Name: homeostasis and negative feedback
Uploaded: 2023-06-23T15:38:43.000Z
Duration: 1 min 16 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

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

What is Homeostasis?

A homeostase é a capacidade do corpo de manter condições internas estáveis em resposta às mudanças no ambiente externo.
Por exemplo, quando está quente lá fora, a temperatura corporal de uma pessoa pode começar a subir e o corpo deve reagir para neutralizar o aumento.
Receptores, centros de controle e efetores coordenam as mudanças fisiológicas necessárias para responder a uma variável.
No caso de um aumento na temperatura corporal, os termorreceptores nas células da pele detectam a temperatura elevada e transmitem a mensagem por meio de impulsos nervosos para o cérebro, o centro de controle.
O cérebro compara o estímulo com um ponto de ajuste - a faixa fisiológica da variável. O ponto de ajuste para uma temperatura normal do corpo humano é de aproximadamente 37°C.
Quando a temperatura corporal excede o ponto de ajuste, o cérebro sinaliza aos efetores, as glândulas sudoríparas, para produzir suor. A evaporação do suor esfria o corpo.
Uma vez que a temperatura corporal retorna ao ponto de ajuste, os receptores enviam feedback ao cérebro para reduzir a produção de suor, garantindo que a homeostase seja mantida.

o que é a homeostase?

Manter a homeostase requer que o corpo mantenha continuamente suas condições internas. Cada condição fisiológica, desde a temperatura corporal até a pressão sanguínea e os níveis de certos nutrientes, tem um ponto de ajuste específico. Um ponto de ajuste é o valor fisiológico ao redor do qual a faixa normal flutua. Uma faixa normal é um conjunto restrito de valores que é ideal para a saúde e, também, estável. Por exemplo, o ponto de ajuste da temperatura corporal humana normal é de aproximadamente 37°C. Parâmetros fisiológicos, como a temperatura corporal e a pressão sanguínea, tendem a flutuar dentro de uma faixa normal de alguns graus acima e abaixo desse ponto. Centros de controle no cérebro e em outras partes do corpo monitoram e reagem a desvios da homeostase utilizando feedback negativo. O feedback negativo é um mecanismo que reverte um desvio em relação ao ponto de ajuste. Portanto, o feedback negativo mantém os parâmetros corporais dentro da faixa normal. A manutenção da homeostase por meio do feedback negativo ocorre em todo o corpo, a todo momento, e entender esse feedback negativo é, portanto, fundamental para entender a fisiologia humana.

Um sensor, também chamado de receptor, é um componente de um sistema de feedback que monitora um valor fisiológico. Esse valor é reportado regularmente ao centro de controle. O centro de controle é o componente de um sistema de feedback que compara o valor reportado com a faixa normal. O centro de controle ativa um efetor se esse valor se desviar muito de seu ponto de ajuste. Um efetor é um componente de um sistema de feedback que inicia uma mudança com o objetivo de reverter a situação e retornar o valor à sua faixa normal.

Por exemplo, para colocar o sistema em operação, um estímulo deve levar um parâmetro fisiológico para além de sua faixa normal (além da homeostase). Esse estímulo é então "captado" por um sensor específico. No controle da glicose no sangue, células endócrinas específicas no pâncreas detectam o excesso de glicose (o estímulo) na corrente sanguínea. Essas células beta pancreáticas respondem ao aumento do nível de glicose no sangue liberando o hormônio insulina na corrente sanguínea. A insulina sinaliza as fibras musculares esqueléticas, as células de gordura (adipócitos) e as células hepáticas para absorverem o excesso de glicose, removendo-a da corrente sanguínea. À medida que a concentração de glicose na corrente sanguínea diminui, a diminuição na concentração - o feedback negativo real - é detectada pelas células alfa pancreáticas e a liberação de insulina é interrompida. Isso impede que os níveis de açúcar no sangue continuem caindo abaixo da faixa normal.

Este texto foi adaptado de <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/">Openstax, Anatomy and Physiology 2e, Section 1.5: </a>Homeostasis

O que é a Homeostase?

Manter a homeostase requer que o corpo mantenha continuamente suas condições internas. Cada condição fisiológica tem um ponto de ajuste específico, ...

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

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. This process reverses a change that moves a body value away from its set point. Control centers in the brain and other body parts monitor these changes and respond when conditions drift too far. Because this happens throughout the body all the time, negative feedback is a key idea in human physiology.

A feedback system has three main parts: a sensor, a control center, and an effector. A sensor, also called a receptor, watches a physiological value and sends that information to the control center. The control center compares the value with the normal range. If the value moves too far from the set point, the control center activates an effector. The effector causes a change that brings the value back toward normal.

Blood glucose control shows how this works. When blood sugar rises too high, pancreatic beta cells detect the excess glucose in the bloodstream. These endocrine cells release insulin into the blood. Insulin tells skeletal muscle fibers, fat cells, and liver cells to take up the extra glucose, which removes it from the bloodstream. As glucose levels fall, pancreatic alpha cells detect the drop, and insulin release stops. This keeps blood sugar from falling below the normal range.

Homeostasis and Negative Feedback

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 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

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...

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

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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...

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body planes

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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

Learn how homeostasis stays stable through negative feedback, set points, sensors, control centers, and the insulin response to blood glucose.

Homeostasis and Negative Feedback | 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

HS.L1

HS.L1U1.20

Alabama Course of Study Science

9-12.B.1.4

Next Generation Science Standards

Texas Essential Knowledge and Skills

BIO.5

BIO.5.C

BIO.12

BIO.12.A

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South Carolina College and Career Ready Science Standards

B-LS1-3.

new-york-state-science-learning-standards

New York State Science Learning Standards

HS-LS1-3.

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Homeostasis and Negative Feedback

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