BIO 260 Human Anatomy Notes

Overview of Anatomy

• Anatomy (morphology): The study of structure.
• Subdivisions of anatomy:
  • Gross or macroscopic
    • Regional
    • Surface
    • Systemic
  • Microscopic
    • Cytology (study of cells)
    • Histology (study of tissues)
  • Developmental
    • Embryology

Specialized Branches of Anatomy

• Pathological anatomy: Study of structural changes in cells, tissues, and organs caused by disease.
• Radiographic anatomy: Study of internal body structures using X-rays and imaging techniques.
• Functional morphology: Study of functional properties of body structures and efficiency of design.

Essential Tools for Studying Anatomy

• Mastery of anatomical terminology
• Observation
• Palpation (feeling with hands)
• Manipulation
• Auscultation (listening to body sounds)

Principle of Complementarity

• Anatomy and physiology are inseparable.
• Function always reflects structure.
• What a structure can do depends on its specific form.

Levels of Structural Organization

• Chemical level: Atoms and molecules.
• Cellular level: Cells and their organelles.
• Tissue level: Groups of similar cells.
• Organ level: Contains two or more types of tissues.
• Organ system level: Organs that work closely together.
• Organismal level: All organ systems.

Organs and Organ Systems

• Example: The heart contains cardiac muscle, epithelial tissue, connective tissue, and neural tissue, all working together as a pump.

The 11 Human Organ Systems

• Integumentary
• Skeletal
• Muscular
• Nervous
• Endocrine
• Cardiovascular
• Lymphatic
• Respiratory
• Urinary
• Digestive
• Reproductive
• Note: The cardiovascular and lymphatic systems are together known as the circulatory system because of their roles in circulating fluids (blood and lymph).

Integumentary System

• Provides protection
• Regulates body temperature
• Site of cutaneous (skin) receptors
• Synthesizes Vitamin D
• Prevents water loss

Skeletal System

• Provides support and protection
• Site of hematopoiesis (blood cell production)
• Stores calcium and phosphorus
• Provides sites for muscle attachments

Muscular System

• Produces body movement
• Generates heat when muscles contract

Nervous System

• Responds to sensory stimuli
• Processes and initiates responses to muscles
• Controls body movement
• Responsible for intelligence, memory, and consciousness

Endocrine System

• Consists of glands and cell clusters that secrete hormones
• Maintains homeostasis (stability) of blood composition and volume
• Controls digestion
• Controls reproduction

Cardiovascular System

• Consists of the heart and blood vessels
• Distributes hormones, nutrients, and gases, and picks up waste products
• Moves blood to distribute oxygen, nutrients, etc.

Lymphatic System

• Transports and filters lymph fluid
• Participates in an immune response when necessary
• Lymph circulation aids in blood

Respiratory System

• Responsible for the exchange of gases between the blood and the air in the lungs

Urinary System

• Removes waste products from the blood
• Filters the blood
• Concentrates waste products in the urine
• Expels urine from the body

Digestive System

• Mechanically and chemically digests food materials
• Absorbs nutrients
• Expels waste products

Male Reproductive System

• Produces male sex cells (sperm)
• Produces male hormones
• Transfers sperm to the female

Female Reproductive System

• Produces female sex cells (oocytes/eggs)
• Produces female hormones
• Receives sperm from the male
• Site for fertilization, offspring development, and milk production

Organ Systems’ Interrelationships

• All cells depend on organ systems to meet their survival needs.
• Organ systems work cooperatively to perform necessary life functions.
• Examples:
  • Digestive system: Takes in nutrients, breaks them down, and eliminates unabsorbed matter (feces).
  • Respiratory system: Takes in oxygen and eliminates carbon dioxide.
  • Cardiovascular system: Via the blood, distributes oxygen and nutrients to all body cells and delivers wastes and carbon dioxide to disposal organs.
  • Urinary system: Eliminates nitrogenous wastes and excess ions.
  • Integumentary system: Protects the body as a whole from the external environment. Nutrients and wastes pass via the interstitial fluid between blood and cells.

Anatomical Terminology

• Anatomical Position

Anatomical Position

• Erect posture
• Facing forward
• Feet pointing forward
• Palms facing forward
• Left and right refer to the model’s (patient’s) left and right
• Supine: when face up
• Prone: when face down

Directional Terms

• Superior (cranial or cephalic): Toward the head
• Inferior (caudal): Toward the feet
• Medial: Toward the midline of the body
• Lateral: Toward the side of the body
• Ventral (anterior): Front side of body
• Dorsal (posterior): Back side of body
• Proximal: Closer to the attachment of a limb to the body trunk or to the point of origin of the body part
• Distal: Farther from the attachment of a limb to the body trunk or from the point of origin of the body part

More Anatomical Terms

• Superficial/cortex: Referring to the surface or outer layer of the body or an organ
• Deep/medulla: Referring to the inner layers or center of the body or an organ

Anatomical Planes

• Frontal (coronal) plane: Divides the body or organ into anterior and posterior parts.
• Sagittal plane: Divides the body or organ into left and right parts.
  • Midsagittal or median: On the midline
  • Parasagittal or sagittal: Not on the midline
• Transverse plane: Divides the body or organ into superior and inferior parts.

Organ Sectioning

• Cross-section: Planar cutting of an organ at a right angle to its axis.
• Longitudinal section: Planar cutting of an organ along its axis.
• Oblique section: Diagonal planar cutting of an organ with respect to its axis.

Major Body Cavities

• Dorsal aspect:
  • Cranial cavity
  • Vertebral (spinal) canal
• Ventral cavity (divided by diaphragm):
  • Thoracic cavity:
    • Pleural cavities
    • Pericardial cavity
    • Mediastinum
  • Abdominopelvic cavity:
    • Abdominal cavity
    • Pelvic cavity

Subdivisions of the Abdominopelvic Cavity

• Four quadrants: Used mostly by medical personnel.
• Nine regions: Used mostly by anatomists.

Major Organs of Abdominopelvic Quadrants

• Right Upper: liver, gall bladder, stomach, pancreas, small intestine, large intestine, right kidney
• Left Upper: liver, stomach, pancreas, spleen, small intestine, large intestine, left kidney
• Right Lower: small intestine, vermiform appendix, large intestine, bladder, reproductive organs
• Left Lower: small intestine, large intestine, bladder, reproductive organs

Smaller Body Cavities

• Oral cavity: The mouth
• Nasal cavity: Within the nose and posterior to it
• Orbital cavities: Openings for the eyes in the skull
• Middle ear cavities: Medial to the tympanic membrane (ear drum) in the skull
• Synovial cavities: Flexible joint cavities (e.g., shoulders, knees, hips)

Anatomical Variability

• Humans vary slightly in both external and internal anatomy.
• Over 90% of all anatomical structures match textbook descriptions, but:
  • Nerves or blood vessels may be somewhat out of place
  • Small muscles may be missing
  • Organ locations may be reversed (situs inversus)
• Extreme anatomical variations are seldom seen

Situs Inversus

• A condition where the internal organs are reversed or mirrored from their normal positions.
  • Example: Liver on the left, spleen on the right