Introduction to Anatomy & Physiology

Definitions and Scope

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

• Physiology: Concerns the function of the body, i.e., 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 toward 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

Maintenance of Life Involves:

• 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 (skeletal muscles) and substances (cardiac and smooth muscle).

• 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: catabolism (breakdown) and anabolism (synthesis).

• Excretion

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

• Reproduction

  • Cellular level: division for growth or repair; organismal level: production of offspring.

• Growth

  • Increase in size of a body part or organism.

Organ Systems Overview

Humans are multicellular; organ systems are designed to serve the cells. There are 11 organ systems that work together to maintain life:

1. Integumentary System: Forms the external body covering, protects deeper tissues, synthesizes vitamin D, houses cutaneous receptors and sweat/oil glands.

2. Skeletal System: Protects and supports body 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.

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

6. Cardiovascular System: Blood vessels transport blood (oxygen, CO2, nutrients, wastes); heart pumps blood.

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

8. Respiratory System: Keeps blood supplied with oxygen, removes CO2.

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

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

11. Reproductive System:

    • Male: Produces sperm, male sex hormones, delivers sperm.

    • Female: Produces eggs, female sex hormones, supports fertilization and fetal development, mammary glands produce milk.

Survival Needs

• Nutrients

• Oxygen

• Water

• Normal body temperature

• Appropriate atmospheric pressure

Homeostasis

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

• Homeostatic imbalance: Disturbances or alterations in internal environment balance.

• Homeostatic control mechanisms: Processes involving receptor, control center, and effector to maintain steady state.

• Negative feedback: Output reduces or shuts off the original effect of the stimulus (e.g., body temperature regulation).

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

Basic Chemistry for Anatomy & Physiology

Matter

• Matter: Anything that has mass and occupies space.

• Can be seen, smelled, or felt; weight is 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.

• Exists as kinetic energy (energy in action) and potential energy (stored energy).

• Energy can be transformed from potential to kinetic.

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, light, X-rays).

Energy Conversions

• Energy may be converted from one form to another (e.g., chemical to electrical in a lamp).

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

Atoms and Elements

• Element: Substance that cannot be broken down into simpler substances by ordinary chemical methods.

• Four elements make up 96% of body: oxygen (O), carbon (C), hydrogen (H), nitrogen (N).

• Each element is made up of atoms: unique building blocks with specific physical and chemical properties.

Atomic Structure

• Protons: Positive charge (+), weigh 1 amu, located in nucleus.

• Neutrons: No electrical charge (0), weigh 1 amu, located in nucleus.

• Electrons: Negative charge (–), negligible mass, orbit around nucleus.

Atomic Number and Mass Number

• Atomic number: Number of protons in nucleus; written as subscript to left of atomic symbol.

• Mass number: Total number of protons and neutrons in nucleus; written as superscript to left of atomic symbol.

Isotopes

• Structural variations of same element; same number of protons, different number of neutrons.

Combining Matter: Molecules, Compounds, and Mixtures

Molecules and Compounds

• Molecule: Two or more atoms bonded together (e.g., O2).

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

• Molecules with only one type of atom are called "molecules," not compounds.

Mixtures

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

• Solutions: Homogeneous mixtures; solute particles are very tiny and do not settle out or scatter light.

• Solvent: Substance present in greatest amount (usually liquid, such as water).

• Solute(s): Substance(s) dissolved in solvent (e.g., glucose in blood, salt in plasma).

Table: Comparison of Mixtures

Additional info: Some content was expanded for clarity and completeness, including the table comparing types of mixtures and more detailed explanations of homeostasis and organ systems.