The human brain is a complex organ consisting of four main parts — the cerebrum, the cerebellum, the diencephalon, and the brainstem. The cerebrum ...

Deep inside the human brain are the hollow fluid-filled cavities called ventricles. There are two lateral ventricles, one in each cerebral hemisphere. ...

The cerebrum is the largest part of the brain. It is divided into two cerebral hemispheres. The outer area of each hemisphere — the cerebral cortex ...

Each cerebral hemisphere has three basic regions. The outermost region is called the cerebral cortex. It is a 2 to 4 mm thick layer of gray matter ...

The cerebral cortex has three functional areas — the motor, sensory, and association areas. The motor areas, located in the frontal lobe, control ...

Association areas are regions of the cerebral cortex that do not have a specific sensory or motor function. Instead, they integrate and interpret ...

The diencephalon is situated above the brainstem, concealed by the cerebral hemispheres. It is majorly made up of three paired structures — the ...

The thalamus consists of several groups of paired nuclei, each acting as a relay station to channel the information from specific brain parts into the ...

The hypothalamus receives somatic and visceral inputs and controls various physiological activities. It consists of several nuclei organized into four ...

The cerebellum is positioned inferior to the posterior part of the cerebrum. As seen in the posterosuperior view, a thin median structure called the ...

The brainstem comprises three regions—the midbrain, pons, and medulla oblongata. The midbrain is situated below the diencephalon and has two bulging ...

The medulla oblongata is a critical region of the brainstem. It contains several nuclei having vital functions. The lateral side of each pyramid has a ...

The limbic system is a functional brain region consisting of specific parts of the diencephalon and cerebrum. The limbic lobe of the cerebral cortex ...

The reticular formation is a complex network of gray and white matter spread across the core of the brainstem. It is roughly divided into three paired ...

Inside the vertebral column is the slender and tubular structure called the spinal cord. It is shorter than the vertebral column, with a length of about ...

In the transverse section of the spinal cord, the gray matter is surrounded by the white matter. The dorsal median sulcus and the ventral median fissure ...

The spinal cord helps relay sensory and motor information between the brain and the PNS. The sensory receptors in the skin detect somatic sensory stimuli, ...

The peripheral nervous system consists of nerves, ganglia, and sensory receptors. Each nerve has an outermost connective tissue layer called the ...

The cranial nerves are 12 pairs of nerves originating directly from the brain and brainstem. These nerves are a part of the peripheral nervous system ...

The olfactory nerve is a sensory nerve, that emerges from the olfactory bulb and innervates the receptors for the sense of smell. The optic nerve is ...

The facial nerve emerges from the pons and innervates the facial muscles, lacrimal glands, tongue, and salivary glands. It is a mixed nerve that controls ...

Spinal nerves are mixed nerves that originate from the spinal cord. A typical nerve begins as dorsal roots having sensory fibers and ventral roots ...

A plexus is an axon network of the anterior rami of nerves from different spinal regions, except for thoracic nerves T2 to T12, which form the intercostal ...

The lumbar, sacral, and coccygeal plexuses serve the lower body. The lumbar plexus is mainly composed of the first four lumbar spinal nerves, that branch ...

The brain is wrapped by three membranes called meninges. The outermost cranial dura mater has the periosteal layer adhering to the inner skull surface and ...

The cerebrospinal fluid, or CSF, is a colorless liquid surrounding the brain and spinal cord. It comprises water, blood plasma, proteins, glucose, and ...