07. OCR A - 2.1.6 Cell division etc - Chapter 7 - Biology - Year 1

Keywords for OCR A Biology - Year 1 - 2.1.6 Cell division etc - Chapter 7

Alveolus

One of the tiny air sacs in the lungs where gases are exchanged between air and blood.

Breathing rate

The number of breaths (inhalation and exhalation) taken per minute.

Cartilage

Strong, flexible connective tissue found in many areas of the bodies of humans and other animals.

Countercurrent exchange system

A system for exchanging materials or heat when the two different components flow in opposite directions past each other.

Elastic recoil

The ability to return to original shape and size following stretching. Particularly of the alveoli of the lungs and of the arteries.

Exchange surfaces

Surfaces over which materials are exchanged from one area to another.

Exoskeleton

An external skeleton of some organisms, e.g. Insects.

Expiratory reserve volume

The extra amount of air that can be forced out of the lungs over and above the normal exhalation (tidal volume).

Fick's law

The rate of diffusion is proportional to surface area and concentration difference, and inversely proportional to diffusion distance.

Gaseous exchange system

The complex systems in which the respiratory gases oxygen and carbon dioxide are exchanged in an organism.

Gills

The gaseous-exchange organs of fish, consisting of arches that support filaments bearing many thin lamellae.

Goblet cells

Differentiated cells specialised to secrete mucus.

Inspiratory reserve volume

The maximum volume of air that can be breathed in over and above a normal inhalation (tidal volume).

Intercostal muscles

Skeletal muscles between the ribs; the external layer contracts during inhalation, while the internal layer contracts during forced exhalation.

Large surface area to volume ratio*

A feature that provides relatively more surface through which substances can be exchanged.

Lung surfactant

Chemical mixture containing phospholipids and both hydrophilic and hydrophobic proteins, which coats the surfaces of the alveoli and prevents them collapsing after every breath.

Operculum

The bony flap covering the gills of bony fish. Part of the mechanism that maintains a constant flow of water over the gas exchange surfaces.

Residual volume

The volume of air that is left in the lungs after forced exhalation. It cannot be measured directly

Root hair cells

Cells found just behind the growing tip of a plant root that have long hairlike extensions that greatly increase the surface area available for the absorption of water and minerals from the soil.

Spiracles

Small openings along the thorax and abdomen of an insect that open and close to control the amount of air moving in and out of the gas exchange system and the level of water loss from the exchange surfaces.

Tidal volume

The volume of air which moves into and out of the lungs with each resting breath.

Total lung capacity

The sum of the vital capacity and the residual volume.

Trachea

The main airway, supported by incomplete rings of cartilage, which carries warm moist air down from the nasal cavity into the chest.

Tracheal fluid

Fluid found at the ends of the tracheoles in insects that helps control the surface area available for gas exchange and water loss.

Ventilation rate

The total volume of air moved into or out of the lungs each minute, calculated as tidal volume multiplied by breathing rate.

Vital capacity

Volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible intake of breath.