brain

(noun)

The control center of the central nervous system, located in the skull.

Related Terms

Examples of brain in the following topics:

  • Blood Flow in the Brain

    • Cerebral circulation refers to the movement of blood through the network of blood vessels supplying the brain.
    • CBF is tightly regulated to meet the brain's metabolic demands.
    • Too much blood can raise intracranial pressure (ICP), which can compress and damage delicate brain tissue.
    • In brain tissue, a biochemical cascade known as the ischemic cascade is triggered when the tissue becomes ischemic, potentially resulting in damage to and death of brain cells.
    • Schematic representation of the circle of Willis, arteries of the brain and brain stem.

  • Brain Tumors

    • A brain tumor is a pathological abnormal growth of cells in the brain.
    • An example of a highly treatable brain tumor subtype is medulloblastoma.
    • Other examples of brain tumor subtypes include oligodendrogliomas and astrocytomas.
    • A brain tumor is an intracranial solid neoplasm—a tumor (defined as an abnormal growth of cells)—within the brain or the central spinal canal.
    • Symptoms of solid neoplasms of the brain (primary brain tumors and secondary tumors alike) can be divided into three main categories:

  • Hemispheric Lateralization

    • The human brain is composed of a right and a left hemisphere, and each hemisphere participates in different aspects of brain function.
    • The structural and chemical variance of a particular brain function, between the two hemispheres of one brain or between the same hemisphere of two different brains, is still being studied.
    • Short of having undergone a hemispherectomy (removal of a cerebral hemisphere), no one is a "left-brain only" or "right-brain only" person.
    • Brain function lateralization is evident in the phenomena of right- or left-handedness, but a person's preferred hand is not a clear indication of the location of brain function.
    • The human brain is divided into two hemispheres–left and right.

  • The Brain

    • The human brain is the center of the human nervous system.
    • A number of psychiatric conditions, such as schizophrenia and depression, are thought to be associated with brain dysfunctions, although the nature of such brain anomalies is not well understood.
    • The cerebral hemispheres form the largest part of the human brain and are situated above most other brain structures.
    • The brain stem consists of the midbrain, pons, and medulla.
    • Distinguish between the cerebellum, cerebral cortex, and brain stem regions of the brain

  • Association Areas

    • There are many different methods that help us to analyze the brain and give us an overview of the relationship between brain and behavior and the ways in which associations are made by multiple brain regions, allowing the appropriate responses to occur in a given situation.
    • Well-known techniques are the EEG (electroencephalography) which records the brain's electrical activity and the fMRI (functional magnetic resonance imaging) method, which tells us more about brain functions.
    • Furthermore, there are techniques for modulating brain activity, analyzing behavior, or modeling brain behavior.
    • *In the lesion method, patients with brain damage are examined to determine which brain structures were damaged and to what extent this influences the patient's behavior.
    • Locations of brain areas historically associated with language processing.

  • Circumventricular Organs

    • Circumventricular organs are situated adjacent to the brain ventricles and sense concentrations of various compounds in the blood.
    • Circumventricular organs (CVOs), are positioned at distinct sites around the margin of the ventricular system of the brain.
    • They are among the few sites in the brain that have an incomplete blood-brain barrier.
    • A useful mnemonic device for remembering this aspect of their function, though not the source of the name, is that they allow factors to 'circumvent' the blood-brain barrier.
    • The sensory organs are able to sense plasma molecules and then pass that information into other regions of the brain.

  • Blood-Brain Barrier

    • Tight junctions present in the blood-brain barrier separate circulating blood from cerebrospinal fluid, regulating diffusion into the brain.
    • The blood-brain barrier (BBB) is a separation of circulating blood from the brain extracellular fluid in the central nervous system (CNS).
    • In a later experiment, his student Edwin Goldmann found that when dye is injected into the cerebrospinal fluid (CSF) of animals' brains directly, the brains did become dyed, but the rest of the body did not.
    • Several areas of the human brain are not protected by the BBB.
    • Thus, infections of the brain are very rare.

  • Cerebrospinal Fluid and Its Circulation

    • The CSF occupies the space between the arachnoid mater (the middle layer of the brain cover, the meninges) and the pia mater (the layer of the meninges closest to the brain).
    • Buoyancy: The actual mass of the human brain is about 1400 grams; however, the net weight of the brain suspended in the CSF is equivalent to a mass of 25 grams.
    • The brain therefore exists in neutral buoyancy, which allows the brain to maintain its density without being impaired by its own weight.
    • Protection: CSF protects the brain tissue from injury when jolted or hit.
    • Prevention of brain ischemia: The prevention of brain ischemia is made by decreasing the amount of CSF in the limited space inside the skull.

  • Epithalamus and Pineal Gland

    • The epithalamus connects the limbic system to other parts of the brain.
    • The habenular commissure is a brain commisure (a band of nerve fibers) situated in front of the pineal gland that connects the habenular nuclei on both sides of the diencephalon.
    • The pineal gland (also called the pineal body, epiphysis cerebri, epiphysis, conarium or the "third eye”) is the only unpaired midline brain structure.
    • The function of the epithalamus is to act as a connection between the limbic system to other parts of the brain.
    • A brain sectioned in the median sagittal plane.

  • Functions of the Brain Stem

    • In vertebrate anatomy, the brainstem is the inferior-most portion of the brain, adjoining and structurally continuous with the brain and spinal cord.
    • The brain stem gives rise to cranial nerves 3 through 12 and provides the main motor and sensory innervation to the face and neck via the cranial nerves.
    • Though small, it is an extremely important part of the brain, as the nerve connections of the motor and sensory systems from the main part of the brain that communicate with the peripheral nervous system pass through the brain stem.
    • The brain stem also plays an important role in the regulation of cardiac and respiratory function.
    • Cranial nerves are nerves that emerge directly from the brain, in contrast to spinal nerves, which emerge from segments of the spinal cord.