Science B1

Science B1

1. PATHOGENS

   • FUNGI-ATHLETES FOOT
   • VIRUSES-FLU
   • BACTERIA-CHOLREA
   • PROTOZOA-MALARIA

2. A BALANCED DIET

   • CARBOHYDRATES AND FATS TO PROVIDE ENERGY
   • PROTEIN FOR GROWTH AND REPAIR
   • MINERALS WHICH IS NEEDED TO MAKE HAEMOGLOBIN IN RED BLOOD CELLS
   • VITAMINS TO PREVENT SCURVY
   • FIBRE WHICH PREVENTS CONSTIPATION
   • WATER WHICH PREVENTS DEHYDRATION

3. BMI

   • BMI- mass (kg) divided by height (m)2 squared

4. BLOOD PRESSURE

   • blood pressure is a measure of the force of blood per unit area as it flows through the arteries
     • IT IS MEASURED IN mmHg which means millimetres of mecury
   • Blood pressure is at its highest when the heart muscle contracts forcing blood into the arteries to all parts of the body.
     • THIS IS CALLED SYSTOLIC BLOOD PRESSURE
   • When the heart relaxes the pressure in the arteries drops. THIS IS CALLED DIASTOLIC BLOOD PRESSURE

5. THE NERVOUS SYSTEM

   • A SENSORY NEURONE
     • Carries nerve impulses from the receptors to the CNS
   • A RELAY NEURONE
     • makes connections between neurones inside the brain and spinal cord
   • A MOTOR NEURONE
     • Carries nerve impulses from the CNS to the muscles and glands
   • the central nervous system is made up of the spinal cord and the brain
   • light receptors in the retina of the eye detect light
     • sound and change of position receptors in the ears (for balance)
     • taste receptors on the tongue detect chemicals in food
       • smell receptors in the nose detect chemicals in the air
     • touch, pressure, pain and temperature receptors in the skin.
       • EFFECTORS are the muscles or glands that make the change in response to the signal from the receptor
   • REFLEX ACTION
     • GIVE FAST AUTOMATIC RESPONSES TO STIMULUS HELPING TO PROTECT THE BODY FROM HARM.
     • EXAMPLES
       • knee jerk reaction
       • withdrawing your hand from a hot plate to prevent burning yourself
   • LONG SIGHT
     • LONG SIGHT IS CAUSED BY AN EYE BALL THAT IS TOO SHORT OR BY A LENS THAT DOESNT SHAPE PROPERLY, IT CAN BE CORRECTED BY A CONVEX LENS WITH CONVERGES THE LIGHT RAYS FROM CLOSE OBJECTS SO THAT THEY FOCUS ON THE RETINA
       • IS WHEN YOU CAN SE DISTANT OBJECTS CLEARLY BUT NOT CLOSE OBJECTS
     • SHORT SIGHT
       • SHORT SIGHT IS CAUSED BY AN EYEBALL THAT IS TOO LONG OR WEAK, IT CAN BE CORRECTED BY A CONCAVE LENS WITH DIVERGES THE LIGHT RAYS SO THAT THEY FOCUS ON THE RETINA
       • SHORT SIGHTEDNESS IS WHEN YOU CAN SEE NEAR OBJECTS CLEARLY BUT NOT DISTANT ONES