AnaPhy

• Anatomy is the study of the structure of body parts and their relationship to one another
• Physiology is the study of the function of body parts and how they work to carry out life-sustaining activities
• Topics of Anatomy:

  • Gross or macroscopic anatomy: study of large, visible structures
  • Regional anatomy: looks at all structures in a particular area of the body
  • System anatomy: looks at just one system (cardiovascular, nervous, muscular, etc.)
  • Surface anatomy: looks at internal structures as they relate to overlying skin
• Microscopic anatomy deals with structures too small to be seen by the naked eye

  • Cytology: microscopic study of cells
  • Histology: microscopic study of tissues
  • Developmental anatomy studies anatomical and physiological development throughout life
  • Embryology: study of developments before birth
• To study anatomy, one must know anatomical terminology and be able to observe, manipulate, palpate, and auscultate
• Topics of Physiology:

  • Based on organ systems (e.g., renal or cardiovascular physiology)
  • Often focuses on cellular and molecular levels of the body
  • Looks at how the body's abilities are dependent on chemical reactions in individual cells
• To study physiology, one must understand basic physical principles (e.g., electrical currents, pressure, and movement) as well as basic chemical principles
• Anatomy and physiology are inseparable

  • Function always reflects structure
  • What a structure can do depends on its specific form
  • Known as the principle of complementarity of structure and function
• Level of Body Organization:

  • Chemical level: atoms, molecules, organelles
  • Cellular level: single cell
  • Tissue level: groups of similar cells
  • Organ level: contains two or more types of tissues
  • Organ system level: organs that work closely together
  • Organismal level: all organ systems combined to make the whole organism
• Basic Life Processes:

  • Maintenance of life involves maintaining boundaries, movement, responsiveness, digestion, metabolism, excretion, reproduction, and growth
• Maintaining boundaries:

  • Separation between internal and external environments must exist
  • Plasma membranes separate cells
  • Skin separates organism from environment
• Movement:

  • Muscular system allows movement of body parts via skeletal muscles
  • Of substances via cardiac muscle (blood) and smooth muscle (digestion, urination)
  • Contractility refers to movement at the cellular level
• Responsiveness:

  • Ability to sense and respond to stimuli
  • Withdrawal reflex prevents injury
  • Control of breathing rate, which must change in response to different activities
• Digestion:

  • Breakdown of ingested foodstuffs, followed by absorption of simple molecules into blood
• Metabolism:

  • All chemical reactions that occur in body cells
  • Sum of all catabolism (breakdown of molecules) and anabolism (synthesis of molecules)
• Excretion:

  • Removal of wastes from metabolism and digestion
  • Urea (from breakdown of proteins), carbon dioxide (from metabolism), feces (unabsorbed foods)
• Reproduction:

  • At the cellular level, reproduction involves division of cells for growth or repair
  • At the organismal level, reproduction is the production of offspring
• Growth:

  • Increase in size of a body part or of organism
• Humans are multicellular, so to function, individual cells must be kept alive

  • Organ systems are designed to service the cells
  • All cells depend on organ systems to meet their survival needs
  • There are 11 organ systems that work together to maintain life
• Examples of interrelationships among body organ systems:

  • Digestive system takes in nutrients, breaks them down, and eliminates unabsorbed matter (feces)
  • Respiratory system takes in oxygen and eliminates carbon dioxide
  • Cardiovascular system distributes oxygen and nutrients to all body cells and delivers wastes and carbon dioxide to disposal organs
  • Urinary system eliminates nitrogenous wastes and excess ions
• Urinary system:

  • Eliminates nitrogenous wastes and excess ions
  • Nutrients and wastes pass between blood and cells via the interstitial fluid
• Integumentary system:

  • Protects the body from the external environment
• Survival Needs:

  • Humans need nutrients, oxygen, water, normal body temperature, and appropriate atmospheric pressure for survival
• Nutrients:

  • Carbohydrates: major source of energy
  • Proteins: needed for cell building and cell chemistry
  • Fats: long-term energy storage
  • Minerals and vitamins: involved in chemical reactions and for structural purposes
• Oxygen:

  • Essential for release of energy from foods
  • The body can survive only a few minutes without oxygen
• Water:

  • Most abundant chemical in the body; provides the watery environment needed for chemical reactions
  • Also is fluid base for secretions and excretions
• Normal body temperature:

  • Rates of chemical reactions are affected if body temperature falls below or goes above 37°C
• Appropriate atmospheric pressure:

  • Specific pressure of air is needed for adequate breathing and gas exchange in lungs
• Homeostasis:

  • Maintenance of relatively stable internal conditions despite continuous changes in the environment
  • A dynamic state of equilibrium, always readjusting as needed
  • Maintained by contributions of all organ systems
• Homeostatic Controls:

  • Body must constantly be monitored and regulated to maintain homeostasis
  • Nervous and endocrine systems, as well as other systems, play a major role in maintaining homeostasis
  • Variables are factors that can change (blood sugar, body temperature, blood volume, etc.)
  • Homeostatic control of variables involves three components: receptor, control center, and effector
• Negative feedback:

  • Most-used feedback mechanism in the body
  • Response reduces or shuts off the original stimulus
  • Examples include the regulation of body temperature and blood glucose by insulin
• Positive feedback:

  • Response enhances or exaggerates the original stimulus
  • May exhibit a cascade or amplifying effect
  • Usually controls infrequent events that do not require continuous adjustment
• Homeostatic Imbalance:

  • Disturbance of homeostasis increases the risk of disease and contributes to changes associated with aging
  • Control systems become less efficient
  • If negative feedback mechanisms become overwhelmed, destructive positive feedback mechanisms may take over