BEEZYREVISOR

GCSE Biology Revision

Learn it. Recall it. Revise it.

GCSE Biology revision

The brain (biology only)

The human nervous system

AQA 4.1.1.1
Your specification

AQA student objectives

Learning pathway

All · Most · Some

ALL 🎯

Identify and describe The Brain as Part of the CNS, Overview of Brain Structure and The Cerebral Cortex in the context of the brain (biology only).

MOST 🎯🎯

Explain the relationships between The Brain as Part of the CNS, Overview of Brain Structure and The Cerebral Cortex and how they contribute to the brain (biology only).

SOME 🎯🎯🎯

Apply and analyse knowledge of The Brain as Part of the CNS, Overview of Brain Structure and The Cerebral Cortex to interpret unfamiliar information about the brain (biology only).

Revision summary

Key knowledge

Read on screen, then print for Cornell-style active revision.

The Brain as Part of the CNS

  • The brain is part of the central nervous system (CNS), which also includes the spinal cord.
  • The brain is responsible for controlling complex, conscious behaviour such as emotions, memory, and decision-making.
  • Unlike reflexes, which are unconscious responses that bypass the brain, conscious responses are processed and directed by the brain.

Overview of Brain Structure

  • The three key structures of the brain you must be able to label are the cerebral cortex, the cerebellum, and the medulla.
  • The spinal cord connects directly to the brain, forming the complete central nervous system together.
  • Different regions of the brain are specialised for different functions, making it an extremely complex organ.

The Cerebral Cortex

  • The cerebral cortex is responsible for higher-level functions including emotions, thoughts, personality, intelligence, and the sense of smell.
  • It is divided into two hemispheres, each of which controls the opposite side of the body.
  • The cerebral cortex is split into approximately 50 different areas, each specialised for a particular function such as speech, movement, or sensory processing.

The Cerebellum

  • The cerebellum, whose name literally means 'little brain', is responsible for the control of movement, balance, and muscle coordination.
  • Without a functioning cerebellum, movements would become erratic and poorly coordinated, as they would not be properly planned.

The Medulla

  • The medulla controls unconscious, automatic functions such as heart rate and breathing rate.
  • During exercise, the medulla triggers the release of adrenaline to increase heart rate, delivering more oxygen and glucose to respiring muscles.
  • These functions are continuously adjusted by the medulla to meet the changing needs of the body, without any conscious effort.

Mapping the Brain

  • Scientists have produced a detailed map of the cerebral cortex that identifies which areas are responsible for specific functions.
  • By studying patients with brain damage in a known region, researchers can link that area to the function the patient has lost, such as impaired speech.
  • Electrical stimulation of specific brain regions is used to map functions, with patients reporting what they experience during stimulation.

MRI Scans

  • MRI (magnetic resonance imaging) scans use magnetic fields and electromagnetic waves to investigate both the structure and activity of the brain.
  • MRI scans can show which parts of the brain are most active during different tasks or activities.
  • A key advantage of MRI scans over CT scans is that they do not use ionising radiation, making them safer for investigating the brain.

Electroencephalograms (EEGs)

  • Electroencephalograms (EEGs) are graphs that record and display the electrical activity of the brain over time.
  • EEGs show which parts of the brain are active at different moments, helping researchers and clinicians understand brain function and identify abnormalities.

Challenges of Brain Surgery and Research

  • The brain contains billions of neurones, making surgery extremely intricate and any small error potentially catastrophic.
  • The side effects and complications of brain surgery can sometimes be more severe than the original condition, meaning surgery is not always worthwhile.
  • The high risk involved in brain research and treatment means progress in understanding the brain can be slower compared to research on other organs.