Foundations of Anatomy & Physiology: Organization, Terminology, and Tissue Types

Introduction to Anatomy & Physiology

Anatomy is the study of body structure, including the relationships among body parts, while physiology focuses on the functions and mechanisms in the body. These disciplines are closely related, as structure supports function.

Branches of Anatomy

• Microscopic Anatomy: Study of structures not visible without magnification.

• Cytology: Study of individual cells.

• Histology: Study of tissues, which are groups of specialized cells.

• Developmental Anatomy: Examines structural changes over time, including embryology (study of early developmental stages).

• Comparative Anatomy: Compares anatomical similarities and differences among species.

• Clinical Anatomy: Focuses on pathological changes during illness.

• Macroscopic (Gross) Anatomy: Study of structures visible without magnification, including:

  • Surface Anatomy: Superficial anatomical markings.

  • Regional Anatomy: Structures in a specific area (e.g., head, neck, trunk).

  • Systemic Anatomy: Organ systems (e.g., digestive, cardiovascular).

  • Surgical Anatomy: Landmarks important for surgery.

  • Radiographic Anatomy: Structures visualized by imaging (X-ray, CT, MRI).

Levels of Organization in the Human Body

The human body is organized into hierarchical levels, each building on the previous:

1. Chemical Level: Atoms and molecules (e.g., water, proteins, lipids, carbohydrates).

2. Cellular Level: Cells and their organelles; the basic unit of life.

3. Tissue Level: Groups of similar cells and their extracellular matrix (e.g., epithelial, muscle, neural, connective tissues).

4. Organ Level: Combination of tissues forming organs (e.g., heart, stomach).

5. Organ System Level: Groups of organs working together (e.g., digestive system).

6. Organism Level: All organ systems functioning together to maintain life.

Characteristics of Living Things

• Responsiveness (Irritability): Ability to detect and respond to stimuli.

• Adaptability: Capacity to adjust to new conditions.

• Growth: Increase in size or number of cells.

• Differentiation: Specialization of cells for specific functions.

• Reproduction: Production of new organisms or cells.

• Movement: Internal (e.g., blood flow) and external (e.g., walking).

• Metabolism: All chemical reactions in the body, including:

  • Anabolism: Building complex molecules from simpler ones (requires energy).

  • Catabolism: Breaking down complex molecules into simpler ones (releases energy).

• Absorption: Uptake of substances by cells.

• Respiration: Exchange and use of oxygen by cells.

• Digestion: Breakdown of food for absorption.

• Excretion: Removal of waste products.

Anatomical Terminology

Body Regions

The body is divided into specific regions for anatomical reference. Key regions include:

• Cephalic (head)

• Cervical (neck)

• Thoracic (chest)

• Abdominal (abdomen)

• Brachial (upper arm)

• Femoral (thigh)

• Crural (leg)

• Carpal (wrist)

• Tarsal (ankle)

Refer to anatomical diagrams for detailed labeling of all regions.

Abdominopelvic Quadrants

• RUQ (Right Upper Quadrant): Liver, gallbladder, right kidney, portions of stomach, small and large intestine.

• LUQ (Left Upper Quadrant): Stomach, spleen, left lobe of liver, pancreas, left kidney, portions of large intestine.

• RLQ (Right Lower Quadrant): Cecum, appendix, right ovary/spermatic cord, portions of small and large intestine.

• LLQ (Left Lower Quadrant): Left ovary/spermatic cord, most of small intestine, portions of large intestine.

Directional Terms

• Superior vs. Inferior: Above vs. below (e.g., head is superior to chest).

• Anterior (Ventral) vs. Posterior (Dorsal): Front vs. back (e.g., navel is on the anterior surface).

• Medial vs. Lateral: Toward the midline vs. away from the midline (e.g., nose is medial to ears).

• Proximal vs. Distal: Closer to vs. farther from the point of attachment (e.g., shoulder is proximal to elbow).

• Superficial vs. Deep: Closer to vs. farther from the body surface (e.g., skin is superficial to bones).

Body Planes and Sections

• Sagittal Plane: Divides body into right and left portions.

• Midsagittal: Cut exactly at the midline.

• Parasagittal: Cut off the midline.

• Frontal (Coronal) Plane: Divides body into anterior and posterior parts.

• Transverse Plane: Divides body into superior and inferior parts (cross-section).

• Oblique Cut: At an angle.

Body Cavities

Body cavities are internal spaces that house and protect organs.

• Ventral (Anterior) Cavity:

  • Thoracic Cavity: Contains heart, lungs, major vessels.

  • Pericardial Cavity: Contains the heart, surrounded by the pericardium.

  • Abdominopelvic Cavity: Below the diaphragm; contains abdominal and pelvic organs.

  • Abdominal Cavity: Stomach, intestines, spleen, liver, etc.

  • Pelvic Cavity: Bladder, reproductive organs.

• Posterior (Dorsal) Cavity:

  • Cranial Cavity: Brain.

  • Vertebral (Spinal) Cavity: Spinal cord.

Membranes line body cavities and organs:

• Visceral membrane: Covers organs (e.g., visceral pleura, pericardium, peritoneum).

• Parietal membrane: Lines cavity walls (e.g., parietal pleura, pericardium, peritoneum).

Common Anatomical Prefixes, Suffixes, and Terms

Term	Meaning
Endo-	Inside, within
Hyper-	Excessive, above normal
Osteo-	Bone
Myo-	Muscle
Neuro-	Nerve
Cardio-	Heart
Pulmo-	Lungs
Visceral	Organs of chest/abdomen
Parietal	Wall of a cavity
Bilateral	Both sides of the body
Unilateral	One side of the body
Medulla	Inside
Cortex	Outside
Infer-	Below
Supra-	Above
Inter-	Between
Common	Shared

Chapter 3: Tissue Level of Organization

A tissue is a group of similar cells and extracellular products that perform a common function. The extracellular matrix is produced by cells and surrounds them, usually including liquid, proteins, and fibers. Tissues are classified into four main types:

1. Epithelial Tissue: Covers body surfaces, lines cavities, and forms glands.

2. Connective Tissue: Supports, binds, and protects other tissues and organs.

3. Muscle Tissue: Responsible for movement.

4. Nervous Tissue: Initiates and transmits electrical impulses.

Epithelial Tissue

• Lines every body surface and inside all body cavities (e.g., skin, lining of digestive tract).

• Functions include protection, absorption, secretion, and sensation.

• Cells are closely packed with minimal extracellular matrix.

• Arranged in sheets; avascular but innervated.

• Classified by number of layers (simple, stratified) and cell shape (squamous, cuboidal, columnar).

Examples:

• Simple squamous epithelium: Single layer of flat cells (e.g., lining of blood vessels).

• Stratified squamous epithelium: Multiple layers for protection (e.g., skin epidermis).

• Columnar epithelium: Tall, column-shaped cells (e.g., lining of intestines).

Additional info: Epithelial tissue may form glands (endocrine and exocrine) and is involved in selective permeability and surface specialization (e.g., cilia, microvilli).