Sunday, May 8, 2022

What Tissues Make Up The Brain

Don't Miss

How Does The Nervous System Work

Nervous Tissue || Structure II 3D Animation Video

The basic workings of the nervous system depend a lot on tiny cells called neurons. The brain has billions of them, and they have many specialized jobs. For example, sensory neurons send information from the eyes, ears, nose, tongue, and skin to the brain. Motor neurons carry messages away from the brain to the rest of the body.

All neurons, however, relay information to each other through a complex electrochemical process, making connections that affect the way we think, learn, move, and behave.

Intelligence, learning, and memory. As we grow and learn, messages travel from one neuron to another over and over, creating connections, or pathways, in the brain. It’s why driving takes so much concentration when someone first learns it, but later is second nature: The pathway became established.

In young children, the brain is highly adaptable. In fact, when one part of a young child’s brain is injured, another part often can learn to take over some of the lost function. But as we age, the brain has to work harder to make new neural pathways, making it harder to master new tasks or change set behavior patterns. That’s why many scientists believe it’s important to keep challenging the brain to learn new things and make new connections it helps keeps the brain active over the course of a lifetime.

The Senses

Smell. Olfactory cells in the mucous membranes lining each nostril react to chemicals we breathe in and send messages along specific nerves to the brain.

What Is The Central Nervous System

The central nervous system controls most functions of the body and mind. It consists of two parts: the brain and the spinal cord.

The brain is the center of our thoughts, the interpreter of our external environment, and the origin of control over body movement. Like a central computer, it interprets information from our eyes , ears , nose , tongue , and skin , as well as from internal organs such as the stomach.

The spinal cord is the highway for communication between the body and the brain. When the spinal cord is injured, the exchange of information between the brain and other parts of the body is disrupted.

Expert Review And References

  • Detailed guide: CNS tumors in children. American Cancer Society. American Cancer Society . Atlanta, GA: American Cancer Society 2008.
  • American Society of Clinical Oncology. Central Nervous System Tumors – Childhood – Overview. 2014.
  • Central nervous system – childhood. American Society of Clinical Oncology . People Living with Cancer. Alexandria, VA.: American Society of Clinical Oncology 2008.
  • Brain tumours in children. Cancerbackup. Cancerbackup. London, UK: Cancerbackup 2008.
  • Brain tumours. Hospital for Sick Children. AboutKidsHealth. Toronto, ON: Hospital for Sick Children 2004.
  • The Hospital for Sick Children . AboutKidsHealth: An Overview of the Brain. 2009: .

Don’t Miss: Roy Jones Jr Brain Damage

White And Gray Matter

The CNS can be roughly divided into white and gray matter. As a very general rule, the brain consists of an outer cortex of gray matter and an inner area housing tracts of white matter.

Both types of tissue contain glial cells, which protect and support neurons. White matter mostly consists of axons and oligodendrocytes a type of glial cell whereas gray matter consists predominantly of neurons.

Also called neuroglia, glial cells are often called support cells for neurons. In the brain, they outnumber nerve cells 10 to 1.

Without glial cells, developing nerves often lose their way and struggle to form functioning synapses.

Glial cells are found in both the CNS and PNS but each system has different types. The following are brief descriptions of the CNS glial cell types:

Astrocytes: these cells have numerous projections and anchor neurons to their blood supply. They also regulate the local environment by removing excess ions and recycling neurotransmitters.

Oligodendrocytes: responsible for creating the myelin sheath this thin layer coats nerve cells, allowing them to send signals quickly and efficiently.

Ependymal cells: lining the spinal cord and the brains ventricles , these create and secrete cerebrospinal fluid and keep it circulating using their whip-like cilia.

Radial glia: act as scaffolding for new nerve cells during the creation of the embryos nervous system.

Structure Of Nervous Tissue

Comparison images of brain tissue and quantitative SOCM ...
  • It is made of nerve cells or neurons, all of which consists of an axon. Axons are long stem-like projections emerging out of the cell, responsible for communicating with other cells called the Target cells, thereby passing impulses
  • The main part is the cell body which contains the nucleus, cytoplasm and cell organelles. Extensions of the cell membrane are referred to as processes.
  • Dendrite is a highly branched processes, responsible for receiving information from other neurons and synapses . Information of other neurons is provided by dendrites to connect with its cell body.
  • Information in a neuron is unidirectional as it passes through neurons from dendrites, across the cell body down the axon.

Recommended Reading: Cebria Lawsuit

Outline Of The Human Brain

The following outline is provided as an overview of and topical guide to the human brain:

Human brain central organ of the nervous system located in the head of a human being, protected by the skull. It has the same general structure as the brains of other mammals, but with a more developed cerebral cortex than any other, leading to the evolutionary success of widespread dominance of the human species across the planet.

While the emphasis below is on physical brain structure, functional aspects are also included. Mind concepts , and cognitive and behavioral aspects, are introduced where they have at least a fairly direct connection to physical aspects of the brain, neurons, spinal cord, nerve networks, neurotransmitters, etc.

What Happens Following A Spinal Cord Injury

A common set of biological events take place following spinal cord injury:

  • Cells from the immune system migrate to the injury site, causing additional damage to some neurons and death to others that survived the initial trauma.
  • The death of oligodendrocytes causes axons to lose their myelination, which greatly impairs the conduction of action potential, messages, or renders the remaining connections useless. The neuronal information highway is further disrupted because many axons are severed, cutting off the lines of communication between the brain and muscles and between the body’s sensory systems and the brain.
  • Within several weeks of the initial injury, the area of tissue damage has been cleared away by microglia, and a fluid-filled cavity surrounded by a glial scar is left behind. Molecules that inhibit regrowth of severed axons are now expressed at this site. The cavitation is called a syrinx, which acts as a barrier to the reconnection of the two sides of the damaged spinal cord.
  • Read Also: How Many Eggs Are There Brain Test

    What Types Of Tissues Make Up The Brain

    The brain is made up largely of neurons, or nerve cells, blood vessels and glial cells. Glial cells create a supporting structure for the brain. The brain is about 60 percent fat.

    There are four kinds of glial cells: oligodendrocytes, astrocytes, ependymal and microglia cells. They protect the brain by keeping out pathogens and toxins.

    The neurons and the fibers that surround them are gray matter. The bundles of axon fibers are white matter. Axons are single nerve fibers through which the nerve cells send out impulses. Axons are usually encased in a sheath of fat called myelin. Oligodendrocyte cells are responsible for myelin.

    The brain’s gray matter is located in the core of the spinal cord and reaches up into the brain stem at the bottom of the brain. White matter wraps around the gray matter in the spinal cord and the brain stem, while gray matter surrounds white matter in the upper parts of the brain. The connections between the cells in the gray matter let the brain interpret signals from the sense organs and plan how to respond to them. White matter serves as communication network between different parts of the brain and between the brain and the spinal cord.

    How The Spinal Cord And Internal Organs Work Together

    Is Your Brain Really Made of FAT?

    In addition to the control of voluntary movement, the central nervous system contains the sympathetic and parasympathetic pathways that control the “fight or flight” response to danger and regulation of bodily functions. These include hormone release, movement of food through the stomach and intestines, and the sensations from and muscular control to all internal organs.

    This diagram illustrates these pathways and the level of the spinal cord projecting to each organ.

    Don’t Miss: What Do Puzzles Do For The Brain

    The Cell Structure Of The Brain

    The brain is made up of two types of cells: neurons and glial cells, also known as neuroglia or glia. The neuron is responsible for sending and receiving nerve impulses or signals. Glial cells are non-neuronal cells that provide support and nutrition, maintain homeostasis, form myelin and facilitate signal transmission in the nervous system. In the human brain, glial cells outnumber neurons by about 50 to one. Glial cells are the most common cells found in primary brain tumors.

    When a person is diagnosed with a brain tumor, a biopsy may be done, in which tissue is removed from the tumor for identification purposes by a pathologist. Pathologists identify the type of cells that are present in this brain tissue, and brain tumors are named based on this association. The type of brain tumor and cells involved impact patient prognosis and treatment.

    The Central Nervous System

    The CNS is made up of the brain and the spinal cord.

    The brain controls everything we do, from how we think to how we behave. It sends electrical messages to the rest of our body along nerve fibres.

    The nerve fibres run out of the brain and join together to make up the spinal cord.

    The spinal cord has bundles of long nerve fibres that carry signals to and from the brain, to all parts of the body. These long nerve fibres are called peripheral nerves.

    You May Like: Parkinson’s Disease Midbrain

    Cells Of The Central Nervous System

    Neurons connect with one another to send and receive messages in the brain and spinal cord. Many neurons working together are responsible for every decision made, every emotion or sensation felt, and every action taken.

    The complexity of the central nervous system is amazing: there are approximately 100 billion neurons in the brain and spinal cord combined. As many as 10,000 different subtypes of neurons have been identified, each specialized to send and receive certain types of information. Each neuron is made up of a cell body, which houses the nucleus. Axons and dendrites form extensions from the cell body.

    Astrocytes, a kind of glial cell, are the primary support cells of the brain and spinal cord. They make and secrete proteins called neurotrophic factors. They also break down and remove proteins or chemicals that might be harmful to neurons .

    Astrocytes aren’t always beneficial: after injury, they divide to make new cells that surround the injury site, forming a glial scar that is a barrier to regenerating axons.

    Microglia are immune cells for the brain. After injury, they migrate to the site of injury to help clear away dead and dying cells. They can also produce small molecules called cytokines that trigger cells of the immune system to respond to the injury site. This clean-up process is likely to play an important role in recovery of function following a spinal injury.

    Oligodendrocytes

    The Brain And Spinal Cord Are The Central Nervous System Nerves And Sensory Organs Make Up The Peripheral Nervous System

    Reproductive Health and Fetal: The brain is made up of two ...

    Together, the central nervous system and the peripheral nervous systems transmit and process sensory information and coordinate bodily functions. The brain and spinal cord function as the control center. They receive data and feedback from the sensory organs and from nerves throughout the body, process the information, and send commands back out. Nerve pathways of the PNS carry the incoming and outgoing signals. Twelve pairs of cranial nerves connect the brain to eyes, ears, and other sensory organs and to head and neck muscles. Thirty-one pairs of spinal nerves branch out from the spinal cord to tissues of the thorax, abdomen, and limbs. Each nerve is responsible for relaying sensory information, sending motor commands, or both.

    You May Like: How To Shrink A Meningioma Brain Tumor Naturally

    How Does The Brain Work

    The brain sends and receives chemical and electrical signals throughout the body. Different signals control different processes, and your brain interprets each. Some make you feel tired, for example, while others make you feel pain.

    Some messages are kept within the brain, while others are relayed through the spine and across the bodys vast network of nerves to distant extremities. To do this, the central nervous system relies on billions of neurons .

    Anatomy Of The Human Brain

    The largest part of the human brain is the cerebrum, which is divided into two hemispheres, according to the Mayfield Clinic. Each hemisphere consists of four lobes: the frontal, parietal, temporal and occipital. The rippled surface of the cerebrum is called the cortex. Underneath the cerebrum lies the brainstem, and behind that sits the cerebellum.

    The frontal lobe is important for cognitive functions, such as thought and planning ahead, and for the control of voluntary movement. The temporal lobe generates memories and emotions. The parietal lobe integrates input from different senses and is important for spatial orientation and navigation. Visual processing takes place in the occipital lobe, near the back of the skull.

    The brainstem connects to the spinal cord and consists of the medulla oblongata, pons and midbrain. The primary functions of the brainstem include relaying information between the brain and the body supplying most of the cranial nerves to the face and head and performing critical functions in controlling the heart, breathing and levels of consciousness .

    The cerebellum lies beneath the cerebrum and has important functions in motor control. It plays a role in coordination and balance and may also have some cognitive functions.

    Read Also: What Part Of The Brain Controls Eyesight

    The Brain Connects Perceptions To Complex Thought Memory And Emotion

    The nervous system does more than route information and process commands. Why do certain smells immediately raise particular memories? The answer appears to lie in the limbic system. The limbic system forms two paired rings within the brain, consisting of the hippocampus, the amygdala, the cingulate gyrus, and the dentate gyrus, along with other structures and tracts. As with other brain segments, the limbic system is involved in multiple nervous system functions and levels of activity. It helps to process both memory and olfactionour sense of smelland it manages a range of emotions. The aroma rising from a pot on the stove may send your hand reaching for a spoon. It may also call up a dinner from earlier times, and make you happy, regretful, or nostalgic.

    Some Key Neurotransmitters At Work

    Dissecting Brains

    Neurotransmitters are chemicals that brain cells use to talk to each other. Some neurotransmitters make cells more active while others block or dampen a cell’s activity .

    Acetylcholine is an excitatory neurotransmitter because it generally makes cells more excitable. It governs muscle contractions and causes glands to secrete hormones. Alzheimers disease, which initially affects memory formation, is associated with a shortage of acetylcholine.

    Glutamate is a major excitatory neurotransmitter. Too much glutamate can kill or damage neurons and has been linked to disorders including Parkinson’s disease, stroke, seizures, and increased sensitivity to pain.

    GABA is an inhibitory neurotransmitter that helps control muscle activity and is an important part of the visual system. Drugs that increase GABA levels in the brain are used to treat epileptic seizures and tremors in patients with Huntingtons disease.

    Serotonin is a neurotransmitter that constricts blood vessels and brings on sleep. It is also involved in temperature regulation. Low levels of serotonin may cause sleep problems and depression, while too much serotonin can lead to seizures.

    Dopamine is an inhibitory neurotransmitter involved in mood and the control of complex movements. The loss of dopamine activity in some portions of the brain leads to the muscular rigidity of Parkinsons disease. Many medications used to treat behavioral disorders work by modifying the action of dopamine in the brain.

    Also Check: How Do Steroids Affect The Brain

    Motor Output And Behavior

    • Motor skill a learned sequence of movements that combine to produce a smooth, efficient action in order to master a particular task. The development of motor skill occurs in the motor cortex, the region of the cerebral cortex in the brain that controls voluntary muscle groups. Covers developmental aspects and influences such as stress, arousal, fatigue, and vigilance.
    • Muscle memory the retention in the brain of memories of certain muscle movements, often enabling those specific movement to be duplicated in the future. Also termed motor learning, it is a form of procedural memory that involves consolidating a specific motor task into memory through repetition. When a movement is repeated over time, a long-term muscle memory is created for that task, eventually allowing it to be performed without conscious effort. This process decreases the need for attention and creates maximum efficiency within the motor and memory systems. Examples of muscle memory are found in many everyday activities that become automatic and improve with practice, such as riding a bicycle, typing on a keyboard, rote typing in a bank personal identification number , playing a melody or phrase on a musical instrument, playing video games, or performing different algorithms for a Rubik’s Cube.

    Ventricles And Cerebrospinal Fluid

    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.

    You May Like: Does Crossword Puzzles Help Brain

    More articles

    Popular Articles