Anatomy, Physiology, and Pathology

• Anatomy studies the body's structure and relationships between systems.
• Physiology studies how body systems function and maintain health.
• Pathology studies abnormalities affecting body functions, often causing illness.

Levels of Structural Complexity

• The body has different levels of structural organization.
• Atoms combine to form molecules.
• Cells are the smallest independent living units.
• Tissues are groups of similar cells with similar functions.
• Organs are composed of different tissues performing specific functions.
• Systems consist of multiple organs and tissues contributing to survival needs.

Anatomical Terms

• Anatomical position: upright, head facing forward, arms at sides with palms forward, feet together.

Directional Terms

• Directional terms describe the location of body parts in relation to others.
• Medial: Nearer to the midline.
• Lateral: Further from the midline or at the side of the body.
• Proximal: Nearer to a limb's point of attachment or body part's origin.
• Distal: Further from a limb's point of attachment or body part's origin.
• Anterior (or ventral): Nearer the front of the body.
• Posterior (or dorsal): Nearer the back of the body.
• Superior: Nearer the head.
• Inferior: Further from the head.

Body Planes

• Median plane: Divides the body longitudinally into right and left halves. A sagittal section is parallel to the median plane.
• Coronal plane: Divides the body longitudinally into anterior and posterior sections.
• Transverse plane: Divides the body into upper and lower parts, creating a cross-section.

Cavities of the Body

• Body organs are contained and protected within four cavities: cranial, thoracic, abdominal, and pelvic.

Cranial Cavity

• Contains the brain.
• Anterior boundary: frontal bone.
• Lateral boundary: temporal bones.
• Posterior boundary: occipital bone.
• Superior boundary: parietal bones.
• Inferior boundary: sphenoid and ethmoid bones, and parts of the frontal, temporal, and occipital bones.

Thoracic Cavity

• Situated in the upper trunk.
• Anterior boundary: sternum and costal cartilages of the ribs.
• Lateral boundary: ribs and intercostal muscles.
• Posterior boundary: thoracic vertebrae.
• Superior boundary: structures forming the root of the neck.
• Inferior boundary: diaphragm.
• Contents include trachea, bronchi, lungs, heart, major blood vessels, oesophagus, lymph vessels, lymph nodes, and nerves.

Abdominal Cavity

• The largest body cavity, oval in shape.
• Superior boundary: diaphragm.
• Anterior boundary: abdominal wall muscles.
• Posterior boundary: lumbar vertebrae and muscles of the posterior abdominal wall.
• Lateral boundary: lower ribs and parts of the abdominal wall muscles.
• Inferior boundary: continuous with the pelvic cavity.
• Contains the stomach, small and large intestines, liver, gall bladder, bile ducts, pancreas, spleen, kidneys, ureters, adrenal glands, blood vessels, lymph vessels, nerves, and lymph nodes.

Pelvic Cavity

• Roughly funnel-shaped, extends from the lower end of the abdominal cavity.
• Superior boundary: continuous with the abdominal cavity.
• Anterior boundary: pubic bones.
• Posterior boundary: sacrum and coccyx.
• Lateral boundary: innominate bones.
• Inferior boundary: muscles of the pelvic floor.
• Contains the sigmoid colon, rectum, anus, some loops of the small intestine, urinary bladder, lower ureters, and urethra.
• In females: uterus, uterine tubes, ovaries, and vagina.
• In males: prostate gland, seminal vesicles, spermatic cords, deferent ducts, ejaculatory ducts, and urethra.