Structure And Function Of Human Brain And Spinal Cord

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The brain is a complex organ made up of specialized nerve and supportive Tissues. It’s surrounded by many bones that together form the skull. The part of the skull where the brain sits is called the cranium. The base, or lower part, of the brain is connected to the spinal cord. Together, the brain and spinal cord are known as the central nervous system (CNS). Many nerves send electrical signals to and from the brain and spinal cord.  

The brain is the body’s control centre. It constantly receives and interprets nerve signals from the body and sends new signals based on this information. Different parts of the brain control movement, speech, emotions, consciousness and internal body functions, such as heart rate, breathing and body temperature.  

The brain has 3 main parts: cerebrum, cerebellum and brain stem.

Cerebrum

The cerebrum is the largest part of the brain. It is divided into 2 halves called the left and right cerebral hemispheres. The 2 hemispheres are connected by a bridge of nerve fibres called the corpus callosum.  The right half of the cerebrum (right hemisphere) controls the left side of the body. The left half of the cerebrum (left hemisphere) controls the right side of the body.  The cerebral cortex is the outer, folded part of the brain. It is also called the grey matter. The cerebral cortex is mostly made up of the cell bodies and dendrites of nerve cells (neurons). Cell bodies contain the nucleus and other main parts of the cell. Dendrites are the short branching fibres that receive signals from other nerve cells. The inner part of the cerebrum is called the white matter. It is mostly made up of the long fibres of a nerve cell (called axons) that send signals to and from the brain to the rest of the body. The fatty coating that surrounds axons (called myelin) gives this part of the brain a whitish appearance.  

 

 

 

Cerebellum

The cerebellum is located under the cerebrum at the back of the brain. It is divided into 2 parts or hemispheres and also has grey and white matter.  The cerebellum is responsible for:  

  • movement
  • posture
  • balance
  • reflexes complex actions (walking, talking)
  • collecting sensory information from the body   

The brain stem is a bundle of nerve tissue at the base of the brain. It connects the cerebrum and cerebellum to the spinal cord.  The brain stem has 3 areas:  

  • midbrain (also called the mesencephalon)
  • pons
  • medulla oblongata

Corpus callosum

The corpus callosum is a bundle of nerve fibres that allows Communication between the 2 cerebral hemispheres. It is the largest fibre bundle in the brain.    

Thalamus

The thalamus is a structure in the middle of the brain that has 2 lobes or sections. It acts as a relay station for almost all information that comes and goes between the brain and the rest of the nervous system in the body.

Hypothalamus

The hypothalamus is a small structure in the middle of the brain below the thalamus. It plays a part in controlling body temperature, hormone secretion, blood pressure, emotions, appetite and sleep patterns.    

 

 

Cranial nerves

There are 12 pairs of cranial nerves that perform specific functions in the head and neck, including giving us our sense of smell, sight (vision), hearing, taste, speech, feeling in the face and movement of the muscles in the face, eyes and tongue. One pair of nerves starts in specialized cells in the roof of the nose and another pair starts in the retina of the eye. The other 10 pairs start in the brain stem.

Structure and function of the spine

The spine is made up of 26 bones divided into 5 sections. These bones surround and protect the spinal cord. This includes 24 vertebrae (divided into cervical, thoracic and lumbar regions), the sacrum and the coccyx.  

Cervical region: These are 7 vertebrae at the top of the spine that run from the base of the skull to the lowest part of the neck.

Thoracic region: These are 12 vertebrae that run from the shoulders to the middle of the back.

Lumbar region: These are 5 vertebrae that run from the middle of the back to the hips.  Sacrum – This is a large section of fused vertebrae at the base of the spine.  

Coccyx (tail bone): This is a small, thin section of fused vertebrae at the end of the spine.    

Spinal cord

The spinal cord is a thick column of nerves surrounded by vertebrae that runs from the brain stem to the lumbar region of the spine. Like the brain, the spinal cord has both grey and white matter. The spinal cord sends information between the brain and most of the body through the spinal nerves.    

Spinal nerves

Pairs of spinal nerves exit the vertebrae along the length of the spinal cord. At the lumbar region, the spinal cord branches into a group of spinal nerves that exit the lumbar vertebrae and sacrum. The spinal nerves control body functions like movement, bladder and bowel control and breathing. The spinal nerves are numbered after nearby vertebrae.

Reflex Action

When a receptor is stimulated, it sends a signal to the central nervous system, where the brain co-ordinates the response. But sometimes a very quick response is needed, one that does not need the involvement of the brain. This is a reflex action.  Reflex actions are rapid and happen without us thinking. For example, you would pull your hand away from a hot flame without thinking about it. The animation below allows you to step through each stage of the reflex arc.

 



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The human brain is the most complex organ in the human body. It is responsible for controlling all of the body’s functions, from voluntary movements to involuntary processes like breathing and digestion. The brain is also responsible for higher-order functions like thought, emotion, and memory.

The brain is divided into three main parts: the cerebrum, the cerebellum, and the brainstem. The cerebrum is the largest part of the brain and is responsible for higher-order functions like thought, emotion, and memory. The cerebellum is responsible for coordination and balance. The brainstem is responsible for controlling basic functions like breathing and heart rate.

The cerebrum is further divided into two hemispheres, the left hemisphere and the right hemisphere. The left hemisphere is responsible for language, logic, and analytical thinking. The right hemisphere is responsible for creativity, intuition, and spatial reasoning.

The cerebrum is covered by a layer of gray matter called the cortex. The cortex is responsible for higher-order functions like thought, emotion, and memory. The cortex is also responsible for controlling voluntary movements.

The cerebrum is divided into four lobes: the frontal lobe, the parietal lobe, the temporal lobe, and the occipital lobe. Each lobe is responsible for different functions.

The frontal lobe is responsible for planning, decision-making, and voluntary movements. The parietal lobe is responsible for processing information from the senses. The temporal lobe is responsible for hearing, memory, and emotion. The occipital lobe is responsible for vision.

The cerebellum is located below the cerebrum and behind the brainstem. The cerebellum is responsible for coordination and balance. The cerebellum also helps to control voluntary movements.

The brainstem is located at the base of the brain. The brainstem is responsible for controlling basic functions like breathing, heart rate, and blood pressure. The brainstem also connects the brain to the spinal cord.

The spinal cord is a long, thin bundle of nerves that runs from the brain to the lower back. The spinal cord is responsible for carrying messages between the brain and the rest of the body. The spinal cord also controls some involuntary movements, such as reflexes.

The spinal cord is made up of two main parts: the gray matter and the white matter. The gray matter is responsible for controlling involuntary movements. The white matter is responsible for carrying messages between the brain and the rest of the body.

The spinal cord is divided into 31 segments, each of which corresponds to a pair of spinal nerves. The spinal nerves branch out from the spinal cord and carry messages to and from the body.

The brain and spinal cord are protected by the skull and the spinal column. The skull is a hard, bony structure that surrounds the brain. The spinal column is a series of bones that protect the spinal cord.

The brain and spinal cord are essential for life. They control all of the body’s functions and allow us to think, feel, and move.

What is the brain?

The brain is the control center of the body. It is made up of billions of nerve cells that communicate with each other using electrical and chemical signals. The brain controls everything we do, from thinking and moving to feeling and breathing.

What is the spinal cord?

The spinal cord is a long, thin bundle of nerves that runs from the brain down the back. It connects the brain to the rest of the body and carries messages back and forth between them. The spinal cord controls many of the body’s automatic functions, such as breathing and heart rate.

What are the functions of the brain?

The brain has many different functions, including:

  • Controlling movement
  • Processing information from the senses
  • Regulating emotions
  • Thinking and planning
  • Making decisions
  • Storing memories

What are the functions of the spinal cord?

The spinal cord has many different functions, including:

  • Carrying messages from the brain to the rest of the body
  • Carrying messages from the rest of the body to the brain
  • Controlling many of the body’s automatic functions, such as breathing and heart rate

What are the parts of the brain?

The brain is divided into three main parts: the cerebrum, the cerebellum, and the brainstem.

  • The cerebrum is the largest part of the brain. It is responsible for higher functions, such as thinking, planning, and decision-making.
  • The cerebellum is responsible for coordination and balance.
  • The brainstem is responsible for controlling basic functions, such as breathing and heart rate.

What are the parts of the spinal cord?

The spinal cord is divided into four main regions: the cervical region, the thoracic region, the lumbar region, and the sacral region.

  • The cervical region is located in the neck. It controls the movement of the head and neck.
  • The thoracic region is located in the chest. It controls the movement of the arms and shoulders.
  • The lumbar region is located in the lower back. It controls the movement of the legs and feet.
  • The sacral region is located in the lower back and sacrum. It controls the bladder and bowel function.

What are some common brain disorders?

Some common brain disorders include:

  • Alzheimer’s disease: A progressive brain disorder that causes memory loss and other cognitive problems.
  • Parkinson’s disease: A disorder that affects the nervous system and causes tremors, stiffness, and difficulty with balance and coordination.
  • Epilepsy: A disorder that affects the brain and causes seizures.
  • Stroke: A blockage in the blood supply to the brain that can cause paralysis, speech problems, and other disabilities.

What are some common spinal cord disorders?

Some common spinal cord disorders include:

  • Spinal cord injury: An injury to the spinal cord that can cause paralysis, loss of sensation, and other disabilities.
  • Multiple sclerosis: A disease that affects the central nervous system and causes a variety of symptoms, including fatigue, numbness, tingling, and vision problems.
  • Spina bifida: A birth defect that occurs when the spinal cord and/or the bones that protect it do not form properly.

What are some treatments for brain disorders?

There is no cure for Alzheimer’s disease, but there are treatments that can help manage the symptoms. Treatment may include medications, therapy, and lifestyle changes.

There is no cure for Parkinson’s disease, but there are treatments that can help manage the symptoms. Treatment may include medications, therapy, and surgery.

There is no cure for epilepsy, but there are treatments that can help control seizures. Treatment may include medications, surgery, and lifestyle changes.

There is no cure for stroke, but there are treatments that can help minimize the damage and improve the chances of recovery. Treatment may include medications, surgery, and rehabilitation.

There is no cure for spinal cord injury, but there are treatments that can help manage the symptoms and improve the Quality Of Life. Treatment may include medications, therapy, and surgery.

There is no cure for multiple sclerosis, but there are treatments that can help manage the symptoms and slow the progression of the disease. Treatment may include medications, therapy, and lifestyle changes.

There is no cure for spina bifida, but there are treatments that can help manage the symptoms and improve the quality of life. Treatment may include surgery, therapy, and medication.

  1. The brain is the control center of the body. It is made up of billions of nerve cells called neurons. Neurons communicate with each other using electrical and chemical signals.
  2. The spinal cord is a long, thin bundle of nerves that runs from the brain down the back. It carries messages between the brain and the rest of the body.
  3. The brain and spinal cord are protected by the skull and the spinal column. The skull is a hard bone that surrounds the brain. The spinal column is a series of bones that protect the spinal cord.
  4. The brain is divided into three main parts: the cerebrum, the cerebellum, and the brainstem. The cerebrum is the largest part of the brain. It is responsible for higher functions such as thinking, planning, and decision-making. The cerebellum is responsible for coordination and balance. The brainstem is responsible for basic functions such as breathing, heart rate, and blood pressure.
  5. The spinal cord is divided into 31 segments. Each segment is connected to a pair of spinal nerves. The spinal nerves carry messages between the brain and the rest of the body.
  6. The brain and spinal cord are responsible for controlling all of the body’s functions. They control everything from breathing to thinking to moving.
  7. The brain and spinal cord are very complex organs. They are made up of billions of cells that work together to control the body.
  8. The brain and spinal cord are very delicate organs. They can be damaged by injury, disease, or infection.
  9. Damage to the brain or spinal cord can cause a variety of problems, including paralysis, loss of sensation, and cognitive impairment.
  10. There is no cure for damage to the brain or spinal cord. However, there are treatments that can help to improve function and quality of life.

Here are some MCQs about the brain and spinal cord:

  1. Which of the following is not a function of the brain?
    (A) Controlling breathing
    (B) Controlling heart rate
    (C) Controlling blood pressure
    (D) Thinking

  2. Which of the following is not a function of the spinal cord?
    (A) Carrying messages between the brain and the rest of the body
    (B) Controlling basic functions such as breathing, heart rate, and blood pressure
    (C) Coordinating movement
    (D) Thinking

  3. Which of the following is the largest part of the brain?
    (A) Cerebrum
    (B) Cerebellum
    (C) Brainstem
    (D) Spinal cord

  4. The brain and spinal cord are protected by the:
    (A) Skull
    (B) Spinal column
    (C) Both the skull and the spinal column
    (D) Neither the skull nor the spinal column

  5. The brain and spinal cord are made up of billions of cells called:
    (A) Neurons
    (B) Glia
    (C) Both neurons and glia
    (D) Neither neurons nor glia

  6. The brain and spinal cord are very complex organs. They are made up of billions of cells that work together to control the body. True or False?

  7. The brain and spinal cord are very delicate organs. They can be damaged by injury, disease, or infection. True or False?

  8. Damage to the brain or spinal cord can cause a variety of problems, including paralysis, loss of sensation, and cognitive impairment. True or False?

  9. There is no cure for damage to the brain or spinal cord. However, there are treatments that can help to improve function and quality of life. True or False?