Overview of Human Anatomy

Overview of Human Anatomy

• Human anatomy is the study of the structure of the human body, including the physical form and position of its parts.
• It encompasses all levels of organization from the cellular to the systemic.
• The study broadly covers gross anatomy (visible structures), microscopic anatomy (structures viewed with microscopes), and developmental anatomy (changes in structure over time).

Anatomical Terminology

• Standardized anatomical terminology is crucial for clear and precise communication among healthcare professionals.
• Precise directional terms (e.g., superior, inferior, anterior, posterior) facilitate description of body locations and relationships.
• Regional terms (e.g., cephalic, cervical) describe specific areas of the body.
• Planes of section (e.g., sagittal, transverse, coronal) help visualize internal structures.

Body Cavities

• Body cavities are spaces enclosed by membranes that contain and protect internal organs.
• The dorsal cavity houses the brain and spinal cord.
• The ventral cavity is larger and houses the major organs of the body, like the heart, lungs, and stomach, further divided into thoracic and abdominal cavities.
• The peritoneal cavity is a specific cavity within the abdominal cavity.

Skeletal System

• The skeletal system provides support, protection, and leverage for movement.
• Bones are composed of living cells embedded in a hard matrix of calcium salts and collagen fibers.
• Bones are classified by shape (long, short, flat, irregular, sesamoid).
• Joints connect bones and allow for movement.

Muscular System

• The muscular system enables movement, maintains posture, and generates heat.
• Muscles are composed of specialized cells called muscle fibers.
• Muscles are categorized based on structure and function: voluntary (skeletal) and involuntary (smooth, cardiac).

Nervous System

• The nervous system coordinates body functions through electrochemical signals.
• It consists of the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves).
• Neurons are specialized cells that transmit signals throughout the body. They vary in structure but all have a cell body, dendrites, and an axon.

Cardiovascular System

• The cardiovascular system circulates blood throughout the body to deliver oxygen, nutrients, and remove waste products.
• The heart pumps blood through the blood vessels (arteries, veins, and capillaries).
• Blood is a connective tissue containing red blood cells to carry oxygen, white blood cells to combat infection, and platelets for blood clotting.

Respiratory System

• The respiratory system facilitates gas exchange between the environment and the body.
• The lungs are the primary organs, enabling the absorption of oxygen and release of carbon dioxide. They contain various alveoli used in that process.

Digestive System

• The digestive system processes food, absorbs nutrients, and eliminates waste.
• Various organs participate including the mouth, esophagus, stomach, intestines, and accessory organs such as the liver and pancreas.

Urinary System

• The urinary system filters blood, eliminates metabolic waste, and regulates water balance.
• The kidneys are the primary filtering organs, producing urine which waste is eliminated via the urinary bladder through the urethra.

Endocrine System

• The endocrine system regulates body functions through hormones, which are chemical messengers.
• It consists of glands that secrete hormones into the bloodstream.
• Essential glands include the thyroid, pituitary, adrenal, and gonads.

Lymphatic and Immune System

• The lymphatic and immune systems defend against disease and infection.
• Includes the lymph nodes, lymphatic vessels, and various cells of the immune system.

Integumentary System

• The integumentary system covers and protects the body from the outside environment.
• Includes the skin, hair follicles, sweat glands, and nails; the skin itself providing sensory input and protection.

Reproductive System

• The reproductive system enables procreation.
• The male and female reproductive systems have separate structures, producing gametes (sperm and eggs) that fuse during fertilization.

Developmental Anatomy

• Developmental anatomy studies the changes in the human body over its lifespan.
• Developmental stages, from conception to adulthood, involves significant changes in structure and functionality, all governed by specific genetic programs.