Distributing materials

Key understanding:To discuss features of effective transport systems and give examples of transport systems in multicellular organisms

• Why do we have transport systems?• What needs to be transported?• What are the features of effective transport

systems?

Circulatory systems

Open circulatory systems • Open ended vessels• Fluid flows freely between cells of the body• Very low pressure and long circuit timesClosed circulatory systems• Fluid (blood) is entirely enclosed within system of vessels and

pumped around body by muscular heart• High blood pressure• Blood is separated from interstitial fluid by vessel walls which

allows it to have greater specialisation

• (page 165)

Blood circulation in mammals

• 2 sequential pathways involved:1) Pulmonary vessels to and from the lungs2) Systemic vessels to and from the rest of the

body

• Arteries carry blood AWAY from the heart• Veins carry blood TO the heart

Transport systems in multicellular organisms

http://www.teachersdomain.org/asset/tdc02_vid_circulator/

Label diagrams

Heart dissectionHeart dissection (see page 173 of biozone)http://

www.youtube.com/watch?v=z3UHpvEJMns&feature=related

• Try to identify:- Left and right atria- Left and right ventricles- The atrioventricular valves- Pulmonary artery and vein- Aorta- Vena cava- Coronary arteries

• Identify the flow of blood on your diagrams(p167)• Deoxygenated blood FROM body flows into RIGHT

ATRIUM via the VENA CAVA• When atria contract it then flows into RIGHT VENTRICLE• When RIGHT VENTRICLE contracts blood flows into

PULMONARY ARTERY • Blood becomes oxygenated• Re-enters the heart through PULMONARY VEIN into LEFT

ATRIUM, then into LEFT VENTRICLE• When LEFT VENTRICLE contracts blood flows to rest of

the body via the AORTA

• Use different colours for oxygenated and deoxygenated blood

• http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_pumping.html

Blood pressure• Pressure can be felt as a pulse when the heart contracts• A persons blood pressure is usually measured by systolic pressure and

diastolic pressure e.g. 120/80• See pages 1743-174

• Diastole (minimum blood pressure)- Ventricles relax and fill with blood- Arterial valves close• Systole (maximum blood pressure)- Ventricles contract and push blood into the arteries- Atrioventricular valves close

- Gives a ‘lub-dub’ sound – this is the sound of the valves closing shut

Blood vessels

1) Arteries (page 168)- Muscular walls- High blood pressure2) Veins (page 171)- More easily stretched3) Capillaries (page 171)- Very thin walls made of only single layer of epithelial

cells- To enable exchange of substances between blood

plasma and interstitial fluid

Tasks and homework

• Biozone - Mammalian Transport p167-174

• Extra reading Heinemann 152-158Other animals• Biozone - Circulatory systems (general)Pages

164- 166