MAVO Year 4 · Coordination and control · Section 10.4
The brain
Structure and functions of the brain
The cerebrum, cerebellum and brainstem perform different but closely connected tasks.
The cerebrum processes sensory information and contributes to conscious perception, thinking and voluntary movement. Sensory areas process information from particular senses; motor areas help initiate and control voluntary movements. These specialised brain areas work together in wider networks.
The cerebellum helps coordinate movement, balance and the timing of actions. It allows movements such as cycling or catching a ball to be adjusted accurately.
The brainstem connects the spinal cord with other brain regions. It carries signals and contains centres involved in breathing, heart rate and other vital functions. Temperature regulation is coordinated mainly by the hypothalamus, another brain region, working with the rest of the nervous and hormonal systems.
Effects of substances on the brain
Medicines, alcohol, nicotine and other drugs can alter communication between neurons. They may change perception, alertness, coordination and reaction speed.
- Depressants, such as alcohol and opioids including heroin, reduce activity in parts of the nervous system. They can impair judgement and coordination; high doses of some depressants can dangerously slow breathing.
- Stimulants, such as nicotine and caffeine in energy drinks, can increase alertness and often raise heart rate.
- Perception-altering substances, such as cannabis and hallucinogenic mushrooms, can change sensory experiences, mood or awareness. Effects differ between substances and doses.
Dependence, addiction and tolerance
Addiction involves difficulty controlling use despite harmful consequences. Physical dependence means the body has adapted and withdrawal symptoms may occur on stopping. Psychological dependence includes cravings or feeling unable to cope without the substance. These concepts overlap but are not identical.
Tolerance means that repeated use produces less effect, so a person may need a higher dose for a similar effect. This can increase risks.
Nicotine acts on brain receptors and influences dopamine, a neurotransmitter involved in reward, motivation and learning. This helps reinforce repeated use; dopamine is not simply a substance producing happiness. Young people's developing brains are particularly vulnerable to the effects of addictive substances.
In the Netherlands, alcohol and tobacco may not be sold to people under 18. Drug laws and the limited toleration of some cannabis sales do not mean these substances are harmless or freely legal.
Glossary
- Motor areas
- Brain regions involved in initiating and controlling voluntary movement.
- Perception-altering substances
- Substances changing sensory experiences, mood or awareness.
- Dopamine
- A neurotransmitter involved in functions including reward learning, motivation and movement.
- Psychoactive drugs
- Substances affecting mental processes through their action on the nervous system.
- Psychological dependence
- Craving a substance or feeling that it is needed to cope or feel well.
- Sensory areas
- Brain regions processing information from sensory systems.
- Cerebrum
- The largest brain region, involved in conscious perception, thought and voluntary movement.
- Brain areas
- Regions or networks of neurons contributing to particular functions.
- Brainstem
- The region connecting spinal cord and other brain structures, with pathways and centres for vital functions.
- Cerebellum
- A brain region important for coordination, balance and motor learning.
- Physical dependence
- Adaptation to a substance that can cause physical withdrawal symptoms when use stops.
- Reaction ability
- The capacity to respond to a stimulus, including how quickly a response occurs.
- Stimulants
- Substances increasing activity or alertness in parts of the nervous system.
- Tolerance
- A reduced response after repeated use, potentially leading to higher doses for the same effect.
- Depressants
- Substances reducing activity in parts of the nervous system and potentially impairing perception and responses.
- Addiction
- Persistent difficulty controlling substance use despite harmful consequences.
- Perceptual ability
- The capacity to detect and interpret sensory information.