Anatomy and Physiology Fundamentals

• Anatomy is the study of structure while physiology is the study of function

Levels of Organization

• The chemical level consists of atoms and molecules
• The cellular level consists of cells, the smallest living unit in the body
• Tissues are organizations of cells performing a common function
• Organs are organizations of tissues performing a common function
• Organ systems are organizations of organs performing a common function
• An organism is the body as a whole

Anatomical Position

• Erect standing posture, arms at the sides, palms facing forward, head and feet facing forward
• Discussions of movement, posture, and relationships among body parts use this as a reference
• In the Supine position the body lies face upward
• In the Prone position the body lies face downward

Anatomical Directions

• Superior means toward the head, upper, or above
• Inferior means toward the feet, lower, or below
• Anterior means front, in front of (aka ventral)
• Posterior means back, in back of (aka dorsal)
• Medial means toward the midline of the body
• Lateral means toward the side of the body (away from its midline)
• Proximal means toward or nearest the trunk of the body or the point of origin of a body part
• Distal means away from or farthest from the trunk or the point of origin of a body part
• Superficial means nearer the surface
• Deep means farther away from the body surface, going towards the internals of the body

Planes of the Body

• Planes are used to subdivide the body into smaller parts to describe locations more specifically
• The Sagittal plane divides the body into right and left parts; the midsagittal divides it exactly in half
• The Frontal plane divides the body into anterior and posterior parts
• The Transverse plane divides the body into superior and inferior parts

Body Cavities

• Body cavities are compartments or open spaces that house the organs
• The two major body cavities are the ventral and dorsal body cavities

Ventral Cavity - Upper

• The thoracic cavity (chest), has a midportion called the mediastinum
• The mediastinum houses the trachea and heart
• The right and left pleural cavities house the lungs

Ventral Cavity - Lower

• The abdominopelvic cavity can be divided into the abdominal cavity, and the pelvic cavity
• The abdominal cavity houses the stomach, intestine, liver, gallbladder, pancreas and spleen
• The pelvic cavity houses reproductive organs, the bladder, and the lowest part of the intestines

Nine Regions of the Abdominopelvic Area

• Right Hypochondriac Region is located (hypo = below) (chondro = cartilage)
• Epigastric Region is located (epi = above) (gastric - stomach or Gastrointestinal)
• Left Hypochondriac Region
• Right Lumbar Region is located (lumbar = lower back)
• The Umbilical Region is located (umbilical = belly button)
• Left Lumbar Region
• Right Iliac (inguinal) Region is located (iliac = part of hip)
• Hypogastric Region
• Left Iliac (inguinal) Region is located (inguinal = groin)

Four Quadrants of the Abdominopelvic Cavity

• The four quadrants are the Upper Right, Upper Left, Lower Right, and Lower Left

Dorsal Body Cavity

• The Cranial Cavity is the space inside the skull that contains the brain
• The Spinal Cavity is the space inside the spinal cavity that contains the spinal cord

Body Regions

• Body regions divide into Axial and appendicular divisions
• The axial regions are the head, the neck, and the torso/trunk
• The appendicular regions are the upper and lower extremities
• In anatomical directions, ‘right’ refers to the subject’s right

Balance of Body Functions

• Homeostasis is the relative uniformity/constancy of the normal body’s internal environment

Two Types of Feedback Loops

• Negative feedback loops cause change in the opposite direction of the initial stimulus, diminishing/halting the original stimulus
• Positive feedback loops cause change in the same direction as the original stimulus, causing amplification

Review Exercises - True or False

• The cell is the smallest living structural unit of the body (True)
• An organ is a group of several types of cells working together to perform a specific function (False)
• Anatomical position is the reference position for directional terms (True)
• The body lies face down in the prone position (True)
• The body lies face up in the supine position (True)
• Anterior and proximal are opposite terms (False)
• Because humans walk upright, ventral and anterior mean the same thing (True)
• The foot is proximal to the knee (FALSE)
• A sagittal section divides the body into right and left parts (True)
• The two major cavities of the body are the dorsal and ventral cavities (True)
• The brain and spinal cord are in the dorsal cavity (True)
• The middle abdominopelvic area contains the umbilical region (True)
• The effector in a negative feedback loop moves the regulated condition back to “normal” (True)
• Contraction of the uterus during childbirth is an example of a positive feedback loop (True)
• The arms and legs are part of the appendicular body portion (True)

Review Exercises - Matching

• Toward the head, upper or above : Superior
• Toward the midline of the body : Medial
• In humans, this term means the same as ventral : Anterior
• Nearest to the point of origin : Proximal
• Toward the back of the body : Posterior
• Nearest the surface of the body : Superficial
• Toward the side of the body : Lateral