What Is the Brain Parenchyma?

The brain parenchyma is essentially the powerhouse of your cognitive and bodily control functions. This vital tissue comprises neurons and glial cells, which account for about 85% of the brain's weight. The remaining 15% consists of stroma, the supportive framework. 

The significance of the brain parenchyma becomes evident, considering that traumatic brain injuries (TBI), which often impact the parenchyma, contribute to a substantial number of deaths and cases of permanent disability annually. Understanding the brain parenchyma and how it functions is crucial, as damage to this area can lead to profound neurological consequences.

The brain parenchyma consists of neurons and glial cells. The neurons fulfill three main functions: afferent neurons are used to transmit messages from sensory organs to the brain and Central Nervous System (CNS), while efferent neurons send information and commands from the CNS to the muscles and glands. The third type, interneurons, are used for communication between the other two types.

These are supported and maintained by three types of glial cells. Oligodendroglia surround and insulate them, while astroglia physically support them and provide them with nutrition. They also eat debris and parts of dead neurons, as do microglia, the third type. Additionally, they regulate the concentration of ions in the space in between cells in the brain parenchyma, which keeps the organ as a whole functioning properly, and support the blood-brain barrier, which prevents certain substances from entering the brain via blood vessels. These cells also help with repairs following an injury.

The other categorization of cells in the brain is stroma, which includes blood vessels and connective tissue. It consists primarily of two sets of arteries, three sets of veins, and smaller capillaries that penetrate into the tissue, and the connective tissue that supports them. Though it doesn't perform the cognitive and management functions that the brain parenchyma does, it's still essential for the brain to function, since it provides it with nutrients and oxygen from the rest of the body. Additionally, problems with the stroma can be extremely serious. For example, if a cerebral blood vessel ruptures, the subsequent hemorrhaging can cause blood to build up in parenchymal tissue, raising the risk for stroke or memory loss.

A number of different conditions can affect the brain parenchyma. Changes due to age, deterioration, trauma, or damage to the stroma can cause a wide range of conditions, including dementia, Alzheimer's, Parkinson's disease, epilepsy, multiple sclerosis, and Amyotrophic Lateral Sclerosis (ALS). Infections can also affect these cells, as in the case of encephalitis or meningitis. Additionally, cell abnormalities can lead to growths and tumors that can put pressure on or permanently damage the surrounding tissue or spread throughout the body.

Brain parenchymal treatment depends on the specific medical condition a patient faces. Generally, injuries to the brain parenchyma are known as brain lesions, which involve damaged brain tissue. There are multiple different treatments for brain lesions, including:

Central nervous system relapse including the brain parenchyma occurs in about 5 percent of patients with systemic non-Hodgkin lymphoma. The condition may also impact the spinal cord, eyes, or leptomeninges. Research shows that the best treatment for isolated central nervous relapse is systemic methotrexate.

High-dose systemic methotrexate and intrathecal chemotherapy used in combination have shown the best results. 

White matter disease is also when the deepest and largest part of the brain tissue wears away. A physician may prescribe cholesterol-lowering medication or pills to help decrease your blood pressure. Also, you should not smoke when facing white matter disease.

Parenchymal brain damage relates to the harming of functional brain tissue. Furthermore, parenchymal brain damage is a complication that takes place due to various medical conditions. It can be a serious side effect from:

Furthermore, parenchymal brain injuries can occur among patients with abusive head trauma. Parenchymal brain damage and injury can lead to blindness, epilepsy, gross motor and cognitive impairment, and behavioral issues. 

Another form of parenchymal brain damage is known as a parenchymal hemorrhage or an intraparenchymal hemorrhage, which is a bleed taking place within the functional tissues of the brain. 

This happens when a blood vessel in the brain ruptures and harms the normal blood flow in the brain. As such, the patient doesn’t get an adequate amount of oxygen in brain tissues. Hypertension or high blood pressure can lead to the rupture of a blood vessel in the brain.

Cerebral amyloid angiopathy can also cause this, which is the accumulation of abnormal proteins in the brain’s arteries.

Brain parenchymal volume loss is seen on cross-sectional imaging and is known as cerebral atrophy. Essentially, it entails losing neurons and links between those neurons. You will find various diseases can lead to brain parenchymal volume loss or brain atrophy, such as:

Further, head or brain injuries can lead to brain parenchymal volume loss and atrophy. Patients who smoke, drink heavily, and/or are at an advanced age tend to increase their risk of brain atrophy. In addition, brain atrophy can lead to dementia among older patients.

They will struggle with thinking and remembering to the point of finding everyday life overly difficult. Such patients can get Alzheimer’s disease due to brain atrophy. These neurodegenerative diseases may cause aphasia, which involves speaking and language issues.

Brain atrophy can also lead to seizures, loss of consciousness, and bitter or metallic tastes.

A parenchymal stroke is a type of hemorrhagic stroke. The two other types of hemorrhagic strokes include arteriovenous and subarachnoid malformations. A parenchymal hemorrhage is a brain bleed that takes place within the parenchymal tissues. It can disrupt blood oxygen flow in brain cells and even lead to the destruction of functional brain tissue.

An intraparenchymal hemorrhage is responsible for less than 20 percent of all strokes, but it does have the highest mortality risks of all stroke types. Headaches, seizures, and neurological deficits can occur from a parenchymal stroke. Patients often have speech, vision, and hearing issues. 

The causes of hemorrhagic strokes include smoking, drinking alcohol heavily, and having high blood pressure or hypertension. Doctors can conduct blood coagulation studies and imaging studies to determine if a patient has a parenchymal hemorrhage.

Physicians may prescribe blood-thinning medication or anticoagulants along with mannitol or hypertonic saline. Platelet therapy is another option for treating that type of stroke.

The brain parenchyma refers to the functional tissue in the brain that is made up of two main types of cells: neurons and glial cells. Neurons are responsible for transmitting information through electrical and chemical signals, while glial cells provide support and protection for neurons. The brain parenchyma is critical for all brain activities, including thought, memory, emotion, and coordination.

Unlike other brain structures such as the meninges (protective layers) or blood vessels, the brain parenchyma specifically denotes the brain's functional tissue. It is the core substance within the central nervous system where the processing of information occurs. Other structures serve supportive or protective roles, but the parenchyma is where the actual 'work' of the brain takes place.

Yes, the brain parenchyma can be damaged due to various causes such as trauma, stroke, infection, or degenerative diseases. Damage to the parenchyma can lead to a loss of function in the affected area, which may manifest as cognitive deficits, sensory loss, or motor dysfunction, depending on the location and extent of the damage. According to the Centers for Disease Control and Prevention (CDC), stroke, a common cause of brain parenchymal damage, affects approximately 795,000 people in the United States each year.

Imaging techniques such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scans are commonly used to assess the brain parenchyma. MRI provides high-resolution images and can detect changes in brain tissue, such as inflammation, bleeding, or scarring. CT scans are faster and can quickly identify fractures or bleeding. Advanced imaging techniques like Diffusion Tensor Imaging (DTI) can even map neural pathways, providing detailed insights into brain structure and function.

Aging can lead to changes in the brain parenchyma, including a reduction in brain volume and weight. This is partly due to the loss of neurons and the shrinking of neuron size. There may also be a decrease in the number of synaptic connections, which can affect cognitive functions. However, the brain can adapt to some of these changes through neuroplasticity, which allows it to reorganize and form new connections. According to a study published in the journal Nature Reviews Neuroscience, the human brain experiences a roughly 5% decrease in volume per decade after the age of 40.