The human brain : facts, functions, and anatomy.

HUMAN BRAIN

Here’s something to wrap your mind around: The human brain is more complex than any other known structure in the universe. Weighing in at three pounds, on average, this spongy mass of fat and protein is made up of two overarching types of cells called glia and neurons. and it contains many billions of each. 

Neurons are notable for their branch-like projections called axons and dendrites, which gather and transmit electrochemical signals. Different types of glial cells provide physical protection to neurons and help keep them, and the brain, healthy.

Together, this complex network of cells gives rise to every aspect of our shared humanity. We could not breathe, play, love, or remember without the brain.

The human brain is the command Center for the human nervous system. it receives signals from the body sensory organs and outputs information to the muscles.

The human brain has the same basic structure as other mammal  drawings but is larger in relation to body size than any other drawing.

Anatomy of the brain

The cerebrum is the largest part of the brain, accounting for 85 percent of the organ's weight. The distinctive, deeply wrinkled outer surface is the cerebral cortex. It's the cerebrum that makes the human brain. and therefore humans so formidable. Animals such as elephants, dolphins, and whales actually have larger brains, but humans have the most developed cerebrum. It's packed to capacity inside our skulls, with deep folds that cleverly maximize the total surface area of the cortex.

The cerebrum has two halves, or hemispheres, that are further divided into four regions, or lobes. The frontal lobes, located behind the forehead, are involved with speech, thought, learning, emotion, and movement. Behind them are the parietal lobes, which process sensory information such as touch, temperature, and pain. 

At the rear of the brain are the occipital lobes, dealing with vision. Lastly, there are the temporal lobes, near the temples, which are involved with hearing and memory.

The second-largest part of the brain is the cerebellum, which sits beneath the back of the cerebrum. It plays an important role in coordinating movement, posture, and balance.

The third-largest part is the diencephalon, located in the core of the brain. A complex of structures roughly the size of an apricot, its two major sections are the thalamus and hypothalamus. The thalamus acts as a relay station for incoming nerve impulses from around the body that are then forwarded to the appropriate brain region for processing. The hypothalamus controls hormone secretions from the nearby pituitary gland. These hormones govern growth and instinctual behaviors, such as when a new mother starts to lactate. The hypothalamus is also important for keeping bodily processes like temperature, hunger, and thirst balanced.

Seated at the organ's base, the brain stem controls reflexes and basic life functions such as heart rate, breathing, and blood pressure. It also regulates when you feel sleepy or awake and connects the cerebrum and cerebellum to the spinal cord.

The brain is extremely sensitive and delicate, and so it requires maximum protection, which is provided by the hard bone of the skull and three tough membranes called meninges. The spaces between these membranes are filled with fluid that cushions the brain and keeps it from being damaged by contact with the inside of the skull.

Blood-brain barrier

Want more proof that the brain is extraordinary? Look no further than the blood-brain barrier. The discovery of this unique feature dates to the 19th century, when various experiments revealed that dye, when injected into the bloodstream, colored all of the body’s organs except the brain and spinal cord. The same dye, when injected into the spinal fluid, tinted only the brain and spinal cord.

This led scientists to learn that the brain has an ingenious, protective layer. Called the blood-brain barrier, it’s made up of special, tightly bound cells that together function as a kind of semi-permeable gate throughout most of the organ.

It keeps the brain environment safe and stable by preventing some toxins, pathogens, and other harmful substances from entering the brain through the bloodstream, while simultaneously allowing oxygen and vital nutrients to pass through. 

Health conditions of the brain

Of course, when a machine as finely calibrated and complex as the brain gets injured or malfunctions, problems arise. One in five Americans suffers from some form of neurological damage, a wide-ranging list that includes stroke, epilepsy, and cerebral palsy, as well as dementia.

disorientation, and mood swings, is the most common cause of dementia. It is the sixth leading cause of death in the United States, and the number of people diagnosed with it is growing. Worldwide, some 50 million people suffer from Alzheimer’s or some form of dementia. 

While there are a handful of drugs available to mitigate Alzheimer’s symptoms, there is no cure. Researchers across the globe continue to develop treatments that one day might put an end to the disease’s devasting effects.

Far more common than neurological disorders, however, are conditions that fall under a broad category called mental illness. Unfortunately, negative attitudes toward people who suffer from mental illness are widespread. The stigma attached to mental illness can create feelings of shame, embarrassment, and rejection, causing many people to suffer in silence. In the United States, where anxiety disorders are the most common forms of mental illness, only about 40 percent of sufferers receive treatment. Anxiety disorders often stem from abnormalities in the brain’s hippocampus and prefrontal cortex.

Attention-deficit/hyperactivity disorder, or ADHD, is a mental health condition that also affects adults but is far more often diagnosed in children. ADHD is characterized by hyperactivity and an inability to stay focused. While the exact cause of ADHD has not yet been determined, scientists believe that it may be linked to several factors, among them genetics or brain injury. Treatment for ADHD may include psychotherapy as well as medications. The latter can help by increasing the brain chemicals dopamine and norepinephrine, which are vital to thinking and focusing.

Depression is another common mental health condition. It is the leading cause of disability worldwide and is often accompanied by anxiety. Depression can be marked by an array of symptoms,including persistent sadness, irritability, and changes in appetite. The good news is that in general, anxiety and depression are highly treatable through various medications. which help the brain use certain chemicals more efficiently. and through forms of therapy

15 facts about human brain you didn't know

#1. Sign of successful brain surgeries go as far back as the stone age.

#2. Adult brain weight about 3 pounds.

#3. About 75% of the brain is made up of water this means that the dehydration even in small amount can have a negative effect on the brain function.

#4. The largest brain of any animal is that of the sperms whale it weighs about 20 pound.

#5. The human brain will grow three times its size in the first year of life it continues to grow until you are about 18 years old.

#6. headaches are caused by a chemical reaction in your brain combined with the muscles and nervous off your neck and head.

#7. The brain of a human contains approximately 100 billion neurons.

#8. It is a myth that humans only use 10% of our brain we actually use all of it we are even using more than 10% when we sleep.

#9. Cholesterol is key to learning and memory however high cholesterol have different effect depending on your age and other factors.

#10. Information runs between neurons in your brain for everything we see think or do these neurons from move information at different speeds the fastest speed of information to pass between neurons is about 250 mph.

#11. Dreams are believed to be a combination of imagination psychological factors and neurological factors that prove that your brain is working even when you are sleeping.

#12. Brain cannot feel pain it interprets pain signals sent to it but it doesn't feel pain.

#13. Alcohol affects your brain in ways that include Blurred vision, slurred speaking and unsteady walk and more these usually disappear once you become Sober again however if you drink often for long periods of time there is an evidence that alcohol can affect your brain permanently and not rivers once you become Sober again long term effects include memory issues and some reduced cognitive function.

#14. Computer or video games may help improve cognitive abilities however more studies must be conducted to learn how much they help for what types of games help.

#15. Your brain uses 20% of the oxygen and blood in your body.

Humans vs. others Animals

Overall brain size doesn't correlate with level of Intelligence for instance the brain of a sperm whale is more than 5 times heavier than the human brain but humans are considered to be a higher intelligence than sperm whale the more accurate measure of how intelligent and animal may be is the ratio between the size of the brain and the body size.

Among humans how our brain size doesn't indicate how smart someone is some genius in their field have a smaller than average brains while other larger than average. for example compare the brains of two highly acclaimed writers the Russian Novelist ivan's brain was found to be a 2021 grams while writer anatole's brain weighted only 1017 grams.

Humans have a very high brain weight to body weight ratio but so do other animals the reason why the humans intelligence in part is neurons and folds humans have more neurons per unit volume than other animals and the only way to do that with the brains layered structure is to make folds in the outer layer.

Left brain vs. Right brain

The human brain is divided into two hemisphere the left and right connected by a bundle of nerve  fibers called the Corpus callosum.

The hemispheres are strongly though not entirely symmetrical. the left brain controls all the muscles on the right hand side of the body. and the right brain controls the left side. one hemisphere may be slightly dominant as with left or right handedness.

The popular notions about left brain and right brain qualities are generalizations that are not well supported by evidence. still there are some important difference between These areas. The left brain contains regions involved in speech and language and is also associated with mathematical calculation and effect retrieval. The right brain plays a role in visual and auditory processing, skills and artistic ability more instinctive or creative things with these functions involved both hemispheres.