Name: sympathetic stress response and body changes
Uploaded: 2019-03-11T09:21:26.000Z
Duration: 1 min 25 s
Channel: JoVE

K12 Standards

Next Generation Science Standards

High School

Life Science

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

HS-LS1-2

The Sympathetic Nervous System

الجهاز العصبي الودي يستعد الجسم لاتخاذ الإجراءات خلال الأوقات من التهديد أو الإجهاد أو الإثارة بما في ذلك تفعيل القتال أو استجابة الرحلة. انها واحدة من الانقسامات الرئيسية الجهاز العصبي اللاإرادي التي تسيطر على وظائف لا إرادية من خلال تنظيم نشاط العضلات الملساء في الأعضاء الحشوية عضلة القلب في القلب وبعض الغدد مثل الغدد العرقية. عندما يتم تنشيط الجهاز العصبي الودي الخلايا العصبية قبل العقدة الصدرية والحبل الشوكي القطني يرسل إشارات إلى الجهاز العصبي المحيطي.يرسل البعض إشاراتهم إلى سلسلة من العقد مجموعات من أجسام الخلايا العصبية الذي يمتد إلى أسفل العمود الفقري. من هنا تقوم الخلايا العصبية بعد العقدة بنقل الإشارة لاستهداف الأنسجة التي تسبب الاستجابات مثل زيادة معدل ضربات القلب والانكماش الأوعية الدموية وتجلب المزيد من الدم إلى العضلات. ترسل الخلايا العصبية السابقة للعقدة إشارات إلى الخلايا العصبية بعد العقدة في العقد بالقرب من أعضائها المستهدفة حيث لديهم تأثيرات مثل تثبيط الهضم في المعدة وإفراز من المثانة العمليات ذات الأولوية المنخفضة في أوقات التوتر.الثلاث مجموعات من الخلايا العصبية قبل العقدة يسافر مباشرة إلى الغدة الكظرية حيث أنها تحفز الإنتاج من الهرمونات مثل ادرينالين أن توسط استجابة الإجهاد في جميع أنحاء الجسم.

ماكوين وبروس س. وجون إتش موريسون. "الدماغ على الإجهاد: ضعف ومرونة قشرة الفص الجبهي على مدار الحياة." الخلايا العصبية 79 ، العدد 1 (10 يوليو 2013): 16-29. [<a href = "https://doi.org/10.1016/j.neuron.2013.06.028" target = "__blank" >المصدر</a>]

الجهاز العصبي الودّي

<h4>نظره عامه</h4>

الجهاز العصبي السمبثاوي _ أحد القسمين الرئيسيين للجهاز العصبي اللاإرادي _ يتم تنشيطه في أوقات الإجهاد. يهيئ الجسم لمواجهة تحديات الظروف الصعبة مع تثبيط وظائف الجسم الأساسية _ مثل الهضم _ التي هي ذات أولوية أقل في الوقت الحالي.

<h4>نظام ”القتال أو الهروب“</h4>

كطالب ، ربما تكون قد مررت بتجربة الدخول إلى الفصل والعثور على اختبار مفاجئ لم تكن تتوقعه. في لحظة الإدراك ، قد تشعر بضيق أمعائك ، وجفاف فمك ، ويبدأ قلبك في التسارع فجأة. هذه علامات على سيطرة الجهاز السمبثاوي استعداداً للرد. على الرغم من أنك قد لا تكون في خطر مباشر ، فقد تطور النظام لتسهيل الاستجابة الفورية للتوتر أو التهديدات: يتم توجيه الدم بعيداً عن الجهاز الهضمي والجلد لزيادة إمدادات الطاقة للعضلات. علاوة على ذلك ، يزداد معدل ضربات القلب وتدفق الدم وتتوسع حدقة العين لتعظيم الإدراك البصري. في الوقت نفسه ، تطلق الغدة الكظرية الإبينفرين في الدورة الدموية. جسدك جاهز الآن لاتخاذ إجراءات ، سواء كان ذلك يعني الهروب السريع من الخطر أو محاربة أي تهديد قد يكون في متناول اليد.

<h4>التحكم في الجهاز السمبثاوي</h4>

يمكن تنشيط الجهاز العصبي السمبثاوي عن طريق أجزاء مختلفة من الدماغ ، حيث يلعب تحت المهاد دوراً مهماً بشكل خاص. يقوم الجهاز العصبي المركزي بإرسال التعليمات السمبثية من الخلايا العصبية السابقة للعقد في الأجزاء الصدرية والقطنية من الحبل الشوكي ، إلى الجهاز العصبي المحيطي _ حيث يكون لها تأثيرها النهائي _ من خلال ثلاثة مسارات رئيسية.

يتضمن المسار الأول الخلايا العصبية السابقة للعقد التي تتصل بسلسلة قريبة من العقد _ مجموعات من أجسام الخلايا العصبية _ والتي تمتد على طول كل جانب من جوانب العمود الفقري ، وغالباً ما تسمى السلسلة الوديّة. هنا ، تنشط الإشارة الخلايا العصبية التالية للعقدة التي تنتقل إلى الأعضاء أو الغدد المستهدفة لتنظيم وظائفها. وتشمل آثارها اتساع حدقة العين _ للسماح بدخول المزيد من الضوء إلى العين ؛ استرخاء المسالك الهوائية _ لجلب المزيد من الأكسجين ، وانقباض الأوعية الدموية وزيادة معدل ضربات القلب _ لدفع المزيد من الدم إلى العضلات.

في المسار الثاني ، ترسل الخلايا العصبية السابقة للعقدة إشارات إلى العقد البعيدة عن الحبل الشوكي ، بالقرب من الأعضاء المستهدفة. هنا ، يقومون بتنشيط الخلايا العصبية اللاحقة للعقدة التي تتحكم في نشاط الأعضاء مثل المعدة والبنكرياس والكبد والأمعاء والمثانة والأعضاء التناسلية. تشمل تأثيرات هذا المسار تثبيط الهضم والتبول وتحفيز هزات الجماع.

في المسار الثالث ، تنتقل مجموعة صغيرة من الخلايا العصبية السابقة للعقدة من الحبل الشوكي مباشرةً إلى الغدة الكظرية ، حيث تحفز إفراز هرمونات الأدرينالين والنورادرينالين في مجرى الدم _ ليساعد على التوسط في الاستجابة للإجهاد في جميع أنحاء الجسم.

<h4>الإجهاد المزمن</h4>

يتطور الجهاز العصبي السمبثاوي للسماح للحيوانات بالاستجابة بشكل أفضل للتهديدات المباشرة مثل المواجهة المفاجئة مع حيوان مفترس أو منافس. في حين أن البشر قد تركوا معظم تلك المخاوف البدائية وراءهم ، إلا أن النظام السمبثاوي بالجسم لا يزال بإمكانه الاستجابة للمواقف العصيبة بالطريقة نفسها تماماً كما هو الحال عند مواجهة قطة السافانا الشرسة. وهذا يشمل إفراز هرمونات الإبينفرين _ وتسمى أيضاً الأدرينالين _ والكورتيزول.

في ظل الظروف العادية ، يتم تنشيط الجهاز لفترة وجيزة ، وهذه الهرمونات لا تتواجد في الدورة الدموية لفترة طويلة. ومع ذلك ، يمكن للضغوط الحديثة في حياتنا اليومية أن تزيد من تنشيط هذا النظام وتعريض الجسم له لفترات أطول ، مما قد يكون له آثار منهكة. يمكن أن يشمل ذلك القلق والاكتئاب وأمراض القلب وزيادة الوزن واضطرابات النوم. يمكن أن تكون متطلبات الحياة الجامعية صعبة ، لذا فمن الأهمية بمكان الانخراط في إدارة صحية للتوتر. بعض استراتيجيات إدارة التوتر تتضمن الأكل الصحي ، والحصول على قسط كافٍ من النوم ، والحفاظ على العلاقات الاجتماعية ، والبحث عن المشورة المهنية عند الضرورة.

نظره عامه

يتم تنشيط الجهاز العصبي الودي - أحد القسمين الرئيسيين للجهاز العصبي اللاإرادي - في أوقات التوتر. إنه ...

Education

JoVE Core

Biology

علم الأحياء

Human Biology

بيولوجيا الإنسان

Nervous System

الجهاز العصبي

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

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 and skin and sends more energy to muscles. It also raises heart rate and blood flow, and it dilates the pupils to improve vision. At the same time, the adrenal gland releases epinephrine into the blood. The body is then ready to flee or fight.

The sympathetic nervous system is controlled by parts of the brain, especially the hypothalamus. Its signals start in preganglionic neurons in the thoracic and lumbar spinal cord and then travel through the peripheral nervous system. These signals follow three main pathways to reach organs and glands.

In the first pathway, preganglionic neurons connect to a nearby chain of ganglia, which are clusters of nerve cell bodies along each side of the spinal column. This chain is often called the sympathetic chain. The signal then activates postganglionic neurons, which act on target organs and glands. Their effects include pupil dilation, airway relaxation for more oxygen, and blood vessel constriction with a faster heart rate to move more blood to muscles.

In the second pathway, preganglionic neurons send signals to ganglia that are farther from the spinal cord and closer to the target organs. These postganglionic neurons control organs such as the stomach, pancreas, liver, intestines, bladder, and genitals. Their effects include slowing digestion and urination, and they can also stimulate orgasms.

In the third pathway, a small group of preganglionic neurons goes directly from the spinal cord to the adrenal gland. This triggers the release of epinephrine and norepinephrine into the bloodstream. These hormones help spread the stress response through the body.

The sympathetic nervous system evolved to help animals handle immediate threats, such as a predator or rival. Humans still use the same response during stressful events, and it can involve epinephrine, also called adrenaline, and cortisol. Under normal conditions, this reaction is brief. But modern stress can keep the system active for too long, which may lead to anxiety, depression, heart disease, weight gain, and sleep disorders. Healthy stress management can include good food, enough sleep, social support, and professional counseling when needed.

Sympathetic Stress Response and Body Changes

sympathetic-stress-response-and-body-changes

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

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

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...

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

Explore how the sympathetic nervous system triggers fight-or-flight body changes, from pupil dilation and faster heart rate to adrenal hormone release and stress control.

Sympathetic Stress Response and Body Changes | JoVE K12

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New York State Science Learning Standards

Structure and Function

HS-LS1-2.

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Characteristics of Life

Biology is a natural science that studies life and living organisms, including their structure, function, development, interactions, evolution, ...

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Cell Structure

Background
Cells represent the most basic biological units of all organisms, whether it be simple, single-celled organisms like bacteria, or large, ...

Visualizing Onion and Cheek Cells
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Remove the entire brown outer skin and ...

Visualizing Onion and Human Cells
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What are Cells?

Cell Diversity

The concept of a cell started with microscopic observations of dead cork tissue by Robert Hooke in 1665. Hooke coined the term &#34;cell&#34; based on the ...

Cytoplasm

The cytoplasm consists of organelles and a framework of protein scaffolds called the cytoskeleton suspended in an aqueous solution, the cytosol. The ...

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression ...

The Central Dogma

The DNA Helix

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DNA as a Genetic Template

Structure of a Gene

A gene is the fundamental unit of heredity. Every individual has two copies of each gene, one inherited from each parent. Although most people contain the ...

Chromosome Structure

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A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is comprised&#160; of nucleotides and proteins are ...

RNA Structure

The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form ...

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Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse ...

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Transcription

Transcription is the synthesis of RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. ...

Globular and Fibrous Proteins

Translation

Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes ...

Intrinsically Disordered Proteins

Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

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Protein and Protein Structures

Conjugated Proteins

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Cofactors and Coenzymes

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Protein Networks

Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells. [Assessment Boundary: Assessment does not include identification of specific cell or tissue types, whole body systems, specific protein structures and functions, or the biochemistry of protein synthesis.]

HS-LS1-1

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Carbohydrate Digestion

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Overview

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The Parasympathetic Nervous System

Overview

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Overview

The sympathetic nervous system&mdash;one of the two major divisions of the autonomic nervous system&mdash;is activated in times of stress. It ...

Oogenesis

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Homeostasis
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Blood Flow

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Blood Withdrawal II

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Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. [Clarification Statement: Emphasis is on functions at the organism system level such as nutrient uptake, water delivery, and organism movement in response to neural stimuli. An example of an interacting system could be an artery depending on the proper function of elastic tissue and smooth muscle to regulate and deliver the proper amount of blood within the circulatory system.] [Assessment Boundary: Assessment does not include interactions and functions at the molecular or chemical reaction level.]

What is Homeostasis?

Maintaining homeostasis requires that the body continuously maintain its internal conditions. Each physiological condition has a particular set point, ...

Negative and Positive Feedback

Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis. [Clarification Statement: Examples of investigations could include heart rate response to exercise, stomate response to moisture and temperature, and root development in response to water levels.] [Assessment Boundary: Assessment does not include the cellular processes involved in the feedback mechanism.]

HS-LS1-3

Sympathetic Stress Response and Body Changes

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