Gas Exchange key words

Addiction

A substance taken for a pleasurable effect but then becomes compulsive and interferes with day-to-day activities

Alveoli

Microscopic air sacs in the lungs where gas exchange takes place

Breathing rate

number of breaths per minute

Bronchi (bronchus)

Tubes leading from trachea to the lungs

Bronchial tree

branching network of air passages in the lungs

Bronchioles

small air passages leading from bronchi to alveoli

Bronchitis

Lung disease caused by irritation of the bronchial tree and infection by bacteria, resulting in breathing difficulties

Capillary

Thin, narrow blood vessels that area a site of exchange of substances between the blood and the tissues

Carboxyhaemoglobin

substance formed when carbon monoxide combines with haemoglobin, displacing oxygen from haemoglobin

Carcinogen

Something that causes cancer e.g. tar and radiation

Cartilage

Tough tissue present in several places in the body, like C-shaped rings in the trachea and between bones at a joint

Cilia

Microscopic hair like projections from the surface of some animal cells, such as those lining the trachea and bronchi. Beating of cilia moves mucus and trapped particles towards the mouth

Compensation point

point where photosynthesis and respiration use and produce equal amounts of oxygen and carbon dioxide. This is where rate of photosynthesis equals rate of respiration

Coronary Heart disease (CHD)

Disease caused by the build up of fatty deposits inside the coronary arteries, narrowing them and reducing blood flow to the heart tissue. Smoking increases the risk

Diaphragm

Muscular sheet separating the thorax from the abdomen. Involved in the mechanism that ventilates the lungs

Emphysema

Lung disease where the walls of the alveoli break down and fuse together again, forming air spaces with a reduced surface area. It results in breathing difficulties

Exhalation/expiration

Breathing out

Guard cell

Pair of specialised cells surrounding a stoma in the epidermis of a leaf. They change shape to open and close the stomata

Haemoglobin

Chemical present in red blood cells that combines with oxygen and carries it around the body

Inhalation/inspiration

Breathing in

Intercostal muscles

Group of muscles situated between the ribs. They are responsible for the movement of the ribs during breathing

Mucus

Sticky liquid secreted by cells lining the trachea and bronchi to trap dust/bacteria

Mutation

Change in structure of the DNA that makes up a gene or chromosome

Nicotine

Addictive drug present in tobacco and cigarette smoke

Pleural fluid

Thin layer of fluid filing the pleural cavity

Pleural membranes

2 layers of membrane forming a continuous envelope around the lungs

Pleural cavity

Space between the pleural membranes

Spongy mesophyll

Tissue found in plant leaves that is specialised for gas exchange

Stomata

Pores in the epidermis of a leaf

Tidal volume

Volume of air breath in and out with each resting breath

Trachea

Windpipe leading from nose and mouth to bronchi

Tumour

Mass of cells produced by mutation and uncontrolled cell division

Ventilation

Movement of air in and out of the lungs

Vital capacity

Largest volume of air that can be moved in and out of the lungs in any one breath