Respiratory Function, Breathing, Respiration

BI 233Exercise 40

Introduction• Pulmonary Ventilation is

the movement of air into and out of the lungs and the exchange of gases across the respiratory membrane

• The ventilation rate is the number of breaths per minute

• The pulmonary volume is the amount of air inhaled and exhaled with each breath

Clinical Application• Adequate pulmonary

ventilation is critical• Reduction in pulmonary

ventilation can cause increased C02 (hypercapnia) producing acidosis

• Increased pulmonary ventilation can lead to a reduction in C02 (hypocapnia) producing alkalosis.

• Changes in C02 concentrations can alter breathing rates

Mechanics of Breathing• Air moves from regions of higher

pressure to regions of lower pressure.

• The lungs fill with air or deflate due to changes in air pressure.

• During inspiration the diaphragm contracts (with external intercostals) increasing the volume in thoracic cavity causing a decrease in pressure in the lungs which causes air to move into the lungs.

• When the diaphragm relaxes the size of thoracic cavity decreases causing increase in pressure and therefore causing expiration.

Measurement of Relaxed Breathing Rate

• Calculate your lab partner’s relaxed breathing rate

• Have partner read lab exercise while you count the number of breaths for 2 minutes.

• Divide by 2• Record your results• Do this again but have lab

partner do strenuous exercise for 2 minutes and then count the number of breaths.

Pulmonary Volumes

• Pulmonary volumes are the amount of air that flows into or out of the lungs during a particular event.

• Tidal Volume(TV): amount of air inhaled or exhaled with each breath under resting conditions (300-500ml) *The numbers given for volumes and

capacities are averages and vary greatly between individuals

Pulmonary Volumes• Inspiratory Reserve

Volume (IRV): Amount of air that can be forcefully inhaled after a normal tidal volume inhalation (3100ml)

• Expiratory reserve volume (ERV): amount of air that can be forcefully exhaled after a normal tidal volume exhalation (1200ml)

• Residual Volume: Air left in lungs (1000ml)

Capacities• Lung capacities are

calculated by summation of volumes

• Vital Capacity (VC): Maximum amount of air that can be exhaled after a maximal inspiration (4800ml)

• Calculate your volumes and capacities including the percent of expected VC

Other Exercises

• Calculate your minute ventilation

• Do flow and resistance exercise and be able to describe the relationship between these.

• Listen to your lab partners respiratory sounds with the stethoscope

Cardiopulmonary Resuscitation

• CPR: typically used for people suffering from a heart attack (myocardial infarct), drug overdoses, drowning or trauma and obstruction of airways. Uses chest compressions of 100 times per minute on the body of the sternum.

Physiology of Exercise and Pulmonary Health

Exercise 41

Exercise

• Aerobic exercises increase heart rate and breathing rates at moderate levels for extended periods of time.

• Anaerobic exercises result in the consumption of available oxygen faster than it can be supplied to the muscle tissue

Forced Expiratory Vital Capacity (FEV)

• Indications of health can be roughly correlated with the amount of air expelled from the lungs in 1 second.

• Expressed as a percent when compared to a person’s vital capacity.

• Should be approx 75%

Pulmonary Obstruction

• Occurs when the respiratory passages are narrowed.

• Can be caused by excess mucus (such as asthma) or inflammation (such as bronchitis.

• Most COPD is caused by smoking.

• VC is normal but FEV1/VC% is low.

• It takes longer to exhale

Pulmonary Restriction

• Occurs when the lungs cannot fully inspire or expire the full volume of air.

• Vital Capacity is reduced• Caused by fibrosis of the

lungs (cystic fibrosis or from asbestos) or adhesions of the lung to the chest (emphysema)

• FEV1/VC% is normal

Harvard Step Test• Was developed to

determine a person’s physical fitness.

• We do not have the steps recommended in lab manual but you can go outside and walk up and down stairs for 3-5 minutes.

• Subject then rests for 30 seconds

• Then partner takes pulses every 30 seconds

• Calculate PFI:

Body Mass Index

• BMI is a general guide to fitness

BMI= Weight in pounds/(height in inches)2 X 703

OrBMI= Mass(kg)/ Height

(M)2

Waist/Hip Ratio

• WHR: According to the American Heart Association, people who carry more weight in their waist region are more at risk for health problems.

• WHR= Circumference of waist/Circumference of hips