Anatomy and Physiology: Introduction

Madison Sutheran Information

• Madison Sutheran holds the qualifications of Hon BSc., RDH, and CAE
• Email: [email protected]
• She teaches preclinic, term 1,2,3 theory, and in clinic
• Hon. BSc. obtained from Trent University
• Dental hygiene education at Dalhousie University
• Canadian College of Educators for CAE

Learning Objectives

• Define anatomy and physiology and comprehend their relationship
• List and discuss the levels of organization in the body in order of increasing complexity
• Define anatomical position
• List and define principal directional terms/sections/planes, used to describe the body and relationships between body parts
• List the nine abdominopelvic regions and the abdominopelvic quadrants
• List the major cavities of the body with their subdivisions
• List the major organs contained in each cavity
• Discuss and contrast the axial and appendicular subdivisions of the body and identify specific anatomical areas in each
• Explain homeostasis and provide an example of a homeostatic mechanism
• Understand the difference between positive and negative feedback loops, with examples of each

Anatomy and Physiology

• Anatomy is the study of the structure of an organism and the relationships of its parts
• Physiology is the study of the functions of living organisms and their parts
• Key question: What is the relationship between anatomy and physiology? OR What is the relationship between structure and function?

Structural Levels of Organization

• The body is organized into various levels:
• Chemical level: Includes atoms and molecules
• Cells: Smallest "living" units, made of various chemicals, performing structure and function in the body
• Tissues: Similar cells working together for a common function
• Organs: Different kinds of tissues working together for a common function
• Organ Systems: Many different organs working together for a common function
• Organism: A living thing

Anatomical Position

• Standing erect, arms at sides, palms forward, head and feet also pointing forward

Other Positions

• Supine: Body lying face upward
• Prone: Body lying face downward

Anatomical Directions

• Anatomical directions describe the position of one body part in relation to another:
• Superior: Toward the head, upper, above
• Inferior: Toward the feet, lower, below
• Anterior: Front, in front of (aka ventral in humans)
• Posterior: Back, in back of (aka dorsal in humans)
• Medial: Toward the midline of a structure/the body
• Lateral: Away from the midline or toward the side of a structure/the body
• Proximal: Toward or nearest the trunk, or nearest the point of origin of a structure. Trunk is the main body part
• Distal: Away from or farthest from the trunk, or farthest from a structure’s point of origin
• Superficial: Nearer the body surface. Superficial injuries occur here
• Deep: Farther away from the body surface, going towards the inside of the body

Anatomical Direction Opposites

• Superior / Inferior
• Anterior / Posterior
• Medial / Lateral
• Proximal / Distal
• Superficial / Deep

Planes and Body Sections

• Subdivide the body to specifically describe location
• Sagittal Plane: Lengthwise plane dividing body into right and left sections
• Midsagittal Plane: Divides the body into two equal halves
• Frontal (Coronal) Plane: Lengthwise plane that divides the body into anterior and posterior sections
• Transverse Plane: Horizontal plane dividing body into upper and lower sections

Body Cavities

• Body cavities are compartments/open spaces housing the organs.
• The two major body cavities:
• Ventral
• Dorsal

Ventral Body Cavity

• Ventral cavity is located at the front of the body, towards the belly
• It is divided into an upper and lower section by the diaphragm (a muscle):
• Upper section: Thoracic cavity (chest)
• Lower section: Abdominopelvic cavity

Ventral Body Cavity: Upper Section

• Thoracic cavity:
• Mediastinum: A mid-portion of the thoracic cavity where the heart and trachea are located
• Pleural cavities:
  • The right lung is located in the right pleural cavity
  • The left lung is in the left pleural cavity

Ventral Body Cavity: Lower Section

• Abdominopelvic cavity:
• Abdominal cavity: Contains the stomach, intestines, liver, gallbladder, pancreas, and spleen
• Pelvic cavity: Contains reproductive organs, urinary bladder

Abdominopelvic Regions and Quadrants

• The abdominopelvic cavity is large, and is further subdivided to describe locations within it, into upper/middle/lower regions.
• These regions are subdivided into a left, right and one central region.
• The nine regions comprise:
  • Right and left hypochondriac regions
  • Epigastric region
  • Right and left lumbar regions
  • Umbilical region
  • Right and left iliac (inguinal) regions
  • Hypogastric region

Abdominopelvic Quadrants

• The abdominopelvic cavity can also be divided into four quadrants
• Right upper/superior
• Right lower/inferior
• Left upper/superior
• Left lower/inferior

Dorsal Body Cavity

• Dorsal cavity is located at the back of the body
• Divided into two cavities:
  • Cranial cavity: Contains the brain
  • Spinal cavity: Contains the spinal cord

Body Regions

• Another way to subdivide the body:
  • Axial region (axial = axis, Midcenter): Head, neck, torso/trunk
  • Appendicular region (appendicular = appendages): Upper and lower extremities (Arms / Legs)

The Balance of Body Functions

• An organism's survival depends on the maintenance or restoration of homeostasis
• Homeostasis: relative constancy of the internal environment (Body likes certain temperature / comfortable, constant)
• Feedback loops: The body uses negative (more often) and positive (less often) feedback loops to maintain or restore homeostasis (Help body deal with changes)

Homeostasis Loops

• Negative feedback loops help to maintain a stable internal environment
• Positive feedback loops amplify processes quickly. These are normally useful in processes that need amplified completion.
  • Labour
  • Blood Clotting

Further Points

• All organs function to maintain homeostasis
• Body functions are related to age
• Peak efficiency is during young adulthood
• Diminishing efficiency occurs after young adulthood