HUMAN ANATOMY AND PHYSIOLOGY
1. Introduction to Human Anatomy & Physiology
What is Anatomy?
Anatomy is the branch of science that deals with the structure of living organisms. It focuses on
the physical makeup of the human body and its parts — bones, muscles, organs, and tissues.
Gross Anatomy (Macroscopic): Study of large body parts visible without a microscope
(e.g., the heart, lungs, and kidneys).
Microscopic Anatomy: Involves structures not visible to the naked eye — includes:
o Histology: Study of tissues
o Cytology: Study of cells
What is Physiology?
Physiology is the scientific study of the functions and mechanisms in a living system. In the
human context, it explains how organs and systems work, both independently and together, to
sustain life.
Example: Anatomy tells us that the heart has four chambers. Physiology tells us how those
chambers pump blood to the body.
Importance of Studying Anatomy and Physiology
Helps understand how the body functions in health and disease.
Essential for careers in healthcare, sports science, nursing, biology, and personal
wellness.
Lays the foundation for medical studies and patient care.
Levels of Structural Organization in the Human Body
The body is organized in a hierarchical structure:
1. Chemical Level
o Includes atoms (e.g., carbon, oxygen) and molecules (e.g., proteins,
carbohydrates, DNA).
o Smallest level of organization, forming the building blocks of life.
2. Cellular Level
, o Cells are the basic structural and functional units of life.
o Different cells have different functions (e.g., nerve cells transmit signals, muscle
cells contract).
3. Tissue Level
o Groups of similar cells that perform a specific function.
o Four main types of tissues:
Epithelial (coverings/linings)
Connective (support, e.g., bone, fat, blood)
Muscle (movement)
Nervous (control and communication)
4. Organ Level
o Composed of at least two different types of tissues working together (most have
all four).
o Examples: stomach, heart, lungs, skin.
5. System Level
o Organs that work closely together to perform major body functions.
o Examples: Digestive system, respiratory system, circulatory system.
6. Organismal Level
o The highest level: all systems functioning together to form the complete human
body.
Basic Life Functions Supported by Physiology
These are the essential processes that distinguish living organisms from non-living things:
Metabolism: All chemical reactions in the body
Responsiveness: Reacting to internal and external stimuli
Movement: Internal (blood, digestion) and external (muscles)
Growth: Increase in size and number of cells
Reproduction: Production of new cells and organisms
Excretion: Removal of waste
Homeostasis: Maintaining a stable internal environment
Homeostasis: The Balance of Life
Homeostasis is the body’s ability to maintain a stable internal environment despite changes in
external conditions.
Controlled by feedback mechanisms:
o Negative feedback: Most common (e.g., regulation of body temperature, blood
glucose)
o Positive feedback: Enhances the original stimulus (e.g., childbirth contractions)
,2. The Skeletal System
🦴 Definition
The skeletal system is the framework of bones and cartilage that supports, shapes, and protects the
human body. It serves as the body's structural foundation and plays vital roles in movement, mineral
storage, and blood cell production.
🦴 Functions of the Skeletal System
1. Support
o Provides structural support for the entire body.
o The skeleton forms the internal framework that holds the body upright.
2. Protection
o Shields vital internal organs.
, Skull protects the brain
Rib cage protects the heart and lungs
Vertebrae protect the spinal cord
3. Movement
o Muscles are attached to bones.
o When muscles contract, they pull on bones, producing movement.
4. Mineral Storage
o Bones store essential minerals such as calcium and phosphorus.
o These minerals are released into the bloodstream as needed.
5. Blood Cell Production (Hematopoiesis)
o Red bone marrow inside certain bones produces red blood cells, white blood cells, and
platelets.
6. Energy Storage
o Yellow bone marrow stores fats as an energy reserve.
🦴 Types of Bones (by Shape)
Type of Bone Description Examples
Long Bones Longer than they are wide Femur, humerus
Short Bones Cube-shaped Carpals (wrist), tarsals
Flat Bones Thin, flattened, often curved Skull, ribs, sternum
Irregular Bones Complex shapes Vertebrae, hip bones
Sesamoid Bones Small, round bones in tendons Patella (kneecap)
🦴 Structure of a Typical Long Bone
1. Diaphysis (shaft):
o The long central portion.
o Contains the medullary cavity filled with yellow marrow.
2. Epiphyses (ends):
o The rounded ends of the bone.
o Covered with articular cartilage to allow smooth movement at joints.
3. Metaphysis:
o The region between diaphysis and epiphysis.
o Contains the growth plate (epiphyseal plate) in children.
4. Periosteum:
o Tough outer covering of the bone.
o Contains blood vessels, nerves, and bone-forming cells.
5. Endosteum:
1. Introduction to Human Anatomy & Physiology
What is Anatomy?
Anatomy is the branch of science that deals with the structure of living organisms. It focuses on
the physical makeup of the human body and its parts — bones, muscles, organs, and tissues.
Gross Anatomy (Macroscopic): Study of large body parts visible without a microscope
(e.g., the heart, lungs, and kidneys).
Microscopic Anatomy: Involves structures not visible to the naked eye — includes:
o Histology: Study of tissues
o Cytology: Study of cells
What is Physiology?
Physiology is the scientific study of the functions and mechanisms in a living system. In the
human context, it explains how organs and systems work, both independently and together, to
sustain life.
Example: Anatomy tells us that the heart has four chambers. Physiology tells us how those
chambers pump blood to the body.
Importance of Studying Anatomy and Physiology
Helps understand how the body functions in health and disease.
Essential for careers in healthcare, sports science, nursing, biology, and personal
wellness.
Lays the foundation for medical studies and patient care.
Levels of Structural Organization in the Human Body
The body is organized in a hierarchical structure:
1. Chemical Level
o Includes atoms (e.g., carbon, oxygen) and molecules (e.g., proteins,
carbohydrates, DNA).
o Smallest level of organization, forming the building blocks of life.
2. Cellular Level
, o Cells are the basic structural and functional units of life.
o Different cells have different functions (e.g., nerve cells transmit signals, muscle
cells contract).
3. Tissue Level
o Groups of similar cells that perform a specific function.
o Four main types of tissues:
Epithelial (coverings/linings)
Connective (support, e.g., bone, fat, blood)
Muscle (movement)
Nervous (control and communication)
4. Organ Level
o Composed of at least two different types of tissues working together (most have
all four).
o Examples: stomach, heart, lungs, skin.
5. System Level
o Organs that work closely together to perform major body functions.
o Examples: Digestive system, respiratory system, circulatory system.
6. Organismal Level
o The highest level: all systems functioning together to form the complete human
body.
Basic Life Functions Supported by Physiology
These are the essential processes that distinguish living organisms from non-living things:
Metabolism: All chemical reactions in the body
Responsiveness: Reacting to internal and external stimuli
Movement: Internal (blood, digestion) and external (muscles)
Growth: Increase in size and number of cells
Reproduction: Production of new cells and organisms
Excretion: Removal of waste
Homeostasis: Maintaining a stable internal environment
Homeostasis: The Balance of Life
Homeostasis is the body’s ability to maintain a stable internal environment despite changes in
external conditions.
Controlled by feedback mechanisms:
o Negative feedback: Most common (e.g., regulation of body temperature, blood
glucose)
o Positive feedback: Enhances the original stimulus (e.g., childbirth contractions)
,2. The Skeletal System
🦴 Definition
The skeletal system is the framework of bones and cartilage that supports, shapes, and protects the
human body. It serves as the body's structural foundation and plays vital roles in movement, mineral
storage, and blood cell production.
🦴 Functions of the Skeletal System
1. Support
o Provides structural support for the entire body.
o The skeleton forms the internal framework that holds the body upright.
2. Protection
o Shields vital internal organs.
, Skull protects the brain
Rib cage protects the heart and lungs
Vertebrae protect the spinal cord
3. Movement
o Muscles are attached to bones.
o When muscles contract, they pull on bones, producing movement.
4. Mineral Storage
o Bones store essential minerals such as calcium and phosphorus.
o These minerals are released into the bloodstream as needed.
5. Blood Cell Production (Hematopoiesis)
o Red bone marrow inside certain bones produces red blood cells, white blood cells, and
platelets.
6. Energy Storage
o Yellow bone marrow stores fats as an energy reserve.
🦴 Types of Bones (by Shape)
Type of Bone Description Examples
Long Bones Longer than they are wide Femur, humerus
Short Bones Cube-shaped Carpals (wrist), tarsals
Flat Bones Thin, flattened, often curved Skull, ribs, sternum
Irregular Bones Complex shapes Vertebrae, hip bones
Sesamoid Bones Small, round bones in tendons Patella (kneecap)
🦴 Structure of a Typical Long Bone
1. Diaphysis (shaft):
o The long central portion.
o Contains the medullary cavity filled with yellow marrow.
2. Epiphyses (ends):
o The rounded ends of the bone.
o Covered with articular cartilage to allow smooth movement at joints.
3. Metaphysis:
o The region between diaphysis and epiphysis.
o Contains the growth plate (epiphyseal plate) in children.
4. Periosteum:
o Tough outer covering of the bone.
o Contains blood vessels, nerves, and bone-forming cells.
5. Endosteum:
