LANGUAGE OF ANATOMY

• Anatomy is the study of the structure and shape of the body and its parts, involving observation to see sizes and relationships of parts
• Anatomy has two kinds:

  • Gross anatomy: focuses on large structures that are easily observable
  • Microscopic anatomy: deals with structures that are too small to be seen with the naked eye, like cells and tissues that can only be viewed with a microscope
• Physiology is the study of how the body and its parts work or function, where structure determines what functions can occur
• The six levels of structural organization in the body are:

  1. Atoms

  2. Cells

  3. Tissues

  4. Organs

  5. Organ systems

  6. Organisms
• The integumentary system forms the external body covering (skin), waterproofs the body, cushions and protects deeper tissue, produces vitamin D, excretes salts in perspiration, helps regulate body temperature, and is the location of cutaneous nerve receptors
• The skeletal system consists of bones, cartilages, ligaments, and joints, providing muscle attachment for movement, protecting vital organs, serving as the site of blood cell formation, and storing minerals
• The muscular system involves skeletal muscles contracting to produce movement of bones
• The nervous system is a fast-acting control system consisting of the brain, spinal cord, nerves, and sensory receptors, responding to internal and external stimuli, with sensory receptors detecting changes and messages sent to the central nervous system for assessment and activation of effectors (muscles and glands)
• The endocrine system secretes hormones into the blood to control body functions like growth, reproduction, and nutrient use, with glands including the pituitary gland, thyroid, parathyroids, adrenal glands, thymus, pancreas, pineal gland, ovaries (females), and testes (males)
• The cardiovascular system includes the heart and blood vessels, where the heart pumps blood, vessels transport blood to tissues, and blood carries oxygen, carbon dioxide, nutrients, hormones, white blood cells, and chemicals
• The lymphatic system includes lymphatic vessels, lymph nodes, and lymphoid organs, complementing the cardiovascular system by returning leaked fluids back to the bloodstream, cleansing the blood, and housing white blood cells involved in immunity
• The digestive system includes the oral cavity (mouth), esophagus, stomach, small and large intestines, rectum, and accessory organs, breaking down food, allowing for nutrient absorption into the blood, and eliminating indigestible material as feces
• The respiratory system includes the nasal passages, pharynx, larynx, trachea, bronchi, and lungs, exchanging gases with the blood through air sacs in the lungs, supplying the body with oxygen, and removing carbon dioxide
• The urinary system includes the kidneys, ureters, urinary bladder, and urethra, eliminating nitrogenous wastes, maintaining acid-base balance, regulating water and electrolyte balance, and helping regulate normal blood pressure
• The reproductive system for males includes the testes, scrotum, penis, accessory glands, and duct system, where the testes produce sperm and the duct system carries sperm to the exterior
• The reproductive system for females includes the ovaries, uterine tubes, uterus, and vagina, where the ovaries produce eggs and the uterus provides a site for fetal development
• Maintaining life involves necessary life functions like maintaining boundaries, movement, responsiveness, digestion, metabolism, excretion, reproduction, and growth
• Survival needs for the body include nutrients, oxygen, water, normal body temperature, and atmospheric pressure
• The human circulatory system is responsible for transporting blood throughout the body
• The heart is the central organ of the circulatory system, pumping blood through a network of blood vessels including arteries (carry blood away from the heart) and veins (carry blood back to the heart)
• The digestive system is a group of organs that work together to break down food into nutrients and absorb them into the body
• The digestive process starts in the mouth where food is chewed and mixed with saliva containing enzymes that break down carbohydrates
• The stomach secretes acids and enzymes to further break down food before it moves to the small intestine where it is mixed with bile from the liver and enzymes from the pancreas to break down fats, proteins, and carbohydrates
• After absorption in the small intestine, undigested food moves to the large intestine where it is formed into feces and expelled from the body
• Special terminology is used in anatomy to prevent misunderstanding, including terms for position, direction, regions, and structures
• Anatomical position is a standard body position used to avoid confusion, where the body stands erect, feet parallel, arms hanging at the sides with palms facing forward and thumbs pointing away from the body
• Directional terms in anatomy explain location, such as superior (toward the head), inferior (away from the head), anterior (front of the body), posterior (backside of the body), medial (toward the midline), lateral (away from the midline), proximal (close to the origin), and distal (farther from the origin)
• Body planes and sections are cuts along imaginary lines known as planes, including sagittal (divides body into left and right parts), frontal (divides body into anterior and posterior parts), and transverse (divides body into superior and inferior parts)
• Body cavities provide varying degrees of protection to organs, with two main internal body cavities: dorsal (cranial and spinal cavities) and ventral (thoracic and abdominopelvic cavities)
• Homeostasis is the maintenance of relatively stable internal conditions, necessary for normal body functioning and to sustain life
• Homeostatic control mechanisms involve receptors, control centers, and effectors to respond to changes in the environment and maintain balance
• Negative feedback mechanisms, like a household thermostat, shut off the original stimulus or reduce its intensity to maintain homeostasis
• Positive feedback mechanisms, rare in the human body, increase the original stimulus to push the variable farther, occurring in processes like blood clotting and during childbirth