Introduction to Anatomy & Physiology: Core Concepts and Terminology

How to Succeed in This Class

• Use the weekly checklists to stay organized and on track with course material.

Characteristics of Living Organisms

Living organisms share several fundamental characteristics that distinguish them from non-living matter.

• Cellular Composition: All living things are composed of one or more cells, which are the basic units of life.

• Metabolism: The sum of all chemical reactions in the body, including anabolic (building up) and catabolic (breaking down) processes.

• Growth and Development: Increase in size (hypertrophy), number of cells (hyperplasia), and progression through life stages.

• Excretion: Removal of waste products; kidneys and lungs are key excretory organs.

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

• Movement: Includes movement of the organism and movement within the organism (e.g., blood flow).

• Reproduction: Production of new cells or organisms.

Levels of Organization of the Human Body

The human body is organized into hierarchical levels, from the simplest to the most complex.

• Chemical or Molecular Level: Atoms and molecules essential for life.

• Cellular Level: Cells are the smallest living units.

• Tissue Level: Groups of similar cells performing a common function. Four basic tissue types: epithelial, connective, muscle, and nervous.

• Organ Level: Structures composed of two or more tissue types working together (e.g., heart, liver).

• System Level: Groups of organs that perform related functions (e.g., digestive system).

• Organism Level: The complete living being.

System, Organs, and Primary Functions Table

This table classifies the major organ systems, their primary organs, and main functions.

System	Organs	Primary Function(s)
1. Integumentary	Skin, hair, nails	Protection, temperature regulation, sensation
2. Skeletal	Bones, joints	Support, protection, movement, blood cell production
3. Muscular	Skeletal muscles	Movement, posture, heat production
4. Nervous	Brain, spinal cord, nerves	Control, coordination, response to stimuli
5. Endocrine	Pituitary, thyroid, adrenal glands, pancreas	Hormone production, regulation of metabolism
6. Cardiovascular	Heart, blood vessels	Transport of nutrients, gases, wastes
7. Lymphatic/Immune	Lymph nodes, spleen, thymus	Defense against pathogens, fluid balance
8. Respiratory	Lungs, trachea, bronchi	Gas exchange (O2/CO2)
9. Digestive	Stomach, intestines, liver, pancreas	Breakdown and absorption of nutrients
10. Urinary	Kidneys, bladder, ureters	Excretion of wastes, fluid and electrolyte balance
11. Reproductive	Ovaries, testes, uterus, prostate	Production of offspring

Definitions

• Biology: The study of living organisms and life processes.

• Anatomy: The study of the structure of body parts and their relationships to one another.

Scientific Method: Observe, develop a hypothesis, experiment, accept/modify/reject hypothesis.

• Gross Anatomy: Study of structures visible to the naked eye (surface, regional, systemic anatomy).

• Microscopic Anatomy: Study of structures too small to be seen without a microscope (cytology, histology).

Medical Terminology

Understanding medical terminology is essential for communication in anatomy and physiology.

• Roots: adipos (fat), arthros (joint), chondros (cartilage), osteo (bone), cardio (heart), cost (rib)

• Prefixes: a- (without), intra- (within), peri- (around), epi- (on), inter- (between), intra- (within)

• Suffixes: -blast (precursor), -itis (inflammation), -algia (pain), -cyte (cell)

• Example: Pathology: path- (disease) + -ology (study of) = study of disease

Body Positions

• Anatomical Position: Body standing upright, facing forward, arms at sides, palms facing forward.

• Prone: Lying face down.

• Supine: Lying face up.

Directional Terminology

Directional terms describe the locations of structures relative to other structures or locations in the body.

• Ventral/Dorsal: Front (belly side) / Back (spine side)

• Anterior/Posterior: Front / Back

• Medial/Lateral: Toward the midline / Away from the midline

• Proximal/Distal: Closer to / farther from the point of attachment (used for limbs)

• Superficial/Deep: Toward the surface / Away from the surface

• Superior/Inferior: Above / Below

Example: The thumb is lateral to the little finger. The lungs are superior to the diaphragm.

Regional Terms to Know

• Head/Neck: cranial, occipital, frontal, nasal, oral, buccal, mental, occipital, mammary, sternal

• Upper Limb: axillary, brachial, antecubital, antebrachial, carpal, pollex

• Trunk: vertebral, cervical, thoracic, lumbar, sacral, abdominal, pelvic

• Lower Limb: femoral, patellar, popliteal, crural, tarsal, calcaneal, plantar

Body Planes

• Sagittal: Divides body into right and left parts

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

• Transverse: Divides body into superior and inferior parts

Body Cavities

Body cavities protect organs and allow movement.

• Dorsal Cavity: Cranial cavity (brain), vertebral cavity (spinal cord)

• Ventral Cavity: Thoracic cavity (mediastinum, pericardial, pleural cavities), abdominopelvic cavity (abdominal, pelvic cavities)

Note: The diaphragm separates the thoracic cavity from the abdominopelvic cavity.

Abdominal Quadrants/Regions

• Right Upper Quadrant (RUQ): Liver, gallbladder, portions of small/large intestine

• Left Upper Quadrant (LUQ): Stomach, pancreas, spleen

• Right Lower Quadrant (RLQ): Appendix, portions of small/large intestine, right ovary, right ureter

• Left Lower Quadrant (LLQ): Portions of small/large intestine, left ovary, left ureter

9 Abdominopelvic Regions: Epigastric, Umbilical, Hypogastric, R/L hypochondriac, R/L lumbar, R/L iliac (inguinal)

Membranes

• Visceral: Covers organs

• Parietal: Lines cavity walls

• Fluid: Reduces friction between membranes

Core Principles in Anatomy & Physiology

Homeostasis & Feedback Loops

Homeostasis is the maintenance of a stable internal environment. Feedback loops are critical for life.

• Feedback loops involve: 1) stimulus, 2) receptor/sensor, 3) control center, 4) effectors, 5) responses

Negative Feedback Loop

• The body counteracts the change to maintain balance.

• Example: Thermoregulation: When body temperature rises, receptors stimulate the hypothalamus, which causes blood vessels to dilate and sweat glands to activate, lowering temperature.

• Blood glucose regulation: Insulin lowers blood glucose; glucagon raises it.

Positive Feedback Loop

• The body enhances the change.

• Examples: Blood clotting, labor/delivery (oxytocin release).

Core Principle Two: Structure & Function

• Structure and function are related at all levels of organization.

Core Principle Three: Gradients Drive Physiological Processes

• Gradients of temperature, concentration, and pressure drive many physiological processes.

Core Principle Four: Cell-Cell Communication

• Cells communicate via action potentials, hormones, and chemicals to coordinate body functions.

Common Medical Imaging Tests

• Radiography (X-ray): Uses X-rays to view dense tissues (bones appear white). Barium contrast X-rays highlight organs like the GI tract.

• Sonography (Ultrasound): Uses sound waves; commonly used for imaging soft tissues and during pregnancy.

• CT Scan: Computed tomography provides detailed cross-sectional images; better for soft tissues than X-rays.

• MRI: Magnetic resonance imaging uses magnetic fields to image soft tissues, especially the brain, muscles, and joints.

• PET Scan: Positron emission tomography shows metabolic activity; used to detect cancer and brain disorders.