Anatomy and Physiology

Anatomy and Physiology

Definitions of Anatomy and Physiology

  • Anatomy: The study of the structures of the body.
    • Etymology: The word "anatomy" comes from a Greek word meaning "to cut apart".
  • Physiology: The study of the function of the structures of the body.

Structure and Function Relationship

  • Structure: A complex anatomical part of a living thing.
  • Function: The activity of a structure, or how it works.
  • Key Concept: Specific anatomical structures enable the body to perform specific functions.
  • Example:
    • Structure: biceps brachii muscle
    • Function: Flexion of both the elbow joint and shoulder joint.

Types of Anatomy

  • Gross Anatomy: Study of structures visible to the naked eye.
  • Microscopic Anatomy: Study of structures not visible without magnification.
  • Importance: Different types of anatomy are helpful in different clinical situations.

Gross Anatomy Subfields

Systemic Anatomy
  • Focuses on studying organ systems, defined as groups of organs that perform a function.
Surface Anatomy
  • Study of superficial anatomical markings and their relationship to deeper structures.
    • Clinical Application:
    • Used to determine venipuncture sites.
    • Example: Median cubital vein for blood draw.
  • Lumbar Puncture: Procedure to collect cerebrospinal fluid, typically performed between L3 and L4 vertebrae. Used for diagnosing central nervous system infections.
Regional Anatomy
  • Study of specific areas of the body, such as the neck, where multiple organ systems intersect.
  • Surgical application: Requires in-depth knowledge of regional anatomy for successful procedures.

Developmental Anatomy and Embryology

  • Developmental Anatomy: Study of anatomical changes from conception to maturity.
  • Embryology: Specifically focuses on development from conception to 8 weeks.

Comparative Anatomy

  • Examines anatomical similarities in different animals, demonstrating common evolutionary ancestry.
  • Example: A limb structure with five digits shared by most animals indicates evolutionary connections.

Microscopic Anatomy: Cytology and Histology

  • Cytology: The study of cells.
  • Histology: The study of tissues, defined as groups of cells working together.
    • Clinical Correlation: Used in diagnosing cervical precancer. Cytology examines individual cells, while histology examines biopsied tissue.

Levels of Organization of the Body

  1. Atoms
  2. Molecules
  3. Cells
  4. Tissues
  5. Organs
  6. Organ systems
  7. Organism
  • Each level of organization is constructed from the preceding one.
Chemical/Molecular Level
  • Atoms combine to form molecules (organic/inorganic).
Cellular Level
  • Cells secrete and regulate.
Tissue Level
  • Tissues with specialized functions:
    • Epithelial Tissue: Covers surfaces, lines internal passageways, produces secretions.
    • Connective Tissue: Provides support, fills internal spaces, stores energy.
    • Muscle Tissue: Contracts to produce movement.
    • Nervous Tissue: Conducts electrical impulses.
Organ Level
  • Organs formed from combined tissues.
Organ System Level
  • Organ systems interact to perform complex functions, e.g., cardiovascular system includes heart, blood vessels, and blood.

Anatomical Position

  • Definition: Standing with legs together, hands at sides, palms facing forward.
  • Positions:
    • Supine Position: Lying face up (like holding a bowl of soup).
    • Prone Position: Lying face down.

Anatomical Directions

  • Definition: Describes the position of body parts relative to one another, using the anatomical position as a reference.
  • Common Directions:
    • Superior/Cephalic/Cranial: Towards the head.
    • Inferior/Caudal: Towards the feet.
    • Anterior/Ventral: Towards the front.
    • Posterior/Dorsal: Towards the back.
    • Medial: Towards the midline.
    • Lateral: Away from midline.
    • Proximal: Towards the point of attachment.
    • Distal: Away from point of attachment.
    • Superficial: Near surface.
    • Deep: Away from surface.
    • Ipsilateral: Same side as reference point.
    • Contralateral: Opposite side from reference point.

Anatomical Sections and Planes

  • Definition: A section is a cut through the body, which forms a plane.
Common Sections and Planes:
  1. Cross/Transverse Plane: Divides body into superior and inferior parts.
  2. Sagittal Plane: Divides body into right and left parts, includes:
    • Midsagittal: Divides down the midline.
    • Parasagittal: Divides lateral to midline.
  3. Coronal/Frontal Plane: Divides into anterior and posterior parts.
Other Section Types:
  • Longitudinal Section: Cut along the long axis of a structure.
  • Oblique Section: Cut through a structure at an angle.

Clinical Correlation of Anatomical Sections

  • Utilized in imaging studies such as X-rays, CT scans, MRIs, and ultrasounds.
  • Observations are made from a perspective where the patient is positioned supine, creating left-right inversions in images.

Body Cavities

  • Body Cavity: Space in the body that houses organs.
Major Body Cavities:
  1. Anterior/Ventral Cavity: Divided into:
    • Thoracic Cavity: Contains pleural (lungs) and mediastinal spaces (heart, trachea).
    • Abdominopelvic Cavity: Contains abdominal organs (digestive system) and pelvic organs (reproductive systems).
  2. Posterior/Dorsal Cavity: Contains cranial cavity (brain) and spinal cavity (spinal cord).
Abdominopelvic Quadrants
  • The abdomen and pelvis can be further divided into 4 quadrants:
    1. Right Upper Quadrant (RUQ): Contains liver.
    2. Left Upper Quadrant (LUQ): Contains stomach.
    3. Right Lower Quadrant (RLQ): Contains appendix.
    4. Left Lower Quadrant (LLQ): Contains sigmoid colon.
  • Clinical importance in diagnosing pain or diseases.

Major Regions of the Body and Anatomical Names

  • Learning major regions and their Greek/Latin names is essential for proficient communication in anatomy.
    • Example: "Brachium" refers to the upper arm (biceps brachii, triceps brachii, brachial artery).
  • Anatomical names have singular and plural forms.
Singular and Plural Endings
  • Changes in endings follow patterns:
    • Singular: -um or -on; Plural: -a (e.g., epithelium -> epithelia).
    • Variations exist based on specific terms (e.g., nucleus -> nuclei).
Application of Related Terminology
  • Understanding anatomical landmarks and corresponding names enhances anatomical precision in communication.
  • Examples include facies (face), thorax (chest), and inguinal (groin).