The Circulatory System

The Circulatory System

1. Blood

   • Plasma
     • Text here
     • carries chemicals around the body
   • Red blood cells
     • formed in bone marrow
     • contain a red, iron-based pigment called haemoglobin
     • transport oxygen
   • White blood cells
     • made in bone marrow
     • fight infection
   • Platelets
     • made in bone marrow
     • form blood clots

2. Blood Vessels

   • Arteries
     • carry blood away from the heart
     • carry blood under high pressure
     • have thick, strong walls to resist the pressure
   • Veins
     • carry blood to the heart
     • carry blood under low pressure
     • have thin walls
     • have valves to prevent blood from flowing backwards
   • Capillaries
     • connect arteries to veins
     • Are tiny and very numerous
     • have very thin walls
     • allow substances to pass in and out

3. The Heart

   • [Image: http://upload.wikimedia.org/wikipedia/commons/1/1c/Heart_diagram_corrected_labels.JPG]

4. Main Parts of the Heart and its Blood Vessels

   • Vena Cava
     • carries low-oxygen blood from all over the body into the heart
   • Right Atrium
     • Pumps low-oxygen blood to the right ventrile
   • Valves
     • prevent backlow of blood
   • Right Ventricle
     • Pumps low-oxygen blood to the lungs
   • Pulmonary Artery
     • carries low-oxygen blood from the heart to the lungs
   • septum
     • seperates low-oxygen and oxygen-rich blood
   • Pulmonary Veins
     • carry oxygen-rich blood from the lungs to the heart
   • left atrium
     • pumps oxygen-rich blood to the left ventricle
   • left ventricle
     • pumps oxygen-rich blood around the body
   • Aorta
     • carries oxygen-rich blood from the heart to all parts of the body

5. The Two Blood Circuits

   • blood flows from the heart to the LUNGS and back to the heart
   • blood flows from the heart to the BODY and back to the heart

6. Pulse Rate and Exercise

   • pulse is caused by the surge of blood in an artery due to a heartbeat
   • avg. pulse rate at rest for an adult is 70 per minute
   • exercise increases the rate of heartbeat and the pulse rate
   • exercise is beneficial to the heart as it:
     • makes the heart stronger
     • reduces weight