Foundations of Anatomy & Physiology: Structural Organization, Life Functions, Chemistry, and Biochemistry

Anatomy and Physiology: Introduction

Definitions and Scope

Anatomy is the study of the structure of body parts and their relationships to one another. Physiology concerns the function of the body, describing how body parts work and carry out life-sustaining activities.

• Anatomy: Focuses on physical structures (e.g., organs, tissues).

• Physiology: Focuses on processes and functions (e.g., how organs work together).

Levels of Structural Organization

Hierarchical Structure

• Chemical Level: Atoms, molecules, and organelles.

• Cellular Level: Single cell; 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

Maintenance of Life

• 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; includes 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/repair), organismal level (production of offspring).

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

Organ Systems Overview

Major Organ Systems and Their Functions

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

• Muscular System: Manipulation, locomotion, facial expression, posture, heat production.

• Nervous System: Fast-acting control, responds to internal/external changes, activates muscles/glands.

• Endocrine System: Secretes hormones for growth, reproduction, metabolism.

• Cardiovascular System: Transports blood, nutrients, gases, wastes; heart pumps blood.

• Lymphatic System/Immunity: Returns leaked fluid to blood, disposes debris, houses immune cells.

• Respiratory System: Supplies oxygen, removes carbon dioxide, gas exchanges.

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

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

• Reproductive System: Produces offspring; male and female organs and hormones.

Survival Needs

Essential Factors for Survival

• Nutrients

• Oxygen

• Water

• Normal Body Temperature

• Appropriate Atmospheric Pressure

Homeostasis

Definition and Mechanisms

• Homeostasis: Maintenance of a stable internal environment (e.g., blood pressure, glucose levels).

• Homeostatic Imbalance: Disturbance or alteration of internal balance.

• Homeostatic Control Mechanisms: Self-regulating processes involving receptor, control center, and effector.

Feedback Mechanisms

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

• Positive Feedback: Output enhances original stimulus (e.g., blood clotting, labor contractions).

Basic Chemistry for Anatomy & Physiology

Matter and Its Properties

• Matter: Anything with mass or that occupies space.

• States of Matter: Solid (definite shape/volume), Liquid (changeable shape/definite volume), Gas (changeable shape/volume).

Energy

• Energy: Capacity to do work or put matter into motion.

• Exists as Kinetic (energy in action) and Potential (stored energy).

• Forms: Chemical, Electrical, Mechanical, Radiant.

Energy Conversions

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

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

Atoms and Elements

Elements and Atomic Structure

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

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

• Atoms: Smallest units of elements, unique building blocks.

• Atomic Symbol: One- or two-letter shorthand (e.g., O for oxygen, Na for sodium).

Subatomic Particles

• Protons: Positive charge, 1 amu.

• Neutrons: No charge, 1 amu.

• Electrons: Negative charge, virtually no weight.

Atomic Number and Mass Number

• Atomic Number: Number of protons in nucleus (e.g., $\text{Li}_3$ for lithium).

• Mass Number: Total number of protons and neutrons (e.g., $^6\text{Li}$).

Isotopes

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

Combining Matter: Molecules, Compounds, and Mixtures

Molecules and Compounds

• Molecule: Two or more atoms bonded together.

• Compound: Molecule with two or more different kinds of atoms (e.g., $\text{C}_6\text{H}_{12}\text{O}_6$).

Mixtures

• Solutions: Homogeneous mixtures; solute dissolved in solvent (e.g., glucose in water).

• Colloids: Heterogeneous mixtures; particles not evenly distributed, cloudy/milky appearance (e.g., blood plasma).

• Suspensions: Heterogeneous mixtures with large particles that settle out (e.g., sand in water, blood cells in plasma).

Chemical Bonds

Types and Properties

• Chemical Bonds: "Energy relationships" between electrons of reacting atoms.

• Electrons occupy electron shells (energy levels).

• Valence Shell: Outermost shell, involved in chemical reactions.

• Octet Rule: Atoms desire 8 electrons in valence shell for stability.

Types of Chemical Bonds

• Ionic Bonds: Atoms gain/lose electrons, become charged ions (cation/anion), attraction forms bond.

• Covalent Bonds: Atoms share electrons; can be single, double, or triple bonds.

• Polar Covalent Bonds: Unequal sharing, results in partial charges (e.g., water molecule).

• Nonpolar Covalent Bonds: Equal sharing, no charge separation (e.g., CO).

• Hydrogen Bonds: Attraction between electropositive hydrogen and electronegative atom (e.g., between water molecules).

Summary Table: Major Elements in the Human Body

Element	Symbol	Approximate % of Body Mass	Main Functions
Oxygen	O	65%	Component of water, needed for cellular respiration
Carbon	C	18%	Backbone of organic molecules
Hydrogen	H	10%	Component of water and most organic molecules
Nitrogen	N	3%	Component of proteins and nucleic acids

Key Equations and Concepts

• Atomic Number: $\text{Atomic Number} = \text{Number of Protons}$

• Mass Number: $\text{Mass Number} = \text{Number of Protons} + \text{Number of Neutrons}$

• Octet Rule: Most atoms are stable with 8 electrons in their valence shell.

Examples and Applications

• Example of Homeostasis: Regulation of body temperature via sweating or shivering.

• Example of Chemical Bond: Water ($\text{H}_2\text{O}$) is formed by polar covalent bonds between hydrogen and oxygen.

• Application: Understanding chemical bonds is essential for grasping how molecules interact in biological systems.

Additional info: These notes expand on the original bullet points to provide full academic context, definitions, and examples suitable for college-level Anatomy & Physiology students.