Name: spinal cord nerves and reflexes
Uploaded: 2024-08-29T22:13:37.000Z
Duration: 1 min 26 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.14

SC.912.L.14.28

Spinal Cord

脊髄は脳の基部から始まり、背中の中央まで伸びており、脳と体の間の重要なコミュニケーションリンクとして機能します。
脊髄は、8つの頸部、12の胸部、5つの腰椎、5つの仙骨、および1つの尾骨セグメントのいくつかのセグメントに分かれています。脊髄から生じる神経は、末梢神経系を介して体の特定の部分に接続しています。
脊髄には、感覚ニューロン、運動ニューロン、介在ニューロンの3種類の神経細胞があります。 
感覚ニューロンは感覚情報を脊髄に伝達し、運動ニューロンは脊髄から腺や筋肉に情報を伝達します。介在ニューロンは、感覚ニューロンと運動ニューロンをつなぎ、脊髄の構造の大部分を構成しています。
さらに、脊髄は脳からの入力なしに反射行動を開始できます。
例えば、熱い鍋に触れると、皮膚の感覚ニューロンが痛みを感知し、信号を脊髄に送ります。入力はすぐに介在ニューロンによって処理され、運動ニューロンが引き起こされ、筋肉が手を引くようにすばやく促します。

脊髄

脊髄は中枢神経系の重要な構成要素で、脳幹の基部から脊柱の腰部まで伸びています。脊髄は身体の安定性を維持し、脳と身体の末梢部との通信を促進するために不可欠です。

脊髄は脊椎の保護骨構造に包まれており、椎骨に対応する 30 のセグメントに分かれています。

これらのセグメントは、広大な神経ネットワークを介して特定の身体領域を接続する重要な役割を果たし、さまざまな身体機能に不可欠な情報の双方向の流れを可能にします。

各脊髄セグメントは、脊柱に沿った位置に基づいて頸部、胸部、腰部、仙骨、尾骨領域に分類される一対の脊髄神経を介して身体の特定の部分に接続します。

これらの神経は椎骨間のスペースを通って脊髄から出て、感覚情報と運動情報を伝達します。

脊髄は、感覚ニューロン、運動ニューロン、介在ニューロンという 3 つの主要な神経細胞で構成されています。 

感覚ニューロンは、感覚受容器から脊髄に外部刺激に関する情報を伝える上で極めて重要な役割を果たします。この情報には、触覚、温度、痛みなどの感覚が含まれます。 

脊髄構造の中で最も数が多い介在ニューロンは、この感覚情報を処理して統合します。介在ニューロンは仲介者として機能し、感覚ニューロンと運動ニューロン間の通信を可能にし、適切な運動反応の調整を促進します。 

運動ニューロンは脊髄から体の筋肉と腺に信号を伝達し、すべての随意運動と多くの不随意運動を開始および制御します。これは、脊髄が運動機能に不可欠な役割を果たしていることを強調しています。

脊髄の注目すべき機能は、脳から独立して反射動作を調整する能力です。反射弓は、感覚入力に反応して直接活性化し、即時の反応を生み出す神経回路です。たとえば、熱い表面に触れると、感覚ニューロンはすぐに脊髄に信号を送ります。介在ニューロンはすぐにこの情報を処理し、運動ニューロンを活性化して、手を素早く引っ込めます。この反射動作は身体を危害から守るために発生し、脊髄の複雑な機能と人体の機能階層における脊髄の重要な役割を浮き彫りにします。

脊髄は脳の基部から始まり、背中の中央まで伸びており、脳と脳との間の重要なコミュニケーションリンクとして機能します...

Education

JoVE Core

Introduction to Psychology

心理学概論

Unit 1

ユニット1

Biopsychology

生物心理学

KEY TERMS AND CONCEPTS

主要用語と概念

spinal cord nerves and reflexes

The spinal cord is a major part of the central nervous system. It runs from the base of the brainstem to the lumbar region of the vertebral column. It helps keep the body stable and carries signals between the brain and the rest of the body.

The spinal cord sits inside the bony spine for protection. It is divided into 30 segments that match the vertebrae. Each segment connects to a specific body region through paired spinal nerves.

These spinal nerves are grouped by where they leave the vertebral column. The regions are cervical, thoracic, lumbar, sacral, and coccygeal. They exit through spaces between the vertebrae and carry sensory and motor information.

The spinal cord contains three main types of nerve cells. Sensory neurons bring information from sensory receptors to the spinal cord. This includes touch, temperature, and pain.

Interneurons are the most numerous nerve cells in the spinal cord. They process and combine sensory input. They also link sensory neurons to motor neurons so the body can respond in the right way.

Motor neurons send signals from the spinal cord to muscles and glands. They control voluntary movement and many involuntary actions. The spinal cord also handles reflex arcs, which are fast neural pathways that work without direct brain control.

A reflex arc can protect the body from harm. When a person touches a hot surface, sensory neurons send a signal to the spinal cord. Interneurons process the message and activate motor neurons, which make the hand pull away quickly.

Spinal Cord Nerves and Reflexes

introduction to biological bases of psychology

introduction-to-biological-bases-of-psychology

Biological Factors Shaping Behavior and Mind

Biopsychology connects biology and psychology by showing how the body influences behavior and mental processes. It focuses on the nervous system, neurotransmitters, hormones, genetics, and evolutionary ideas. Together, these areas help explain why people think, feel, and act the way they do. The nervous system is the main foundation of biopsychology. It has two parts: the central nervous system, or CNS, and the peripheral nervous system, or PNS. The CNS includes the brain and spinal cord and...

nervous system

Nervous System: CNS, PNS, and Reflexes

The nervous system helps the body sense, move, and respond. It works through a network of nerve cells that carry signals around the body. This system has two main parts: the central nervous system and the peripheral nervous system. The central nervous system, or CNS, includes the brain and spinal cord. The brain acts as the body’s control center. It processes sensory information and helps coordinate responses. The spinal cord serves as a major pathway for signals between the brain and the rest...

neurons as communicators of the brain

Neuron Parts and Signal Transmission

Neurons are the cells that carry information through the brain and nervous system. They use electrical and chemical signals to help control body functions, from heartbeat regulation to complex thinking. Their structure is built for fast, efficient communication. The cell body, or soma, is the neuron’s control center. It contains the nucleus, which holds the cell’s genetic material and helps maintain the neuron’s health and function. The cytoplasm around it contains organelles that make...

neuronal communication

How Neurons Send Signals

Neurons send signals through electrochemical communication that supports brain and nervous system function. A key part of this process is the action potential, a rapid electrical change that starts when the neuron’s internal charge rises above a threshold. That signal then travels along the axon to the axon terminal, where it is ready to pass to another neuron. The connection point between two neurons is called a synapse. Synapses can be electrical or chemical, and each type moves information...

neurotransmitters

Brain Chemicals That Shape Mood and Movement

Neurotransmitters are chemical messengers that help neurons communicate. They play a major role in nervous system function, as well as in mood, movement, sleep, and social behavior. Serotonin is made in the brain and intestines. It is linked to well-being and happiness, and it helps regulate mood, appetite, and sleep. When serotonin levels are out of balance in the brain or in peripheral sites, depression and sleep problems can occur. Dopamine is produced in several brain areas, including the...

cerebral hemispheres

How the Brain’s Two Halves Work

The brain’s two cerebral hemispheres work together to process information and control the body. The left and right hemispheres are linked by the corpus callosum, a large bundle of nerve fibers. This connection lets the two sides share sensory and motor information, with each hemisphere controlling the opposite side of the body. The hemispheres are also specialized for different tasks. This is called lateralization, which means certain functions are handled more strongly by one side than the...

lobes of the cerebrum

How Brain Lobes Shape Perception

The cerebral cortex is divided into two hemispheres, and each hemisphere has four lobes: frontal, parietal, temporal, and occipital. Together, these lobes support the brain’s main cognitive and sensory jobs. They work as a team to help you think, feel, move, and respond to the world. The frontal lobe sits behind the forehead and acts as a control center for personality, intelligence, and voluntary muscle movement. It also contains the prefrontal cortex, a region that helps with planning,...

spinal cord

The spinal cord is a major part of the central nervous system. It runs from the base of the brainstem to the lumbar region of the vertebral column. It helps keep the body stable and carries signals between the brain and the rest of the body. The spinal cord sits inside the bony spine for protection. It is divided into 30 segments that match the vertebrae. Each segment connects to a specific body region through paired spinal nerves. These spinal nerves are grouped by where they leave the...

lateralization

Brain Hemisphere Specialization

Brain hemisphere specialization divides mental tasks between the left and right sides of the brain. This split can improve neural efficiency and support more complex human abilities. Each hemisphere tends to handle the work it does best, which helps cognitive processing run more smoothly. The left hemisphere is especially strong in logic and language-related tasks. It supports analytical thinking, which means breaking a problem into parts and solving it step by step. This is important for...

human genetics

Genes, Behavior, and Mental Health

Human genetics explains how genes can influence behavior, emotions, and mental health. It also shows how a person’s genetic code can shape physical traits and the risk of disease. Each individual carries a unique set of genes, so the effects can be subtle or more noticeable. Genes help direct how the brain, hormones, and cells work. These body systems are all shaped by genetic instructions, and they help produce differences in thoughts and behavior. Human genetics therefore links biology with...

genetic material

Chromosomes, DNA, and Inherited Traits

Chromosomes, DNA, and inherited traits explain how genetic information is organized in the human body. Each cell contains a nucleus, and the nucleus holds 46 chromosomes arranged in 23 pairs. These chromosomes are tightly coiled structures made of DNA, which carries the instructions passed from parents to offspring. An individual inherits one set of chromosomes from the mother through the egg and one set from the father through the sperm. This combination creates a unique genetic makeup. Of...

genetic variation

How Alleles Shape Inherited Traits

Genetic variation helps explain why individuals in the same species can look and act differently. It comes from differences in DNA sequences. This diversity matters because it helps a species survive and adapt when the environment changes. Variation starts at fertilization, when an egg and sperm cell join. Each of these cells carries 23 chromosomes, so the fertilized egg can have up to 46 chromosomes. Chromosomes are long DNA strands that contain genes, which are the basic units of heredity. <br...

behavioral genetics and its designs

How Behavior Genetics Studies Inheritance

Behavior genetics studies how inherited genes influence human behavior. It looks at how genes passed from parents to offspring help shape behavioral traits and tendencies. The field also examines how inherited factors and environmental influences work together. Researchers use family studies, twin studies, and adoption studies to separate genetic and environmental effects. Family studies track traits within biological families to find possible genetic patterns. They have helped identify...

organization of the brain

Brain Regions and Their Key Functions

The brain is the main control center of the nervous system. It processes sensory input, makes decisions, and directs body actions. Its structure is divided into the hindbrain, midbrain, and forebrain, and each part supports important functions. The hindbrain sits at the base of the brain. It helps regulate automatic life processes. The medulla oblongata controls involuntary functions such as heartbeat, breathing, and blood pressure. Nearby, the pons acts as a bridge between brain regions,...

evolutionary psychology

Evolutionary Psychology and Human Behavior

Evolutionary psychology explains human behavior and mental processes through natural selection. It uses Darwin’s idea that traits can spread when they help survival and reproduction. In this view, some common behaviors may be adaptations that were useful to our ancestors. One clear example is fear of snakes. This fear is nearly universal, which suggests that early humans who avoided snakes were more likely to survive deadly encounters. Over many generations, that caution could be passed on and...

neuroplasticity

How the Brain Rewires Itself

Neuroplasticity is the brain’s ability to change its structure and function in response to learning, experience, or injury. It allows neural circuits to reorganize over time. This flexibility supports lifelong development and adaptation. One part of this change begins when dendrites and axons grow. Dendrites receive signals, and axons send them. As they grow, the brain’s circuitry becomes more complex and can support more connections. Next, synaptogenesis occurs. Synaptogenesis is the...

brain imaging

Brain Scanning Techniques

Brain scanning techniques help scientists and doctors see the structure and activity of the human brain. These methods support the diagnosis, study, and treatment of neurological and psychiatric disorders. The main techniques include computerized axial tomography, or CT, positron-emission tomography, or PET, magnetic resonance imaging, or MRI, functional magnetic resonance imaging, or fMRI, and transcranial magnetic stimulation, or TMS. CT scans use X-ray technology to build detailed...

the endocrine system

Endocrine Glands and Hormone Signals

The endocrine system is a network of glands that send hormone signals through the body. Hormones are chemical messengers that help control many body functions. They enter the bloodstream and travel to cells with the right receptors, or target sites, so the signal can be received. Because of this, hormone effects are widespread, unlike the more localized effects of neurotransmitters. This signaling helps the body keep a stable internal environment, called homeostasis. Several major glands...

somatosensory, motor, and association cortex

somatosensory-motor-and-association-cortex

Brain Cortex Areas for Sensation and Movement

The brain cortex uses separate areas for sensation, movement, and higher thinking. The somatosensory cortex is in the parietal lobes. It helps the brain interpret touch, temperature, and proprioception, which is awareness of body position. The somatosensory cortex has an organized map of the body. Neurons at the top of this region mainly process signals from the lower body. Neurons at the bottom handle input from the upper body. This layout helps the brain locate sensory input with precision.

major hormones and their functions

Hormone Imbalances and Their Effects

Hormones are chemical messengers made by endocrine glands. They help control body functions and keep internal conditions stable. When hormone levels shift too far up or down, normal body processes can be disrupted. Several major hormones have clear roles in the body. Oxytocin is made in the hypothalamus and released by the pituitary gland. It supports social bonding, childbirth, and lactation. Low oxytocin can affect social interaction and stress response, and it may contribute to depression.

inheritance

Genes, Traits, and Mendel's Rules

Genes, traits, and Mendel's rules explain how characteristics pass from parents to offspring. Gregor Mendel's pea plant experiments changed how scientists understand heredity. His work showed that traits are controlled by discrete units inside organisms called genes. Genes usually come in pairs. One gene is inherited from each parent, and together they make a person's genotype. Genotype is the genetic blueprint for potential traits. Examples include blood type, eye color, and inherited...

gene-environment interactions

How Environment Shapes Gene Expression

Environmental factors can change how genes are expressed. Gene expression is a dynamic process, and traits can differ even in people with the same DNA. Radiation, temperature, behavior, nutrition, and stress all help shape the final outcome. The reaction range helps explain this process. It means genes set a possible range for a trait, while the environment helps decide where a person falls within that range. For example, genetics may allow a height range from 5'5" to 6'1", but nutrition,...

heritability

Heritability and the Environment

Heritability describes how genetic differences contribute to trait variation in a population. It is a statistical measure, so it shows how much of the spread in a trait can be linked to genes across a group. It does not tell you how “genetic” a trait is in an individual person. Heritability is usually expressed as a percentage. That percentage can change depending on which population is studied and what environmental conditions are present. This means heritability is context-dependent, not...

natural selection and adaptation

Adaptation in Changing Environments

Natural selection explains how organisms become better suited to their environments over time. It favors individuals with traits that improve survival and reproduction. Adaptation is the result. It includes genetic changes that help an organism function in specific conditions, such as extreme cold or thinner air at high altitudes. Adaptation is not only physical. Psychological adaptation also helps organisms, especially humans, succeed in their surroundings. These responses come from both...

natural selection and mating preferences

How Selection Shapes Mate Choice

Natural selection and mating preferences work together to shape how organisms survive and reproduce. Natural selection favors traits that help an organism fit its environment. Mating preferences are part of sexual selection, which influences who mates with whom and how genes are passed on. Evolutionary psychologists argue that these preferences are tied to instincts that support reproduction. For females, conception, pregnancy, and nursing create a strong need to choose mates who can offer...

criticisms of the evolutionary perspective

criticisms-of-the-evolutionary-perspective

Social Learning vs. Evolutionary Psychology

Social learning theory and evolutionary psychology offer two different ways to explain sexual behavior. A study in which strangers gave students compliments and then asked for casual sex showed a clear gender gap. None of the women said yes, while 70% of the men agreed. Evolutionary psychology explains this result by arguing that natural selection may have shaped women to be more selective about sexual partners. From this view, selectivity can help improve survival and reproductive success. It...

key terms and concepts

Explore how spinal cord segments, spinal nerves, and nerve cells work together to relay signals, control movement, and trigger fast reflexes.

Spinal Cord Nerves and Reflexes | JoVE K12

JoVE Core Introduction to Psychology offers an engaging learning experience on the fundamental principles of psychology through concise video lessons. Students will explore important topics such as cognitive processes, emotional regulation, and neural mechanisms, establishing a strong foundation in the study of the mind and human behavior. This series provides an accessible and captivating approach to grasp the essential concepts of the discipline.

introduction to psychology

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SC.912.L.14.1

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SC.912.L.14.2

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SC.912.L.14.4

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D. Most multicellular organisms are composed of organ systems whose structures reflect their particular function.

Spinal Cord Nerves and Reflexes

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