Mechanics of Breathing 1 

1. Which two muscles are responsible for inspiration at rest?
2. When the chest expands during inspiration, what happens to the pressure within the lungs?
3. Expiration is a passive process at rest. But which muscles are responsible for expiration during exercise?
4. During expiration, the diaphragm contracts downwards flattens. True or False?

A1. External intercostal muscles and diaphragm

A2. It decreases. This creates a pressure differential between the inside and outside of the body which causes air to rush into the lungs to equalise the pressures inside and outside the body.

A3. Internal intercostal muscles and abdominals (rectus abdominis & transverse abdominis)

A4. False, it relaxes into a dome shape.

Mechanics of Breathing 2

1. Other than the external intercostal muscles and diaphragm, which muscles are recruited during exercise to aid inspiration?
2. What happens to the pressure within the lungs during expiration?
3. Are the internal and external intercostal muscles recruited for expiration during exercise?
4. During expiration the diaphragm is forced upwards into the shape of a dome. True or False?

A1. Sternocleidomastoid, scaleni, pectoralis major

A2. It increases to a point where it becomes higher than atmospheric pressure. This causes air to rush out of the lungs until equilibrium is reached.

A3. Internal intercostal muscles

A4. True

Control of Breathing

1. The area that regulates breathing is known as what?
2. What are the two parts of the respiratory centre?
3. The muscles under the control of the inspiratory centre are the diaphragm and the internal intercostal muscles. True or False?
4. Name two types of receptor that act upon the inspiratory centre.

A1. Respiratory Control Centre

A2. The inspiratory and expiratory centres

A3. False. the muscles under the control of the inspiratory centre are the diaphragm and the external intercostal muscles.

A4. Any two from: chemoreceptors, baroreceptors, thermoreceptors

Partial Pressure

1. Gases always move from areas of high pressure to areas of low pressure. True or False?
2. Is the partial pressure of oxygen in the alveolar air higher or lower than that in the capillaries surrounding the alveoli?
3. The term used to describe the movement of a gas across a membrane is known as?
4. Does the oxygen diffusion capacity increase, decrease or remain the same as exercise commences?

A1. True. Gases always move from high to low partial pressure, until equilbrium is reached.

A2. Higher. This ensures that oxygen moves from the alveoli into the bloodstream.

A3. Diffusion

A4. Increases. This is largely due to an increase in cardiac output and elevated blood pressure.

Effects of Altitude

1. Does the relative percentage of oxygen in the atmosphere increase, decrease or stay the same with an increase in altitude?
2. Does the partial pressure of oxygen decrease with altitude?
3. Does the pressure gradient between the blood and the tissues decrease with altitude?
4. Which is least likely to to increase with altitude: respiratory rate, heart rate, VO₂ max or cardiac output?

A1. It stays the same. The relative percentages of gases do not change. It is the overall pressure of the air and therefore the partial pressures of individual gases that decrease with altitude.

A2. Yes

A3. Yes. A reduced pressure gradient means that there is a decreased movement of oxygen from the blood into the tissues.

A4. VO₂ max - it decrease with altitude.

Haemoglobin

1. What is the formula HbO₂ better known as?
2. Approximately what percentage of carbon dioxide produced during exercise combines with haemoglobin?
3. Approximately how much oxygen is carried by haemoglobin?
4. Give two factors that cause the dissociation of oxygen from haemoglobin.

A1. Oxyhaemoglobin

A2. 20%

A3. 97%

A4. Any two from: increased carbon dioxide production, increased body temperature, decreased muscle pH

Oxyhaemoglobin Dissociation Curve

1. At the lungs, approximately how much of the haemoglobin is saturated with oxygen?
2. What factors cause a reduction in the saturation of haemoglobin with oxygen during exercise?
3. What happens to the oxyhaemoglobin dissociation curve during exercise?
4. What is the effect of the Bohr shift?

A1. 97%

A2. An increased blood acidity (fall in pH), increased CO₂ content, increased lactic acid production, increased body/muscle temperature.

A3. It shifts to the right.

A4. It frees up more oxygen, which can be subsequently be used by the working muscles.

Lung Volumes

1. Which two variables are used to calculate minute ventilation?
2. State the equation that describes their relationship.
3. What are the typical resting values of these variables?
4. Does inspiratory reserve volume increase with exercise?
5. What piece of equipment is used to measure lung volumes?
6. Tidal volume is the volume of air inspired and expired  per breath. True or False?

A1. Tidal volume, frequency of breathing

A2. Minute ventilation (VE) = Tidal Volume (TV) x frequency (F)

A3. TV = 500ml, F = 15/min (therefore VE = 7.5 litres/min)

A4. No. It decreases to enable tidal volume to increase during exercise.

A5. A Spirometer

A6. False. Tidal volume is the volume of air inspired or expired per breath.

Smoking

1. Name the gas contained in cigarette smoke that reduces the availability of oxygen to the tissues.
2. Smoking causes the heart rate to increase, even at rest. True or False?
3. Smoking can cause a reduction in VO₂max (the maximum volume of oxygen utilised by the muscles) by approximately how much?
4. What substance can coat the respiratory structures, hindering gaseous exchange?

A1. Carbon monoxide

A2. True. The heart must work harder in order to compensate for the reduced transportation of oxygen.

A3. 10%

A4. Tar

Healthy, balanced lifestyle

1. Give two health related consequences of smoking.
2. Exercise can improve the functioning of the cardiovascular system. One way is through the enlargement of the heart. What is this known as?
3. The strength of skeletal tissues such as bones improves following an exercise programme. What accounts for this increase in strength?
4. One negative impact of stress on the health of an individual is hypertension. Explain what is meant by 'hypertension'.

A1. Any two from: restricted oxygen transport, narrowing of the respiratory airways, deposition of tar, cardiovascular disease, coronary heart disease, lung cancer, emphysema

A2. Cardiac hypertrophy

A3. Bone density increases

A4. Hypertension is high blood pressure that is consistently over 160/95 mmHg