Transport systems in animals

Providing for the cell’s needs

The cell theory states that all living organisms are made up of cells or substances produced by cells.

All cells need nutrients eg glucose and oxygen in order to function properly, be active and grow.

The cells use the nutrients and produce wastes eg carbon dioxide that must be removed as they can be toxic and damage the cells.

The process that provides energy for the activity of cells is cellular respiration. The formula for cellular respiration is:

glucose + oxygen carbon dioxide + water + ENERGYC6H12O6 + O2 CO2 + H2O + Energy (ATP + waste heat)

Why we need organ systemsOrganisms which are single-celled or very

small and thin (less than 1 mm) can exchange materials through their body surfaces.

Because most multi-cellular organisms are too large for exchange of nutrients and wastes to occur through their body surfaces, they need organs to allow this exchange. Most multi-cellular organisms have organs arranged in systems to do this:

• A transport system - called the circulatory system to bring these nutrients to the cells, and to carry away wastes,

• A system to allow exchange of oxygen and carbon dioxide - called the respiratory system

• A system to obtain nutrients - called the digestive system

• A system to deal with and remove wastes from the body - called the excretory system

Open circulatory systems

• Open systems have one or more pumps (hearts) and tubes that empty into body cavities. The fluid (haemolymph) can leave the vessels.

• Found in smaller invertebrates

Mollusc

Insect

Crustacean

Closed circulatory systems

• Closed systems have one or more hearts and blood vessels that feed back to the heart. The fluid (blood) does not leave the vessels.

• Found mainly in the vertebrates• The number of chambers in the heart varies

The circulatory system carries blood and dissolved

substances to and from different places in the body. The Heart has the job of pumping these things around

the body. The Heart pumps blood and substances around

the

body in tubes called blood vessels. The Heart and blood vessels together make up the

Circulatory System.

What is a closed circulatory system?

The Mammalian Heart

Left Ventricle

Left AtriumRight Atrium

Right Ventricle

Right atrioventricular valve (tricuspid)

Pulmonary artery - Vein from Lungs

Aorta - Artery to Head and Body

Pulmonary artery - Artery to Lungs

Superior vena cava - Vein from Head and Body

Semi lunar valves

Left atrioventricular valve (bicuspid)

Blood flows out of and away from the ventricular chambers via arteries Arteries branch into arterioles

Arterioles branch into capillariesGas exchange occurs across capillaries, whose walls are one cell thick

Capillaries connect to venules Venules connect to veinsVeins return blood to the heart

Mammalian circulation