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BIOL 2113 Lecture Study Guide: Human Body Orientation, Chemistry, Cells, and Tissues

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The Human Body: An Orientation

Body Systems and Organ Functions

The human body is organized into several systems, each with specific organs and functions. Understanding which organs belong to which system is fundamental in anatomy and physiology.

  • Body Systems: Examples include the digestive system (stomach, intestines), respiratory system (lungs, trachea), cardiovascular system (heart, blood vessels), etc.

  • Organ Functions: Each organ contributes to the overall function of its system (e.g., the heart pumps blood in the cardiovascular system).

Body Cavities and Orientation

Body cavities house and protect internal organs. Orientation terms describe locations and directions in the body.

  • Major Body Cavities: Dorsal (cranial and vertebral) and ventral (thoracic and abdominopelvic).

  • Orientation Terms: Anterior/posterior, superior/inferior, medial/lateral, proximal/distal, superficial/deep.

Disciplines of Anatomy

Anatomy is divided into several disciplines, each focusing on different aspects of body structure.

  • Gross Anatomy: Study of structures visible to the naked eye.

  • Microscopic Anatomy: Study of structures requiring magnification (e.g., histology – study of tissues).

  • Developmental Anatomy: Study of structural changes throughout life.

Levels of Structural Organization

The human body is organized from the simplest to the most complex levels:

  1. Chemical (atoms, molecules)

  2. Cellular (cells)

  3. Tissue (groups of similar cells)

  4. Organ (two or more tissue types)

  5. Organ System (organs working together)

  6. Organismal (the whole body)

Abdominopelvic Regions

The abdominopelvic cavity is divided into nine regions for anatomical reference:

  • Right/Left Hypochondriac

  • Epigastric

  • Right/Left Lumbar

  • Umbilical

  • Right/Left Iliac (Inguinal)

  • Hypogastric (Pubic)

Homeostasis

Homeostasis is the maintenance of a stable internal environment. It is regulated by feedback mechanisms.

  • Components of a Feedback Loop:

    • Receptor: Detects changes

    • Control Center: Processes information

    • Effector: Responds to restore balance

  • Negative Feedback: Reduces the effect of the stimulus (e.g., body temperature regulation).

  • Positive Feedback: Enhances the stimulus (e.g., blood clotting, labor contractions).

  • Homeostatic Imbalance: Disturbance of homeostasis, often leading to disease.

Necessary Life Functions and Survival Needs

  • Life Functions: Maintaining boundaries, movement, responsiveness, digestion, metabolism, excretion, reproduction, growth.

  • Survival Needs: Nutrients, oxygen, water, normal body temperature, appropriate atmospheric pressure (all must be present in appropriate amounts).

Body Serosa

Serous membranes (serosa) line body cavities and cover organs, reducing friction.

  • Double-layered: Parietal (lines cavity), Visceral (covers organ)

  • Types: Pleura (lungs), Pericardium (heart), Peritoneum (abdominal cavity)

  • Serous Fluid: Lubricates, reduces friction

Chemistry Comes Alive

Types of Chemical Bonds

  • Ionic Bonds: Transfer of electrons between atoms (e.g., NaCl).

  • Covalent Bonds: Sharing of electrons.

    • Polar Covalent: Unequal sharing (e.g., H2O)

    • Nonpolar Covalent: Equal sharing (e.g., O2)

  • Hydrogen Bonds: Weak attractions, important for water properties and DNA structure.

Carbohydrates: Monosaccharides and Disaccharides

  • Monosaccharides: Simple sugars (e.g., glucose, fructose, galactose)

  • Disaccharides: Two monosaccharides joined (e.g., sucrose, lactose, maltose)

Definitions and Examples

Term

Definition

Example

Buffer

Substance that resists changes in pH

Bicarbonate in blood

Organic Compound

Contains carbon and hydrogen

Glucose (C6H12O6)

Colloid

Heterogeneous mixture; particles do not settle

Gelatin

Suspension

Heterogeneous mixture; particles settle out

Blood

Solution

Homogeneous mixture

Salt water

Properties of Water

  • High Heat Capacity: Absorbs and releases heat slowly

  • High Heat of Vaporization: Requires much energy to evaporate (basis for sweating)

  • Polar Solvent: Dissolves many substances

  • Reactivity: Involved in hydrolysis and dehydration reactions

  • Cushioning: Protects organs (e.g., cerebrospinal fluid)

Energy Terms

  • Anabolic: Build larger molecules; absorb energy

  • Catabolic: Break down molecules; release energy

  • Endergonic: Absorb energy

  • Exergonic: Release energy

Cells: The Living Units

Cell Structure and Organelles

  • Generalized Cell Components: Plasma membrane, cytoplasm, nucleus

  • Key Organelles and Functions:

    • Mitochondria: ATP production ("powerhouse of the cell")

    • Ribosomes: Protein synthesis

    • Endoplasmic Reticulum (ER): Synthesis of proteins (rough ER) and lipids (smooth ER)

    • Golgi Apparatus: Modifies, sorts, and packages proteins

    • Lysosomes: Digestive enzymes

    • Peroxisomes: Detoxification

Plasma Membrane Structure

  • Membrane Lipids: Phospholipids (most abundant), cholesterol, glycolipids

  • Phospholipid Bilayer: Provides barrier and fluidity

Cell Junctions

  • Tight Junctions: Create watertight seals between cells

  • Desmosomes: Anchor cells together, resist shearing

  • Gap Junctions: Allow communication between cells

Cell Surface Structures

  • Microvilli: Increase surface area for absorption

  • Cilia: Move substances across cell surface

  • Flagella: Propel the cell (e.g., sperm)

Membrane Transport

  • Passive Diffusion: Movement down concentration gradient without energy

  • Facilitated Diffusion: Uses carrier proteins or channels

  • Osmosis: Diffusion of water across a membrane

  • Symport: Two substances move in the same direction

  • Antiport: Two substances move in opposite directions

Solutions and Tonicity

  • Solute: Substance dissolved

  • Solvent: Substance doing the dissolving (usually water)

  • Hypotonic: Lower solute concentration than cell

  • Isotonic: Same solute concentration as cell

  • Hypertonic: Higher solute concentration than cell

Central Dogma of Molecular Biology

The flow of genetic information in cells follows this sequence:

  • DNA → (transcription) → RNA → (translation) → Protein/Polypeptide

Endocytosis Types

  • Pinocytosis: "Cell drinking"; uptake of extracellular fluid

  • Phagocytosis: "Cell eating"; engulfment of large particles

  • Receptor-mediated Endocytosis: Specific uptake of molecules via receptors

Cell Cycle and Mitosis

  • Interphase: Cell grows and DNA replicates

  • Mitosis Phases (PMAT):

    • Prophase: Chromosomes condense

    • Metaphase: Chromosomes align at the center

    • Anaphase: Chromatids separate

    • Telophase: Nuclear envelopes reform

Tissue: The Living Fabric

Four Basic Tissue Types

  • Epithelium: Covers and protects surfaces

  • Nervous Tissue: Communicates via electrical signals

  • Muscle Tissue: Produces movement

  • Connective Tissue: Supports and protects organs

Additional info: This guide expands on checklist points with academic context and examples for clarity and exam preparation.

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