The Nervous System
- Created by: JessicaGrey
- Created on: 04-04-16 14:41
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- The Nervous System
- Central nervous system (CNS) is made up of the brain and spine
- Enables humans to react to their surroundings and coordinate their behaviour
- Receptors detect stimuli.
- Eye receptors detect light
- Light receptor cells have a nucleus, cytoplasm and cell membrane.
- Ear receptors detect sound and change in position (balance)
- Nose and tongue receptors detect chemicals
- Skin receptors detect pressure, touch, temperature and pain
- Eye receptors detect light
- Simple reflex action: Stimulus> Receptors> Sensory neurone> Relay neurone> Motor neurone> Effector (muscle or gland)
- At junction/ synapse electrical impluse changed to chemical so if can diffuse across synapse, then change back to electrical
- Eg sprinter detects starting gun> sound receptor in ears> sensory neurone> CNS> motor neurone> effector> response
- In the human body some conditions are controlled; water content, ion content, blood sugar levels and temperature
- Water in: drinking + food. Water out: sweating + water lost as urine via the kidneys
- Ion minerals in; food. Ions out by sweat and as urine via kidneys
- Temperature need to stay constant to allow enzymes to work (37degrees)
- Blood sugar levels need to stay constant to provide the cells with a constant supply of energy
- Central nervous system (CNS) is made up of the brain and spine
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