Name: homeostasis and body feedback control
Uploaded: 2023-04-30T10:08:28.000Z
Duration: 1 min 18 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Life Sciences

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

From Molecules To Organisms: Structures And Processes

HS-LS1-3

Positive and Negative Feedback Loops

Funkcje biologiczne, takie jak szlaki metaboliczne lub szlaki sygnalizacji komórkowej, są regulowane przez mechanizmy sprzężenia zwrotnego, które obejmują pętle ujemnego i dodatniego sprzężenia zwrotnego.
Pozytywne sprzężenie zwrotne występuje, gdy produkt procesu stymuluje dalszy wzrost jego produkcji, co prowadzi do zwiększonej reakcji.
Proces krzepnięcia krwi jest jednym z typowych przykładów pętli dodatniego sprzężenia zwrotnego.
Przecięcie w ścianie naczynia krwionośnego działa jak bodziec, który pobudza naczynia i pobliskie płytki krwi do uwalniania sygnałów chemicznych, aktywując kilka czynników krzepnięcia i przyciągając płytki krwi do miejsca urazu, inicjując zakrzep krwi. Płytki krwi wydzielają sygnały chemiczne, aby przyciągnąć więcej płytek krwi do miejsca, aż rozwijający się skrzep całkowicie uszczelni ranę.
Pętla ujemnego sprzężenia zwrotnego występuje, gdy produkt reakcji zmniejsza bodziec początkowy.
Na przykład, gdy poziom glukozy we krwi wzrasta, trzustka uwalnia insulinę, która wyzwala wychwyt glukozy przez komórki wątroby, obniżając poziom glukozy we krwi.
Po przywróceniu poziomu glukozy we krwi trzustka przestaje wytwarzać insulinę.

pozytywne i negatywne pętle sprzężenia zwrotnego

Narządy i układy narządów zwierząt stale dostosowują się do zmian wewnętrznych i zewnętrznych w procesie zwanym homeostazą („stanem ustalonym”). Przykładami tych zmian są regulacja poziomu glukozy lub wapnia we krwi lub reakcje wewnętrzne na temperaturę zewnętrzną. Homeostaza wymaga utrzymania wewnętrznej równowagi dynamicznej: 

 <ul style="padding-left: 35px; list-style-type: disc;"> 
 <li>Dynamiczna, ponieważ stale dostosowuje się do zmian, jakie napotykają układy organizmu.</li> 
 <li>Równowaga, ponieważ funkcje organizmu są utrzymywane w określonych zakresach. Nawet zwierzę, które jest pozornie nieaktywne, utrzymuje tę równowagę homeostatyczną.</li> 
 </ul> 

 Proces homeostatyczny 

 Celem homeostazy jest utrzymanie równowagi wokół punktu lub wartości zwanej wartością zadaną. Chociaż występują normalne wahania od wartości zadanej, systemy organizmu zwykle będą próbowały wrócić do tego punktu. Zmiana w środowisku wewnętrznym lub zewnętrznym nazywana jest bodźcem i jest wykrywana przez receptor; odpowiedzią systemu jest dostosowanie parametru odchylenia w kierunku wartości zadanej. 

 Kontrola homeostazy 

 Kiedy zmiana następuje poza środowiskiem zwierzęcia, należy dokonać dostosowania. Receptor wyczuwa zmianę w środowisku, następnie wysyła sygnał do centrum kontroli (w większości przypadków do mózgu), które z kolei generuje odpowiedź sygnalizowaną efektorowi. Efektor to mięsień (który kurczy się lub rozluźnia) lub gruczoł wydzielający. Te sygnały i reakcje są kontrolowane przez nieświadome autonomiczne pętle sprzężenia zwrotnego. Ujemne pętle sprzężenia zwrotnego utrzymują homeostazę. Pozytywne sprzężenie zwrotne wypychają organizm dalej z homeostazy, ale mogą być niezbędne do funkcjonowania funkcji życiowych. Zatem homeostaza jest kontrolowana przez układ nerwowy i hormonalny ssaków. 

 Wartość zadana 

 Istnieje możliwość dostosowania wartości zadanej systemu. Gdy tak się stanie, pętla sprzężenia zwrotnego pracuje nad utrzymaniem nowego ustawienia. Przykładem tego jest ciśnienie krwi: z biegiem czasu normalna lub zadana wartość ciśnienia krwi może wzrosnąć w wyniku ciągłego wzrostu ciśnienia krwi. Organizm nie rozpoznaje już wzniesienia jako nieprawidłowego i nie podejmuje żadnych prób powrotu do niższej wartości zadanej. Rezultatem jest regularne podwyższone ciśnienie krwi, które może zaszkodzić organizmowi. Leki mogą obniżyć ciśnienie krwi i obniżyć nastawę w systemie do zdrowszego poziomu. Nazywa się to procesem zmiany wartości zadanej w pętli sprzężenia zwrotnego. 

 Można dokonać zmian w grupie układów narządów ciała, aby utrzymać zadaną wartość w innym układzie. Nazywa się to aklimatyzacją. Dzieje się tak na przykład wtedy, gdy zwierzę migruje na wysokość wyższą niż ta, do której było pierwotnie przyzwyczajone. Aby przystosować się do niższego poziomu tlenu na większej wysokości, organizm zwiększa liczbę czerwonych krwinek krążących we krwi, aby zapewnić odpowiedni dopływ tlenu do tkanek. Innym przykładem aklimatyzacji jest sezonowe zmiany sierści u niektórych zwierząt: cięższa sierść zimą zapewnia odpowiednie zatrzymywanie ciepła, a jaśniejsza sierść latem pomaga utrzymać temperaturę ciała przed wzrostem do szkodliwego poziomu.

 Ten tekst jest adaptacją <a href="https://openstax.org/books/biology-2e/pages/33-3-homeostasis">Openstax, Biology 2e, Section 33.3: </a><a href="https://openstax.org/books/biology-2e/pages/33-3-homeostasis">Homeostasis</a>

Pozytywne i negatywne pętle sprzężenia zwrotnego

Narządy i układy narządów zwierząt stale dostosowują się do zmian wewnętrznych i zewnętrznych w procesie zwanym homeostazą ("stan ustalony"). Przykłady...

Education

JoVE Core

Cell Biology

Biologia komórki

Unit 1

Jednostka 1

Introduction to Metabolism

Wprowadzenie do metabolizmu

KEY TERMS AND CONCEPTS

Kluczowe terminy i pojęcia

homeostasis and body feedback control

Homeostasis keeps body conditions in a steady range through feedback control. Animal organs and organ systems constantly adjust to internal and external changes. This balance is called a dynamic equilibrium because the body keeps adapting while still staying within specific ranges.

The goal of homeostasis is to stay near a set point, which is the value the body tries to maintain. A change in the internal or external environment is a stimulus. A receptor detects that change and sends a signal to a control center, which is usually the brain. The control center then sends a response to an effector.

Effectors are muscles that contract or relax, or glands that secrete. These signals and responses are managed by unconscious autonomic feedback loops. Negative feedback loops help maintain homeostasis. Positive feedback loops push the organism farther from homeostasis, but they may still be necessary for life functions.

Homeostasis in mammals is controlled by the nervous system and the endocrine system. Even an animal that seems inactive is still maintaining this internal balance. The system keeps working to return body functions toward the set point after small changes.

A set point can also change over time. Blood pressure is one example. If blood pressure stays high for a long time, the normal set point can rise. The body then treats the higher pressure as normal and does not try to return to the lower level. This can harm the body, but medication can lower blood pressure and shift the set point to a healthier level.

Groups of body systems can also adjust to help maintain a set point in another system. This is called acclimatization. It can happen when an animal moves to a higher altitude. To deal with lower oxygen levels, the body increases the number of red blood cells in the blood so tissues still get enough oxygen. Some animals also change their coats with the seasons. A heavier winter coat helps retain heat, and a lighter summer coat helps prevent body temperature from rising too high.

Homeostasis and Body Feedback Control

overview of metabolism

Metabolism in Plants, Animals, and Microbes

Metabolism is the set of chemical reactions that keep living cells working. These reactions are linked through many pathways. Together, they support the normal function of cells in plants, animals, and microbes. In plants, sunlight is the main energy source. Chlorophyll pigments in the leaves absorb this light. The plant then uses that energy for photosynthesis. During photosynthesis, water is oxidized to oxygen and carbon dioxide is reduced to glucose. Glucose then serves as a starting...

carbohydrate metabolism

Carbohydrates, Digestion, and Blood Sugar

Carbohydrates are an important source of energy and a key part of human nutrition. They are made of carbon, hydrogen, and oxygen. One gram of carbohydrate provides four kilo-calories of energy, so carbohydrates are the body’s most efficient instant fuel. Starch makes up about 60% of the carbohydrates people eat. It is broken down by amylase enzymes, but amylase cannot work in the stomach’s acidic environment. That is why starch digestion happens in the mouth and the small intestine. Simple...

glycolysis: preparatory phase

Glycolysis: Energy Investment Steps

Glycolysis begins with energy investment steps in the cytoplasm of both prokaryotic and eukaryotic cells. It is the first step in cellular metabolism, which is the complete breakdown of glucose to extract energy. In heterotrophic cells, glucose enters by secondary active transport or through GLUT proteins, which are glucose transporter proteins that help glucose diffuse into the cell. The pathway starts with one six-carbon, ring-shaped glucose molecule and ends with two three-carbon molecules...

glycolysis: pay-off phase

Glycolysis: ATP and NADH Output

The pay-off phase of glycolysis turns the two three-carbon sugar molecules into ATP, NADH, and pyruvate. By this stage, the cell has already spent two ATP molecules. The remaining reactions recover that investment and add two more ATP molecules and two high-energy NADH molecules. The sixth step oxidizes glyceraldehyde 3-phosphate, a three-carbon sugar made earlier in glycolysis. High-energy electrons are transferred to NAD+, which becomes NADH. A second phosphate group is then added to form...

fates of pyruvate

Pyruvate Pathways in Fermentation

Pyruvate is a key product of glycolysis and can follow different pathways depending on oxygen availability. During glycolysis, glucose is oxidized to pyruvate, NAD+ is reduced to NADH, and two ATP are made by substrate-level phosphorylation. In aerobic organisms, pyruvate then enters the citric acid cycle, which helps produce the reduced coenzymes NADH and FADH2. These coenzymes are later oxidized in the electron transport chain to make ATP and regenerate NAD+ and FAD. When oxygen is absent,...

role of reduced coenzymes nadh and fadh&#8322;

Electron Carriers in Cellular Energy

Electron carriers help store and move energy during nutrient breakdown. Cells can save released energy by reducing these carriers or by making ATP, the cell’s main energy molecule. These mobile electron carriers bind high-energy electrons and shuttle them between compounds in metabolic pathways. The main carriers discussed here come from the B vitamin group and are nucleotide derivatives. They include nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate, and flavin...

overview of nitrogen metabolism

Nitrogen Cycle in Soil and Plants

Nitrogen moves through soil, plants, animals, and microbes in a cycle that keeps this macronutrient available for life. It is a major part of proteins and nucleic acids, so cells need it to build both amino acids and nucleotides. In nature, nitrogen is recycled from organic compounds and stored in several forms, including ammonia, ammonium ions, nitrate, nitrite, and nitrogen gas. Many of the key steps in this cycle are carried out only by prokaryotes. The largest nitrogen pool in terrestrial...

overview of fatty acid metabolism

Fatty Acids: Energy, Membranes, and Cholesterol

Fatty acids help cells store and use energy, and they also support important cell structures. Lipids are nonpolar and hydrophobic, so they do not mix well with water. Major lipid types include fats and oils, waxes, phospholipids, and steroids. Cells break down fatty acids by beta-oxidation. This process happens in the matrix of the mitochondria and cuts fatty acid chains into two-carbon acetyl groups. CoA picks up these groups to form acetyl CoA, which then enters the citric acid cycle. Extra...

sugars as energy storage molecules

Glucose Storage in Plants and Animals

Glucose storage in plants and animals helps cells manage energy for metabolism. Sugar is a simple carbohydrate, and cells use it because a lot of energy is stored in its bonds. Consumed carbohydrates often come from photosynthesizing organisms, especially plants. Plants make glucose during photosynthesis by using sunlight to convert carbon dioxide into sugar molecules. Because this builds a larger, energy-storing molecule, the process needs an energy input. Glucose can then be stored for later...

fats as energy storage molecules

How Triglycerides Fuel ATP Production

Triglycerides store long-term energy in fats. A triglyceride is built from glycerol and three fatty acids. When the body needs energy, these molecules are broken down first. This breakdown is called lipolysis, and it happens in the cytoplasm by hydrolysis. Lipolysis splits triglycerides into fatty acids and glycerol. The glycerol then enters glycolysis as DHAP, which connects fat breakdown to the cell’s main energy pathway. The fatty acids are then oxidized by beta-oxidation into acetyl-CoA.

regulation of metabolism

How Cells Control Metabolic Enzymes

Cells control metabolic enzymes to match changing needs and conditions. Different cells use different enzymes and energy levels, and those needs can also change within the same cell over time. Stomach cells, fat storage cells, skin cells, blood cells, and nerve cells do not all need the same metabolic activity. A digestive cell also works harder soon after a meal than it does many hours later. As cell needs change, the amount and activity of enzymes change too. Enzymes lower activation energy,...

positive and negative feedback loops

Homeostasis keeps body conditions in a steady range through feedback control. Animal organs and organ systems constantly adjust to internal and external changes. This balance is called a dynamic equilibrium because the body keeps adapting while still staying within specific ranges. The goal of homeostasis is to stay near a set point, which is the value the body tries to maintain. A change in the internal or external environment is a stimulus. A receptor detects that change and sends a signal...

key terms and concepts

Learn how receptors, control centers, and effectors work in homeostasis. Compare negative and positive feedback loops, set points, and acclimatization.

Homeostasis and Body Feedback Control | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

Alabama Course of Study Science

9-12

Human Anatomy and Physiology

From Molecules to Organisms: Structures and Processes

9-12.HA.1.6

Next Generation Science Standards

Life Science

Texas Essential Knowledge and Skills

Biology

BIO.12

BIO.12.A

Nucleic Acids and Nucleotides

Nucleic acids are the most important macromolecules for the continuity of life. They carry the cell&#39;s genetic blueprint and have instructions for its ...

Nucleic Acid Structure

The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group ...

DNA Base Pairing

Erwin Chargaff&#x2019;s rules on DNA equivalence paved the way for the discovery of base pairing in DNA. Chargaff&#x2019;s rules state that in a ...

From DNA to Protein

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The DNA Helix

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most viruses. DNA ...

The Central Dogma

The central dogma explains the flow of genetic information from DNA nucleotides to the amino acid sequence of proteins.
RNA is the Missing Link Between ...

Genomic DNA in Prokaryotes

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Genomic DNA in Eukaryotes

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Overview

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most ...

DNA Packaging

Overview

Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotes must pack their DNA tightly inside ...

RNA Structure

Overview
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RNA Stability

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pre-mRNA Processing

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Overview
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DNA as a Genetic Template

What is Gene Expression?

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Transcription

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Translation

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Ribosomes

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tRNA Activation

Initiation of Translation

Termination of Translation

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Cell Diversity

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Structure of Cardiac Muscles

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structure-and-organization-of-smooth-muscles

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...

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Lampbrush Chromosomes

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Euchromatin

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Heterochromatin

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Chromatin Position Affects Gene Expression

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Organization of Genes

Chromosome Structure

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The centromere is a DNA ...

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. Emphasis is on the conceptual understanding that DNA sequences determine the amino acid sequence and thus protein structure. Students can produce scientific writing, or presentations, and/or physical models that communicate constructed explanations.

HS-LS1-1

Characteristics of Life

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

https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/10647.jpg

Levels of Organization

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The Scientific Method

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Taxonomy

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Phylogeny

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Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. Emphasis is on functions at the organism system level such as nutrient uptake, water delivery, or 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.

HS-LS1-2

Overview of Metabolism

Living cells constantly carry out various chemical reactions which are necessary for their proper functioning. These reactions are interlinked to one ...

Regulation of Metabolism

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Animal organs and organ systems constantly adjust to internal and external changes through a process called homeostasis (&#34;steady state&#34;). Examples ...

Functions of Life

Human life is characterized by a variety of functions that are essential for survival and well-being. These functions include metabolism, movement, ...

Requirements for Human Life

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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

Homeostatic Imbalance

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pH Homeostasis

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homeostatic-imbalances-in-body-temperature

Homeostatic Imbalances in Body Temperature

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...

Regulation of Food Intake

The hypothalamus releases peptides influencing feeding behavior.
Two hypothalamic neuronal groups participate in this process.
Neuropeptide Y (NPY) and ...

Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis in living organisms. Examples of investigations could include heart rate responses to exercise, stomate responses to moisture and temperature, root development in response to water levels, or cell response to hypertonic and hypotonic environments.

What is the Cell Cycle?

The cell cycle refers to the sequence of events occurring throughout a typical cell&#8217;s life. In eukaryotic cells, the somatic cell cycle has two ...

Interphase

The cell cycle occurs over approximately 24 hours (in a typical human cell) and in two distinct stages: interphase, which includes three phases of the ...

The Cell Cycle Control System

Positive Regulator Molecules

Inhibition of CDK Activity

S-Cdk Initiates DNA Replication

Use a model to illustrate the role of the cell cycle and differentiation in producing and maintaining complex organisms. Emphasis is on conceptual understanding that mitosis passes on genetically identical materials via replication, not on the details of each phase in mitosis.

HS-LS1-4

Homeostasis and Body Feedback Control

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