Brain - Names of the 12 cranial nerves, Parts of Brain

Published on 13-Aug-2025

Brain

The brain is one of the most important organs with many functions. It controls our emotions, activities, memory, regular tasks, reactions to events, hunger, hormones, motions, skills, vision, and more. In short, it controls the entire body and all its functions.

The brain and spinal cord together form the central nervous system (CNS).

Structure of the Brain

The brain can be divided into three main parts:

  • Forebrain

  • Midbrain

  • Hindbrain

Seven Main Parts of the Brain

  • Cerebral cortex

  • Cerebellum

  • Hypothalamus

  • Thalamus

  • Pituitary gland

  • Pineal gland

  • Amygdala

  • Hippocampus

  • Midbrain

The cerebrum is the most significant part of the brain, regulating the body's temperature and movement.

Composition of the Brain

  • Soft tissue with gray and white matter

  • Contains small blood vessels, non-neuronal cells, and nerve cells

  • High amounts of water and fat

  • Pinkish-brown color due to capillaries

  • White matter is deep inside, gray matter is mainly on the surface

Size and Weight:

  • About 5.5 x 6.5 x 3.6 inches (140 x 167 x 93 mm)

  • Weight: 3 pounds (1.3 kg)

Main Divisions of the Brain

Forebrain (Prosencephalon)

  • Largest region of the brain

  • Contains thalamus, hypothalamus, epithalamus, subthalamus

  • Controls bodily functions, information processing, thinking, language, and movement

  • Principal divisions: diencephalon and telencephalon

Midbrain (Mesencephalon)

  • Forward-most portion of the brain

  • Controls vision, hearing, motor functions, sleep-wake cycle, alertness, and body temperature

  • Smallest part of the brain (~2 cm in length)

  • Contains cranial nerve nuclei, tectum, tegmentum, colliculi, crura cerebri

Hindbrain (Rhombencephalon)

  • Located in the lower back part of the brain

  • Includes most of the brainstem and the cerebellum (largest structure of the hindbrain)

  • Controls unconscious processes like sleep-wake cycle and breathing

  • Parts: pons, cerebellum, medulla oblongata

Ventricles of the Brain

  • Located in the brain parenchyma

  • Network of cavities filled with cerebrospinal fluid (CSF)

  • Four ventricles:

    • Two lateral ventricles

    • Third ventricle

    • Fourth ventricle

  • CSF keeps the brain buoyant and cushioned

Human Cranial Nerves

  • 12 paired nerves at the back of the brain

  • Transmit electrical signals between the brain, face, neck, and torso

  • Help us taste, smell, feel sensations, express emotions, blink, and move the tongue

12 Cranial Nerves:

  1. Olfactory nerve

  2. Optic nerve

  3. Oculomotor nerve

  4. Trochlear nerve

  5. Trigeminal nerve

  6. Abducens nerve

  7. Facial nerve

  8. Vestibulocochlear nerve

  9. Glossopharyngeal nerve

  10. Vagus nerve

  11. Accessory nerve

  12. Hypoglossal nerve

Types of Nerves

Sensory Nerves

  • Carry signals to the brain for touch, taste, smell, and vision

  • Five sensory receptors:

    1. Mechanoreceptors

    2. Thermoreceptors

    3. Nociceptors

    4. Electromagnetic receptors

    5. Chemoreceptors

  • Damage can affect touch, vibrations, and sensations

Motor Nerves

  • Located in the CNS, mainly spinal cord

  • Send signals from the CNS to muscles

  • Proper function requires antioxidants and Vitamin E to reduce MND risk

Mixed Nerves

  • Composed of both motor and sensory fibers

  • Transmit messages in both directions simultaneously

Johns Hopkins Medicine. (2025, April). Brain Anatomy and How the Brain Works. https://www.hopkinsmedicine.org/health/conditions-and-diseases/anatomy-of-the-brain

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