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Hormones are chemical messengers. They are released from special gland cells and travel in the bloodstream to reach their target organs, where they will have their effect. Whereas nerve cells carry electr...

Reflexes are quick and automatic reactions to harmful stimuli. Reflexes are important as they protect the body from harm. We don’t have to learn reflexes because they occur automatically from the moment w...

Neurones are the specialised cells that make up the nervous system. Bundles of neurones are known as nerves. Neurones carry electrical impulses around the entire body.

The nervous system is made up of two parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS is made up of the brain and the spinal cord. The PNS is made up of sensory and...

High cholesterol diets lead to high cholesterol levels in the blood. Low density lipoproteins, known as LDLs or BAD-cholesterol, build up in the artery walls. They form solid plaques which narrow the arte...