Name: feedback loops in body balance
Uploaded: 2023-06-23T15:38:43.000Z
Duration: 1 min 18 s
Channel: JoVE

K12 Standards

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North Carolina K-12 Science Standard Course of Study

9-12

Biology

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

From Molecules to Organisms- Structures and Processes

LS.Bio.3.1

Negative and Positive Feedback

Funções biológicas, como vias metabólicas ou vias de sinalização celular, são reguladas por mecanismos de feedback, que compreendem ciclos de feedback negativo e positivo.
O feedback positivo ocorre quando o produto de um processo estimula um aumento adicional em sua produção, levando a uma resposta aumentada.
O processo de coagulação do sangue é um dos exemplos comuns de um ciclo de feedback positivo.
Um corte na parede do vaso sanguíneo atua como um estímulo que aciona os vasos e as plaquetas próximas para liberar sinais químicos, ativando vários fatores de coagulação e atraindo plaquetas para o local da lesão, iniciando um coágulo sanguíneo. As plaquetas secretam sinais químicos para atrair mais plaquetas para o local até que o coágulo em desenvolvimento sele completamente a ferida.
Um ciclo de feedback negativo ocorre quando o produto de uma reação reduz o estímulo inicial.
Por exemplo, quando os níveis de glicose no sangue aumentam, o pâncreas libera insulina, que desencadeia a captação de glicose pelas células do fígado, reduzindo os níveis de glicose no sangue.
Uma vez que os níveis de glicose no sangue são restaurados, o pâncreas interrompe a produção de insulina.

feedback negativo e positivo

Os órgãos e sistemas de órgãos em animais ajustam-se constantemente às mudanças internas e externas por meio de um processo denominado homeostase ("estado estacionário"). Exemplos dessas alterações incluem a regulação do nível de glicose ou cálcio no sangue, ou respostas internas a temperaturas externas. A homeostase requer a manutenção de um equilíbrio dinâmico interno: 
 <ul style="padding-left: 35px; list-style-type: disc;"> 
 <li>Dinâmico porque ele se ajusta constantemente às mudanças que os sistemas do corpo encontram.</li> 
 <li>Equilíbrio porque as funções do corpo são mantidas dentro de intervalos específicos. Mesmo um animal aparentemente inativo mantém esse equilíbrio homeostático.</li> 
 </ul> 

 Processo Homeostático 

 O objetivo da homeostase é a manutenção do equilíbrio em torno de um ponto, ou valor, denominado ponto de ajuste. Embora existam flutuações normais em relação ao ponto de ajuste, os sistemas do corpo geralmente tentarão voltar a esse ponto. Uma mudança no ambiente interno ou externo é chamada de estímulo e é detectada por um receptor; a resposta do sistema é ajustar o parâmetro de desvio em direção ao ponto de ajuste. 

 Controle da Homeostase 

 Quando ocorre uma mudança fora do ambiente interno do animal, um ajuste deve ser feito. O receptor sente a mudança no ambiente e depois envia um sinal ao centro de controle (na maioria dos casos, o cérebro), que por sua vez gera uma resposta que é sinalizada a um efetor. O efetor é um músculo (que se contrai ou relaxa) ou uma glândula que secreta. Esses sinais e respostas são controlados por ciclos de feedback autônomo inconscientes. Os ciclos de feedback negativo mantêm a homeostase. Os ciclos de feedback positivo empurram o organismo ainda mais para fora da homeostase, mas podem ser necessários para as funções vitais. Assim, a homeostase é controlada pelos sistemas nervoso e endócrino dos mamíferos. 

 Ponto de ajuste 

 É possível ajustar o ponto de ajuste de um sistema. Quando isso acontece, o ciclo de feedback funciona para manter a nova configuração. Um exemplo disso é a pressão arterial: com o tempo, o ponto normal, ou definido, para a pressão arterial pode aumentar como resultado de aumentos contínuos da pressão arterial. O corpo não reconhece mais a elevação como anormal e nenhuma tentativa é feita para retornar ao ponto de ajuste inferior. O resultado é uma pressão arterial regularmente mais alta que pode prejudicar o corpo. A medicação pode reduzir a pressão arterial e reduzir o ponto de ajuste no sistema para um nível mais saudável. Isto é conhecido como um processo de alteração do ponto de ajuste em um ciclo de feedback. 

 Podem ser feitas alterações em um grupo de sistemas de órgãos corporais para manter um ponto de ajuste em outro sistema. Isso é chamado de aclimatação. Isto ocorre, por exemplo, quando um animal migra para uma altitude superior àquela a que estava originalmente habituado. Para se ajustar aos níveis mais baixos de oxigênio em altitudes mais elevadas, o corpo aumenta o número de glóbulos vermelhos circulando no sangue para garantir o fornecimento adequado de oxigênio aos tecidos. Como outro exemplo de aclimatação, alguns animais apresentam mudanças sazonais em sua pelagem: uma pelagem mais pesada no inverno garante a retenção adequada de calor, e uma pelagem mais leve no verão ajuda a evitar que a temperatura corporal suba a níveis prejudiciais. 

 Este texto é adaptado de <a href="https://openstax.org/books/biology-2e/pages/33-3-homeostasis">Openstax, Biology 2e, Seção 33.3: </a><a href="https://openstax.org/books/biology-2e/pages/33-3-homeostasis">Homeostase</a>

Feedback Negativo e Positivo

Os órgãos e sistemas de órgãos animais se ajustam constantemente às mudanças internas e externas por meio de um processo chamado homeostase ("estado estacionário"). Exemplos...

Education

JoVE Core

Anatomy and Physiology

Anatomia e Fisiologia

Unit 1

Unidade 1

Introduction to the Human Body

Introdução ao Corpo Humano

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

feedback loops in body balance

Negative and positive feedback help keep body conditions stable. These feedback loops control many body processes and support homeostasis, which is the maintenance of a steady internal environment.

Negative feedback reduces a change and brings a system back toward its normal state. Positive feedback increases a change and pushes a process further in the same direction. Together, they show how the body can fine-tune responses when conditions shift.

These control systems are important in many parts of biology. They help explain how the body responds to change and how certain processes stay balanced or move toward a clear outcome.

Feedback Loops in Body Balance

overview of anatomy and physiology

How Anatomy and Physiology Work Together

Human anatomy studies the structures of the body. Some body structures are so small that they can only be seen and examined with a microscope. Others are large enough to be viewed, handled, measured, and weighed. The word anatomy comes from a Greek root meaning “to cut apart.” Early study of the human body began with observing the outside of the body and the injuries seen in soldiers and other patients. Later, physicians were allowed to dissect dead bodies to learn more. Dissection means...

structural organization of the human body: an overview

structural-organization-of-the-human-body-an-overview

Levels of Organization in the Human Body

The human body is organized in levels that build from simple parts to a complete living being. These levels increase in complexity from subatomic particles, atoms, and molecules to organelles, cells, tissues, organs, organ systems, and the organism. At the chemical level, scientists study the smallest building blocks of matter. Matter is made of elements, which are pure substances such as hydrogen, oxygen, carbon, nitrogen, calcium, and iron. The smallest unit of an element is an atom, and...

functions of life

How the Human Body Keeps Going

Human life depends on metabolism, movement, development, growth, and reproduction. These functions help the body stay alive, maintain itself, and continue the species. Together, they show how the body uses energy and changes over time. Metabolism is the body’s use of energy and food molecules. It helps the body make fuel for movement, support body functions, and build and maintain body structures. Metabolism includes two kinds of reactions: anabolism and catabolism. Anabolism is the process...

requirements for human life

Human Survival Needs in the Body

Human survival depends on air, water, food, a narrow temperature range, and a narrow range of atmospheric pressure. The Earth and its atmosphere provide these conditions, but the body can only function well when they stay within limits. Oxygen is one of the most important needs. Atmospheric air is only about 20 percent oxygen, but that oxygen supports the chemical reactions that keep the body alive, including the reactions that make ATP. Brain cells are especially sensitive to a lack of oxygen...

what is homeostasis?

Homeostasis and Negative Feedback

Homeostasis keeps the body’s internal conditions stable. The body does this by holding each physiological condition near a set point. A set point is the value around which the normal range changes, and the normal range is the small group of values that is healthiest and most stable. Human body temperature is a common example. Its set point is about 37°C, or 98.6°F, and it can shift a little above or below that point while still staying in range. Negative feedback helps maintain homeostasis.

negative and positive feedback

Negative and positive feedback help keep body conditions stable. These feedback loops control many body processes and support homeostasis, which is the maintenance of a steady internal environment. Negative feedback reduces a change and brings a system back toward its normal state. Positive feedback increases a change and pushes a process further in the same direction. Together, they show how the body can fine-tune responses when conditions shift. These control systems are important in many...

homeostatic imbalance

How Feedback Failure Disrupts Homeostasis

Homeostasis keeps the body’s internal conditions stable so cells, tissues, organs, and organ systems can work properly. The body uses control systems to regulate temperature, blood pressure, pH balance, and fluid balance. These controls depend on feedback loops, which can be positive or negative. Homeostatic imbalance happens when those feedback loops fail and the body can no longer maintain a stable internal environment. Injury, disease, environmental changes, genetic mutations, and aging can...

anatomical terminology

Anatomical Terms and Body Position

Anatomical terms help describe the human body clearly in biology and medicine. Health care professionals and anatomists use this standard language to avoid confusion and to make descriptions more precise. Most anatomical words come from Greek and Latin roots, and these roots usually stay the same because the languages are rarely used in everyday conversation. Many anatomical words are built from a root plus a prefix or suffix. The root often names an organ, tissue, or condition. The prefix or...

anatomical positions

Body Positions Used in Anatomy

Body positions used in anatomy give a shared way to describe where body parts are and how they face. These standard references help people talk about anatomical structures with the same meaning. The anatomical position is the main reference point for body orientation. In anatomical position, the body stands upright and faces forward. The feet are parallel and flat on the floor. The arms rest at the sides with the palms facing forward, and the head and eyes point forward. The most common...

regional terms

Anatomy Regions and Body Landmark Terms

Anatomy regions and body landmark terms help identify specific parts of the human body. These regional terms divide the body into areas with structures that support similar functions. They also make it easier to describe the exact area affected by an injury or disease. The human body is organized into two major regions: the axial region and the appendicular region. The axial region includes the body from the head to the abdomen and forms the central body axis. The appendicular region includes...

directional terms

Anatomical Direction and Body Position

Anatomical direction and body position terms help describe where one body structure is located in relation to another. These terms use comparisons, such as one tissue being inferior to another or a tumor being superficial to a deeper structure. They are based on the standard anatomical reference position, which uses the body in an upright pose. Anterior and posterior are a common pair of directional terms. Anterior, also called ventral, means toward the front of the body. Posterior, also...

body planes

Anatomy Sections and Body Planes

Anatomy sections and body planes are imaginary flat surfaces used to divide the body for study. They help show the orientation, relationships, and spatial layout of anatomical structures. These reference planes are also useful for describing organs and body parts in a standard way. The sagittal plane divides the body or an organ vertically into right and left sides. When that cut goes through the middle and makes equal halves, it is called the midsagittal or median plane. When it makes unequal...

anatomical movements

Body Joint Motion Terms

Body joint motion terms describe how bones and muscles move at different joints. These standard names make it easier to talk about range of motion in the body. They are used to describe actions at the shoulder, hip, elbow, knee, wrist, fingers, toes, and spine. Flexion and extension are movements in the sagittal plane, also called the anterior-posterior plane. Flexion is the forward bending motion of the head or vertebral column. Extension is the backward movement or straightening of a joint,...

abdominal regions and quadrants

Abdominal Pain and Organ Location

The abdominal cavity is divided into quadrants and regions to help locate organs and describe pain clearly. Clinicians and anatomists use imaginary lines to mark the abdominopelvic cavity. This system makes it easier to communicate about a patient’s symptoms or a suspicious mass. The simpler method divides the area into four quadrants. One horizontal line and one vertical line cross at the umbilicus, or navel. These quadrants are the right upper quadrant, right lower quadrant, left upper...

key terms and concepts

Explore how negative and positive feedback help maintain body balance and homeostasis. Learn how these control loops change responses in biology.

Feedback Loops in Body Balance | JoVE K12

anatomy and physiology

O JoVE Core Anatomia e Fisiologia apresenta detalhes anatômicos e fisiológicos do corpo humano em animações  abrangentes, claras e envolventes. Esta coleção de vídeos se concentra nas estruturas, componentes, funções e requisitos do corpo humano. É complementada por vídeos de cientistas em ação que demonstram a aplicação desse conhecimento em instalações médicas e de pesquisa do mundo real.

Pennsylvania State Academic Standards

Life Science

Structure and Function

3.1.9-12.C

Louisiana Student Standards for Science

High School

Life Sciences

From Molecules To Organisms: Structures And Processes

HS-LS1-3

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Ohio’s Learning Standards and Model Curriculum

Cells

Cell structure and function

Human Anatomy and Physiology

Levels Of Organization

Homeostasis

Virginia  Standards of Learning

HIgh School

BIO.2

BIO.2.a

Minnesota Academic Standards in Science

1.2.1 9L.1.2.1.1

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New Jersey Student Learning Standards for Science

From Molecules to Organisms: Structures and Processes

Arizona Science Standards

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Alabama Course of Study Science

9-12.B.1.4

Next Generation Science Standards

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BIO.5

BIO.5.C

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South Carolina College and Career Ready Science Standards

B-LS1-3.

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New York State Science Learning Standards

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Feedback Loops in Body Balance

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