Horizontal Hemisphere

Question 1

Describe the cortical surface

Answer 1

The outer surface of the brain has ridges (called gyri), shallow grooves (called sulci), and deep grooves (called fissures, like the lateral fissure shown here).

Question 2

Describe grey matter

Answer 2

• Contains the cell bodies of neurons.
• Cortex: The outer layer of grey matter where thinking and processing happen. It’s the “site of the conscious mind” and helps with planning and interpreting information.
• Basal Nuclei: A group of cells deep inside that help control movement.
• Thalamus: Acts like a relay station, sending information to the cortex.

Question 3

Describe white matter

Answer 3

• Contains axons (the long parts of neurons), most of which are covered with myelin to help signals travel quickly.
• Corpus Callosum: A thick band of white matter that connects the two sides of the brain, allowing them to communicate.

Question 4

Summarise the horizontal hemisphere

Answer 4

• Grey matter does the processing and thinking.
• White matter carries signals across the brain.
• Structures like the thalamus and basal nuclei play specific roles in movement and information relay.