A&P I Exam 1 Study Guide: The Human Body Orientation & Chemistry Comes Alive

Chapter 1: The Human Body: An Orientation

Introduction to Anatomy and Physiology

Anatomy and physiology are foundational sciences in understanding the structure and function of the human body. This chapter introduces key concepts, terminology, and organizational principles.

• Anatomy vs. Physiology: Anatomy is the study of body structure; physiology is the study of body function. An anatomical description details what something is and where it is located, while a physiological description explains how it works.

• Subdivisions of Anatomy: Includes gross anatomy (structures visible to the naked eye), microscopic anatomy (structures seen with a microscope), and developmental anatomy (changes throughout life).

• Subdivisions of Physiology: Includes cellular physiology, organ physiology, and systemic physiology.

• Levels of Structural Organization: The human body is organized into levels: chemical, cellular, tissue, organ, organ system, and organism.

• Necessary Life Functions: Includes maintaining boundaries, movement, responsiveness, digestion, metabolism, excretion, reproduction, and growth.

• Survival Needs: Humans require nutrients, oxygen, water, normal body temperature, and appropriate atmospheric pressure.

• Homeostasis: The maintenance of a stable internal environment. Involves receptor, control center, and effector. Negative feedback reduces the effect of the stimulus; positive feedback increases it.

• Anatomical Position and Directional Terms: Standard position for anatomical reference. Directional terms include superior/inferior, anterior/posterior, medial/lateral, proximal/distal, superficial/deep.

• Body Planes and Sections: Sagittal (left/right), frontal (anterior/posterior), transverse (superior/inferior).

• Body Cavities: Dorsal (cranial and vertebral) and ventral (thoracic and abdominopelvic) cavities. Each contains specific organs.

• Regions of the Body: The body is divided into regions for anatomical study (e.g., abdominal, thoracic).

Example: The heart is located in the thoracic cavity, medial to the lungs, and superior to the diaphragm.

Additional info: Homeostasis is crucial for survival; failure leads to disease.

Chapter 2: Chemistry Comes Alive

Basic Chemistry Concepts

Chemistry underlies all physiological processes. Understanding atoms, molecules, and chemical reactions is essential for studying the human body.

• Forms of Energy: Chemical, electrical, mechanical, and radiant energy. Chemical energy is stored in bonds; electrical energy results from movement of charged particles.

• Elements and Atoms: Elements are pure substances; atoms are the smallest units of elements. Major elements in the body include carbon, hydrogen, oxygen, and nitrogen.

• Structure of an Atom: Consists of protons (+), neutrons (0), and electrons (-). Protons and neutrons are in the nucleus; electrons orbit the nucleus.

• Atomic Number and Mass Number: Atomic number = number of protons; mass number = protons + neutrons.

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Radioisotopes: Unstable isotopes that decay, emitting radiation. Used in medical imaging.

• Molecules and Compounds: Molecules are two or more atoms bonded together; compounds are molecules of different elements.

• Ions: Atoms that have gained or lost electrons. Cations are positively charged; anions are negatively charged.

• Chemical Bonds: Ionic (transfer of electrons), covalent (sharing electrons), and hydrogen bonds (weak attractions).

• Types of Chemical Reactions: Synthesis (A + B → AB), decomposition (AB → A + B), exchange (AB + C → AC + B).

• Factors Affecting Reaction Rate: Temperature, concentration, particle size, and catalysts (enzymes).

• Water: Most abundant inorganic compound; excellent solvent; involved in temperature regulation and chemical reactions.

• Acids and Bases: Acids release H+; bases release OH-. pH measures hydrogen ion concentration.

• Buffers: Substances that minimize pH changes.

• Organic Compounds: Include carbohydrates, lipids, proteins, and nucleic acids. All contain carbon.

• Carbohydrates: Provide energy; include monosaccharides, disaccharides, and polysaccharides.

• Lipids: Fats, phospholipids, steroids; important for energy storage and cell membranes.

• Proteins: Made of amino acids; function as enzymes, structural components, and signaling molecules.

• Levels of Protein Structure: Primary, secondary, tertiary, and quaternary. Denaturation disrupts structure and function.

• Nucleic Acids: DNA and RNA; store and transmit genetic information.

Example: Enzymes are proteins that act as biological catalysts, speeding up chemical reactions in the body.

Additional info: The pH scale ranges from 0 (acidic) to 14 (basic); human blood pH is tightly regulated around 7.4.

Table: Comparison of Chemical Bonds

Bond Type	Description	Strength	Example
Ionic	Transfer of electrons between atoms	Moderate	NaCl (table salt)
Covalent	Sharing of electrons between atoms	Strong	H2O (water)
Hydrogen	Weak attraction between polar molecules	Weak	Between water molecules

Key Equations

• pH Calculation:

$\text{pH} = -\log_{10}[\text{H}^+]$

• General Chemical Reaction:

$\text{Reactants} \rightarrow \text{Products}$