Introduction to Anatomy & Physiology

This study guide covers foundational concepts in anatomy and physiology, including organ systems, anatomical planes, body cavities, and the basics of biological chemistry essential for understanding human structure and function.

Organ Systems and Disease Protection

Lymphatic System

The lymphatic system is primarily responsible for protecting the body from disease. It is a network of tissues and organs that help rid the body of toxins, waste, and other unwanted materials. The main function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body.

• Key Components: Lymph nodes, lymphatic vessels, spleen, thymus, tonsils.

• Function: Defends against pathogens and maintains fluid balance.

• Example: Lymph nodes filter bacteria and viruses from lymph fluid.

Anatomical Planes

Transverse Plane

Anatomical planes are imaginary lines used to divide the body into sections for study and reference. The transverse plane (also called the horizontal plane) divides the body into superior (upper) and inferior (lower) sections.

• Other Planes:

  • Sagittal Plane: Divides the body into left and right sections.

  • Midsagittal Plane: Divides the body into equal left and right halves.

  • Frontal (Coronal) Plane: Divides the body into anterior (front) and posterior (back) sections.

• Application: Used in medical imaging and anatomical descriptions.

Body Cavities

Cranial Cavity

The cranial cavity is one of the major body cavities and houses the brain. It is located within the skull and provides protection for the central nervous system.

• Other Major Cavities:

  • Thoracic cavity: Contains the heart and lungs.

  • Abdominal cavity: Contains digestive organs.

  • Spinal cavity: Contains the spinal cord.

• Function: Protects vital organs from physical damage.

Biological Chemistry in Anatomy & Physiology

Elements in the Human Body

Elements are pure substances that cannot be broken down by chemical means. Four major elements account for 96% of the body's mass:

• Oxygen (O): 65%

• Carbon (C): 18%

• Hydrogen (H): 10%

• Nitrogen (N): 3%

Other important elements include potassium (K), calcium (Ca), chlorine (Cl), magnesium (Mg), phosphorus (P), and sulfur (S), as well as trace elements like iron (Fe), copper (Cu), and zinc (Zn).

Atoms and Subatomic Particles

An atom is the smallest unit of an element, composed of:

• Protons: Positively charged particles in the nucleus.

• Neutrons: Neutral particles in the nucleus.

• Electrons: Negatively charged particles in electron shells around the nucleus.

Atomic Number: The number of protons in an atom, which determines the element.

Valence Electrons and Stability

• Valence electrons: Electrons in the outermost shell, important for chemical bonding.

• Octet Rule: Atoms are most stable with eight electrons in their valence shell.

• Duet Rule: Atoms with five or fewer electrons are stable with two in their valence shell.

Chemical Bonds

• Ionic Bonds: Electrons are transferred between atoms, forming ions.

• Covalent Bonds: Electrons are shared between atoms.

  • Polar Covalent Bonds: Unequal sharing of electrons (e.g., water).

  • Nonpolar Covalent Bonds: Equal sharing of electrons (e.g., hydrogen gas).

• Hydrogen Bonds: Weak attractions between polar molecules.

Types of Mixtures

Properties of Water

• High heat capacity: Absorbs heat without significant temperature change.

• Evaporation: Carries heat away, aiding temperature regulation.

• Cushioning: Protects organs due to high density.

• Lubrication: Reduces friction between surfaces.

Hydrophilic vs. Hydrophobic Compounds

• Hydrophilic: Water-loving; ionic and polar covalent compounds dissolve in water.

• Hydrophobic: Water-fearing; nonpolar covalent compounds do not dissolve in water.

Acids, Bases, and pH

• Acid: Proton (H+) donor.

• Base: Proton (H+) acceptor.

• pH Scale: Measures hydrogen ion concentration; ranges from 0 (acidic) to 14 (basic).

Organic Molecules

Energy Molecules: ATP

Adenosine triphosphate (ATP) is the main energy-storing molecule in cells. Energy is stored when a phosphate group is added to adenosine diphosphate (ADP):

• ATP Formation:

• ATP Breakdown:

ATP provides energy for cellular processes such as muscle contraction and active transport.

Additional info: These notes expand on the original slides and questions to provide a comprehensive overview suitable for college-level Anatomy & Physiology students.