General Anatomy Lecture 1: Introduction to Human Anatomy

Introduction to Human Anatomy

• Anatomy is the science that deals with the structures of all parts of the body, their function, relation, microscopical organization, and process by which they developed.
• The word "anatomy" comes from the Greek words "ana" meaning "up" and "tome" meaning "cut" or "dissect".

Branches of Anatomy

• Gross Anatomy (Macroscopic Anatomy): studies structures visible to the naked eye, such as external and internal bodily organs.
• Microscopical Anatomy (Histology): studies small structures that can only be seen with a microscope.
• Neuroanatomy: studies the central and peripheral nervous system, both grossly and microscopically.
• Pathological Anatomy: deals with morphologic changes in tissues, both grossly and microscopically.
• Radiological Anatomy: studies body structures using radiography and other imaging methods, such as ultrasound, CT scans, and MRI.

Levels of Organization of the Human Body

• Atom: the basic and fundamental unit of matter.
• Molecule and Macromolecule: formed by chemical bonds between two or more atoms.
• Organelle: a group of molecules.
• Cell: formed by a group of organelles.
• Tissue: a combination of different types of cells that perform specialized functions.
• Organ: a structure composed of two or more tissue types.
• Organ System: a group of organs that work together to perform major functions.
• Organism: the highest level of organization, a living subject with a cellular structure that can perform all physiologic functions necessary for life.

Body Regions

• The entire human body is divided into regions, including:
  • Head and neck
  • Chest
  • Abdomen and pelvis
  • Upper extremities
  • Lower extremities
• Each main region is divided into several smaller regions.

Body Cavities

• A body cavity is a space or compartment that accommodates organs and contains fluid.
• There are two major body cavities:
  • Dorsal body cavities:
    • Cranial cavity contains the brain
    • Vertebral cavity contains the spinal cord
  • Ventral body cavity:
    • Thoracic cavity contains pericardial and pleural cavities
    • Abdominal cavity contains esophagus, stomach, large intestine, small intestine, liver, spleen, pancreas, and kidneys
    • Pelvic cavity contains urinary bladder and ureter

Anatomical Position

• The standard anatomical position of the human body is standing upright and facing forward with the legs parallel to each other.
• The upper limbs hang at either side, and the palms face forward.

Anatomical Planes

• The anatomical planes are imaginary planes used to describe the location of structures in human anatomy.
• There are four anatomical planes:
  • Sagittal plane: a vertical plane that passes through the body longitudinally, dividing it into a left and right section.
  • Median (mid sagittal) plane: a vertical plane that passes down the midline of the body, separating it into equal halves.
  • Coronal plane: a vertical plane that passes through the body longitudinally, dividing it into a front (anterior) and back (posterior) section.
  • Transverse plane (cross section): a horizontal plane that divides the body into an upper (superior) and lower (inferior) section.

Descriptive Terms of Position

• Anterior (ventral): toward the front
• Posterior (dorsal): toward the back
• Medial: toward the midline of the body
• Lateral: away from the midline of the body
• Proximal: near the origin of the structure
• Distal: away from the origin of the structure
• External: toward the surface (superficial)
• Internal: away from the surface (deep)
• Superior: up toward the head
• Inferior: down toward the foot
• Central: at the midline
• Peripheral: away from the midline

Descriptive Terms of Movement

• Flexion: bend the joint
• Extension: make the joint straight
• Abduction: move the structure away from the midline
• Adduction: move the structure toward the midline
• Pronation: move the palm of the hand upward
• Supination: move the palm of the hand downward
• Inversion: move the sole of the foot toward the midline
• Eversion: move the sole of the foot away from the midline
• Dorsiflexion: stand on the heel
• Plantar flexion: stand on the toes
• Depression: move the part downward
• Elevation: move the part upward

Body Tissues

• Tissue is a group of cells that have similar structure and function together as a unit.
• There are four main types of body tissues:
  • Epithelial tissues: form the covering of all body surfaces, line body cavities, and are the major tissue in glands.
  • Connective tissues: bind structures together, form a framework and support for organs, store fat, transport substances, protect against disease, and help repair tissue damage.
  • Muscle tissue: composed of cells that have the special ability to shorten or contract in order to produce movement of body parts.
  • Nervous tissue: responsible for coordinating and controlling all body activities.

Body Membranes

• Body membranes are thin sheets of tissue that cover the body, line body cavities, and cover organs within the cavities.
• There are two main categories of body membranes:
  • Epithelial tissue membranes: include mucous, serous, and cutaneous membranes.
  • Connective tissue membranes: include synovial membranes and meninges.

Learn about the basics of human anatomy, including the structure, function, and relations of body parts, as well as their microscopic organization and development. This quiz covers the introduction to human anatomy.