respiration the increased rate of respiration in the cellsin the cells

PPCO2CO2 in the blood in the blood increaseincrease while while PPO2 O2 decreasedecrease

The The carotid & aortic bodiescarotid & aortic bodies are are stimulated stimulated nerve nerve inspiratory inspiratory centrecentre

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High [CO2] in the blood High [CO2] in the blood lowers the pH valuelowers the pH value (carbonic acid (carbonic acid hydrogen hydrogen ions + bicarbonate ions)ions + bicarbonate ions)

High [H+] (low pH)High [H+] (low pH) stimulates the central stimulates the central chemoreseptors to emit chemoreseptors to emit nerve impulses nerve impulses breathing/inspiratory breathing/inspiratory centre centre impulses impulses intercostal muscles & intercostal muscles & diaphragm musclesdiaphragm muscles

The The intercostal muscles & intercostal muscles & the diaphragm muscles the diaphragm muscles contract rapidlycontract rapidly the rate the rate of breathing & the rate of of breathing & the rate of ventilation increase.ventilation increase.

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The lung expand, stretch receptor in The lung expand, stretch receptor in the wall of bronchi & bronchioles are the wall of bronchi & bronchioles are stimulatedstimulated nerve nerve expiratory expiratory centre centre ‘switch off’ inspiratory ‘switch off’ inspiratory centrecentre

Diaphragm & external intercostal Diaphragm & external intercostal relax relax expiration expiration

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The rate of ventilationThe rate of ventilation = vol. of air = vol. of air breathed per minute & signifies the breathed per minute & signifies the depth of breathing depth of breathing the rate of the rate of gaseous exchange between the air in gaseous exchange between the air in the alveolus & the bloodthe alveolus & the blood in the in the capillaries.capillaries.

Enable Enable more O2 to be supplied & more O2 to be supplied & more CO2 to be removedmore CO2 to be removed until the until the level of pH in the blood returns to level of pH in the blood returns to normalnormal

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Respiratory Response in Difference Respiratory Response in Difference SituationsSituations

At high altitudesAt high altitudes 4000m above sea level, 40% less O2 4000m above sea level, 40% less O2 develop develop

hypoxia (a shortage of O2)hypoxia (a shortage of O2) Mountain sickness (breathless, headache, nausea, Mountain sickness (breathless, headache, nausea,

vomiting & heart palpitations)vomiting & heart palpitations) Chemoreceptors (carotid & aortic bodies) send nerve Chemoreceptors (carotid & aortic bodies) send nerve

to the medulla oblongata to the medulla oblongata increase the rate of increase the rate of respiration & the rate of heartbeat respiration & the rate of heartbeat acclimatised acclimatised

FearFear Fear/ feeling anxious, the rate of breathing & the rate Fear/ feeling anxious, the rate of breathing & the rate

of heartbeat will increaseof heartbeat will increase The adrenal glands secrete the hormone adrenaline The adrenal glands secrete the hormone adrenaline

into the bloodstream into the bloodstream target organ target organ prepare the prepare the body actionbody action

Enable muscles to obtain enough oxygen & to remove Enable muscles to obtain enough oxygen & to remove the excess CO2 quicklythe excess CO2 quickly

Provide enough energy to prepare the body to act Provide enough energy to prepare the body to act under such tense situationsunder such tense situations

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7.5 The Importance of 7.5 The Importance of Maintaining a Healthy Maintaining a Healthy Respiratory SystemRespiratory System

Do not smokeDo not smoke bronchitis, bronchitis, emphysema & lung canceremphysema & lung cancer

Keep away from smokersKeep away from smokers to avoid 2 to avoid 2ndnd hand smoke hand smoke lung diseases lung diseases

HazeHaze – – stay indoorsstay indoors or cover your nose or cover your nose & mouth with a mask& mouth with a mask

Exercise to keep lungs healthyExercise to keep lungs healthy breathe deeply, lungs become stronger breathe deeply, lungs become stronger & better at supplying body with O2& better at supplying body with O2

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What is in tobacco smoke?What is in tobacco smoke? TarTar

Thick, sticky dark brown substanceThick, sticky dark brown substance – – carcinogenic, damages lungs tissues, breakdown carcinogenic, damages lungs tissues, breakdown the alveoli (decreasing the total surface area) the alveoli (decreasing the total surface area) causes bronchitis, smoker coughcauses bronchitis, smoker cough

NicotineNicotine Highly addictive chemicalHighly addictive chemical – causes blood platelets – causes blood platelets

to become sticky (lead to clotting), raise up blood to become sticky (lead to clotting), raise up blood pressure & heart rate, narrows the arteries pressure & heart rate, narrows the arteries HBP HBP

Carbon monoxideCarbon monoxide

Combine Combine Poisonous, odorlessPoisonous, odorless with haemoglobin with haemoglobin carboxyhaemoglobincarboxyhaemoglobin

Limits the body’s ability to transport O2 Limits the body’s ability to transport O2 breathlessnessbreathlessness

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