Introduction to Anatomy & Physiology

This study guide provides foundational concepts in anatomy and physiology, focusing on definitions, organization, requirements for life, homeostasis, and anatomical terminology. Mastery of these topics is essential for success in college-level Anatomy & Physiology courses.

Vocabulary and Key Definitions

Essential Terms in Anatomy & Physiology

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

• Physiology: The study of the function of the body and how its parts work to carry out life-sustaining activities.

• Gross Anatomy: The study of large body structures visible to the naked eye.

• Regional Anatomy: The study of all structures in a particular region of the body.

• Surface Anatomy: The study of internal structures as they relate to the overlying skin surface.

• Cytology: The study of cells.

• Histology: The study of tissues.

• Cell: The basic structural and functional unit of living organisms.

• Tissue: Groups of similar cells that perform a common function.

• Organ: A structure composed of at least two tissue types that performs a specific function.

• Organ System: A group of organs that work together to accomplish a common purpose.

• Organism: The living being that has a cellular structure and can independently perform all physiologic functions necessary for life.

• Homeostasis: The maintenance of relatively stable internal conditions despite continuous changes in the environment.

Form (Anatomy) Determines Function (Physiology)

Relationship Between Structure and Function

• Anatomy is the study of the structure of body parts and their relationships to each other.

• Physiology is the study of the function of body parts.

• The principle of complementarity of structure and function states that function always reflects structure; what a structure can do depends on its specific form.

• Example: The structure of bones makes them strong and able to support body weight; the thin walls of air sacs in the lungs allow for gas exchange.

Topics of Anatomy

Major Subdivisions

• Gross (Macroscopic) Anatomy: Study of large body structures visible to the naked eye.

• Approaches to gross anatomy:

  • Regional Anatomy: All structures in a particular region (e.g., abdomen).

  • Systemic Anatomy: Body structure studied system by system (e.g., cardiovascular system).

  • Surface Anatomy: Study of internal structures as related to the skin surface.

• Microscopic Anatomy: Study of structures too small to be seen with the naked eye.

  • Cytology: Study of cells.

  • Histology: Study of tissues.

• Developmental Anatomy: Study of structural changes throughout the lifespan.

Topics of Physiology

Subdivisions and Focus

• Physiology is often divided by organ systems (e.g., renal physiology, neurophysiology).

• Focuses on cellular and molecular events that underlie organ system function.

• Structure and function are inseparable; physiological processes depend on anatomical structures.

Body Organization

Levels of Structural Organization

• From simplest to most complex:

  1. Chemical level (atoms, molecules)

  2. Cellular level (cells)

  3. Tissue level (groups of similar cells)

  4. Organ level (contains two or more types of tissues)

  5. Organ system level (organs that work closely together)

  6. Organismal level (all organ systems combined to make the whole organism)

• Example: Atoms form molecules, which make up cells; cells form tissues; tissues form organs; organs form organ systems; organ systems form the organism.

Requirements for Life

Necessary Life Functions

• Maintaining boundaries: Separation between internal and external environments (e.g., plasma membranes, skin).

• Movement: Of body parts (skeletal muscle), substances (cardiac and smooth muscle).

• Responsiveness (Excitability): Ability to sense and respond to stimuli (e.g., withdrawal reflex, control of breathing rate).

• Digestion: Breakdown of ingested foodstuffs to simple molecules that can be absorbed.

• Metabolism: All chemical reactions in the body (catabolism and anabolism).

• Excretion: Removal of wastes (e.g., urea, carbon dioxide, feces).

• Reproduction: Cellular division for growth or repair; production of offspring.

• Growth: Increase in size of a body part or organism.

Survival Needs

• Nutrients

• Oxygen

• Water

• Normal body temperature

• Appropriate atmospheric pressure

Homeostasis

Definition and Importance

• Homeostasis: Maintenance of a stable internal environment despite external changes.

• Dynamic state of equilibrium; involves continuous monitoring and regulation.

• Maintained by negative feedback mechanisms.

• Imbalance leads to increased risk of disease.

Homeostatic Control Mechanisms

• Three main components:

  1. Receptor: Monitors environment and responds to stimuli.

  2. Control Center: Determines set point, analyzes input, and determines response.

  3. Effector: Carries out the control center's response to the stimulus.

• Negative Feedback: Response reduces or shuts off the original stimulus (e.g., regulation of body temperature, blood glucose).

• Positive Feedback: Response enhances or exaggerates the original stimulus (e.g., labor contractions, blood clotting).

Negative Feedback Loop Example

Anatomical Terms

Directional Terms

• Used to describe the location of one body part relative to another.

• Examples: superior (above), inferior (below), anterior (front), posterior (back), medial (toward midline), lateral (away from midline), proximal (closer to origin), distal (farther from origin).

Body Planes

• Sagittal Plane: Divides the body into right and left parts.

  • Midsagittal (median): Lies on the midline.

  • Parasagittal: Not on the midline.

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

• Transverse (Horizontal) Plane: Divides the body into superior and inferior parts.

Body Cavities

• Dorsal Body Cavity: Protects the nervous system; includes cranial and vertebral cavities.

• Ventral Body Cavity: Houses internal organs (viscera); includes thoracic and abdominopelvic cavities.

Summary Table: Levels of Organization

Key Equations and Concepts

• Homeostatic Regulation (Generalized):

• Metabolism: Sum of all chemical reactions in the body.

• Negative Feedback Example: Regulation of blood glucose by insulin.

• Positive Feedback Example: Enhancement of labor contractions by oxytocin.

Additional info:

• Students are encouraged to use flashcards and practice anatomical terms regularly for mastery.

• Understanding the principle of complementarity is crucial: structure and function are always linked in biology.