Introduction to Anatomy

• Anatomy is the study of the structure of living organisms.
• It includes the study of cells, tissues, organs, and systems of the body.

Subdivisions of Anatomy

• Gross Anatomy (Macroscopic Anatomy): The study of structures visible to the naked eye.
• Microscopic Anatomy (Histology): The study of structures at the microscopic level.
• Developmental Anatomy: The study of changes in structure from conception to adulthood.
• Surface Anatomy: The study of external features and their relation to internal organs.
• Comparative Anatomy: The study of the anatomy of different species to understand evolutionary relationships.
• Systemic Anatomy: The study of the body by organ systems.
• Regional Anatomy: The study of the body by regions (e.g., head, neck, thorax).

Anatomical Position

• Anatomical position is a standardized reference point.
• Body is erect, feet flat, arms at the sides, palms facing forward.

Anatomical Planes

• Sagittal Plane: Divides the body into right and left parts.
  • Midsagittal (median) plane divides the body into equal right and left halves.
  • Parasagittal plane is offset from the midline.
• Frontal (Coronal) Plane: Divides the body into anterior (front) and posterior (back) parts.
• Transverse (Horizontal) Plane: Divides the body into superior (upper) and inferior (lower) parts.
• Oblique Plane: Passes through the body at an angle.

Anatomical Directions

• Superior (Cranial or Cephalic): Towards the head or upper part of a structure.
• Inferior (Caudal): Away from the head or towards the lower part of a structure.
• Anterior (Ventral): Towards the front of the body.
• Posterior (Dorsal): Towards the back of the body.
• Medial: Towards the midline of the body.
• Lateral: Away from the midline of the body.
• Proximal: Closer to the point of attachment or origin.
• Distal: Farther from the point of attachment or origin.
• Superficial (External): Closer to the surface of the body.
• Deep (Internal): Away from the surface of the body.

Body Cavities

• Dorsal Body Cavity: Located near the posterior (dorsal) side of the body.
  • Cranial Cavity: Contains the brain.
  • Vertebral (Spinal) Cavity: Contains the spinal cord.
• Ventral Body Cavity: Located near the anterior (ventral) side of the body.
  • Thoracic Cavity: Enclosed by the ribs and contains the heart and lungs.
    • Pleural Cavities: Each surrounds a lung.
    • Mediastinum: Central region of the thoracic cavity, containing the heart, great vessels, trachea, and esophagus.
      • Pericardial Cavity: Surrounds the heart.
  • Abdominopelvic Cavity: Inferior to the thoracic cavity and separated by the diaphragm.
    • Abdominal Cavity: Contains the stomach, intestines, liver, and other organs.
    • Pelvic Cavity: Contains the urinary bladder, portions of the intestines, and internal reproductive organs.

Serous Membranes

• Serous membranes line the walls of the ventral body cavities and cover the organs within them.
• Parietal Layer: Lines the cavity walls.
• Visceral Layer: Covers the organs.
• Serous Fluid: Lubricates the space between the parietal and visceral layers, reducing friction.
• Examples:
  • Pleura: Lines the pleural cavities and covers the lungs.
  • Pericardium: Lines the pericardial cavity and covers the heart.
  • Peritoneum: Lines the abdominopelvic cavity and covers the organs within it.

Integumentary System

• Skin, hair, nails, and associated glands.
• Protection, temperature regulation, sensation, and vitamin D synthesis.

Skeletal System

• Bones, cartilage, ligaments, and bone marrow.
• Support, protection, movement, mineral storage, and blood cell formation.

Muscular System

• Skeletal muscles, tendons.
• Movement, posture, and heat production.

Nervous System

• Brain, spinal cord, nerves, and sensory receptors.
• Rapid communication, control, and coordination of body functions.

Endocrine System

• Glands that produce hormones (e.g., pituitary, thyroid, adrenal glands).
• Slower, long-term communication and regulation of body functions.

Cardiovascular System

• Heart, blood vessels (arteries, veins, capillaries), and blood.
• Transport of oxygen, nutrients, hormones, and waste products.

Lymphatic System

• Lymph vessels, lymph nodes, spleen, thymus, and tonsils.
• Immune function, fluid balance, and absorption of fats.

Respiratory System

• Lungs, trachea, bronchi, and associated structures.
• Gas exchange (oxygen and carbon dioxide).

Digestive System

• Mouth, esophagus, stomach, intestines, liver, pancreas, etc.
• Breakdown and absorption of nutrients, elimination of waste.

Urinary System

• Kidneys, ureters, urinary bladder, and urethra.
• Filtration of blood, regulation of fluid and electrolyte balance, and elimination of waste.

Reproductive System

• Male: Testes, ducts, penis, etc.
• Female: Ovaries, uterus, vagina, etc.
• Production of offspring and sex hormones.

Homeostasis

• Maintenance of a stable internal environment despite external changes.
• Involves feedback mechanisms.
  • Negative Feedback: Reverses a change to maintain a set point (e.g., body temperature regulation).
  • Positive Feedback: Amplifies a change, leading to a greater deviation from the set point (e.g., blood clotting).

Cell Structure

• Plasma membrane, cytoplasm, and nucleus.
• Organelles: Structures within the cell that carry out specific functions (e.g., mitochondria, ribosomes).

Tissues

• Groups of similar cells performing specific functions.
• Four main types:
  • Epithelial Tissue: Covers surfaces and lines body cavities (protection, secretion, absorption).
  • Connective Tissue: Supports, connects, and separates different types of tissues and organs in the body (support, binding, insulation). Includes bone, cartilage, and blood.
  • Muscle Tissue: Responsible for movement (contraction).
    • Skeletal Muscle: Voluntary movement.
    • Smooth Muscle: Involuntary movement.
    • Cardiac Muscle: Heart contractions.
  • Nervous Tissue: Communication and control (neurons and glial cells).

Organ Systems

• Groups of organs that work together to perform specific functions.
• Examples include the digestive system, respiratory system, and cardiovascular system.

Organ Development

• Organs develop from three primary germ layers during embryonic development.
• Ectoderm: Gives rise to the epidermis and nervous system.
• Mesoderm: Gives rise to muscle, bone, blood, and other connective tissues.
• Endoderm: Gives rise to the lining of the digestive and respiratory tracts, as well as associated glands.

Histological Techniques

• Tissue preparation, sectioning, and staining for microscopic examination.
• Stains enhance visualization of tissue components (e.g., hematoxylin and eosin (H&E) staining).

Imaging Techniques

• X-rays, CT scans, MRIs, and ultrasounds are used to visualize internal structures.
• Angiography is used to visualize blood vessels.
• Endoscopy is used to visualize the inside of organs and cavities.

Variation in Anatomy

• Anatomical variations occur among individuals.
• Knowledge of common variations is important in clinical practice.

Clinical Anatomy

• Application of anatomical knowledge in clinical settings.
• Includes diagnosis, treatment, and surgical procedures.