bio flashcards

Respiration

The oxidation reaction that releases energy from foods such as glucose.

Breathing

The mechanism that moves air into and out of the lungs, allowing gas exchange to take place.

Gas exchange system

The preferred term used in the book for the lungs and associated structures instead of 'respiratory system'.

Thorax

The chest enclosing the lungs.

Diaphragm

A muscular sheet of tissue separating the thorax from the abdomen, with a shallow dome shape and a fibrous middle part.

Intercostal muscles

Two sets of muscles joining each rib to the next ('costals' are rib bones).

Bronchial tree

The highly branching network formed by the air passages of the lungs.

Trachea

The windpipe where air passes down from the nose or mouth.

Bronchi

Two tubes that the trachea splits into (singular: bronchus), one leading to each lung.

Bronchioles

Smaller and smaller tubes that each bronchus divides into, eventually ending at microscopic air sacs.

Alveoli

Microscopic air sacs (singular: alveolus) where gas exchange with the blood takes place.

Cartilage

Rings of gristle found in the walls of the trachea and bronchi that support the airways and keep them open.

Pleural membranes

Two thin, moist membranes making up a continuous envelope around the lungs, forming an airtight seal.

Pleural cavity

The space between the two pleural membranes, filled with a thin layer of liquid.

Pleural fluid

A thin layer of liquid in the pleural cavity acting as lubrication so lungs don't stick to the chest wall during breathing.

Mucus

A sticky liquid secreted by cells in the trachea and larger airways lining to trap dirt particles or bacteria.

Cilia

Tiny hair-like structures on cells that beat backwards and forwards, sweeping mucus and trapped particles out towards the mouth.

Ventilation

Moving air in and out of the lungs, which requires a difference in air pressure.

External intercostals

Intercostal muscles whose outer set contract to pull the ribs up and out during inhalation.

Internal intercostals

Intercostal muscles that contract during deep exhalation to pull the ribs down and in.

Alveoli surface area

The two lungs contain about 700,000,000 tiny air sacs giving a total surface area of 60 square meters.

Atmospheric air oxygen percentage

Approximately 21%

Exhaled air oxygen percentage

Approximately 16%

Atmospheric air carbon dioxide percentage

Approximately 0.04%

Exhaled air carbon dioxide percentage

Approximately 4%

Atmospheric air nitrogen percentage

78%

Exhaled air nitrogen percentage

79%

Diffusion gradient for oxygen

Oxygen diffuses from the air in the alveoli across the alveolar wall and into the blood due to higher concentration in the alveulus.

Diffusion gradient for carbon dioxide

Carbon dioxide diffuses out of the blood and into the alveolus because there is more carbon dioxide in the blood than in the air in the lungs.

Bronchitis

A lung disease caused by irritation of the bronchial tree along with bacterial infections in mucus, blocking normal air flow and causing 'smoker's cough'.

Emphysema

A lung disease where smoke damages alveolar walls, causing them to break down and fuse together into enlarged, irregular air spaces, reducing surface area.