BRAIN COMPONENTS AND THEIR FUNCTIONS

The brain is the most complex and important organ of the human body. It has different components and each component has specific functions. Some of the basic components of the brain are:

Cerebral Cortex - is the outermost layer of the brain. It covers the cerebrum and is divided into the left and right hemispheres of the brain.  It wrinkles up into grooves to include more neurons. Cerebral Cortex is what we see when we look at the brain. Cerebral cortex is also called as grey matter and is responsible for the distinct human traits like higher order thinking and language and also traits like imagination and reasoning.

Cerebrum - is the largest part of the brain, covered by cerebral cortex and controls complex things like thinking, voluntary behavior, perceiving and understanding language. Cerebrum is split into two hemispheres (left and right) that are connected by a bundle of fibers called the corpus callosum. Each of the hemispheres has different parts or lobes, namely frontal lobe, parietal lobe, occipital lobe and temporal lobe.

The different lobes make up the fore brain.

Corpus Callosum - is a bundle of nerve fibers, located under the cerebrum, at the center of the brain. It connects the two cerebral hemispheres of the brain and helps them communicate. It also helps proper functioning of the eye movement, attention and spatial perception. If there was no corpus collosum the left and the right hemispheres of the brain would not be able to communicate and the brain would be divided.

Thalamus - is located above the brain stem. It acts as a relay station between different parts of the brain. All of the sensory signals (vision, touch, hearing) except those associated with smell, pass through the thalamus to the cerebral cortex and vice versa.

Hypothalamus - is located underneath the thalamus. It's main function is homeostasis, or controlling factors like blood pressure, body temperature, hunger, thirst, weight, emotions, circadian rhythms (24 hr cycle in the physiological processes of living beings). It also controls the pituitary gland by secreting hormones.

Limbic system - is situated deep within the brain and consists of these main structures; Amygdala, Hippocampus, Fornix, Thalamus, Hypothalamus, Olfactory cortex and Cingulate gyrus. Limbic system controls emotions, basic drives like thirst and hunger, pleasure/pain, smell, modd and memory.

Basal Ganglia - is a group of cell bodies, connected to the cerebral cortex, thalamus and other brain areas. It is situated at the base of the fore brain. Basal Ganglia is concerned with the coordination of movement. Dysfunction in Basal Ganglia is responsible for some well-known neurological disorders such as Parkinson's and Huntington's diseases.

Brain Stem - connects the brain to the spinal cord. It consists of three parts medulla oblongata, pons and midbrain. The medulla oblongata is the lowest portion of the brain stem and is continuous with the spinal cord. It helps in transferring messages from the different parts of brain to the spinal cord. It controls autonomous nervous activities such as breathing, swallowing, sneezing, heart rate and digestive processes. Pons are located just above the medulla and connect it to the cerebral cortex. It relays sensory information between the cerebrum and cerebellum. Midbrain is above the pons and is the smallest region of the brain stem. It acts as a relay station for the auditory and visual information.

Cerebellum - is located in the hindbrain, behind the brain stem. The cerebellum is connected to the brain stem, basal ganglia and the cerebral hemispheres. Together they control the smooth coordination of movement.

Cranial Nerves - are twelve pair of nerves seen on the bottom of the brain. Most of them originate from the brain stem.

Neurons - are the cells that makes up the brain . There are about 100 billion neurons in the human body. The neuron is made up of cell body, dendrites and axons. The neuron cell body contains the nucleus and cytoplasm. The axon extends from the neuron cell body and often gives rise to many smaller branches before ending at nerve terminals. Dendrites extend from the neuron cell body and receive messages from other neurons. The dendrites are covered with synapses formed by the ends of axons from other neurons. Synapses are the contact points where one neuron communicates with another. Ions flow from outside of one neuron to inside of other neuron through the ion channels. The difference in charge creates an action potential, which triggers neurotransmitters.