Overview of Anatomy and Physiology

Study Notes

The study of anatomy and physiology is typically based on a healthy, average-sized individual (22-year-old male weighing 155 lbs or a 22-year-old female weighing 125 lbs).

Anatomy is the study of the body's structure.
Gross Anatomy involves studying large body structures:
- Regional Anatomy focuses on specific regions of the body.
- Systematic Anatomy examines each body system separately.
- Surface Anatomy studies internal structures as they relate to the skin's surface.
Microscopic Anatomy examines structures invisible to the naked eye:
- Cytology studies cells.
- Histology studies tissues.
Developmental Anatomy traces structural changes throughout life:
- Embryology focuses on developmental changes before birth.

Physiology examines the functions of the body.
Its subdivisions often focus on specific organ systems, like neurophysiology or cardiovascular physiology.
It often focuses on events at the cellular or molecular level.

Structure and function are interconnected, meaning function is directly related to structure.
This principle of complementarity is essential to understanding the body.

Reductionism is a scientific approach that simplifies complex concepts by breaking them down into simpler components.
Physiology often uses reductionism to understand the complex functions of the body by examining them at the cellular or molecular level.

The body's organization is hierarchical, ranging from smallest units (atoms) to the largest (organism).
The levels of organization are:
- Chemical Level: atoms combine to form molecules.
- Cellular Level: cells are composed of molecules.
- Tissue Level: groups of similar cells with a shared function.
  - The four main tissue types are epithelial, muscle, connective, and nervous.
- Organ Level: structures composed of two or more tissue types, each performing a specialized function.
- Organ System Level: multiple organs working together to accomplish a common purpose.
- Organismal Level: a complete organism consisting of all the organ systems working together.

Integumentary System:
- Forms the external body covering (skin).
- Protects deeper tissues from injury.
- Synthesizes vitamin D.
- Contains receptors for external stimuli and sweat/oil glands.
- Includes hair and nails.
Skeletal System:
- Protects and supports organs.
- Provides framework for muscle movement.
- Site of blood cell synthesis and mineral storage.
Muscular System:
- Allows manipulation of the environment, locomotion, and facial expression.
- Maintains posture and generates heat.
Nervous System:
- The body's rapid control system.
- Responds to internal and external stimuli by activating appropriate muscles and glands.
Endocrine System:
- Glands secrete hormones that regulate various body processes.
Cardiovascular System:
- Blood vessels transport blood and nutrients throughout the body.
- The heart pumps blood.
Lymphatic System:
- Collects fluid leaked from blood vessels and returns it to the blood.
- Removes debris from lymphatic vessels.
- Houses white blood cells (lymphocytes) involved in immunity.
Respiratory System:
- Supplies blood with oxygen and removes carbon dioxide.
- Gas exchange occurs through the walls of the lungs.