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

Negative and Positive Feedback

תפקודים ביולוגיים כגון מסלולים מטבוליים או מסלולי איתות תאי מווסתים על ידי מנגנוני משוב, הכוללים לולאות משוב שליליות וחיוביות.
משוב חיובי מתרחש כאשר תוצר של תהליך מגרה עלייה נוספת בייצורו, מה שמוביל לתגובה מוגברת.
תהליך קרישת הדם הוא אחת הדוגמאות הנפוצות ללולאת משוב חיובי.
חתך בדופן כלי הדם פועל כגירוי המפעיל את כלי הדם ואת טסיות הדם הסמוכות לשחרר אותות כימיים, מפעיל מספר גורמי קרישה ומושך טסיות למקום הפציעה, יוזם קריש דם. הטסיות מפרישות אותות כימיים כדי למשוך טסיות נוספות לאתר עד שהקריש המתפתח אוטם לחלוטין את הפצע.
לולאת משוב שלילי מתרחשת כאשר תוצר התגובה מפחית את הגירוי הראשוני.
לדוגמה, כאשר רמות הגלוקוז בדם עולות, הלבלב משחרר אינסולין, אשר מפעיל ספיגת גלוקוז על ידי תאי הכבד, הפחתת רמות הגלוקוז בדם.
לאחר רמות הגלוקוז בדם משוחזרים, הלבלב מפסיק את הייצור של אינסולין.

משוב שלילי וחיובי

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האיברים ומערכות האיברים של בעלי חיים מסתגלים כל הזמן לשינויים פנימיים וחיצוניים באמצעות תהליך הנקרא הומאוסטזיס ("מצב יציב"). דוגמאות לשינויים אלו כוללות ויסות של רמת הגלוקוז או הסידן בדם או תגובות פנימיות לטמפרטורות חיצוניות. הומאוסטזיס דורש שמירה על שיווי משקל דינמי פנימי:

דינמי כי הוא מסתגל כל הזמן לשינויים בהם נתקלות מערכות הגוף. שיווי משקל מכיוון שתפקודי הגוף נשמרים בטווחים ספציפיים. אפילו חיה שככל הנראה אינה פעילה שומרת על שיווי המשקל ההומיאוסטטי הזה.

תהליך הומיאוסטטי

המטרה של הומאוסטזיס היא שמירה על שיווי משקל סביב נקודה או ערך הנקרא נקודת קבע. בעוד שישנן תנודות נורמליות מנקודת הקבע, מערכות הגוף ינסו בדרך כלל לחזור לנקודה זו. שינוי בסביבה הפנימית או החיצונית נקרא גירוי והוא מזוהה על ידי קולטן; התגובה של המערכת היא להתאים את פרמטר הסטייה לכיוון נקודת הקבע.

שליטה על הומאוסטזיס

כאשר מתרחש שינוי מחוץ לסביבה של בעל חיים, יש לבצע התאמה. הקולטן חש את השינוי בסביבה, ואז שולח אות למרכז הבקרה (ברוב המקרים, המוח) אשר בתורו יוצר תגובה שמאומנת לגורם. האפקטור הוא שריר (שמתכווץ או נרגע), או בלוטה שמפרישה. האותות והתגובות הללו נשלטים על ידי לולאות משוב אוטונומיות לא מודעות. לולאות משוב שלילי שומרות על ההומאוסטזיס. לולאות משוב חיובי דוחפות את האורגניזם עוד יותר מההומאוסטזיס, אך עשויות להיות הכרחיות לתפקודי חיים. לפיכך, ההומאוסטזיס נשלט על ידי מערכות העצבים והמערכות האנדוקריניות של היונקים.

נקודת קבע

ניתן לשנות את נקודת הקבע של מערכת. כאשר זה קורה, לולאת המשוב פועלת לשמור על ההגדרה החדשה. דוגמה לכך היא לחץ דם: עם הזמן, הנקודה הרגילה או הקבע של לחץ הדם יכולה לעלות כתוצאה מהמשך העלייה בלחץ הדם. הגוף כבר לא מזהה את הגובה כלא נורמלי, ולא נעשה ניסיון לחזור לנקודת הקבע הנמוכה יותר. התוצאה היא לחץ דם רגיל גבוה שעלול להזיק לגוף. טיפול תרופתי יכול להוריד את לחץ הדם ולהפחית את נקודת הקבע במערכת לרמה בריאה יותר. זה ידוע כתהליך של שינוי של נקודת הקבע בלולאת משוב.

ניתן לבצע שינויים בקבוצה של מערכות איברים בגוף כדי לשמור על נקודת קבע במערכת אחרת. זה נקרא התאקלמות. זה קורה, למשל, כאשר בעל חיים עובר לגובה רב יותר מזה שהיה רגיל אליו במקור. כדי להסתגל לרמות חמצן נמוכות יותר בגובה רב, הגוף מגדיל את מספר תאי הדם האדומים במחזור הדם כדי להבטיח אספקת חמצן מספקת לרקמות. כדוגמה נוספת להתאקלמות, לחלק מהחיות יש שינויים עונתיים בפרוותם: פרווה כבדה יותר בחורף מבטיחה שמירת חום נאותה, ופרווה קלה יותר בקיץ עוזרת לשמור על חום הגוף שלא יעלה לרמות מזיקות.
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איברים ומערכות איברים של בעלי חיים מסתגלים כל הזמן לשינויים פנימיים וחיצוניים באמצעות תהליך שנקרא הומאוסטזיס ("מצב יציב"). דוגמאות...

Education

JoVE Core

Anatomy and Physiology

אנטומיה ופיזיולוגיה

Unit 1

יחידה 1

Introduction to the Human Body

מבוא לגוף האדם

KEY TERMS AND CONCEPTS

מונחים ומושגים מרכזיים

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

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

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

ohios-learning-standards-and-model-curriculum

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

new-jersey-student-learning-standards-for-science

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

south-carolina-college-and-career-ready-science-standards

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.

Compounds Essential to Human Function

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Macromolecules

Biomolecules
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Nucleic Acid Structure

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ATP Energy Storage and Release

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Construct an explanation to illustrate relationships between structure and function of major macromolecules essential for life.

LS.Bio.1.1

Introduction to Enzymes

The use of enzymes by humans dates to 7000 BCE. Humans first used enzymes to ferment sugars and produce alcohol without knowing that this was an ...

Enzymes and Activation Energy

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Introduction to Enzyme Kinetics

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Turnover Number and Catalytic Efficiency

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Catalytically Perfect Enzymes

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introduction-to-mechanisms-of-enzyme-catalysis

Introduction to Mechanisms of Enzyme Catalysis

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Ligand Binding and Linkage

Cooperative Allosteric Transitions

Ribozymes

Carry out investigations to illustrate how enzymes act as catalysts for biochemical reactions and how environmental factors affect enzyme activity.

LS.Bio.1.2

What are Cells?

Cells are the smallest and basic units of life, whether it is a single cell that forms the entire organism, e.g., in a bacterium or trillions of them, ...

Cell Size

Cell sizes vary widely among and within organisms. Bacterial cells range between 1-10 micrometers (&#x3BC;m)and are considerably smaller than most ...

Eukaryotic Compartmentalization

One of the distinguishing features of eukaryotic cells is that they contain membrane-bound organelles, such as the nucleus and mitochondria, that carry ...

Prokaryotic Cells

Prokaryotes are small unicellular organisms that include the domains&#x2014;Archaea and Bacteria. Bacteria include many common organisms, such as ...

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 ...

Endoplasmic Reticulum

Endoplasmic ReticulumThe endoplasmic reticulum (ER) is an extensive network of membranous sacs and tubules in eukaryotic cells, continuous with the outer ...

Ribosomes

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

Golgi Apparatus

As they leave the Endoplasmic Reticulum (ER), properly folded and assembled proteins are selectively packaged into vesicles. These vesicles are ...

Lysosomes

Lysosomes are membrane-enclosed spherical sacs derived from the Golgi apparatus. The most important function of the lysosome is degrading macromolecules ...

Peroxisomes

Peroxisomes and mitochondria are two important oxygen-utilizing organelles in eukaryotic cells. Mitochondria carry out cellular respiration&#x2014;the ...

Introduction to the Cytoskeleton

Overview of the Cytoskeleton
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Introduction to Actin

Actin is a highly conserved cytoskeletal protein found abundantly in eukaryotic cells. It constitutes 10% weight of the total cellular protein in muscle ...

Cell Structure

Background
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overview-of-myosin-structure-and-function

Overview of Myosin Structure and Function

Myosins are a family of molecular motor proteins, first identified in the skeletal muscles, where they are responsible for muscle contraction. Along with ...

Use models to explain how the structure of organelles determines its function and supports overall cell processes.

LS.Bio.1.3

Analyze how the relationship between structure and function supports life processes within organisms.

Feedback Loops in Body Balance

Description

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