Chapter 8 Part 1

Anatomy and Physiology Overview

• Anatomy studies the structure and makeup of an organism.
• Gross anatomy studies organs and their locations in the body.
• Microscopic anatomy studies tissue and cellular components not visible to the naked eye.
• Physiology studies the processes and functions of the body.
• Body systems operate simultaneously, relying on interactions to maintain homeostasis.
• Homeostasis is a state of balance for effective organ and system function.
• Maintaining it preserves conditions for normal life processes like temperature, acid-base balance, and gas/mineral concentrations.
• Pathophysiology studies how body functions change with disease or disrupted homeostasis.

Characteristics of Living Things

• Absorption: Ability to absorb materials through membranes, like in the digestive tract.
• Circulation: Ability to transport substances throughout the body via fluids.
• Digestion: Ability to convert food sources into simpler compounds.
• Excretion: Ability to excrete waste materials.
• Growth: Ability to increase in size.
• Movement: Ability to change locations, positions, or move internal structures.
• Reproduction: Ability to create new cells or new organisms (offspring).
• Respiration: Ability to use food and oxygen to release energy.
• Responsiveness: Ability to respond to internal and external stimuli.

Levels of Organization

• The body is organized to work as a whole, progressing from chemical to organism level.
• Six basic units of organization: chemical, cellular, tissue, organ, organ system, organism.
• Changes within cells influence body functions and structures.
• Chemicals in the body include water, proteins, carbohydrates, lipids, nucleic acids, and salts, along with foods, drinks, and medications.

Chemical Level Details

• Mass determines the weight of an object based on Earth's gravity.
• Matter includes liquids, gases, and solids, inside and outside the body.
• Elements are the simplest form of matter that cannot be broken down.
• Examples of elements: Carbon, hydrogen, oxygen, and nitrogen.
• Atoms are the smallest unit of an element, varying in size, mass, and how they combine.
• Atoms combine with similar atoms by forming chemical bonds Atoms are composed of protons (positive charge), electrons (negative charge), and neutrons (neutral).
• An atom with equal protons and electrons has a net charge of zero.
• Atom mass is determined by the number of protons and neutrons in its nucleus.
• Electrons orbit the nucleus at high speed, forming a spherical electron cloud.
• Atomic number: number of protons in an atom.
• Atomic weight: number of protons and neutrons in the nucleus.
• Isotopes: atoms with the same number of protons but different numbers of neutrons.

Molecular Bonds

• Bonding with other atoms by forming chemical bonds can result in interactions between these electrons; they can gain, lose, or share their electrons.
• Ionic bonds: form between ions (atoms that gain or lose electrons).
• Cations: ions with a positive charge.
• Anions: ions with a negative charge.
• Oppositely charged ions attract each other to form an ionic bond.
• Covalent bonds: form when atoms share electrons to form molecules.
• Polar molecules: have equal protons and electrons, but one end is slightly negative and the other slightly positive (e.g., water).
• Peptide bond: another type of covalent bond.
• Hydrogen bonds: form between a hydrogen atom and a negatively charged atom (oxygen, nitrogen, or fluorine).
• Important in protein and nucleic structure, forming between polar regions of large molecules.

Molecular and Structural Composition

• Molecular formula: represents the numbers and types of atoms in a molecule (e.g., water is H2O)
• Structural formulas: signify how atoms are joined and arranged in molecules.
• Single bonds are shown with a single line, double bonds with a double line.
• Compound: a substance broken down into two or more elements.
• Molecules of a compound have specific types and amounts of atoms.

Minerals and Compounds

• Mineral: a naturally occurring inorganic element used in the body's chemical reactions.
• Minerals are necessary for sustaining normal cell function.
• Minerals are obtained from plant foods or animals that have eaten plants and are concentrated in bones and teeth.
• Classified as macrominerals (macronutrients) or microminerals (trace elements).
• Macrominerals: daily dietary requirement is 100 mg or more (e.g., calcium, magnesium, phosphorus).
• Microminerals: body needs less than 100 mg daily (e.g., chromium, copper, iodine, iron, selenium, zinc).
• Organic compounds: contain the element carbon and long chains of carbon atoms linked by covalent bonds.
• Carbon atoms usually form additional covalent bonds with hydrogen or oxygen atoms.
• Biochemical compounds: inorganic compounds in living organisms, essential for chemical reactions.
• Examples of biochemical compounds include: carbohydrates, proteins, lipids, vitamins, and nucleic acids.