chapter 1

• Anatomy is the science of body structures and relationships
• Physiology is the science of body functions
• Anatomy and physiology are inseparable, where function reflects structure
• Chemical level:

  • Composed of atoms and molecules
  • Atoms are the smallest units of matter
  • Two or more atoms combine to form a molecule, such as a water (H2O) molecule
• Cellular level:

  • Organelles carry out specific functions within a cell
  • The cell is the smallest unit of life
  • Cells are made up of molecules
• Tissue level:

  • Tissues are groups of similar cells with a common specialized function
  • 4 types of tissues in the human body: Epithelial tissue, Connective tissue, Muscle tissue, Nervous tissue
• Organ level:

  • Organs are different tissues working together to perform specific functions
• Organ System level:

  • An organ system is a group of organs that work together to coordinate activities
  • There are 11 organ systems in the human body
• Organismal level:

  • In an organism, all body systems function interdependently
• Integumentary System

  Skeletal System

  Muscular System

  Nervous System

  Endocrine System

  Cardiovascular System

  Lymphatic System

  Respiratory System

  Digestive System

  Urinary System

  Reproductive System
• The organ system responsible for the synthesis of vitamin D is the Integumentary System
• Living organisms are organized structures that consist of one or more cells
• Living organisms must be able to respond to changes in their environment
• Living organisms reproduce either sexually or asexually to send copies of genes into future generations
• Evolution by natural selection results in organisms being better suited or adapted to their environment
• Living organisms follow patterns of growth and development that are genetically determined
• Homeostasis is the ability to maintain stable internal environments necessary for chemical reactions to happen
• Living organisms need energy to carry out life functions, which comes from transforming energy from one form to another
• Viruses do not meet the criteria that biologists use to define life
• The ability to maintain a stable internal environment is called homeostasis
• Cells are the basic unit of life
• The cell theory is based on 3 concepts: every living organism is composed of 1 or more cells, the cell is the basic unit of life, and all cells come from pre-existing cells
• Cell size is limited because the ratio of surface area to volume decreases as a cell becomes larger
• Homeostasis is the ability to maintain stable internal conditions even though the outside world changes continuously
• The body must constantly be monitored to maintain homeostasis, involving the nervous and endocrine systems
• Homeostatic control involves 3 components: receptor, control center, and effector
• Negative feedback is the most-used feedback mechanism in the body, where the response reduces or shuts off the original stimulus to bring the body back to normal range
• Positive feedback enhances or exaggerates the original stimulus, causing the variable to continue in the same direction as the initial change
• Many diseases result from a homeostatic imbalance, which is the inability of the body to restore a stable internal environment
• In a negative feedback loop when body temperature rises, the receptor (sensor that monitors the change) is the receptor