Anatomy and Physiology: Foundations

Definitions and Scope

• Anatomy: The study of the structure of body parts and their relationships to one another.

• Physiology: The study of the function of the body, focusing on how body parts work and carry out life-sustaining activities.

Levels of Structural Organization

• Chemical level: Atoms, molecules, and organelles.

• Cellular level: Single cell; the basic structural and functional unit of life.

• Tissue level: Groups of similar cells working together for a specific function (e.g., blood, muscle, nerves).

• 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.

Necessary Life Functions

• Maintaining boundaries: Separation between internal and external environments (e.g., plasma membranes, skin).

• Movement: Muscular system allows movement, manipulation of environment, and locomotion.

• Responsiveness: Ability to sense and respond to stimuli (e.g., withdrawal reflex, control of breathing rate).

• Digestion: Breakdown of ingested foodstuffs, absorption of simple molecules into blood.

• Metabolism: All chemical reactions in body cells, including catabolism (breakdown) and anabolism (synthesis).

• Excretion: Removal of wastes from metabolism and digestion (e.g., urea, carbon dioxide, feces).

• Reproduction: Cellular level (cell division for growth/repair); organismal level (production of offspring).

• Growth: Increase in size of a body part or organism.

Organ Systems Overview

Humans are multicellular; to function, individual cells must be kept alive. Organ systems are designed to serve the cells, and all cells depend on organ systems to meet their survival needs. There are 11 organ systems:

1. Integumentary System: External body covering, protects deeper tissues, synthesizes vitamin D, houses receptors and glands.

2. Skeletal System: Protects and supports organs, provides framework for muscles, forms blood cells, stores minerals.

3. Muscular System: Allows manipulation, locomotion, facial expression, maintains posture, produces heat.

4. Nervous System: Fast-acting control system, responds to internal/external changes by activating muscles/glands.

5. Endocrine System: Glands secrete hormones regulating growth, reproduction, metabolism.

6. Cardiovascular System: Blood vessels transport blood, heart pumps blood.

7. Lymphatic/Immune System: Picks up fluid leaked from blood, disposes debris, houses white blood cells, mounts immune response.

8. Respiratory System: Keeps blood supplied with oxygen, removes carbon dioxide, gas exchange through air sacs.

9. Digestive System: Breaks down food, absorbs nutrients, eliminates indigestible foodstuffs as feces.

10. Urinary System: Eliminates nitrogenous wastes, regulates water, electrolytes, acid-base balance.

11. Reproductive System: Produces offspring; male (sperm, delivery), female (eggs, site for fertilization, nourishment of newborn).

Survival Needs

• Nutrients

• Oxygen

• Water

• Normal body temperature

• Appropriate atmospheric pressure

Homeostasis

• Homeostasis: The condition of maintaining the body's internal environment in a relatively constant state (e.g., temperature, blood pressure, glucose levels).

• Homeostatic imbalance: Anything that disturbs or alters the balance of the internal environment.

• Homeostatic control mechanisms: Self-regulating mechanisms involving a receptor, control center, and effector.

• Negative feedback: Output shuts off the original effect or reduces intensity (e.g., thermostat).

• Positive feedback: Response enhances the original stimulus (e.g., blood clotting, labor contractions).

Basic Chemistry for Anatomy & Physiology

Matter

• Matter: Anything that has mass or occupies space; can be seen, smelled, or felt.

• Weight: Mass plus the effects of gravity.

States of Matter

• Solid: Definite shape and volume.

• Liquid: Changeable shape, definite volume.

• Gas: Changeable shape and volume.

Energy

• Energy: The capacity to do work or put matter into motion; does not have mass or take up space.

• The greater the work done, the more energy is used up.

Kinetic vs. Potential Energy

• Kinetic energy: Energy in action.

• Potential energy: Stored (inactive) energy.

• Energy can be transformed from potential to kinetic and vice versa.

Forms of Energy

• Chemical energy: Stored in bonds of chemical substances.

• Electrical energy: Results from movement of charged particles.

• Mechanical energy: Directly involved in moving matter.

• Radiant/electromagnetic energy: Travels in waves (e.g., heat, visible light, X-rays).

Energy Form Conversions

• Energy may be converted from one form to another (e.g., chemical to light energy).

• Energy conversion is inefficient; some energy is "lost" as heat.

Atoms and Elements

• Elements: Substances that cannot be broken down into simpler substances by ordinary chemical methods.

• Four elements make up 96% of the body: Oxygen (65%), Carbon (18%), Hydrogen (10%), Nitrogen (3%).

• Each element is made up of atoms, the smallest particles with properties of that element.

• Atomic symbol: One- or two-letter chemical shorthand for each element (e.g., O for oxygen, C for carbon).

Subatomic Particles

• Protons: Positive charge (+), 1 atomic mass unit (amu).

• Neutrons: No charge, 1 amu.

• Electrons: Negative charge (-), virtually no weight.

• Number of protons = number of electrons in a neutral atom.

• Protons and neutrons are in the nucleus; electrons orbit the nucleus.

Atomic Number and Mass Number

• Atomic number: Number of protons in the nucleus (written as subscript to left of symbol).

• Mass number: Total number of protons and neutrons (written as superscript to left of symbol).

Isotopes

• Structural variations of the same element (different number of neutrons).

Combining Matter: Molecules, Compounds, and Mixtures

Molecules and Compounds

• Molecule: General term for 2 or more atoms bonded together.

• Compound: Specific molecule with 2 or more different kinds of atoms bonded together (e.g., C6H12O6).

Mixtures

• Most matter exists as mixtures: two or more components physically intermixed.

1. Solutions: Homogeneous mixtures; particles evenly distributed. Solvent: substance in greatest amount (e.g., water). Solute: substance dissolved (e.g., glucose in blood plasma).

2. Colloids: Heterogeneous mixtures; particles not evenly distributed, do not settle out (e.g., cytosol).

3. Suspensions: Heterogeneous mixtures with large, visible particles that settle out (e.g., blood).

Chemical Bonds

Types of Chemical Bonds

• Ionic bonds: Atoms gain or lose electrons, becoming charged ions (cations: positive, anions: negative). Attraction of opposite charges forms ionic bond.

• Covalent bonds: Sharing of two or more valence shell electrons between atoms. Can be single, double, or triple bonds.

• Nonpolar covalent bonds: Equal sharing of electrons (e.g., CO2).

• Polar covalent bonds: Unequal sharing, resulting in partial charges (e.g., H2O).

• Hydrogen bonds: Attractive force between electropositive hydrogen and an electronegative atom of another molecule.

Electron Shells and the Octet Rule

• Electrons occupy areas called electron shells (energy levels).

• Shell 1: holds 2 electrons; Shell 2: holds 8; Shell 3: holds 18.

• Outermost shell is the valence shell; electrons here are involved in chemical reactions.

• Octet rule: Atoms desire 8 electrons in their valence shell (except H and He, which want 2).

Summary Table: Major Elements in the Human Body

Key Equations

• Atomic number:

• Mass number:

Additional info:

• Some context and examples were expanded for clarity and completeness, such as the explanation of homeostatic mechanisms and the summary table of elements.