Sec 3 Biology Respiration in Humans topical questions

Name, in order, the structures that air passes through between the trachea and the alveoli.

State the role of the cilia that line the trachea.

State the word equation for aerobic respiration.

Name the muscle whose contraction flattens it during inspiration, and state what happens to the volume of the chest cavity.

State the word equation for anaerobic respiration in human muscle, and give one reason its energy yield is small.

Describe how the ribs and intercostal muscles bring about expiration during hard exercise.

Explain two ways in which the alveoli are adapted for efficient gaseous exchange.

At rest a student’s tidal volume is 500 cm³ with 15 breaths per minute; during exercise it is 1000 cm³ with 30 breaths per minute. Calculate the ventilation rate at rest and during exercise, and state how many times greater the exercise value is.

Explain why carbon monoxide in tobacco smoke is harmful to the body.

Explain how cartilage, mucus and cilia each help keep the lungs healthy.

Inspired air contains 21% oxygen and 0.04% carbon dioxide; expired air contains 16% oxygen and 4% carbon dioxide. For every 1000 cm³ of air breathed in, calculate the volume of oxygen absorbed and state how many times more concentrated the expired carbon dioxide is.

Explain how the body increases its oxygen delivery to hard-working muscles during exercise, naming the changes in breathing and in the circulation.

Describe fully the mechanism of inspiration, and explain why it is described as an active process.

A sprinter finishes a 400 m race owing an oxygen debt of 3.6 dm³. While resting she absorbs 0.30 dm³ of oxygen per minute for debt repayment. Calculate how long her breathing rate stays above resting level, and explain what the oxygen is used for.

A sample of inspired air contains 21% oxygen and 0.04% carbon dioxide; the same student’s expired air contains 16% oxygen and 4% carbon dioxide. Calculate the percentage of the inhaled oxygen that is absorbed into the blood, and explain the changes in both gases.

During a 100 m sprint, explain fully why a runner’s leg muscles respire anaerobically, what this produces, and how the body deals with the products after the race.

Plan an investigation to compare a person’s breathing rate at rest and after exercise. State how breathing rate is measured, how the exercise is standardised, which variables are controlled, and the expected pattern of results.

A smoker has 10% of her haemoglobin locked up as carboxyhaemoglobin. (a) State the percentage reduction in her blood’s oxygen-carrying capacity. (b) A non-smoker’s blood delivers 250 cm³ of oxygen per minute to the tissues at rest; calculate the smoker’s delivery, and explain why exercise becomes harder for her.