Name: how the blood-brain barrier works
Uploaded: 2025-10-23T11:47:15.000Z
Duration: 49 s
Channel: JoVE

- [내레이터] 인간의 뇌는 중추신경계의모세혈관을 정렬시키는 내피세포로구성된 혈액 뇌 장벽이라는보호 장벽을 통해서 순환계에서격리되어 있습니다.혈액 뇌 장벽은 또한 기저막과 성상세포라불리는 모세혈관과 밀착되어 있는 특수신경세포로 구성됩니다.이들 구성 요소는 원치 않는 물질의통과를 방지하는데 도움을줍니다.이 장벽은 연접복합체를 형성하는다양한 유형의 단백질을 통해뇌의 혈액과 간질액 사이의화학적 교류를 통제합니다.일반적으로 지용해성 화합물만이장벽을 통과할 수 있으며수용성 화합물은 능동 혹은수동수송을 통해 통과합니다.

Daneman, Richard, and Alexandre Prat. "혈액-뇌 장벽." Cold Spring Harbor Perspectives in Biology 7, no. 1 (2015년 1월). [<a href="https://doi.org/10.1101/cshperspect.a020412" target="__blank">소스</a>]

Andreone, Benjamin J., Baptiste Lacoste, and Chenghua Gu. "Neuronal and Vascular Interactions(신경 및 혈관 상호작용)."Annual Review of Neuroscience 38 (2015년 7월 8일): 25–46. [<a href="https://doi.org/10.1146/annurev-neuro-071714-033835" target="__blank">소스</a>]

혈액-뇌 장벽

The Blood-brain Barrier

<h4>개요</h4>
 
 혈액-뇌 장벽(blood-brain barrier, 줄여서 BBB; 혈뇌장벽)은 이온, 분자, 병원체 같은 물질의 이동을 엄격하게 제어하면서 뇌에 혈액 속의 영양분을 공급하는 전문 혈관 구조를 말합니다. 혈액-뇌 장벽의 한쪽에는 단단하게 연결된 내피 세포(endothelial cell)와 다른 쪽에는 성상세포(astrocyte; 성상교세포; 별아교세포)로 구성되어 있습니다. 이 세포들은 함께 뇌를 보호하고 치료제 전달에 도전을 제기하는 반투과성 장벽을 제공합니다.
 
 <h4>세포 구성 요소</h4>
 
 BBB는 내피 세포와 성상 세포 등 다양한 세포 성분으로 구성되어 있습니다. 이 세포들은 공통의 기저막(basement membrane)을 공유하고 요소가 순환과 뇌를 둘러싼 간질액(interstitial fluid)사이를 통과하는 것을 함께 조절합니다.
 
 첫 번째 유형의 세포 구성 요소인 특수 내피 세포는 대뇌 모세혈관의 벽을 구성합니다. 내피 세포는 매우 단단하고 복잡한 세포간 접합부(intercellular junction)로 연결되어 있습니다. 이러한 접합은 선택적이고 물리적인 장벽을 만들어 포도당과 인슐린과 같은 평균 크기에서 큰 크기의 분자를 포함한 대부분의 물질의 단순 확산(simple diffusion)을 막습니다.
 
 두 번째 세포 유형인 성상세포는 중추신경계(central nervous system)의 신경교세포(glial cell; 교세포; 신경아교세포)의 일종이며 뇌혈관과의 상호작용과 밀접한 연관성을 통해 뇌의 내피 세포 기능, 혈액 흐름, 이온 균형에 영향을 끼칩니다. 성상세포는 혈관과 뉴런 사이를 직접 연결합니다. 성상세포는 종족(end feet)이라는 돌기(process)를 이용해 한쪽 끝으론 혈관을 감싸고 다른쪽 끝은 시냅스(synapse)에서 뉴런과 밀접하게 접촉합니다.
 
 <h4>화학 물질 교환</h4>
 
 물질이 BBB를 통과하는 능력과 이런 물질 교환이 일어나는 효율은 각 분자 또는 이온의 화학적, 분자적 특성에 달려 있습니다. 일반적으로 산소와 이산화탄소와 같은 작은 지용성 성분은 내피층을 통해 빠르게 단순 확산을 합니다. 이와는 대조적으로 더 크거나 수용성 성분은 종종 내피 세포를 통한 수동수송(passive transport) 또는 능동수송(active transport)을 수반할 수 있는 보다 선택적인 과정이 필요합니다. 이러한 물질의 교환은 일반적으로 내피 세포의 표면에 있는 분자별 수용체(receptor)와 수송 단백질(transport proteins) 상대적 풍부함과 효율성에 따라 더 느리게 일어나거나 전혀 발생하지 않을 수 있습니다.
 
 <h4>BBB는 뇌를 보호합니다</h4>
 
 BBB에 의해 촉진되는 신경의 보호는 적절한 뇌 건강과 기능에 매우 중요합니다. BBB의 잘못된 조절은 부적절한 혈액 공급으로 인해 다발성 경화증(multiple sclerosis), 감염, 허혈(ischemia) 등을 포함한 심각한 신경질환으로 이어질 수 있습니다. 반대로 BBB의 활동은 중추신경계로 향하는 신경활성제약의 통과를 방지하거나 감소 시켜 일부 신경질환의 치료에 해로울 수 있습니다. 이런 이유로 신경학적 표적이 있는 약물은 BBB를 쉽게 통과하도록 설계되어야 합니다.

개요

혈액뇌장벽(BBB)은 혈액 내 영양분을 뇌에 공급하는 특수 혈관 구조를 말하며 엄격하게 ...

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Biology

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인체 생물학

Nervous System

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KEY TERMS AND CONCEPTS

주요 용어 및 개념

how the blood-brain barrier works

The blood-brain barrier is a specialized system of blood vessels that helps control what enters the brain. It delivers nutrients from the blood while tightly regulating ions, molecules, pathogens, and other substances. This semipermeable barrier protects the brain and also makes it harder to deliver some therapies.

The blood-brain barrier includes several cellular parts, especially endothelial cells and astrocytes. These cells share a common basement membrane and regulate movement between the circulation and the fluid around the brain. Specialized endothelial cells form the walls of cerebral capillaries. They are joined by very tight intercellular junctions, which create a selective physical barrier. This barrier blocks simple diffusion of most substances, including molecules as large as glucose and insulin.

Astrocytes are glial cells in the central nervous system. They influence endothelial cell function, blood flow, and ion balance in the brain. Astrocytes connect closely with the cerebral vasculature. Their processes, called endfeet, wrap around blood vessels on one end and make contact with neurons at synapses on the other. This gives them a direct link between blood vessels and nerve cells.

What crosses the barrier depends on a molecule's chemical and molecular properties. Small lipid-soluble substances, such as oxygen and carbon dioxide, move across by rapid simple diffusion. Larger or water-soluble substances usually need a more selective process. They may move through an endothelial cell by passive or active transport. In many cases, this exchange is slower, or it may not occur at all, depending on receptors and transport proteins on the endothelial surface.

The blood-brain barrier is essential for brain health and normal function. When it does not work properly, severe neurological diseases can occur, including multiple sclerosis, infection, and ischemia from poor blood supply. The barrier can also make treatment difficult because it can reduce the passage of neuroactive drugs into the central nervous system. For that reason, medicines aimed at the brain must be designed to pass through the blood-brain barrier.

How the Blood-Brain Barrier Works

what is a nervous system?

Nervous System Parts and Control

The nervous system is a network of specialized cells that keeps the body working and helps it respond to the world around it. It controls essential functions such as heart rate and breathing. It also supports movement that helps an organism escape danger. In vertebrates, the nervous system has two major parts: the central nervous system, or CNS, and the peripheral nervous system, or PNS. The CNS includes the brain, spinal cord, and retina, which is the sensory tissue of the visual system. The...

the parasympathetic nervous system

Rest and Digest: Parasympathetic Control

The parasympathetic nervous system helps the body stay calm and return to a rested state. It is one of the two major divisions of the autonomic nervous system, which controls many unconscious functions such as heart rate and digestion. Its neurons are found in the brain and the peripheral nervous system, and they send axons to muscles, organs, and glands. This system is often called the “rest and digest” system because it supports body processes that restore homeostasis. It is most active...

the sympathetic nervous system

Sympathetic Stress Response and Body Changes

The sympathetic nervous system helps the body respond to stress and danger. It is one of the two main divisions of the autonomic nervous system. When it turns on, it prepares the body for action and puts lower-priority functions, such as digestion, on hold. This response is often called the fight-or-flight system. A surprise exam can trigger it, and students may notice a tight stomach, a dry mouth, and a fast heartbeat. In a real threat, the system shifts blood away from the digestive system...

the blood-brain barrier

The blood-brain barrier is a specialized system of blood vessels that helps control what enters the brain. It delivers nutrients from the blood while tightly regulating ions, molecules, pathogens, and other substances. This semipermeable barrier protects the brain and also makes it harder to deliver some therapies. The blood-brain barrier includes several cellular parts, especially endothelial cells and astrocytes. These cells share a common basement membrane and regulate movement between the...

neuron structure

How Neurons Send Signals

Neurons send signals through a clear set of structures that let them receive, process, and pass on information. They are the main cells of the nervous system and use electrochemical signals to communicate. Neurons also talk to other cells through neurotransmitters at junctions called synapses. Most neurons share three main parts: a cell body, also called the soma, dendrites, and an axon. The soma holds the nucleus and other organelles needed for cell function. Dendrites usually receive...

glial cells

Glial Cells and Nervous System Support

Glial cells support the nervous system and work alongside neurons. They are one of the two main cell types in the nervous system. Unlike neurons, glia do not send electrical signals, but they help with nearly every other part of nervous system function. In humans, glial cells are about as numerous as neurons in the brain. In the central nervous system, glia include astrocytes, oligodendrocytes, microglia, and ependymal cells. Astrocytes are the most common glial cells. They form organized,...

action potentials

How Nerve Signals Travel in Axons

Neurons send signals through action potentials, the rapid electrical changes that move along the axon. These signals lead to neurotransmitter release at axon terminals, which passes information through the nervous system. An action potential is an all-or-none change in membrane potential, the voltage across a cell membrane. A neuron usually has a resting membrane potential of about -70 millivolts. When it receives signals from neurotransmitters or sensory input, the membrane can become more...

the resting membrane potential

How Neurons Keep a Negative Resting Charge

Neurons keep a negative resting charge across their membrane. This electrical difference, called the membrane potential, comes from how ions move and how the membrane lets them pass. In a resting neuron, the inside is typically around -70 millivolts and is more negative than the outside, so the cell is polarized. Two main factors create this resting state. First, the membrane is selectively permeable, which means most ions and molecules cannot cross the lipid bilayer without help from ion...

long-term potentiation

Synaptic Strengthening in Learning and Memory

Long-term potentiation, or LTP, is a form of synaptic strengthening in the brain. It changes the strength of chemical synapses over time between pre- and postsynaptic neurons. LTP works against long-term depression, or LTD, which weakens synapses. Together, LTP and LTD are major mechanisms behind learning and memory. LTP can happen when a presynaptic neuron fires again and again and keeps stimulating a postsynaptic neuron. This is called Hebbian LTP, based on Donald Hebb’s idea that neurons...

long-term depression

Synaptic Pruning in Long-term Depression

Long-term depression, or LTD, is a form of synaptic plasticity that weakens chemical synapses over time. It acts between presynaptic and postsynaptic neurons. LTD works in opposition to long-term potentiation, or LTP, which strengthens synapses. Together, LTD and LTP are two of the main mechanisms behind learning and memory. LTD helps the brain avoid staying locked in a fully strengthened state. If synapses were always maximally strengthened, the brain would become less efficient and it would...

the synapse

How Neurons Signal at Synapses

Neurons communicate through synapses, the points where two neurons meet to pass on signals. At a synapse, the sending neuron is the presynaptic cell, and the receiving neuron is the postsynaptic cell. Most neurons can serve in both roles because they send and receive information. Electrical synapses move signals directly between cells. The presynaptic and postsynaptic cells are linked by gap junctions, which are proteins that physically connect them. This type of synapse can pass electrical...

key terms and concepts

Learn how the blood-brain barrier protects the brain, which cells build it, what can cross it, and why it matters for disease and drug delivery.

How the Blood-Brain Barrier Works | JoVE K12

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How the Blood-Brain Barrier Works

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