Anatomy & Physiology Exam 1 Study Guide: Human Body Orientation and Basic Chemistry

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Chapter 1: The Human Body – An Orientation

Definition of Anatomy

Anatomy is the study of the structure of body parts and their relationships to one another. It provides the foundation for understanding physiology and is essential for all health-related fields.

Gross (macroscopic) anatomy: Study of large body structures visible to the naked eye (e.g., heart, bones).
Microscopic anatomy: Study of structures too small to be seen with the naked eye (e.g., cells, tissues).
Developmental anatomy: Study of structural changes throughout the lifespan.

Definition of Physiology

Physiology is the study of the function of the body’s structural machinery—how the body parts work and carry out their life-sustaining activities.

Focuses on events at the cellular and molecular level.
Relies on principles of physics and chemistry.

Examples of Subdivisions of Physiology

Neurophysiology: Explores the workings of the nervous system, such as nerve impulses and synaptic transmission.
Cardiovascular Physiology: Examines the operation of the heart and blood vessels, including blood flow and pressure regulation.

Topics of Anatomy and Subdivisions

Regional anatomy: All structures in a particular region (e.g., abdomen).
Systemic anatomy: Body structure studied system by system (e.g., skeletal system).
Surface anatomy: Study of internal structures as they relate to the overlying skin surface.

Principle of Complementarity of Structure and Function

The concept that function always reflects structure. What a structure can do depends on its specific form. For example, bones can support and protect body organs because they contain hard mineral deposits.

Body Organization

The human body is organized into several levels:

Chemical level: Atoms combine to form molecules.
Cellular level: Cells are made up of molecules.
Tissue level: Tissues consist of similar types of cells.
Organ level: Organs are made up of different types of tissues.
Organ system level: Organ systems consist of different organs that work together.
Organismal level: The human organism is made up of many organ systems.

Homeostasis

Homeostasis is the maintenance of a relatively stable internal environment despite continuous external changes. It is vital for normal body functioning and sustaining life.

Significance: Maintains conditions necessary for cell function (e.g., temperature, pH, fluid balance).

Feedback Mechanisms

Negative feedback: The response reduces or shuts off the original stimulus. Example: Regulation of body temperature, blood glucose levels.
Positive feedback: The response enhances or exaggerates the original stimulus. Example: Blood clotting, labor contractions.

Homeostatic Imbalance and Disease

Disturbance of homeostasis increases risk of disease and contributes to changes associated with aging.
When negative feedback mechanisms are overwhelmed, destructive positive feedback mechanisms may take over (e.g., heart failure).

Orientation and Directional Terms (Table 1.1)

Directional terms help describe the locations of structures relative to other structures or locations in the body.

Term	Meaning	Example
Superior (cranial)	Toward the head or upper part of a structure	The head is superior to the abdomen.
Inferior (caudal)	Away from the head or toward the lower part	The navel is inferior to the chin.
Anterior (ventral)	Toward the front of the body	The breastbone is anterior to the spine.
Posterior (dorsal)	Toward the back of the body	The heart is posterior to the breastbone.
Medial	Toward the midline	The heart is medial to the arm.
Lateral	Away from the midline	The arms are lateral to the chest.
Proximal	Closer to the origin of the body part	The elbow is proximal to the wrist.
Distal	Farther from the origin	The knee is distal to the thigh.
Superficial	Toward or at the body surface	The skin is superficial to the skeletal muscles.
Deep	Away from the body surface	The lungs are deep to the skin.

Chapter 2: Chemistry Comes Alive

2.1 Energy

Energy is the capacity to do work or put matter into motion. It exists in two main forms:

Kinetic energy: Energy in action (e.g., movement of muscles).
Potential energy: Stored energy (e.g., energy stored in chemical bonds).

Forms of energy: Chemical, electrical, mechanical, and radiant (electromagnetic) energy.

2.2 Properties of an Element

Chemical element: A pure substance composed of only one type of atom; cannot be broken down by ordinary chemical means.
Common elements in the human body: Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N) – these four make up about 96% of body mass.
Atom: The smallest unit of an element that retains the properties of that element.
Atomic number: The number of protons in the nucleus of an atom; determines the element’s identity.

2.3 Atoms Bound Together

Molecule: Two or more atoms bonded together (e.g., O2).
Compound: Two or more different kinds of atoms chemically bonded (e.g., H2O).
Mixtures: Substances composed of two or more components physically intermixed.

Three Basic Types of Mixtures

Solutions: Homogeneous mixtures; solute particles are very tiny and do not settle out or scatter light (e.g., saline solution).
Colloids (emulsions): Heterogeneous mixtures; solute particles are larger than in a solution and scatter light, but do not settle out (e.g., cytosol).
Suspensions: Heterogeneous mixtures with large, visible solutes that tend to settle out (e.g., blood).

Concentrations of Solutions

Percent (%): Parts of solute per 100 parts of solution.
mg/dL: Milligrams of solute per deciliter of solution.

2.4 Chemical Bonds

Ionic bonds: Formed by the transfer of one or more electrons from one atom to another, resulting in ions (e.g., NaCl).
Covalent bonds: Formed by the sharing of two or more electrons between atoms (e.g., O2).
Hydrogen bonds: Weak attractions between a hydrogen atom and an electronegative atom (e.g., between water molecules).

2.5 Chemical Reactions

Chemical reactions occur when chemical bonds are formed, rearranged, or broken. Types include synthesis, decomposition, and exchange reactions.

Synthesis (anabolic) reactions: Atoms or molecules combine to form a larger, more complex molecule.
Decomposition (catabolic) reactions: A molecule is broken down into smaller molecules or atoms.
Exchange (displacement) reactions: Involve both synthesis and decomposition.

2.6 pH Scale

The pH scale measures the concentration of hydrogen ions (H+) in a solution. It ranges from 0 (most acidic) to 14 (most basic), with 7 being neutral.

Acidic solutions: pH less than 7; higher H+ concentration.
Basic (alkaline) solutions: pH greater than 7; lower H+ concentration.
Neutral solution: pH = 7 (e.g., pure water).

2.7 Organic Compounds: Dehydration and Synthesis Reactions

Dehydration synthesis: A chemical reaction in which two molecules are joined by removing a water molecule. Important in forming macromolecules like proteins and carbohydrates.
Hydrolysis: The reverse process, where water is added to break bonds.

2.8 Carbohydrates

Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen, usually in a 1:2:1 ratio. They serve as the main source of energy for the body.

Building blocks: Monosaccharides (simple sugars, e.g., glucose).
General structure: Chains or rings of carbon atoms with attached hydrogen and oxygen.
Biological function: Provide energy, serve as structural components (e.g., ribose in RNA).

2.9 Lipids

Lipids are a diverse group of hydrophobic molecules, including fats, oils, and steroids.

Building blocks: Glycerol and fatty acids.
General structure: Triglycerides (three fatty acids attached to glycerol), phospholipids, and steroids.
Biological function: Energy storage, insulation, protection, and as components of cell membranes.

Example: Phospholipids form the bilayer of cell membranes.

2.10 Proteins

Proteins are complex molecules made of amino acids joined by peptide bonds. They perform a vast array of functions in the body.

Structure: Composed of one or more polypeptide chains folded into a specific shape.
Levels of structure:
- Primary: Sequence of amino acids.
- Secondary: Alpha helices and beta sheets formed by hydrogen bonding.
- Tertiary: Three-dimensional folding due to side chain interactions.
- Quaternary: Association of multiple polypeptide chains.
Biological function: Enzymes, structural support, transport, movement, and regulation.