It regulates body temperature, synchronizes sleep patterns, controls hunger and thirst and also plays a role in some aspects of memory and emotion. Small, almond-shaped structures, an amygdala is located under each half hemisphere of the brain. A curved seahorse-shaped organ on the underside of each temporal lobe, the hippocampus is part of a larger structure called the hippocampal formation.
It supports memory, learning, navigation and perception of space. The pineal gland is located deep in the brain and attached by a stalk to the top of the third ventricle. The pineal gland responds to light and dark and secretes melatonin, which regulates circadian rhythms and the sleep-wake cycle. Deep in the brain are four open areas with passageways between them. They also open into the central spinal canal and the area beneath arachnoid layer of the meninges.
The ventricles manufacture cerebrospinal fluid , or CSF, a watery fluid that circulates in and around the ventricles and the spinal cord, and between the meninges. CSF surrounds and cushions the spinal cord and brain, washes out waste and impurities, and delivers nutrients. Two sets of blood vessels supply blood and oxygen to the brain: the vertebral arteries and the carotid arteries. The external carotid arteries extend up the sides of your neck, and are where you can feel your pulse when you touch the area with your fingertips.
The internal carotid arteries branch into the skull and circulate blood to the front part of the brain. The vertebral arteries follow the spinal column into the skull, where they join together at the brainstem and form the basilar artery , which supplies blood to the rear portions of the brain. The circle of Willis , a loop of blood vessels near the bottom of the brain that connects major arteries, circulates blood from the front of the brain to the back and helps the arterial systems communicate with one another.
The first two nerves originate in the cerebrum, and the remaining 10 cranial nerves emerge from the brainstem, which has three parts: the midbrain, the pons and the medulla. Health Home Conditions and Diseases. What is the brain made of? What is the gray matter and white matter? How does the brain work? Main Parts of the Brain and Their Functions At a high level, the brain can be divided into the cerebrum, brainstem and cerebellum. Cerebrum The cerebrum front of brain comprises gray matter the cerebral cortex and white matter at its center.
Brainstem The brainstem middle of brain connects the cerebrum with the spinal cord. The midbrain or mesencephalon is a very complex structure with a range of different neuron clusters nuclei and colliculi , neural pathways and other structures. These features facilitate various functions, from hearing and movement to calculating responses and environmental changes.
The pons is the origin for four of the 12 cranial nerves, which enable a range of activities such as tear production, chewing, blinking, focusing vision, balance, hearing and facial expression.
At the bottom of the brainstem, the medulla is where the brain meets the spinal cord. The medulla is essential to survival. Functions of the medulla regulate many bodily activities, including heart rhythm, breathing, blood flow, and oxygen and carbon dioxide levels. The medulla produces reflexive activities such as sneezing, vomiting, coughing and swallowing. Brain Coverings: Meninges Three layers of protective covering called meninges surround the brain and the spinal cord.
The outermost layer, the dura mater , is thick and tough. It includes two layers: The periosteal layer of the dura mater lines the inner dome of the skull cranium and the meningeal layer is below that. Spaces between the layers allow for the passage of veins and arteries that supply blood flow to the brain.
The arachnoid mater is a thin, weblike layer of connective tissue that does not contain nerves or blood vessels. Below the arachnoid mater is the cerebrospinal fluid, or CSF. Its interlacing feedback mechanisms can be disrupted by damage to one or more components through injury, disease, or the aging process.
Impaired balance can be accompanied by other symptoms such as dizziness, vertigo, vision problems, nausea, fatigue, and concentration difficulties. The complexity of the human balance system creates challenges in diagnosing and treating the underlying cause of imbalance. Motor Control: Theory and Practical Applications.
Anatomy The human inner ear contains two divisions: the hearing auditory component—the cochlea, and a balance vestibular component—the peripheral vestibular system. Peripheral in this context refers to a system that is outside of the central.
The peripheral vestibular system includes the organs of the inner ear, also known as the labyrinth, which contains two primary structures: the cochlea, responsible for hearing, and the vestibular apparatus, responsible for maintaining balance, stability and spatial orientation.
The vestibular system includes the parts of the inner ear and brain that help control balance and eye movements. If the system is damaged by disease, aging, or injury, vestibular disorders can result, and are often associated with one or more of these symptoms, among others:.
The quality of information your website provides is amazing. View This Section's Articles. What is Vestibular? Article Summary Maintaining balance depends on information received by the brain from the eyes, muscles and joints, and vestibular organs in the inner ear. What is balance? Sensory input Maintaining balance depends on information received by the brain from three peripheral sources: eyes, muscles and joints, and vestibular organs Figure 1.
Input from the eyes Sensory receptors in the retina are called rods and cones. Input from the muscles and joints Proprioceptive information from the skin, muscles, and joints involves sensory receptors that are sensitive to stretch or pressure in the surrounding tissues.
Input from the vestibular system Sensory information about motion, equilibrium, and spatial orientation is provided by the vestibular apparatus, which in each ear includes the utricle, saccule, and three semicircular canals.
Integration of sensory input Balance information provided by the peripheral sensory organs—eyes, muscles and joints, and the two sides of the vestibular system—is sent to the brain stem. Processing of conflicting sensory input A person can become disoriented if the sensory input received from his or her eyes, muscles and joints, or vestibular organs sources conflicts with one another. Motor output As sensory integration takes place, the brain stem transmits impulses to the muscles that control movements of the eyes, head and neck, trunk, and legs, thus allowing a person to both maintain balance and have clear vision while moving.
Motor output to the muscles and joints A baby learns to balance through practice and repetition as impulses sent from the sensory receptors to the brain stem and then out to the muscles form a new pathway.
Motor output to the eyes The vestibular system sends motor control signals via the nervous system to the muscles of the eyes with an automatic function called the vestibulo-ocular reflex VOR.
The coordinated balance system The human balance system involves a complex set of sensorimotor-control systems. View References. Journal of Vestibular Research ;16 3 — If the system is damaged by disease, aging, or injury, vestibular disorders can result, and are often associated with one or more of these symptoms, among others: — Dizziness — Imbalance — Vertigo — Tinnitus — Hearing loss — Brain fog — Vision impairment — Cognitive changes And more….
VeDA is a nonprofit that relies on donations to support our education and advocacy efforts. Your support makes a real difference. These organs contain small crystals that are displaced during these movements to stimulate tiny hairs, which transmit the message via the vestibular, or balance nerve to the cerebellum. It also helps us maintain awareness of positioning when, for example, walking, running or riding in a vehicle.
In addition, sensors in the skin, joints and muscles provide information to the brain on movement, the position of parts of the body in relation to each other, and the position of the body in relation to the environment.
Using this feedback, the brain sends messages to instruct muscles to move and make the adjustments to body position that will maintain balance and coordination. Follow Us: Facebook Twitter.
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