Gas Exchange Flashcards

Flashcards covering gas exchange, the breathing system, and the effects of smoking and exercise.

What is the thorax?

The human chest cavity consisting of the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli, and pleural membranes.

What features do all gas exchange surfaces have in common?

Large surface area, thin walls, good ventilation, and good blood supply.

What is the role of the intercostal muscles?

Muscles that work antagonistically to facilitate breathing.

What is the diaphragm?

A thin sheet of muscle that separates the chest cavity from the abdomen and helps in breathing.

What happens during inhalation?

The diaphragm contracts and flattens, external intercostal muscles contract to pull ribs up and out, increasing chest cavity volume and decreasing air pressure inside the lungs.

What happens during normal exhalation?

The diaphragm relaxes and moves upwards, external intercostal muscles relax so ribs drop down and inwards, decreasing chest cavity volume and increasing air pressure inside the lungs.

What occurs during forced exhalation?

Internal intercostal muscles pull the ribs down and in, decreasing the volume of the thorax further to force air out more quickly.

How are alveoli adapted for gas exchange?

Many rounded alveolar sacs providing a large surface area, thin single layers of cells, ventilation maintaining concentration gradients, and a good blood supply maintaining concentration gradients.

What is the main function of Alveoli?

They are highly adapted and specialised for gas exchange.

What harmful chemicals are found in cigarettes?

Nicotine (narrows blood vessels, increases heart rate), carbon monoxide (reduces blood's oxygen-carrying capacity), and tar (carcinogen linked to COPD and lung cancer).

How does smoking lead to chronic bronchitis?

Tar stimulates goblet cells and mucus glands to produce more mucus, blocking bronchioles and leading to infections; cilia are damaged, preventing mucus removal.

How does smoking cause emphysema?

Phagocytes release elastase, breaking down elastic fibers in alveoli, causing them to lose elasticity and burst, reducing surface area for gas exchange.

Why does exercise cause an increase in breathing frequency?

Muscles need more oxygen and produce more carbon dioxide, leading to an increased breathing rate.

Why does breathing rate remain elevated after exercise?

Lactic acid builds up in muscles and needs to be removed by combining it with oxygen.

What are some indicators of an unfit individual's breathing during and after exercise?

A higher resting breathing rate, a more rapid increase in breathing rate during exercise, and a longer recovery period.

How can you control variables when investigating the effect of exercise on breathing?

Ensure students are of similar size, general fitness, age, gender, and provide the same meal before exercise; use exercise with easily controlled intensity.