Embryonic Brain Development and Functions

Prosencephalon

Divides into telencephalon and diencephalon.

Mesencephalon

Gives rise to the midbrain; the cerebral aqueduct runs through it.

Rhombencephalon

Derives adult structures such as pons, cerebellum, and medulla oblongata.

Cerebrum

One of the four major adult brain regions.

Diencephalon

One of the four major adult brain regions.

Brainstem

One of the four major adult brain regions.

Cerebellum

One of the four major adult brain regions.

Lateral ventricles

Located in each cerebral hemisphere; they contain CSF produced by the choroid plexus.

Choroid plexus

Produces CSF by ependymal cells.

Cerebrospinal fluid (CSF)

Functions include buoyancy/shock absorption and nutrient/waste exchange.

Meningeal layers

Dura mater → arachnoid mater → pia mater.

Medulla oblongata

Contains cranial nerve nuclei and autonomic centers.

Cardiovascular center

Regulates heart rate and blood pressure in the medulla.

Gracile and cuneate nuclei

Relay fine touch and proprioception to the thalamus.

Pons

Located superior to medulla and inferior to midbrain on ventral surface.

Middle cerebellar peduncles

Connect the pons to the cerebellum.

Pontine respiratory group

Fine-tunes respiratory rhythm.

Cerebellum location

Dorsal to pons and medulla, under occipital lobes.

Arbor vitae

Cerebellar white-matter branching pattern.

Cerebellum functions

Coordination of balance; fine motor control; learned motor patterns.

Tectum structures

Superior colliculi (visual reflexes); inferior colliculi (auditory reflexes).

Substantia nigra

Midbrain nucleus critical for dopamine production.

Cerebral peduncles

Contain descending motor tracts.

Cerebral aqueduct

Channel that carries CSF between third and fourth ventricles.

Thalamus

Relay sensory information (except smell) to cortex.

Hypothalamus functions

Autonomic regulation; endocrine control; temperature; hunger/thirst; sleep-wake; emotions.

Pineal gland

Produces melatonin in the epithalamus.

Subthalamus

Involved in motor modulation.

Hippocampus

Limbic structure essential for memory formation.

Amygdala

Main function is processing fear and emotions.

Cingulate gyrus

Manages emotional expression.

Fornix and mammillary bodies

Two other components of the limbic memory circuit.

Cerebrum lobes

Frontal; parietal; temporal; occipital; insula.

EEG

Measures summed electrical activity of cortical neurons.

Alpha waves

Dominant during relaxed wakefulness (8-13 Hz).

Delta waves

Appear during deep sleep (0.5-4 Hz).

Beta waves

Indicate active concentration (13-30 Hz).

Optic nerve (II)

Responsible for vision.

Facial nerve (VII)

Controls facial expression and taste.

Phrenic nerve (C3-C5)

Innervates the diaphragm, aided by vagus (X).

Vestibulocochlear nerve (VIII)

Conveys hearing and balance.

Vagus nerve (X)

Supplies thoracoabdominal organs.