Overview of Anatomy and Body Systems

Definition: Study of the structure of organisms and their parts.
Branches:
- Gross Anatomy: Study of structures visible to the naked eye.
- Microscopic Anatomy: Study of structures at the cellular and tissue level.
  - Includes histology (study of tissues) and cytology (study of cells).

Directional Terms:
- Superior (above), Inferior (below)
- Anterior (front), Posterior (back)
- Medial (toward the midline), Lateral (away from the midline)
- Proximal (closer to the point of attachment), Distal (further from the point of attachment)
Planes of Section:
- Sagittal Plane: Divides the body into left and right.
- Frontal (Coronal) Plane: Divides the body into anterior and posterior.
- Transverse (Horizontal) Plane: Divides the body into superior and inferior.

Skeletal System
- Composed of bones and joints.
- Functions: Support, movement, protection, blood cell production, mineral storage.
Muscular System
- Composed of skeletal, smooth, and cardiac muscles.
- Functions: Movement, posture, heat production.
Nervous System
- Composed of the brain, spinal cord, and nerves.
- Functions: Control of body functions, response to stimuli, communication.
Circulatory System
- Composed of the heart and blood vessels.
- Functions: Transports nutrients, gases, hormones, and waste products.
Respiratory System
- Composed of the lungs, trachea, and bronchi.
- Functions: Gas exchange, oxygen intake, carbon dioxide removal.
Digestive System
- Composed of the gastrointestinal tract and accessory organs.
- Functions: Breakdown of food, absorption of nutrients, elimination of waste.
Endocrine System
- Composed of glands that secrete hormones.
- Functions: Regulation of metabolism, growth, reproduction, and homeostasis.
Urinary System
- Composed of the kidneys, ureters, bladder, and urethra.
- Functions: Excretion of waste, regulation of blood volume and pressure.
Reproductive System
- Male: Testes, penis, associated glands.
- Female: Ovaries, uterus, vagina.
- Functions: Production of gametes, hormones, and reproduction.

Cells: Basic unit of life.
Tissues: Groups of similar cells performing a common function.
- Types: Epithelial, connective, muscle, nervous.
Organs: Structures composed of two or more tissue types working together.
Organ Systems: Groups of organs that work together to perform complex functions.

Definition: The process by which the body maintains a stable internal environment.
Importance: Critical for the proper functioning of cells and overall health.

Normal Variations: Minor differences in anatomy that are common and not indicative of disease.
Pathological Variations: Abnormal structures or functions due to disease or injury.

Anatomy explores the structure and organization of living organisms and their components.
Gross anatomy observes structures visible without magnification, while microscopic anatomy examines tissues and cells.
Histology focuses specifically on tissues, whereas cytology investigates cellular structures.

Directional terms include:
- Superior: higher position
- Inferior: lower position
- Anterior: front side
- Posterior: back side
- Medial: closer to the body's midline
- Lateral: farther from the midline
- Proximal: nearer to point of attachment
- Distal: away from the point of attachment
Anatomical planes define body sections:
- Sagittal Plane: divides body into left and right halves.
- Frontal (Coronal) Plane: separates anterior and posterior sections.
- Transverse (Horizontal) Plane: creates superior and inferior portions.

Skeletal System:
- Contains bones and joints; serves to support, facilitate movement, guard organs, produce blood cells, and store minerals.
Muscular System:
- Made up of skeletal, smooth, and cardiac muscles; responsible for movement, maintaining posture, and generating heat.
Nervous System:
- Comprises brain, spinal cord, and nerves; essential for regulating body functions, responding to stimuli, and enabling communication.
Circulatory System:
- Includes heart and blood vessels; key role in transporting nutrients, gases, hormones, and metabolic wastes.
Respiratory System:
- Consists of lungs, trachea, and bronchi; crucial for gas exchange, delivering oxygen, and expelling carbon dioxide.
Digestive System:
- Comprises gastrointestinal tract and accessory organs; vital for food breakdown, nutrient absorption, and waste elimination.
Endocrine System:
- Features hormone-secreting glands; regulates metabolism, growth, reproductive processes, and homeostatic balance.
Urinary System:
- Consists of kidneys, ureters, bladder, and urethra; responsible for waste excretion and blood volume/pressure regulation.
Reproductive System:
- Male components include testes and penis; female components consist of ovaries and uterus; both systems focused on gamete and hormone production, along with reproduction.

Cells: Fundamental life units, serving as building blocks for tissues.
Tissues: Composed of similar cells with shared functions; categorized into four types: epithelial, connective, muscle, and nervous.
Organs: Complex structures formed from two or more tissue types working in concert.
Organ Systems: Networks of organs collaborating to execute intricate physiological tasks.

Homeostasis is the mechanism by which the body sustains a balanced internal environment.
Essential for cell functionality and overall health maintenance.

Normal Variations: Minor anatomical differences commonly seen in individuals, not considered pathological.
Pathological Variations: Unusual structures or functional deviations stemming from disease or injury.