A brain is an essential organ in the body that is located in the middle of the nervous system in most invertebrate and all vertebrate animals. The organ is found in the head and near sensory organs such as hearing, vision, and smell. This complex organ has billions of neurons that are connected to several neurons by synapses. These neurons use long protoplasmic fibers known as axons to communicate with each other. Besides, axons transport signal passes known as action potentials that are used to the distant body or brain parts to target recipient cells. Physiologically, the brain performs on the whole body through driving hormones and produce muscle activity.
The dominant hemisphere on the left side of the brain is responsible for speech and expression. On the contrary, the right side plays an essential role in interpreting spatial processing and visual information. For this reason, people who use the left hand are required to undergo specialized testing before surgery to determine the center of their speech. Brain injury can cause language disturbance called aphasia that affects comprehension, production of speech, writing, or reading. Moreover, damage to the Broca area that lies in the left lobe causes difficulty in moving facial muscles or tongue to produce speech sounds.
Memory is a detailed process that has 3 phases of recalling, storing, and deciding on relevant information (encoding). The brain has different areas that take part in a distinct category of memory. Encoding is responsible for moving events from short term memory to long term memory after paying attention and rehearsing. The working memory also called the short term memory, takes place in the prefrontal cortex. It is able to keep information for one minute and limit capacity. For instance, dialing number and memorizing sentence. Long term memory occurs in the hippocampus, and it is activated by remembering something for a long time. Lastly, skill memory stores learned memories like brushing teeth or driving.
3. Blood supply
Blood is transported to the brain through arteries called vertebral arteries and internal carotid arteries. Internal carotid arteries are used to supply cerebrum, while vertebral arteries are responsible for providing brainstem, cerebellum, and cerebrum. The left and right vertebral arteries connect to make basilar artery after passing in the skull. The circle of Willis (base of the brain) enables communication of internal carotid arteries and basilar artery, which is essential for the safety of the mind. The flow of collateral blood can come across the base of the brain and prevent damage to the brain in case the major vessel is blocked.
A brain consist of two kinds of cells called nerve and glial cells. Neurons exist in different shapes and sizes, but they all have an axon, dendrites and cell body. Additionally, neurons transport information by chemical and electrical signals. Synapse is a small gap that enables neurons to transmit energy. Neurons also have several arms called dendrites that serve as antennae by picking information from nerve cells. The message is conveyed to the body cell that determines if the data should be passed. The vital message is taken to the final point of the axon, where neurotransmitters open to the synapse. Besides that, glia cells nourish, protect, and give structural support to neurons.
5. Cranial nerves
The brain talks with the body by twelve cranial nerves and spinal cord. These cranial nerves are the ones that control the movement of eye, hearing, taste, facial sensation, face movement, swallowing, tongue, neck, and shoulder muscles come from the brain stem.