Knowing the anatomy of each region of the human body is essential. However, how does the brain communicate with other regions, for instance the hand, to produce a movement or to sense objects? Through nerves, a concept explained by neuroanatomy. The nervous system controls every function of the human body. For example, it is involved in physiological processes like body temperature, voluntary movements, and higher-order thinking such as consciousness and emotional behaviour.
The nervous system has two structural divisions, central and peripheral. The central nervous system (CNS) consists of the brain and the spinal cord, which are protected by layers called meninges and bathed in cerebrospinal fluid. The brain is the master regulator of the body and has four main parts: cerebrum, subcortical structures, brainstem, and cerebellum. The cerebrum is divided into five lobes and forms the largest part of the human brain, being responsible for cognition.
However, every part of the brain is equally important. Do you know the main hero keeping a patient alive during a ‘vegetative state’ or a coma? It’s solely the brainstem, as the cerebrum is dysfunctional.
The spinal cord is the continuation of the brainstem, travelling through the vertebral column. It consists of five regions called cervical, thoracic, lumbar, sacral, and coccyx. Spinal nerves emerge from the spinal cord through the vertebrae, carrying nerve impulses to and from the periphery. The brain and spinal cord communicate via neural pathways called tracts. Ascending tracts carry peripheral information up towards the brain, while descending tracts transport information back down from the brain.
The peripheral nervous system (PNS) refers to all neural tissue located outside the CNS. It consists of 12 pairs of cranial nerves, the 31 pairs of spinal nerves mentioned previously, and all their branches. The PNS reaches and innervates every single anatomical structure of the human body.
As you can see, the regions of the human body are extremely complex. Starting from the top, the head allows you to gather information via sensorial structures, but not only, while the brain integrates and controls everything via the nervous system. The head rests on the neck, which provides a passageway for structures traveling to and from the thorax. Below the neck is the trunk, which is composed of the thoracic, abdominal, pelvic, and back regions. The trunk supports the body, facilitates movements, and protects various anatomical structures, such as internal organs, blood vessels, and nerves which are situated inside the respective cavities. Attached to it are two upper and lower limbs, which allow you to function as a human being, move, interact with your environment, and many more.