Anatomy and Physiology Overview | Body Cavities | Body Systems - CPC Course Class -3

 INTRODUCTION 

In the previous class, we learned about medical terminology, including prefixes, suffixes, root words, abbreviations, and directional terms.

Now that we understand basic medical terminology, it is time to learn another important foundation of medical coding: Anatomy and Physiology.

For a medical coder, understanding anatomy helps you identify what body part or anatomical structure is involved, while physiology helps you understand how that structure functions.

This knowledge becomes especially important when reading physician documentation, operative reports, procedure notes, diagnostic reports, and other medical records.

In this Class 3 lesson, we will cover:

• What is Anatomy?
• What is Physiology?
• Anatomy vs. Physiology
• Levels of organization of the human body
• Anatomical position
• Body cavities
• Major body systems
• Important organs of each system
• Why anatomy is important for CPC coding
• Basic practice questions

1. What Is Anatomy?

Anatomy is the study of the structure of the human body.

In simple words:

Anatomy tells us what the body structure is and where it is located.

For example:

• The heart is located in the thoracic cavity.
• The brain is located inside the cranial cavity.
• The lungs are located in the thoracic cavity.
• The stomach is located in the abdominal region.
• The urinary bladder is located in the pelvic region.

Understanding the location of organs is important for medical coding because medical documentation frequently identifies procedures and conditions by their anatomical site.

Example

A physician documents:

“Procedure performed on the right kidney.”

The coder needs to understand:

• Kidney = anatomical structure
• Right = laterality
• Procedure = what was performed

This basic anatomical understanding helps the coder interpret the documentation correctly.

2. What Is Physiology?

Physiology is the study of how the body and its structures function.

In simple words:

Physiology tells us how a body structure works.

For example:

The anatomy of the heart tells us that it is an organ located in the thoracic cavity.

The physiology of the heart tells us that it pumps blood throughout the body.

Similarly:

Anatomy: The lungs are located in the thoracic cavity.

Physiology: The lungs participate in breathing and gas exchange.

Therefore:

Anatomy = Structure

Physiology = Function

Both concepts are important for understanding medical documentation.

3. Anatomy vs. Physiology

A simple way to remember the difference is:

Anatomy	Physiology
Study of structure	Study of function
What is it?	How does it work?
Location of organs	Function of organs
Body parts and structures	Activities and processes

Example: Kidney

Anatomy: Kidney is an organ located in the posterior abdominal region.

Physiology: The kidneys filter blood and help remove waste through urine.

Example: Heart

Anatomy: Heart is an organ located in the thoracic cavity.

Physiology: Heart pumps blood throughout the body.

This distinction is useful when interpreting clinical documentation.

4. Levels of Organization of the Human Body

The human body can be understood through different levels of organization.

A simple sequence is:

Cell → Tissue → Organ → Organ System → Organism

Let’s understand this step by step.

Cell

A cell is the basic structural and functional unit of the body.

Tissue

Similar cells work together to form tissues.

Organ

Different tissues combine to form an organ.

For example, the heart is an organ.

Organ System

Multiple organs work together to perform important functions.

For example, the heart and blood vessels work together as part of the cardiovascular system.

Organism

All organ systems together make the complete human body.

So remember:

Cells form tissues → tissues form organs → organs work together in organ systems → organ systems make up the human body.

5. Anatomical Position

Another important concept for medical coding students is the anatomical position.

The standard anatomical position describes the body as:

• Standing upright
• Facing forward
• Head facing forward
• Arms positioned at the sides
• Palms facing forward
• Feet facing forward

Why is this important?

Healthcare professionals use standardized anatomical terminology to describe the location of structures.

For example:

• Right
• Left
• Anterior
• Posterior
• Medial
• Lateral
• Proximal
• Distal

Important Coding Point

When documentation states right knee, the right side refers to the patient’s right side.

Understanding laterality is particularly important when reviewing procedure documentation.

6. What Are Body Cavities?

A body cavity is a space within the body that contains and protects internal organs.

The major body cavities covered in this class are:

1. Cranial cavity
2. Vertebral/spinal cavity
3. Thoracic cavity
4. Abdominal cavity
5. Pelvic cavity

Let’s understand each one.

7. Cranial Cavity

The cranial cavity is located inside the skull.

The major organ located within the cranial cavity is the:

Brain

Remember:

Cranial cavity → Brain

For example, when documentation describes a procedure involving the brain, understanding its relationship to the cranial cavity helps you understand the anatomical location.

8. Vertebral or Spinal Cavity

The vertebral cavity, also called the spinal cavity or vertebral canal, contains and protects the:

Spinal cord

Remember:

Vertebral cavity → Spinal cord

This is important when interpreting documentation involving spinal structures and procedures.

9. Thoracic Cavity

The thoracic cavity is located in the chest.

Major structures include:

• Heart
• Lungs

Other important structures are also present in the thoracic region.

The thoracic cavity is separated from the abdominal cavity by the:

Diaphragm

Remember:

Thoracic cavity = Chest

Major organs = Heart and lungs

Example

If documentation states:

“Procedure performed on the lung,”

you should recognize that the lung is located within the thoracic cavity.

10. Abdominal Cavity

The abdominal cavity is located below the diaphragm.

Important organs include:

• Stomach
• Liver
• Gallbladder
• Pancreas
• Spleen
• Small intestine
• Large intestine

The kidneys are located in the posterior abdominal region.

Examples of procedures

Appendectomy
Removal of the appendix.

Cholecystectomy
Removal of the gallbladder.

Gastrectomy
Removal of part or all of the stomach.

Understanding the location of these organs helps medical coders understand procedure documentation.

11. Pelvic Cavity

The pelvic cavity contains structures including:

• Urinary bladder
• Rectum
• Reproductive organs

For example, the uterus is located within the pelvic region.

Example

A physician documents:

“Hysterectomy performed.”

A medical coder should understand that a hysterectomy involves surgical removal of the uterus.

Understanding the anatomical location helps the coder interpret the procedure.

12. Quick Body Cavity Revision

Let’s quickly revise the major cavities.

Body Cavity	Major Structure/Organs
Cranial	Brain
Vertebral/Spinal	Spinal cord
Thoracic	Heart and lungs
Abdominal	Stomach, liver, intestines and other abdominal organs
Pelvic	Bladder, rectum and reproductive organs

Important Point

The diaphragm separates the thoracic cavity from the abdominal cavity.

13. Major Body Systems

Now let’s move to another important topic:

Major Body Systems

The human body contains multiple organ systems.

A medical coder should understand the major organs and basic functions of these systems.

14. Cardiovascular System

The cardiovascular system, also called the circulatory system, includes:

• Heart
• Blood
• Blood vessels

Its major function is to circulate blood throughout the body.

The heart pumps blood.

Arteries generally carry blood away from the heart.

Veins generally carry blood toward the heart.

Coding examples

Medical coders may encounter procedures such as:

• Cardiac catheterization
• Coronary angiography
• Coronary artery bypass grafting, or CABG
• Pacemaker procedures
• Heart valve procedures

Therefore, understanding cardiovascular anatomy is important for coders.

15. Respiratory System

The respiratory system is responsible for breathing and gas exchange.

Major structures include:

• Nose
• Pharynx
• Larynx
• Trachea
• Bronchi
• Lungs

The lungs are the major organs involved in gas exchange.

Example

Bronchoscopy involves examination of the respiratory passages using a bronchoscope.

Understanding respiratory anatomy helps the coder understand the procedure documentation.

16. Digestive System

The digestive system processes food and helps absorb nutrients.

Major structures include:

• Mouth
• Esophagus
• Stomach
• Small intestine
• Large intestine
• Rectum
• Anus

Accessory organs include:

• Liver
• Gallbladder
• Pancreas

Coding examples

EGD involves examination of the upper gastrointestinal tract.

Colonoscopy involves examination of the colon.

Appendectomy involves removal of the appendix.

Cholecystectomy involves removal of the gallbladder.

Understanding the anatomy of the digestive system is important when reviewing GI procedure documentation.

17. Nervous System

The nervous system controls and coordinates many functions of the body.

It includes:

Central Nervous System

• Brain
• Spinal cord

Peripheral Nervous System

• Nerves outside the brain and spinal cord

The brain performs many important functions, while the spinal cord provides a major pathway for communication between the brain and the body.

Coding examples

Medical coders may encounter:

• Brain surgery
• Craniotomy
• Spinal procedures
• Nerve procedures

Understanding nervous system anatomy helps when reviewing these procedures.

18. Musculoskeletal System

The musculoskeletal system provides:

• Support
• Movement
• Protection

It includes:

• Bones
• Muscles
• Joints
• Ligaments
• Tendons
• Cartilage

Common procedures

Examples include:

• Fracture treatment
• Joint replacement
• Arthroscopy
• Tendon repair

Coding example

Suppose the documentation says:

“Right knee arthroscopy.”

Break it down:

Right → Laterality

Knee → Anatomical site

Arthroscopy → Procedure/technique

This is the type of anatomical thinking that helps a CPC student understand procedure documentation.

19. Urinary System

The urinary system includes:

• Kidneys
• Ureters
• Urinary bladder
• Urethra

The system is involved in urine production, storage, and elimination and also has important roles in fluid and electrolyte regulation.

Coding examples

Cystoscopy involves examination of the urinary tract using a cystoscope.

Nephrectomy involves removal of a kidney.

Understanding urinary system anatomy helps coders interpret these procedures.

20. Reproductive System

The reproductive system differs between males and females.

Male reproductive structures include:

• Testes
• Epididymis
• Vas deferens
• Prostate
• Seminal vesicles
• Penis

Female reproductive structures include:

• Ovaries
• Fallopian tubes
• Uterus
• Cervix
• Vagina

Coding examples

• Hysterectomy
• Oophorectomy
• Salpingectomy
• Prostate procedures

Understanding the anatomical structures involved is important when reviewing reproductive system procedures.

21. Endocrine System

The endocrine system consists of glands that produce hormones.

Important endocrine glands include:

• Pituitary gland
• Thyroid gland
• Parathyroid glands
• Adrenal glands
• Pancreas
• Reproductive glands

For example, the thyroid gland produces hormones that help regulate metabolism.

Coding example

Thyroidectomy means surgical removal of part or all of the thyroid gland.

22. Lymphatic and Immune Systems

The lymphatic and immune systems help maintain fluid balance and protect the body against infection and disease.

Important structures include:

• Lymph nodes
• Lymphatic vessels
• Spleen
• Thymus
• Other lymphatic tissues

Coding example

A physician may perform a lymph node biopsy.

Understanding the structure and location of lymph nodes helps the coder interpret the documentation.

23. Integumentary System

The integumentary system includes:

• Skin
• Hair
• Nails
• Sweat glands
• Sebaceous glands

The skin is the body’s largest organ.

This system is particularly important for procedure coding because coders frequently encounter procedures involving the skin and related structures.

Examples include:

• Skin biopsy
• Lesion excision
• Wound care
• Debridement
• Laceration repair
• Burn treatment

Example

Documentation:

“Excision of skin lesion from the left forearm.”

Important information includes:

Skin → Integumentary system

Forearm → Anatomical site

Left → Laterality

The coder then reviews the complete documentation and applicable CPT guidelines before selecting the appropriate code.

24. Special Senses

The special senses include structures associated with:

• Vision
• Hearing
• Balance
• Smell
• Taste

Examples include:

Eyes → Vision

Ears → Hearing and balance

Nose → Smell

Tongue → Taste

These structures can be involved in various diagnostic and surgical procedures.

25. Why Is Anatomy Important for CPC?

Now let’s answer one of the most important questions:

Why does a CPC student need to learn anatomy?

Because CPT coding often depends on:

• The procedure performed
• The anatomical site
• The body structure involved
• The technique used
• The extent of the procedure
• Laterality, when applicable

For example:

“Right knee arthroscopy.”

A coder should identify:

What? → Arthroscopy

Where? → Knee

Which side? → Right

This approach helps you understand procedure documentation before moving to actual CPT code selection.

Remember:

WHAT was done + WHERE was it done + HOW was it done?

This is an important thought process for CPC students.

26. Class 3 Quick Revision

Let’s revise today’s complete class.

Anatomy

Structure of the body

Physiology

Function of the body

Body Cavities

Cranial → Brain

Vertebral → Spinal cord

Thoracic → Heart and lungs

Abdominal → Major abdominal organs

Pelvic → Pelvic organs

Major Body Systems

• Cardiovascular
• Respiratory
• Digestive
• Nervous
• Musculoskeletal
• Urinary
• Reproductive
• Endocrine
• Lymphatic/Immune
• Integumentary
• Special senses

27. Practice Questions

Question 1

Which cavity contains the brain?

A. Thoracic
B. Cranial
C. Abdominal
D. Pelvic

Answer: B. Cranial cavity

Question 2

Which organ is located in the thoracic cavity?

A. Stomach
B. Urinary bladder
C. Heart
D. Appendix

Answer: C. Heart

Question 3

Which system includes the heart and blood vessels?

A. Respiratory
B. Cardiovascular
C. Digestive
D. Nervous

Answer: B. Cardiovascular system

Question 4

Which system includes the kidneys, ureters, urinary bladder, and urethra?

A. Digestive
B. Urinary
C. Respiratory
D. Endocrine

Answer: B. Urinary system

Question 5

What is the difference between anatomy and physiology?

Answer:

Anatomy = Structure

Physiology = Function

28. Homework

Before moving to Class 4, try this simple activity.

Take a blank sheet of paper and draw a basic human body.

Label these structures:

• Brain
• Heart
• Lungs
• Liver
• Stomach
• Small intestine
• Large intestine
• Kidneys
• Urinary bladder
• Reproductive organs

Then write the body system associated with each structure.

This simple exercise will help you remember anatomy much faster.

Conclusion

Congratulations! 

You have completed Class 3 of the CPC Medical Coding Course.

Today we learned the basic difference between anatomy and physiology, the major body cavities, and the important body systems and their organs.

Remember:

Anatomy = Structure
Physiology = Function

And for CPC coding, remember:

WHAT was done + WHERE was it done + HOW was it done?

Anatomy is not something you need to memorize in one day. Build your knowledge step by step and keep connecting every anatomical structure to the medical procedures you encounter.