As Biology Chapter 4 Keywords

Front 1

Lungs

Back 1

Specialised surfaces for efficient gas exchange between the air and blood. They are a pair of lobed structures made up of a series of highly branched tubules which end in tiny air sacs.

Front 2

Trachea

Back 2

A flexible airway that is supported by rings of cartilage. The walls are made up of muscle lined with ciliated epithelium cells and goblet cells.

Front 3

Bronchi

Back 3

Two divisions of the trachea, each leading to one lung. Like the trachea, they also produce mucus to trap dirt particles. The larger bronchi are supported by cartilage, which is reduced as the bronchi get smaller.

Front 4

Bronchioles

Back 4

A series of branching subdivisions of the bronchi. Their walls are made up of muscle lined with epithelium cells. This allows them to constrict, so they can control the flow of air in and out of the alveoli.

Front 5

Alveoli

Back 5

Minute air-sacs at the end of the bronchioles. They contain some collagen and elastic fibres, and are lined with epithelium cells. Elastic fibres allow for stretching when they fill with air.

Front 6

Rib cage

Back 6

A bony box used to support and protect the lungs. The ribs can be moved by the muscles between them.

Front 7

Ventilation

Back 7

The process of breathing - where air is constantly moved in and out of the lungs.

Front 8

Inspiration

Back 8

When the air pressure of atmosphere is greater than the air pressure inside the lungs, air is forced into the lungs.

Front 9

Expiration

Back 9

When the air pressure inside the lungs is greater than the air pressure of the atmosphere, air is forced out of the lungs.

Front 10

Thorax

Back 10

The cavity enclosed by the ribs, in which the heart and lungs are contained.

Front 11

Internal intercostal muscles

Back 11

Muscles that lie between the ribs, whose contraction leads to expiration.

Front 12

External intercostal muscles

Back 12

Muscles that lie between the ribs, whose contraction leads to inspiration.

Front 13

Diaphragm

Back 13

A sheet of muscle that separates the thorax and the abdomen.

Front 14

Pulmonary ventilation

Back 14

The total volume of air that is moved into the lungs during one minute.

P.V = tidal volume x ventilation rate

Front 15

Tidal volume

Back 15

The volume of air normally taken in at each breath when the body is at rest (Usually 0.5 dm^3).

Front 16

Ventilation rate

Back 16

The number of breaths taken in one minute (usually 12-20 breaths).

Front 17

Endothelium

Back 17

A single layer of thin cells that line the capillary.

Front 18

Pulmonary tuberculosis

Back 18

An infectious disease that is spread through the air by droplets. The disease has bacteria that will affect the upper lung region due to more oxygen. White blood cells are released as a response and so inflammation occurs - the primary response.

Front 19

Pulmonary fibrosis

Back 19

Arises when scars form of the epithelium of the lungs. Fibrosis means oxygen cannot diffuse into the blood efficiently because the diffusion pathway has been lengthened by scarring and the volume of air that the lungs can contain has been reduced.

Front 20

Asthma

Back 20

Localised allergic reaction. Allergens trigger the release of histamine by white blood cells of bronchi/oles linings. It causes greater resistance to the flow in and out of the alveoli. This is difficult to ventilate lungs and so maintain a diffusion gradient across the exchange surface.

Front 21

Emphysema

Back 21

The elastic tissue in the lungs becomes permanently stretched and the lungs are no longer able to force out all air from the alveoli. The surface area of the alveoli is reduced and they sometimes burst, so little gas exchange can takes place.

Front 22

Chronic

Back 22

Continuing for a long time.