The Human Body / Human Anatomy / The Skeleton / Human Body Structure / Key Points About the Human Body

The Human Body 

Understanding the human body is like exploring the most advanced machine ever created. From tiny microscopic cells to complex organ systems, every part works together to keep us alive, active, and healthy. In this guide, we break down Human Anatomy and Human Physiology in a simple, engaging way—perfect for students preparing for exams or anyone curious about how the body works.

1. The Human Body

If we zoom deep into the human body—beyond organs, tissues, and even bones—we reach the smallest building block: the cell.

Cell → Tissues → Organs → Organ Systems → Organism

• The average adult has 30–40 trillion cells

• Around 242 billion new cells are produced every day

• Similar cells group together to form tissues

• Tissues combine to create organs

• Organs work together to form organ systems

• All organ systems together make a complete human being

2. Human Anatomy

Human anatomy is the study of the structure of the body—what parts we have, where they are located, and how they are shaped.

Let’s explore the main structural components.

The Skeleton 

When you walk, jump, climb, or even sit upright, your skeleton is working for you. Babies are born with about 300 bones, but many fuse over time, leaving 206 bones in an adult.

Functions of the Skeleton

• Supports body shape

• Protects vital organs (brain, heart, lungs, liver)

• Allows movement with the help of muscles

• Produces blood cells (bone marrow)

• Stores minerals like calcium and phosphorus

Joints

Bones meet at joints.

Two major types:

• Movable joints – allow bending, twisting, rotation

• Immovable joints – fixed, fused (like skull bones)

Examples of joint movements:

• Rotation (turning your head)

• Flexion/extension (bending your elbow)

• Abduction/adduction (moving arms sideways)

Muscles (Movers of the Body)

Muscles are special tissues attached to bones by tendons. They work in pairs, meaning:

• One muscle contracts → the bone moves

• The opposite muscle relaxes → the bone returns to position

Example:

When you bend the arm, biceps contract and triceps relax.

Types of Muscles

• Skeletal muscles – voluntary, attached to bones

• Smooth muscles – involuntary, found in organs

• Cardiac muscle – found only in the heart

3. Human Body Structure

Internal organs are housed inside protective spaces called body cavities.

Major Body Cavities

• Cranial cavity – protects the brain

• Pleural cavity – houses the lungs

• Abdominal cavity – liver, stomach, intestines, spleen

• Pelvic cavity – reproductive organs, bladder

4. Human Physiology  (How the Body Works)

Physiology focuses on the functions of organs—how they work and respond to stress, activity, and disease.

Claude Bernard is known as the Father of Physiology, and his research forms the basis of modern medical science.

5. Major Organ Systems of the Human Body

Let’s explore each system in a clear, exam-friendly way.

A. Circulatory System (Cardiovascular System)

This is the body's transport system.

It includes the:

• Heart

• Arteries

• Veins

• Capillaries

Types of Circulation

• Systemic circulation – heart → body → heart

• Pulmonary circulation – heart → lungs → heart

• Coronary circulation – blood supply to the heart itself

Function

• Supplies oxygen and nutrients

• Removes waste like carbon dioxide

• Maintains temperature and pH balance

B. Digestive System

This system converts food into nutrients the body can use.

Main Organs

• Mouth, teeth, tongue

• Oesophagus

• Stomach

• Liver

• Pancreas

• Small intestine

• Large intestine

• Rectum

Process of Digestion (Simple Explanation)

1. Chewing breaks food into small pieces

2. Saliva forms a soft mass called the bolus

3. Food moves down the oesophagus

4. Stomach acids break food into a paste

5. Small intestine absorbs nutrients

6. Large intestine absorbs water

7. Waste is stored in the rectum and eliminated

C. Reproductive System

Allows humans to produce offspring.

Female Reproductive System

• Ovaries – produce eggs

• Uterus – where the fetus develops

• Fallopian tubes – path of the egg

• Vagina – birth canal

Male Reproductive System

• Testes – produce sperm

• Vas deferens – transport sperm

• Prostate & glands – produce fluid

• Penis – transfers sperm

D. Respiratory System

The respiratory system manages breathing.

Main Organs

• Nose

• Trachea

• Bronchi

• Bronchioles

• Lungs

• Diaphragm

How Breathing Works

• Inhalation brings oxygen into the lungs

• Oxygen passes into blood through alveoli

• Exhalation removes carbon dioxide

E. Nervous System

This is the body’s control center—it coordinates everything you do.

Two Main Divisions

1. Central Nervous System (CNS)

• Brain

  • Forebrain (thinking, memory, emotions)

  • Midbrain (visual & auditory reflexes)

  • Hindbrain (movement, coordination, balance)

• Spinal Cord – pathway for signals

2. Peripheral Nervous System (PNS)

Somatic Nervous System

• Controls voluntary actions

• Example: Moving your arm, avoiding obstacles while biking

Autonomic Nervous System

• Controls involuntary functions

  • Heartbeat

  • Digestion

  • Breathing rate

6. Key Points About the Human Body

• Everything begins with cells—the basic unit of life

• Anatomy = structure

• Physiology = function

• Humans have evolved to walk upright and use hands with great precision

• The body has 79 confirmed organs, but new discoveries continue (like Interstitium in 2018)

• Five vital organs necessary for survival:
  Brain, Heart, Liver, Lungs, Kidneys

 (FAQs)

Q1: What is human anatomy?

It is the study of the structure of human body parts and how they fit together.

Q2: What is human physiology?

It deals with the functions of organs and how the body works internally.

Q3: Who is the father of physiology?

Claude Bernard.

Q4: Why is physiology important?

It helps us understand diseases, treatments, and how the body responds to stress.

Q5: Who is the father of anatomy?

Andreas Vesalius.

Q6: What are the types of anatomy?

• Gross anatomy

• Microscopic anatomy

Q7: Why is anatomy relevant?

It helps us understand the structure and relationships of body parts.

Q8: How are anatomy and physiology different?

Anatomy = structure

Physiology = function

Q9: What are the major organs of the body?

Brain, heart, lungs, kidneys, liver, stomach, intestines.

Q10: What are the major systems of the body?

Cardiovascular, digestive, respiratory, nervous, excretory, endocrine, lymphatic, reproductive, muscular, skeletal systems.

✔ Final Note

This article has been rewritten for clarity, student engagement, and easy exam preparation, while maintaining professional scientific accuracy.