Lecture Notes: The Human Brain

Introduction

• The brain is the command center of the body.
• Receives information from senses and controls thoughts/movement.

Main Parts of the Brain

Cerebrum

• Largest part of the brain.
• Divided into two hemispheres.
• Outer layer: Cortex (Latin for "bark").
  • Surface is 1/8 inch thick.
  • Contains millions of cells with fibers for message transmission.
  • 2/3 of the cortex surface hides in folds (gyri and sulci).

Regions of the Cortex

• Frontal Lobe:
  • Personality, emotions, higher thinking (problem-solving), movement control.
  • Develops until mid-20s.
• Temporal Lobe:
  • Processes hearing & other senses, language, and reading.
• Parietal Lobe:
  • Involved with senses, attention, and language.
• Occipital Lobe:
  • Visual processing; recognition of shapes and colors.

Thalamus

• Located in the center of the brain.
• Relays sensory and motor information.
• Helps with consciousness, sleep, and alertness.

Cranial Nerves

• 12 pairs of nerves carry sensory and motor information.

Cerebellum

• Key role in motor control, coordination, and spatial navigation.

Brain Stem

• Connects brain to spinal cord.
• Includes:
  • Pons: Helps control breathing.
  • Medulla Oblongata: Regulates heart and body reflexes (e.g., vomiting, coughing).

Limbic System

• Processes emotions and drives.
• Brain’s reward circuit (releases dopamine).
• Parts:
  • Amygdala: Processes emotions.
  • Hippocampus: Memory indexing, storage, and retrieval.

Dopamine and Addiction

• Drugs cause strong dopamine release leading to a "high."
• Addiction can result from repeated activation of the reward pathway.

Other Important Glands

• Hypothalamus: Wakes you up; triggers adrenaline.
• Pituitary Gland: Controls growth, temperature, pregnancy, childbirth.
• Pineal Gland: Regulates sleep and circadian rhythms.

Conclusion

• The brain is complex, beautiful, and vital for intelligence and daily life.
• Importance of exercising, protecting, and understanding the brain.