Understand
Learn what your body is made of and how its structures work together.
PERSONAL CARE · PAGE 06
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Your body is a system — not a collection of separate parts.
Knowing Your Body provides the biological foundation for understanding many of the other Personal Care topics in GHE.
01 · WHY IT MATTERS
Understanding your body is part of becoming health literate.
You do not need to become a doctor to understand your body. Basic knowledge of biology can help you understand health information, recognize reliable evidence, ask informed questions and make sense of how different factors influence health.
Question
Build enough scientific understanding to ask better health questions.
Connect
Discover how biology interacts with behaviour, environment and society.
02 · ANATOMY
Structure: What is the body made of?
Anatomy is the study of the structures of the body and how those structures are organized.
CHEMICALS
→
CELLS
→
TISSUES
→
ORGANS
→
SYSTEMS
→
BODY
Cells
The basic living units of the human body. Different cells have specialized structures and functions.
Tissues
Groups of specialized cells organized to perform particular functions.
Organs
Structures made from different tissues that work together to perform important functions.
A central principle of biology:
Structure and function are closely connected.
03 · PHYSIOLOGY
Function: How does the body work?
Physiology explores how cells, tissues, organs and systems perform their functions and interact with one another.
Communication
Nervous and endocrine systems help coordinate activities throughout the body.
Transport
Blood and circulation move oxygen, nutrients, hormones and other substances.
Exchange
The lungs, digestive system and other organs exchange materials with the environment.
Protection
Skin, immune defences and other systems help protect the body from threats.
04 · HOMEOSTASIS
Keeping the body's internal environment within a healthy range.
The body constantly monitors and adjusts many internal conditions. This dynamic regulation is called homeostasis.
HOMEOSTASIS
Dynamic Balance
Continuous adjustment rather than
perfect stillness.
Temperature
The body regulates heat production
and heat loss.
Blood Glucose
Hormonal systems help regulate
glucose availability.
Water & Electrolytes
The body regulates fluids and
important dissolved substances.
Oxygen & Carbon Dioxide
Respiratory and cardiovascular systems
work together to maintain gas exchange.
Think like a scientist:
The body is constantly responding to change.
Healthy physiology is dynamic.
05 · BODY SYSTEMS
No body system works alone.
Each system has specialized functions, but healthy life depends on continuous interaction among systems.
Nervous System
Senses, processes information and coordinates rapid responses.
Cardiovascular System
Heart, blood and blood vessels transport materials throughout the body.
Respiratory System
Supports gas exchange and contributes to regulation of the body's internal environment.
Digestive System
Breaks down food and enables absorption of nutrients and water.
Musculoskeletal System
Provides support, movement and protection.
Immune & Lymphatic Systems
Help defend the body and maintain fluid and immune balance.
Endocrine System
Uses hormones to regulate processes such as growth, metabolism and reproduction.
Urinary System
Helps regulate fluids, electrolytes and removal of metabolic waste.
Reproductive System
Supports reproductive functions and contributes to human development.
Dermatology
Skin, hair and nails provide important protective, sensory and regulatory functions.
Systems thinking:
The heart does not work alone. The lungs,
blood, nervous system, kidneys, hormones and
muscles all contribute to keeping the body alive.
06 · GENETICS
Genetics: What makes each person biologically unique?
Genetics explores how information in DNA is organized, expressed, inherited and sometimes changed. Genes influence many characteristics and aspects of health, but genes do not act alone.
DNA
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GENES
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PROTEINS
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CELLS
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TRAITS & FUNCTIONS
Genetic Variation
People naturally differ in many biological characteristics. Variation is a fundamental feature of human populations.
Inheritance
Genetic information can be passed from biological parents to children through patterns of inheritance.
Genes & Environment
Health often reflects interactions among genetic, environmental, behavioural and social factors.
Remember:
Genetic risk is not the same as certainty.
Biology is important, but biology is not destiny.
GENETIC & INHERITED CONDITIONS
When genetic differences affect health.
Some health conditions are strongly influenced by genetic changes. Others result from complex interactions among many genes and environmental factors.
Single-Gene Conditions
Conditions associated with changes in a particular gene.
Chromosomal Conditions
Conditions associated with changes in the number or structure of chromosomes.
Multifactorial Conditions
Health outcomes influenced by multiple genes together with environmental and behavioural factors.
Genetic Counselling
Genetic information can be complex. Questions about personal or family genetic risk should be discussed with appropriately qualified health professionals.
07 · PATHOPHYSIOLOGY
What happens when normal function changes?
Pathophysiology examines how changes in normal biological processes contribute to disease, dysfunction and health outcomes.
NORMAL
Structure & function
→
CHANGE
Disruption or adaptation
→
CONSEQUENCE
Altered biological function
→
HEALTH OUTCOME
Possible symptoms, signs or disease
Inflammation
A coordinated biological response that can help the body respond to injury or infection but can also contribute to disease when dysregulated.
Infection
Microorganisms can interact with tissues and trigger immune responses that affect normal physiology.
Injury
Physical or other forms of injury can disrupt tissues and interfere with normal function.
Abnormal Cell Growth
Changes in cellular regulation can contribute to abnormal growth and disease processes.
Important health-literacy principle:
A biological change, symptom or risk factor
does not by itself establish a diagnosis.
08 · SYSTEMS THINKING
The body works as an interconnected network.
Understanding health often requires following a chain of interactions rather than looking at one organ in isolation.
Oxygen & Energy
Environment → Lungs → Blood → Tissues → Energy
Breathing and circulation work together to deliver oxygen where cells need it.
Regulation
Brain → Hormones → Organs → Cells → Response
Nervous and endocrine signalling helps coordinate many body functions.
Movement
Brain → Nerves → Muscles → Bones → Movement
Movement depends on coordinated activity across multiple systems.
09 · BIOLOGY + THE WORLD
Is health only inside the body?
Biology matters enormously—but people live in environments and societies that can influence exposure, opportunity, stress, nutrition, physical activity, safety and access to care.
Environment
Air, water, climate and physical surroundings
can affect health.
Nutrition
Food availability and dietary patterns
influence biological processes.
Education
Knowledge and health literacy can influence
health decisions and opportunities.
Housing & Safety
Living conditions can influence exposure
to hazards and opportunities for health.
Healthcare Access
Access to appropriate services can influence
prevention, diagnosis and treatment.
Equity
Health opportunities are not distributed
equally across populations.
10 · SELF → WORLD
From understanding yourself to understanding health.
Understand Your Body
Learn how your body is organized and how its systems function.
Recognize Variation
People share fundamental biology while differing naturally in many characteristics.
Understand Environment
Ask how surroundings and opportunities influence health.
Think Population Health
Consider prevention, health systems, access and equity.
Think Globally
Explore how biology, environment, inequality and global change interact.
11 · EVIDENCE
Learn to distinguish evidence from assumption.
Understanding biology is also learning how scientific knowledge is developed, tested, revised and communicated.
What is the claim?
Clearly identify what someone is saying about health or the human body.
What is the evidence?
Look for trustworthy scientific and health sources.
How strong is it?
Consider whether the evidence actually supports the conclusion.
What remains uncertain?
Good science recognizes uncertainty and continues to investigate important questions.
12 · REFLECT
What did you discover?
- What surprised you about how body systems work together?
- How is physiology different from anatomy?
- Why is homeostasis important?
- Why is genetic risk not the same as certainty?
- How can environment influence biological health?
ACT
Go one step further.
- Choose one body system and explore it further.
- Find one reliable source about genetics or physiology.
- Write down one health question you would like to understand better.
- Share one evidence-based thing you learned.
13 · REFERENCES & ADDITIONAL RESOURCES
Explore further.
These resources can help young explorers move from introductory understanding toward deeper study.
NextGenU — Anatomy & Physiology
A comprehensive introductory course covering anatomy, physiology, levels of organization, body systems, homeostasis and health promotion.
Explore NextGenU →OpenStax Anatomy & Physiology
A comprehensive open educational resource for deeper study of human anatomy and physiology.
Explore OpenStax →Genetics & Inheritance
Explore DNA, genes, inheritance, variation and genetic conditions through reliable scientific resources.
GHE learning principle:
Use health information to learn and ask better
questions—not to diagnose yourself.