Exam 1 Review: Introduction to Anatomy, Physiology, Chemistry of Life, Cells, and Histology

Body Directions, Planes, and Anatomical Terms

Anatomical Position and Terminology

The anatomical position is a standardized posture used to describe locations and directions on the human body. Understanding anatomical terms is essential for accurately describing body parts and their relationships.

• Anatomical Position: Standing upright, facing forward, arms at sides, palms facing forward.

• Directional Terms: Proximal (closer to point of attachment), Distal (farther from point of attachment), Lateral (away from midline), Medial (toward midline), Superior (above), Inferior (below), Anterior (front), Posterior (back).

• Body Planes: Frontal (coronal) divides body into anterior and posterior, Sagittal divides into left and right, Transverse divides into superior and inferior.

Structural Organization of Organ Systems

The human body is organized into hierarchical levels, from atoms to organ systems.

• Levels: Chemical → Cellular → Tissue → Organ → Organ System → Organism

• Organ Systems: Examples include the cardiovascular, respiratory, digestive, nervous, and musculoskeletal systems.

Homeostasis and Feedback Systems

Homeostasis is the maintenance of a stable internal environment. Feedback systems regulate physiological processes.

• Negative Feedback: Counteracts changes (e.g., temperature regulation).

• Positive Feedback: Amplifies changes (e.g., blood clotting).

• Components: Receptor, control center, effector.

Systems of the Human Body and Functions

Each organ system has specific functions vital for survival.

• Examples: Respiratory (gas exchange), Digestive (nutrient absorption), Nervous (control and communication).

The Chemistry of Life

Metabolism: Catabolic and Anabolic Reactions

Metabolism encompasses all chemical reactions in the body.

• Catabolic: Breakdown of molecules, releases energy.

• Anabolic: Synthesis of molecules, requires energy.

• Redox Reactions: Involve transfer of electrons; oxidation (loss), reduction (gain).

Types of Chemical Bonds

Chemical bonds hold atoms together.

• Ionic Bonds: Transfer of electrons.

• Covalent Bonds: Sharing of electrons.

• Hydrogen Bonds: Weak attraction between molecules.

Enzyme Functions in Reactions

Enzymes are biological catalysts that speed up reactions.

• Lower Activation Energy: Allow reactions to occur faster.

• Specificity: Each enzyme acts on a specific substrate.

Chemical Reaction Rate Limiting Factors

Several factors affect the rate of chemical reactions.

• Temperature, pH, Concentration of reactants, Presence of catalysts.

Types of Body Energy

The body uses various forms of energy.

• Chemical Energy: Stored in bonds (e.g., ATP).

• Electrical Energy: Movement of charged particles.

• Mechanical Energy: Movement of body parts.

• Thermal Energy: Heat.

pH, Acids, and Bases

pH measures hydrogen ion concentration.

• Acids: Release H+ ions, pH < 7.

• Bases: Accept H+ ions, pH > 7.

• Neutral: pH = 7.

• Formula: $\text{pH} = -\log_{10}[\text{H}^+]$

The Cell

Cell Cycle and Mitotic Phases

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

• Interphase: G1 (growth), S (DNA synthesis), G2 (preparation).

• Mitosis: Prophase, Metaphase, Anaphase, Telophase.

• Cytokinesis: Division of cytoplasm.

DNA, Chromosome, Chromatin, Chromatid

DNA is the genetic material organized into chromosomes.

• Chromatin: DNA + proteins, loose form.

• Chromosome: Condensed chromatin during cell division.

• Chromatid: One half of a duplicated chromosome.

RNA and ATP

• RNA: Ribonucleic acid, involved in protein synthesis.

• ATP: Adenosine triphosphate, main energy carrier.

• ATP Hydrolysis: $\text{ATP} + \text{H}_2\text{O} \rightarrow \text{ADP} + \text{P}_i + \text{Energy}$

Genes and Protein Synthesis Phases

Genes code for proteins via transcription and translation.

• Transcription: DNA → mRNA.

• Translation: mRNA → Protein.

• Genetic Code: Codons (three-base sequences) specify amino acids.

Cell Organelles and Functions

Organelles are specialized structures within cells.

• Nucleus: Contains DNA.

• Mitochondria: Powerhouse, ATP production.

• Ribosomes: Protein synthesis.

• Endoplasmic Reticulum: Protein and lipid synthesis.

• Golgi Apparatus: Modifies and packages proteins.

• Lysosomes: Digestion of cellular waste.

The Plasma Membrane

Composition of the Plasma Membrane

The plasma membrane is a selectively permeable barrier.

• Phospholipid Bilayer: Hydrophilic heads, hydrophobic tails.

• Proteins: Integral, peripheral, channels, receptors.

• Carbohydrates: Glycoproteins, glycolipids for cell recognition.

• Cholesterol: Maintains fluidity.

Types of Body Solutions and Tonicity

Solutions are classified by their solute concentration relative to cells.

• Isotonic: Equal solute concentration.

• Hypertonic: Higher solute concentration outside cell.

• Hypotonic: Lower solute concentration outside cell.

Transport and Concentration Gradients

Substances move across membranes via passive or active transport.

• Passive Transport: No energy required (diffusion, osmosis).

• Active Transport: Requires energy (ATP).

• Concentration Gradient: Difference in concentration across a membrane.

Diffusion and Osmosis

• Diffusion: Movement of molecules from high to low concentration.

• Osmosis: Diffusion of water across a membrane.

Cell Shapes

Cells vary in shape depending on their function.

• Examples: Squamous (flat), cuboidal (cube-shaped), columnar (tall).

Histology: Tissues and Membranes

Four Types of Tissues and Locations

The body is composed of four basic tissue types.

• Epithelial: Covers surfaces, lines cavities.

• Connective: Supports, binds, protects.

• Muscle: Movement.

• Nervous: Communication.

Glands: Types and Functions

Glands are specialized epithelial cells.

• Exocrine: Secrete products into ducts (e.g., sweat, salivary).

• Endocrine: Secrete hormones into blood.

Body Membranes: True and Membrane-like

Membranes line body cavities and surfaces.

• True Membranes: Mucous, serous, cutaneous.

• Membrane-like: Synovial membranes (joints).

Table: Four Types of Tissues and Their Locations

Type	Location	Function
Epithelial	Skin, lining of GI tract	Protection, absorption
Connective	Bone, blood, cartilage	Support, transport
Muscle	Skeletal muscles, heart	Movement
Nervous	Brain, nerves	Communication

Table: Types of Chemical Bonds

Bond Type	Description	Example
Ionic	Transfer of electrons	NaCl
Covalent	Sharing of electrons	H2O
Hydrogen	Weak attraction	Between water molecules

Table: Types of Body Solutions

Type	Solute Concentration	Effect on Cell
Isotonic	Equal	No change
Hypertonic	Higher outside	Cell shrinks
Hypotonic	Lower outside	Cell swells

Table: Cell Cycle Phases

Phase	Description
Interphase	Growth and DNA replication
Prophase	Chromosomes condense
Metaphase	Chromosomes align
Anaphase	Chromatids separate
Telophase	Nuclear envelope reforms
Cytokinesis	Division of cytoplasm