Human Nervous System (Part 2) - How the Brain Works! (Animation)

The human brain develops in the womb, with folds forming in the cerebrum to enable an incredible number of neurons in a small space. The brain is divided into the brain stem (medulla oblongata, pons, midbrain), cerebellum, and cerebrum. The cerebrum has left and right hemispheres, further divided into frontal, parietal, temporal, and occipital lobes, with the insular cortex underneath.

The brain is protected by the skull and three meninges: pia mater, arachnoid mater, and dura mater. Cerebrospinal fluid, produced in the brain at about 500 mL per day, circulates between the pia mater and arachnoid mater, acting as a cushion to protect the brain from rapid movements or blows to the head. This fluid also circulates in brain ventricles.

The brain consists of nerve fibers (white matter) and nerve cell bodies (gray matter). Nerve cells have a cell body, nucleus, dendrites with spines, and an axon for transmitting electrical signals. Synapses facilitate communication between nerve cells, consisting of pre-synaptic, post-synaptic parts, and a gap. Axons are often myelinated by oligodendrocytes for faster impulse transmission.

Nerve cell death can lead to diseases like Alzheimer's, causing brain shrinkage and cognitive issues. Different brain areas perform specific functions: the prefrontal cortex for personality and problem-solving, Broca's area for language, and the motor cortex with the somatosensory cortex for coordinated movements. The left brain controls the right body side, and vice versa.

The thalamus, known as the gateway to consciousness, processes and filters all sensory perceptions (except smell) before they reach the cerebral cortex, allowing us to focus on vital stimuli. The Corpus Callosum, a bundle of nerve fibers, connects the brain hemispheres, enabling communication and coordination between them.

The hypothalamus is a crucial control center for the autonomic nervous system, regulating temperature, blood pressure, thirst, and hunger. The limbic system, including the hippocampus (memory formation) and amygdala (danger memory), plays vital roles. The cerebellum, with its high cell density and Purkinje cells, coordinates planned movements into harmonious sequences.

The pituitary gland regulates hormones for growth, reproduction, and metabolism. The pineal gland (epiphysis cerebri) secretes melatonin in the dark, influencing our sleep-wake cycle.