Anatomy & Physiology Exam 1 Study Guide: Core Concepts and Sample Questions

Lecture 1: Levels of Organization & Homeostasis

Levels of Organization in the Body

The human body is organized into hierarchical levels, each with specific functions and structures.

• Chemical Level: Atoms and molecules essential for life.

• Cellular Level: Cells, the basic units of life.

• Tissue Level: Groups of similar cells performing a common function.

• Organ Level: Structures composed of two or more tissue types.

• Organ System Level: Groups of organs working together.

• Organism Level: The complete living being.

Example: The digestive system includes organs such as the stomach and intestines, which work together to process food.

Homeostasis

Homeostasis refers to the maintenance of a stable internal environment despite changes in external conditions.

• Negative Feedback System: Mechanism that reverses a change to keep a variable within a normal range.

• Positive Feedback System: Mechanism that amplifies a change, moving the system away from its starting state.

Example: Regulation of body temperature is controlled by negative feedback.

Lecture 2: Atomic Structure & Chemical Bonds

Atomic Structure

Atoms are composed of protons, neutrons, and electrons. The arrangement of electrons determines chemical behavior.

• Valence Shells: The outermost electron shell of an atom.

• Octet Rule: Atoms tend to gain, lose, or share electrons to achieve eight electrons in their valence shell.

Example: Sulfur has 6 electrons in its outer shell and forms covalent bonds to achieve stability.

Chemical Bonds

• Non-polar Covalent Bonds: Electrons are shared equally.

• Polar Covalent Bonds: Electrons are shared unequally, creating partial charges.

• Ionic Bonds: Electrons are transferred from one atom to another, creating ions.

• Hydrogen Bonds: Weak attractions between polar molecules.

Isotopes & Radioactivity

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

• Radioactive Isotopes: Unstable isotopes that decay, emitting radiation; used as tracers in medical research.

Example: Carbon-14 is a radioactive isotope used in radiometric dating.

Lecture 3: Hydrolysis Reactions

Hydrolysis Reactions

Hydrolysis is a chemical process that splits molecules by adding water.

• Definition: Hydrolysis breaks down polymers into monomers.

• Example: Digestion of proteins into amino acids.

Equation:

$ext{AB} + ext{H}_2 ext{O} \rightarrow ext{A} + ext{B}$

Lecture 4: Cell Structure & DNA

Organelle Characteristics

Organelles are specialized structures within cells that perform distinct functions.

• Plasma Membrane: Controls entry and exit of substances.

• Junction Types: Structures that connect cells (tight junctions, gap junctions, desmosomes).

DNA Structure

DNA is the molecule that stores genetic information.

• Double Helix: The structure of DNA consists of two strands twisted into a helix.

• Nucleotide: The building block of DNA, composed of a sugar, phosphate, and base.

Example: The sequence of nucleotides encodes genetic instructions.

Cell Theory

• All living things are composed of cells.

• Cells arise from pre-existing cells.

• Cells are the basic unit of structure and function.

Cell Transport & Golgi Apparatus

• Transport Vesicles: Move substances within the cell.

• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for delivery.

Lecture 5: Membrane Transport & Gradients

Concentration Gradients

A concentration gradient is the difference in the concentration of a substance across a space.

• Iso-: Equal concentration.

• Hyper-: Higher concentration.

• Hypo-: Lower concentration.

Example: Water moves from hypo- to hypertonic solutions by osmosis.

Lecture 6: Tissues & Membranes

Epithelial Tissue Characteristics

Epithelial tissues cover body surfaces and line cavities.

• Functions: Protection, absorption, secretion, and filtration.

• Characteristics: Closely packed cells, polarity, avascularity, high regeneration.

Connective Tissue Types

• Loose Connective Tissue: Supports and binds other tissues.

• Dense Connective Tissue: Provides strength and support.

• Specialized Connective Tissue: Includes bone, cartilage, blood.

Membrane Characteristics

• Mucous Membranes: Line body cavities open to the exterior.

• Serous Membranes: Line closed body cavities.

• Cutaneous Membrane: The skin.

Sample Questions Table

The following table summarizes the types of sample questions provided in the study guide, including their main focus and correct answer (where applicable).

Topic	Sample Question	Correct Answer
Body Systems	The human body is divided into ____ major systems.	11
Chemical Bonds	A sulfur atom has 6 electrons in its outer shell. As a result, it forms ____ covalent bonds with other atoms.	2
Radioactive Isotopes	Radioactive isotopes are useful as "tracers" in medical research because organisms incorporate radioactive isotopes of an element into their molecules (True/False).	True
DNA Structure	The structure of DNA is properly described as a ____ in which a single strand of DNA is made up of ____.	Double helix; nucleotide
Cell Theory	The "cell theory" as stated by Schleiden & Schwann states that:	All of the above
Golgi Apparatus	The Golgi apparatus functions in conjunction with the ____ by modifying the products produced there.	Endoplasmic reticulum