Principles of Biomedical Science Comprehensive Review Notes

Unit 1: Lesson 1.1 - Forensic Science and Investigation

Activity 1.1.1: A Sketchy Scene

• Crime Scene Search Methods:

  • Strip/Line Method: Used on large, outdoor crime scenes. Searchers move in straight lines.

  • Grid Method: Similar to strip, but searchers move in one direction and then perpendicular to form a grid. Used on large, outdoor scenes.

  • Spiral Method: Used on scenes with no physical barriers (e.g., open water). Can be inward or outward spirals.

  • Wheel/Ray Method: Searchers start from a critical point and travel outward along straight lines. Used on small, circular scenes.

  • Zone/Quadrant Method: The scene is divided into zones and each zone is searched. Used on indoor scenes or scenes with defined rooms.

  • Link Method: This method is not geometric; it follows a lead or link from one piece of evidence to the next. Used in various environments.

• Biomedical Scientist: A professional who uses biology and medicine to assist in areas such as healthcare, research, and legal investigations.

• Crime Scene Sketching Guidelines:

  • Point of Origin: A fixed point (like a wall or heavy furniture) from which all evidence measurements are taken.

  • Listing/Labeling Evidence: Each piece of evidence is assigned a number or letter in the sketch.

  • Legend: A key that provides the date, time, location, temperature, and identity of the evidence numbers/letters.

  • Scale: A ratio that relates the dimensions of the sketch to the actual dimensions of the crime scene (e.g., $1\,cm = 1\,ft$).

Activity 1.1.2: Reliable Witnesses

• Polygraph Test: Commonly known as a "lie detector," it uses sensors to record physiological changes during questioning.

• Physiological Changes During Lying:

  • Increased heart rate.

  • Increased respiratory (breathing) rate.

  • Increased skin conductivity (sweating).

  • Increased blood pressure.

• Pulse Measurement Techniques:

  • Radial Artery: Located on the thumb side of the wrist.

  • Carotid Artery: Located on the side of the neck, under the jawline.

• Cardiopulmonary Interaction: The heart pumps deoxygenated blood to the lungs to pick up oxygen and release carbon dioxide ($CO_2$). The oxygenated blood returns to the heart to be pumped to the rest of the body.

• Polygraph Data Analysis: A subject's lying data is compared to their baseline data (responses to neutral questions). Significant spikes or deviations from the baseline suggest deception.

• Experimental Design Steps:

  1. Identify the question/problem.

  2. Formulate a hypothesis.

  3. Design the experiment.

  4. Carry out the experiment/collect data.

  5. Analyze the data.

  6. State the conclusion.

• Variables and Controls:

  • Hypothesis: A testable prediction of the experimental outcome.

  • Independent Variable: The variable that is intentionally changed by the researcher.

  • Dependent Variable: The variable being measured; it changes based on the independent variable.

  • Control Group: The group that does not receive the experimental treatment, used as a baseline for comparison.

  • Constants: All factors that are kept the same for every group to ensure only the independent variable affects the result.

Activity 1.1.3: The Traces We Leave Behind

• Trace Evidence: Small, often microscopic, pieces of evidence like hair, fibers, or glass shards.

• Locard’s Exchange Principle: Every contact leaves a trace. Whenever two objects come into contact, a cross-transfer of physical material occurs.

• Forensic Technician: A professional who processes crime scenes and analyzes evidence in a lab.

• Anatomy of Hair:

  1. Cuticle: The outermost layer (scales).

  2. Cortex: The middle layer containing pigment (color).

  3. Medulla: The innermost channel or core.

• Fingerprint Patterns:

  • Arch: Ridges enter on one side and exit on the other.

  • Loop: Ridges enter and exit on the same side.

  • Whorl: Ridges form circular or spiral patterns.

• Minutiae: Tiny ridge characteristics (e.g., ending ridge, bifurcation, short ridge) used to individualize fingerprints.

• Digital Forensics: The recovery and investigation of material found in digital devices.

• Digital Forensics Investigator: An expert who analyzes data from computers, phones, and networks to assist in legal cases.

Activity 1.1.4: Blood Evidence

• Blood Components:

  • Erythrocytes (Red Blood Cells): Carry oxygen via hemoglobin.

  • Leukocytes (White Blood Cells): Part of the immune system; fight infection.

  • Thrombocytes (Platelets): Facilitate blood clotting.

  • Plasma: The liquid portion of blood that carries nutrients, hormones, and waste.

• Blue Blood Myth: Human blood is never blue. Deoxygenated blood is deep red but appears blue through the skin due to light reflection.

• Testing Types:

  • Presumptive Test: A quick test used to suggest if a substance might be blood (e.g., Kastle-Meyer, Luminol, LMG).

  • Confirmatory Test: A lab-based test that definitively identifies a substance as blood.

  • Controls: A Positive Control should yield a positive result; a Negative Control (usually water) should yield no result.

• Hemoglobin: An iron-containing protein in red blood cells that binds to oxygen.

• PPE: Personal Protective Equipment (gloves, goggles, gowns).

  • Glove Safety: Pinch the outside of one glove at the wrist to remove; slide fingers under the remaining glove at the wrist to remove inside-out.

• ABO Blood Typing:

  • Antigens: Proteins on the surface of RBCs that determine blood type (A, B, or Rh).

  • Antibodies: Proteins in the plasma that attack foreign antigens.

  • Agglutination: The clumping of blood cells when an antibody meets its specific antigen (e.g., Anti-A serum clumps Type A blood).

  • Universal Donor: Type O negative ($O^-$).

  • Universal Recipient: Type AB positive ($AB^+$).

• Blood Spatter Analysis:

  • Blood Spatter Analyst: Uses the shape and distribution of blood drops to reconstruct a crime scene.

  • Drop Shapes: Drops falling from 90 degrees (directly above) are circular. As the angle of impact decreases, the drop becomes more elongated.

• Line of Best Fit: A straight line on a graph that best represents the data points, used to interpolate or extrapolate values.

Activity 1.1.5: DNA Evidence

• DNA (Deoxyribonucleic Acid): The molecule that carries genetic instructions for all living things.

• Instructions: DNA contains the blueprints for making proteins.

• Shape: A Double Helix (twisted ladder).

• Nucleotides: The building blocks of DNA, consisting of:

  1. Deoxyribose Sugar (Part of the ladder sides/backbone).

  2. Phosphate Group (Part of the ladder sides/backbone).

  3. Nitrogenous Base (Part of the ladder steps).

• Nitrogenous Bases:

  • Purines: Adenine (A) and Guanine (G) — double-ring structure.

  • Pyrimidines: Thymine (T) and Cytosine (C) — single-ring structure.

  • Base Pairing: A pairs with T; C pairs with G.

  • Hydrogen Bonds: A-T contains $2$ hydrogen bonds; C-G contains $3$ hydrogen bonds.

• Chargaff’s Rule: The amount of Adenine equals Thymine, and the amount of Cytosine equals Guanine ($A=T$ and $C=G$).

• Genetic Variation: While we have the same four bases, the sequence of those bases is unique to every individual.

• Genetics Levels:

  • Genes: Specific sequences of DNA that code for proteins.

  • Chromosomes: Long, tightly coiled strands of DNA.

  • Genome: The complete set of an organism's genetic material.

• Cells:

  • Organelles: Specialized structures within a cell.

  • Prokaryotic Cells: No nucleus or membrane-bound organelles (e.g., bacteria).

  • Eukaryotic Cells: Have a nucleus and specialized organelles (e.g., plants, animals).

• DNA Analysis Techniques:

  • Extraction: Removing DNA from the nucleus of a cell.

  • PCR (Polymerase Chain Reaction): Making millions of copies of a specific DNA segment.

  • Restriction Enzymes: Proteins that cut DNA at specific sequences (restriction sites).

    • Sticky Ends: Overhanging segments after a cut.

    • Blunt Ends: Straight cuts with no overhang.

  • RFLPs (Restriction Fragment Length Polymorphisms): The different length fragments resulting from restriction enzyme digestion.

Activity 1.1.6: DNA Analysis

• Gel Electrophoresis: A technique used to separate DNA fragments by size.

  • The Gel: Usually Agarose; feels like firm Jello.

  • Movement: DNA is negatively charged ($-$), so it moves toward the positive electrode ($+$) when an electric current is applied.

  • Fragment Speed: Small fragments move faster and further; large fragments stay closer to the wells (starting point).

  • DNA Marker/Ladder: A set of DNA fragments of known lengths used for comparison.

• Forensic Expert: Investigates specific evidence types for court cases.

Unit 1: Lesson 1.2 - Post-Mortem and Body Systems

Activity 1.2.1: Anatomy of an Autopsy

• Death Definitions:

  • Manner of Death: The high-level category of death (Homicide, Suicide, Accidental, Natural, Undetermined).

  • Cause of Death: The specific injury or disease that led to death (e.g., gunshot wound).

  • Mechanism of Death: The specific physiological failure (e.g., exsanguination/bleeding out).

• Autopsy: A post-mortem exam to determine cause and manner of death.

• Medical Examiner vs. Coroner:

  • Medical Examiner: A physician (MD) who performs autopsies.

  • Coroner: An elected official; may not be a doctor.

• Body Systems:

  • Respiratory: Gas exchange ($O_2$ in, $CO_2$ out).

  • Cardiovascular: Pumping blood/nutrients.

  • Integumentary: Skin; protection and temperature.

  • Urinary: Waste filtration (kidneys).

  • Nervous: Communication (brain, nerves).

  • Endocrine: Hormones.

  • Skeletal/Muscular: Support and movement.

  • Lymphatic/Immune: Fluid balance and fighting disease.

  • Digestive: Nutrient absorption.

Activity 1.2.2: Time of Death

• Time Scales:

  • Physiological: When body functions actually cease.

  • Estimated: Best guess by medical examiner based on evidence.

  • Legal: Time recorded on the death certificate.

• Post-Mortem Changes:

  • Algor Mortis: Body cooling ($1.5\,^\circ F$ per hour under standard conditions).

  • Rigor Mortis: Muscle stiffening (begins $2-4$ hours post-mortem).

  • Livor Mortis: Blood pooling (lividity).

• Glaister Equation: Used to estimate time since death based on core temperature.

• Forensic Entomology: Studying insects (e.g., Blow fly life cycle) to determine time of death.

Activity 1.2.3 and 1.2.4: Toxicology and Histology

• Toxicology: Study of toxins and their effects on the body.

• Digestion Path: Oral cavity → Esophagus → Stomach → Small Intestine → Large Intestine.

• Metabolism: Sum of chemical reactions in the body to break down or build up materials.

• Histology: The study of tissues.

• Levels of Organization: Cell → Tissue → Organ → Organ System.

• Nervous System: Central (Brain/Spinal Cord) and Peripheral (Nerves).

• Brain Lobes:

  • Frontal: Planning, movement, personality.

  • Parietal: Sensory information.

  • Temporal: Hearing/speech.

  • Occipital: Vision.

• Brain Injury:

  • TBI: Traumatic Brain Injury (acute).

  • CTE: Chronic Traumatic Encephalopathy (chronic/long-term from repeated hitting).

Activity 1.2.5: Gross Anatomy Examination

• Heart Anatomy:

  • $4$ chambers: Right Atrium, Right Ventricle, Left Atrium, Left Ventricle.

  • Valves: Prevent backflow.

  • Arteries: Take blood away from heart (High $O_2$, except Pulmonary Artery).

  • Veins: Take blood to heart (Low $O_2$, except Pulmonary Vein).

• Circulation:

  • Pulmonary: Between heart and lungs.

  • Systemic: Between heart and the rest of the body.

• Path of Blood: Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Valve → Pulmonary Artery → Lungs → Pulmonary Vein → Left Atrium → Mitral Valve → Left Ventricle → Aortic Valve → Aorta → Body → Vena Cava → Right Atrium.

Unit 2: Lesson 2.1 - Clinical Medicine

Activity 2.1.1: Building a Medical History

• Medical Team: Primary Care Physician, Medical Student, Nurse, Medical Assistant, Patient Liaison, Pediatrician.

• Demeanor: Outward behavior; Tact: Sensitivity in dealing with others; Empathy: Understanding another's feelings.

• Chief Complaint: The main reason the patient is seeking care.

• Signs vs. Symptoms:

  • Signs: Objective/measurable (e.g., rash, low blood pressure).

  • Symptoms: Subjective/felt by the patient (e.g., headache, nausea).

Activity 2.1.2: Vital Signs

• Vital Signs Normal Ranges:

  • Temperature: $98.6\,^\circ F$ (Fever: >$100.4\,^\circ F$, Hypothermia: <$95\,^\circ F$).

  • Heart Rate: $60-100\,bpm$.

  • Respiratory Rate: $12-20\,bpm$.

  • Oxygen Saturation ($SpO_2$): $95-100\%$. (Urgent if <$90\%$, take via pulse oximeter on finger or earlobe).

  • Blood Pressure: Normal is <$120/80\,mmHg$.

    • Systolic: Heart contracting (top number).

    • Diastolic: Heart at rest (bottom number).

    • Hypertension: High blood pressure.

• BMI Calculation:

  • $BMI = (\frac{\text{weight (lbs)}}{\text{height (in)}^2}) \times 703$

Activity 2.1.3 - 2.1.4: Routine Testing and Lab Work

• Physical Exam Signs:

  • 20/20 Vision: You can see at $20$ feet what a normal person sees at $20$ feet.

  • Skin Cancer ABCDE's: Asymmetry, Border, Color, Diameter, Evolving.

• Blood Work:

  • Phlebotomist: Expert at drawing blood (Venipuncture).

  • CBC (Complete Blood Count): Counts WBCs, RBCs, Hemoglobin, Hematocrit, Platelets.

    • Anemia: Low red blood cell or hemoglobin count.

  • Cholesterol: HDL (Good - high density) vs. LDL (Bad - low density). Plaque is the buildup of LDL in arteries.

  • Metabolic Panel (BMP): Measures Glucose, Electrolytes, and Blood Urea Nitrogen (BUN).

Activity 2.1.5: Telehealth and Diabetes

• Diabetes:

  • Type 1: Body makes little to no insulin; autoimmune.

  • Type 2: Body becomes resistant to insulin; often related to lifestyle.

  • Hyperglycemia: High blood sugar.

• Feedback Loops:

  • Negative Feedback: Reverses a change to maintain homeostasis (e.g., insulin lowering glucose levels).

  • Positive Feedback: Intensifies a change (e.g., blood clotting or childbirth).

• Glucagon: Hormone released when blood sugar is low; causes the liver to release glucose.

• Macromolecules:

  • Carbohydrates: Energy source (e.g., glucose).

  • Lipids: Energy storage and cell membranes (e.g., fats).

  • Proteins: Structure and enzymes.

  • Nucleic Acids: Information storage (DNA/RNA).

Activity 2.1.6: Patient Privacy (HIPAA)

• HIPAA: Health Insurance Portability and Accountability Act (1996).

• Protected Information: Name, address, birth date, Social Security number, medical diagnosis.

• Exceptions: Information can be shared for public health threats, law enforcement (court order), or to facilitate treatment/payment.

Unit 2: Lesson 2.2 - Heredity and Genetics

Activity 2.2.1: Mitosis vs. Meiosis

• Mitosis: Creates $2$ identical somatic (body) cells.

  • Phases: Interphase (DNA replication) → Prophase → Metaphase (line up in middle) → Anaphase (pull apart) → Telophase.

  • Human outcome: $46$ chromosomes.

• Meiosis: Creates $4$ unique gametes (sex cells).

  • Human outcome: $23$ chromosomes.

  • Crossing Over: Occurs in Prophase I, increasing genetic diversity.

• Chromosome Structures:

  • Centromere: Center junction.

  • Chromatids: The two identical "arms."

• Non-disjunction: Failure of chromosomes to separate properly; causes Trisomy (3 copies) or Monosomy (1 copy).

Activity 2.2.2 - 2.2.3: Protein Science and Inheritance

• Transcription: DNA → mRNA (occurs in the nucleus).

• Translation: mRNA → Amino Acids/Protein (occurs in the ribosome).

• DNA vs. RNA: RNA uses Ribose sugar, is single-stranded, and uses Uracil (U) instead of Thymine (T).

• Codon: A sequence of $3$ bases that codes for an amino acid.

  • Start Codon: AUG (Methionine).

• Genetics Terms:

  • Homozygous: Two identical alleles (AA or aa).

  • Heterozygous: Two different alleles (Aa).

  • Genotype: Genetic makeup (letters).

  • Phenotype: Physical expression (the trait).

• Inherited Diseases:

  • NF1: Autosomal dominant disorder.

  • FH (Familial Hypercholesterolemia): Autosomal dominant disorder causing high LDL levels.

Unit 3: Lesson 3.1 - Infectious Diseases

Activity 3.1.1 - 3.1.3: Agents of Disease

• Agents: Prions, Viruses, Bacteria, Protists, Helminths, Fungi.

• Epidemiology Terms:

  • Endemic: Constant presence in a population.

  • Outbreak: Sudden increase in cases in a localized area.

  • Pandemic: Worldwide outbreak.

  • Nosocomial: Hospital-acquired infection.

• Immunity:

  • Innate: Non-specific (skin, mucus).

  • Acquired: Specific (antibodies from vaccines or previous infection).

• R-Naught ($R_0$):

  • R_0 = \frac{\text{# new cases}}{\text{# existing cases}}

  • If R_0 > 1, the infection is spreading.

Activity 3.1.5 - 3.1.6: Microbiology

• Aseptic Technique: Methods to prevent contamination (flaming loops, wearing gloves).

• Gram Staining:

  • Gram Positive ($+$): Purple; thick peptidoglycan layer.

  • Gram Negative ($-$): Pink; thin peptidoglycan layer.

• Bacterial Shapes: Cocci (circles), Bacilli (rods), Spirillum (spirals).

Unit 3: Lesson 3.2 - Emergency Response

Activity 3.2.1 - 3.2.4: Emergency and Crisis Care

• Primary Assessment ABC’s: Airway, Breathing, Circulation.

• Drug Delivery:

  • Enteral: Through digestive tract (Oral).

  • Parenteral: Non-digestive (Injections).

• Tonicity:

  • Hypertonic: Water moves OUT; cell shrinks.

  • Hypotonic: Water moves IN; cell swells.

  • Isotonic: Equilibrium; cell stays the same.

• Triage Categories:

  • Emergent (Red): Life-threatening.

  • Urgent (Yellow): Serious but stable.

  • Non-Urgent (Green): Minor injuries.

  • Expectant (Black): Dead or unlikely to survive.

• Bleeding: Use a Tourniquet for life-threatening limb bleeds; apply pressure for torso bleeds.