Intro to Anatomy and Physiology

Levels of Organization

• Organism: the highest level of organization
• Organ system: a group of organs working together
• Organ: a structure that performs a specific function
• Tissue: a group of similar cells
• Cellular: the level of individual cells
• Molecular/Chemical: the level of molecules and atoms

Homeostasis

• Definition: a stable internal environment
• Homeostatic regulation: the body's way of maintaining homeostasis
• Receptors: react to changes in the body and send information to control centers
• Control centers: process information and send it to effectors
• Effectors: take action to maintain homeostasis
• Negative feedback: the body's automatic response to changes in homeostasis

Organ Systems

• Integumentary (skin): first barrier of defense against external factors
• Skeletal: provides support and structure
• Muscular: enables movement and activity
• Nervous: responds to stimuli and controls the body's responses
• Cardiovascular: transports blood and oxygen throughout the body
• Lymphatic: prevents disease and stops infections
• Endocrine: regulates hormone production
• Respiratory: exchanges oxygen and carbon dioxide
• Digestive: breaks down nutrients and absorbs them into the bloodstream
• Urinary: excretes waste and excess fluids
• Reproductive: produces offspring

Chemical Levels

Atomic Structure

• Atom: composed of protons, neutrons, and electrons
• Protons: positively charged, found in the nucleus
• Neutrons: neutral, found in the nucleus
• Electrons: negatively charged, found in electron shells
• Atomic weight: equal to the number of protons
• Mass number: equal to protons + neutrons
• Nucleus: the center of the atom
• Electron shell: holds electrons

Isotopes

• Definition: same element with different numbers of neutrons
• Example: carbon-12 and carbon-14

Chemical Bonds

• Atoms with full outer shells are stable
• Atoms without full outer shells form bonds
• Ions: atoms with a positive or negative charge
• Cations: positively charged ions
• Anions: negatively charged ions
• Ionic bonds: formed when atoms gain or lose electrons
• Covalent bonds: formed when atoms share electrons
• Single bond: formed when two atoms share one pair of electrons
• Double bond: formed when two atoms share two pairs of electrons

Organic and Inorganic Compounds

• Organic compounds:
  • Contain carbon and hydrogen
  • Examples: carbohydrates, proteins, nucleic acids, and lipids
  • Many are soluble in water
• Inorganic compounds:
  • Do not contain carbon and hydrogen
  • Examples: acids, bases, H2O, and CO2
  • Acids: break apart hydrogen
  • Bases: remove hydrogen