Breathing & Lungs
A small terminal cavity found at the end of the bronchioles of the lung where gaseous exchange between air and blood takes place. / alveolus or alveoliA common breathing disorder caused by narrowing of the bronchioles of the lungs, with accompanying mucus secretion. This can be brought on by the presence of pollen, house mites, dog and cat dander or vigorous exercise. / asthma
Situations or substances that bring about an asthma attack. / asthma triggers
The physical process of taking in oxygen (inhalation or inspiration) and giving out of carbon dioxide and water vapour to the air (exhalation or expiration). It is also called external respiration. / breathing
The number of breaths per minute. The average in an adult human is 16 per minute. / breathing rate
The lungs and associated muscles and ribs required for inspiration and expiration. / breathing system
One of the numerous minute divisions of the bronchus. / bronchiole
An inflammatory condition affecting the bronchi. Caused by respiratory bacteria, viruses and long-term exposure to irritants such as cigarette smoke and air pollutants. Results in a build up of mucus in the bronchi. / bronchitis
Substance in an inhaler, used by a person suffering from asthma. It widens the bronchioles and makes it easier to breathe. / bronchodilator
One of two main divisions of the trachea (windpipe) leading to a lung. / bronchus or bronchi
Tiny, hair-like cytoplasmic extensions of a cell which beat rhythmically. In lower animals they are for locomotion; in higher forms, for propulsion of substances, e.g. mucus from the trachea. / cilia
A muscular sheet or membrane separating the thorax and abdomen. Situated below the lungs and above the liver, stomach and spleen. It is dome-shaped at rest. / diaphragm
A flap of cartilaginous tissue at the base of the tongue, which covers the opening to the larynx and trachea when swallowing and thus prevents food going ‘down the wrong way’. / epiglottis
The process of breathing out air from the lungs. / exhalation
This is a passive process, i.e. requires no energy. This is expelling air from the lungs. The diaphragm and intercostal muscles relax causing the ribs and diaphragm to return to their original positions. These actions result in a decreased volume of the thorax (chest cavity) and an increase in the air pressure in the lungs, consequently air is expelled from the lungs. / expiration
At respiratory surfaces (lungs in humans, gills in fish) it is the removal of waste gas (carbon dioxide) and the taking in of necessary gas (oxygen). In the leaves of plants during photosynthesis carbon dioxide moves in through the stomata and oxygen moves out through the stomata. / gas (gaseous) exchange
The opening of the larynx. / glottis
The process of breathing in. / inhalation
An active process, i.e. requires energy. This is taking air into the lungs. The intercostal muscles between the ribs contract causing the ribs to move upwards and outwards. The circular muscles of the diaphragm contract and cause it to flatten. These actions result in an increased volume of the thorax and a decrease in the air pressure in the lungs – consequently air is drawn into the lungs. / inspiration
The muscles located between the ribs. / intercostal muscle(s)
Voice box, located at top of trachea. Produces sounds. / larynx
One of a pair of spongy organs that functions during breathing for gaseous exchange. / lung(s)
Slimy substance produced by certain membranes, consisting mainly of glycoprotein. It lubricates, moistens and protects tissues, and may contain enzymes. / mucus
Of or pertaining or relating to the nose. / nasal
The space between the roof of the mouth and the base of the skull. Divided in two by a septum and each half connects to the exterior via the nostrils. / nasal cavity
The two openings in the nose that allow air to the lungs. / nostrils
Blood that has oxygen attached to the haemoglobin. / oxygenated blood
The space between the membranes of the pleura. / pleural cavity
Fluid found between the pleura which reduces friction when breathing. / pleural fluid
Two thin membranes of epithelium – one lines the cavity of the thorax and the other covers the outer surface of the lungs. / pleural membranes
The number of inspirations per minute. The average for an adult at rest is approximately sixteen. Controlled by the ventilation centre of the medulla oblongata. / rate of breathing
Specialised region where gaseous exchange takes place, e.g. alveoli of humans, gills of fish, skin of earthworm. / respiratory surface
Group of organs concerned with gaseous exchange, e.g. lungs, muscles, etc. / respiratory system
Tube through which air enters a body, animal, insect, etc. / trachea
Area of the medulla oblongata sensitive to the level of carbon dioxide in the blood and the pH of the blood. When carbon dioxide levels increase, pH lowers (i.e. gets more acidic) and this area increases the rate of breathing. / ventilation centre
Two pairs of membranous folds of the larynx, whose edges vibrate in an air-stream to produce sounds/voice. Situated near the glottis. / vocal cords
Page 3 of 3