Chapter 1.5: Anatomical Terms

Anatomical Position

The anatomical position is a standardized posture used to describe locations and directions on the human body. It is essential for clear communication in anatomy.

• Body upright, facing forward

• Feet slightly apart

• Arms at sides, palms facing forward

Directional Terms

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

• Superior: Above (toward the head)

• Inferior: Below (toward the feet)

• Anterior (Ventral): Front of the body

• Posterior (Dorsal): Back of the body

• Medial: Toward the midline

• Lateral: Away from the midline

• Proximal: Closer to the point of attachment

• Distal: Farther from the point of attachment

• Superficial: Closer to the body surface

• Deep: Farther inside the body

Body Planes

Body planes are imaginary lines used to divide the body into sections.

• Sagittal: Divides the body into left and right parts

• Midsagittal (Median): Divides the body into equal left and right halves

• Frontal (Coronal): Divides the body into anterior (front) and posterior (back) parts

• Transverse: Divides the body into superior (top) and inferior (bottom) parts

Chapter 2: Basic Chemistry

Atoms and Elements

An atom is the smallest unit of matter that retains the properties of an element. Atoms are composed of subatomic particles:

• Proton: Positive charge (+), located in the nucleus

• Neutron: Neutral charge (0), located in the nucleus

• Electron: Negative charge (-), located outside the nucleus

The four major elements in the human body are Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N) (CHON).

Chemical Bonds

Chemical bonds are forces that hold atoms together in molecules.

• Ionic bond: Electrons are transferred from one atom to another, forming charged ions

• Covalent bond: Electrons are shared between atoms

• Hydrogen bond: Weak attraction between molecules or parts of molecules

Acids, Bases, and pH

Acids release hydrogen ions (H+), while bases accept hydrogen ions. The pH scale measures the concentration of H+ in a solution:

• pH < 7: Acidic

• pH = 7: Neutral

• pH > 7: Basic (alkaline)

Chemical Reactions

Chemical reactions involve the making or breaking of chemical bonds.

• Synthesis: Two or more substances combine to form a new compound

• Decomposition: A compound breaks down into two or more simpler substances

• Exchange: Parts of two compounds switch places

Organic Molecules

Organic molecules are compounds containing carbon and are essential for life.

Carbohydrates

• Monosaccharides: Single sugar units (e.g., glucose, fructose, galactose)

• Disaccharides: Two linked sugar units (e.g., sucrose, lactose, maltose)

• Polysaccharides: Many sugar units (e.g., glycogen, starch)

• Main function: Quick energy source

• Glucose: Used to make ATP

Lipids

• Triglycerides: Glycerol + 3 fatty acids (energy storage)

• Phospholipids: Major component of cell membranes

• Cholesterol: Found in membranes; precursor for steroid hormones, vitamin D, bile salts

• Main functions: Stored energy, insulation, cell membranes

Proteins

• Made of: Amino acids

• Functions: Structural materials, enzymes, transport, defense

• Enzymes: Proteins that speed up chemical reactions

Nucleic Acids

• DNA: Stores genetic instructions

• RNA: Carries out instructions for protein synthesis

• Nucleotide: Building block of DNA and RNA

• mRNA: Messenger RNA; carries coded message for making proteins

ATP

• ATP (Adenosine Triphosphate): Main energy molecule used by cells

Chapter 3: Cells

Generalized Human Cell

The cell is the smallest structural and functional unit of life. Major parts:

• Plasma membrane

• Cytoplasm

• Nucleus

Plasma Membrane

The plasma membrane surrounds the cell and controls exchange with the environment. It is mainly composed of a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates.

• Hydrophilic heads: Interact with water

• Hydrophobic tails: Avoid water

• Selectively permeable: Allows some substances through, restricts others

Transport Across the Membrane

Passive Transport

• No ATP required

• Movement down concentration gradient (HIGH → LOW)

• Types: Simple diffusion, facilitated diffusion, osmosis

Diffusion

• Movement of particles from high to low concentration

• No ATP required

Facilitated Diffusion

• Movement from high to low concentration with help of membrane protein

• No ATP required

Osmosis

• Movement of water across a selectively permeable membrane

Tonicity

Active Transport

• Requires energy (usually ATP)

• Moves substances against concentration/electrical gradients

Sodium-Potassium Pump

• Primary active transport

• Uses ATP

• Pumps 3 Na+ OUT, 2 K+ IN

• Maintains concentration gradients and resting membrane potential

Endocytosis and Exocytosis

• Endocytosis: Brings substances into cell

• Exocytosis: Moves substances out of cell

• Phagocytosis: Brings in large/solid particles

• Pinocytosis: Brings in dissolved substances

Cell Organelles

Protein Shipping Path

• Ribosome → Rough ER → Golgi → Plasma membrane → Exocytosis

Cell Cycle

The cell cycle describes the sequence of events in cell growth and division.

• Interphase: Cell grows, DNA is copied, cell prepares for division

• G1: Cell grows

• S: DNA is copied

• G2: Cell prepares for division

Mitosis (PMAT)

• Prophase: Chromosomes become visible; cell prepares for division

• Metaphase: Chromosomes line up in the middle

• Anaphase: Chromosomes move apart

• Telophase: Two nuclei form

Essay Questions & Key Concepts

Homeostatic Control Mechanisms

Homeostasis is the maintenance of a stable internal environment. The process involves:

• Receptor: Detects change

• Control Center: Receives information, determines response

• Effector: Carries out response

Negative feedback reverses the original change (e.g., temperature regulation). Positive feedback increases the original change until a specific event is completed (e.g., blood clotting, labor contractions).

Classification of Carbohydrates, Lipids, and Proteins

• Carbohydrates: Monosaccharides, disaccharides, polysaccharides; mainly used for energy

• Lipids: Triglycerides, phospholipids, steroids; energy storage, insulation, cell membranes

• Proteins: Made of amino acids; structural materials, enzymes, many functions

Plasma Membrane Structure and Function

• Phospholipid bilayer: Hydrophilic heads, hydrophobic tails

• Proteins, cholesterol, carbohydrates: Embedded in membrane

• Selectively permeable: Controls traffic in and out of cell

Sodium-Potassium Pump

• Primary active transport

• Uses ATP

• Pumps 3 Na+ OUT, 2 K+ IN

• Maintains membrane potential

Absolute Must-Know List

• Directional terms: Superior, Inferior, Anterior, Posterior, Medial, Lateral, Proximal, Distal, Superficial, Deep

• Body planes: Sagittal, Frontal, Transverse

• Atomic structure: Proton (+), Electron (−), Neutron (0)

• Major elements: CHON

• Chemical bonds: Ionic (transfer), Covalent (share)

• Acids/bases: Acid releases H+, low pH = acidic, high pH = basic

• Carbohydrates: Quick energy

• Triglyceride: Glycerol + 3 fatty acids

• Phospholipids: Cell membranes

• Proteins: Amino acids

• ATP: Energy

• Cell: Smallest unit of life

• Passive transport: No ATP, HIGH → LOW

• Active transport: Uses ATP

• Osmosis: Water

• Tonicity: Hypertonic (shrink), Hypotonic (swell), Isotonic (same)

• Sodium-potassium pump: 3 Na+ OUT, 2 K+ IN, ATP

• Endocytosis (IN), Exocytosis (OUT)

• Cell organelles: Mitochondria (ATP), Ribosome (protein), Rough ER (proteins), Smooth ER (lipids/detox), Golgi (package/ship), Lysosome (digestion/cleanup)

• Cell cycle: G1 (grow), S (copy DNA), G2 (prepare), PMAT (Prophase, Metaphase, Anaphase, Telophase)

• Metaphase: Middle, Anaphase: Apart