CHAPTER 30

MODULE 3O. BASIC ANATOMY AND PHYSIOLOGY 

What is Anatomy and Physiology? 

• Anatomy is the study of the structure of the human body – what it's made of and where things are located. 

• Physiology is the study of how the body functions – how organs, tissues, and systems work together to keep us alive. 

Levels of Organization in the Body 

1. Cells – The smallest unit of life (e.g., muscle cell, nerve cell) 

2. Tissues – Groups of similar cells (e.g., muscle tissue, nervous tissue) 

3. Organs – Structures made of different tissues (e.g., heart, kidney) 

4. Systems – Groups of organs that work together (e.g., digestive system) 

5. Organism – The complete human body 

Major Body Systems and Their Functions 

System 

Main Organs 

Function 

Circulatory 

Heart, blood vessels, blood 

Transports oxygen, nutrients, and waste throughout the body 

Respiratory 

Lungs, trachea, nose 

Brings in oxygen, removes carbon dioxide 

Digestive 

Mouth, stomach, intestines, liver 

Breaks down food and absorbs nutrients 

Nervous 

Brain, spinal cord, nerves 

Controls body activities and sends messages 

Muscular 

Muscles 

Enables movement and posture 

Skeletal 

Bones, joints 

Provides support, protects organs, helps with movement 

Excretory (Urinary) 

Kidneys, bladder, urethra 

Removes waste from the body via urine 

Reproductive 

Male: testes; Female: ovaries, uterus 

Produces offspring 

Endocrine 

Glands (thyroid, adrenal, pancreas) 

Produces hormones to regulate body functions 

Integumentary 

Skin, hair, nails 

Protects the body, regulates temperature 

Lymphatic/Immune 

Lymph nodes, spleen, white blood cells 

Fights infections and diseases 

Body Systems Working Together 

Example: 

• When you exercise, your muscles (muscular system) need more oxygen. 

• The heart (circulatory system) pumps faster. 

• The lungs (respiratory system) bring in more oxygen. 

• Your nervous system tells your body how to respond. 

Body Cavities and Major Organs 

Cavity 

Organs Inside 

Cranial 

Brain 

Thoracic 

Heart, lungs 

Abdominal 

Stomach, liver, intestines, kidneys 

Pelvic 

Bladder, reproductive organs 

Common Terms to Know 

• Anterior (front) vs. Posterior (back) 

• Superior (above) vs. Inferior (below) 

• Medial (toward the center) vs. Lateral (toward the sides) 

• Proximal (closer to the body center) vs. Distal (farther from center)