Notes, summaries, assignments, exams, and problems for Biology

First Line of Defense:

• 1) Mechanical Barriers & Surface Secretions:
  • A) Skin
  • B) Mucus Membrane:
    • 1) Sticky Mucus Membrane
    • Cilia
    • Mechanical Cleansing Action: Saliva, Tears, Urine
    • Low pH Stomach
    • Tears & Saliva: Lysozyme
    • Peristalsis in GIT
• 2) Normal Bacterial Flora
• 3) Naturally Occurring Antimicrobial Substances:
  • A) Type I Interferon: Antiviral Effect
  • B) Lysozyme: Lysis of Bacteria
  • C) Complement System: Responsible for Lysing Microorganisms
• 4) Body Hormones
• 5) Genetic Predisposition
• 6) Body Temperature: Pyrexia
• 7) Oxygen Tension
• 8) Inflammation

Serum Soluble Proteins:

• 1) C-Reactive Protein: Binds bacteria, activates complement, causes bacterial lysis (opsonin)
• 2) Ceruloplasmin: Oxidizes iron, inhibiting microbe iron uptake
• 3) Haptoglobin: Binds hemoglobin, inhibiting

Mineral Trioxide Aggregate (MTA) Applications

Pulp Therapy

• Pulp capping
• Furcation repair
• Strip perforation repair
• Root resorption repair
• Immature teeth
• Root end filling material

Elements of Pulp Regeneration

Therapy for exposed dental pulps using stem cells and a biofunctional scaffold, inhibiting or eliminating infection to facilitate pulp generation.

Nickel-Titanium (NiTi) Rotary Instruments

Advantages of NiTi Reciprocation

• Mimics manual movement
• Reduces risks associated with continuous rotation in curved canals

Types of Posts

1. Carbon fiber epoxy resin posts
2. Zirconia posts
3. Glass fiber reinforced posts
4. Ultra-high strength polyethylene fiber reinforced posts

Advantages of NiTi Rotary

• Gradual, evenly tapered radicular preparation
• Fewer instruments required
• Reduced

Metabolic and Biochemical Processes

BMI Calculation: BMI = Kg/M². Interpretation: <25 = Normal, 25-30 = Overweight, >30 = Obese. Ethanolamine (Ethan-NH₃), Choline = N(CH₃)₃

Leptin and Adipose Tissue

Leptin is released from adipose tissue when mass is high. It travels through the blood to the arcuate nucleus, binds to neuronal cells, and activates the JAK-STAT pathway. This increases gene expression of POMC, which produces alpha-MSH (a neurotransmitter). Alpha-MSH reaches neurons connected to adipose tissue, releasing norepinephrine. Norepinephrine binds to beta-adrenergic receptors on adipose tissue, promoting an increase (via the G-protein coupled receptor pathway and activation of PKA). This leads to upregulation of UCP1 expression and... Continue reading "Metabolic Pathways and Liposome Drug Delivery" »

Biological Organization of the Human Body

The hierarchy of life follows this progression: Atom → Molecule → Cell → Tissue → Organ → Organ System → Organism (Wingspan = Height).

Body Symmetry and Structure

• Radial: Symmetry around a central axis.
• Bilateral: Divided equally across a plane.
• Asymmetrical: Inability to be divided.

Humans exhibit bilateral symmetry and are proportionate.

Functional Principles

Function follows form. For example, the Cell Membrane acts as a Plasma Membrane, while the Cutaneous Membrane acts as skin.

Life Processes and Homeostasis

Essential life functions include:

• Maintenance of Boundaries: Separating internal from external (Integumentary).
• Movement: Muscular and Skeletal systems.
• Responsiveness: Nervous and Endocrine

Digestive System Vocabulary

1. Bile – a digestive fluid that helps digest fats
2. Appendix – a small organ attached to the large intestine
3. Celiac disease – an autoimmune disease caused by gluten
4. Defecation – feces / the process of passing stool
5. Weight gain – putting on weight / an increase in body weight
6. Palpate – to examine by touch
7. Stool – solid waste eliminated from the body
8. Bowel – the intestines (small or large)

Digestive Functions and Pathologies

• The pancreas produces and contains digestive enzymes.
• Peptic ulcers may affect the lining of the stomach.
• The last part of the digestive tract is in the large intestine/colon.
• Bile is produced by the liver and released into the duodenum.
• Adverse reaction – reakcja niepożądana
• Autoimmune disorder

Synaptic Transmission Fundamentals

• Synapse: The gap between neurons (synaptic cleft).
• Synaptic Knob: The terminal structure containing vesicles.
• Neurotransmitters: Chemicals that transmit signals.
  • Acetylcholine: Activates muscles.
  • Monoamines: Involved in cognitive processes (emotion, arousal, memory).
  • Amino Acids, Peptides, and Estrogen.
• Vesicles: Store neurotransmitters.
• Axon Hillock: Essential for initiating the firing of a neuron (action potential generation).

Postsynaptic Potentials (EPSP and IPSP)

• EPSP (Excitatory Postsynaptic Potential): Moves the membrane potential toward the threshold.
• IPSP (Inhibitory Postsynaptic Potential): Moves the membrane potential away from the threshold.

Vision and Refractive Errors

• Nearsightedness (Myopia):
  • The eyeball

Classification of Antimicrobial Agents

Antimicrobial agents are substances that kill or inhibit the growth of microorganisms such as bacteria, fungi, viruses, or parasites. They are classified based on their spectrum of activity, mechanism of action, and the type of microorganisms they target.

1. Based on Target Microorganisms

• Antibacterial agents: Target bacteria (e.g., penicillins, tetracyclines)
• Antifungal agents: Target fungi (e.g., amphotericin B, fluconazole)
• Antiviral agents: Target viruses (e.g., acyclovir, oseltamivir)
• Antiparasitic agents: Target parasites (e.g., chloroquine, metronidazole)

2. Based on Mechanism of Action

Cotrimoxazole and Therapeutic Uses

Cotrimoxazole (also known as trimethoprim-sulfamethoxazole or TMP-SMX) is a broad-spectrum antibiotic that combines two antimicrobial agents:

• Trimethoprim (TMP)
• Sulfamethoxazole (SMX)

These two components work synergistically to block two steps in the bacterial synthesis of folic acid, which is essential for bacterial growth and replication.

Mechanism of Action

• Sulfamethoxazole: Inhibits dihydropteroate synthase, blocking the conversion of PABA to dihydrofolic acid.
• Trimethoprim: Inhibits dihydrofolate reductase, blocking the conversion of dihydrofolic acid to tetrahydrofolic acid.

By combining both, cotrimoxazole effectively prevents bacterial DNA synthesis.

Therapeutic Uses of Cotrimoxazole

Cotrimoxazole is used to... Continue reading "Cotrimoxazole: Mechanism, Therapeutic Uses, and Safety" »

Periodontal Flap Design Principles

Selection of flap design depends on:

• Surgical anatomy
• Extension problems
• Need to change flap position
• Bone removal requirements
• Esthetic concerns
• Protection of the donor site

Classification of Periodontal Flaps

Flap Elevation

• Full thickness
• Partial thickness

Flap Management

• Split papilla flap
• Papilla preservation flap

Flap Placement

• Undisplaced
• Apically positioned
• Coronally positioned

Mucoperiosteal Flap Types

• Envelope/sulcular
• 3-corner
• 4-corner

Gingivectomy: Indications and Contraindications

Indications

• Suprabony pockets
• Furcation involvement
• Gingival enlargement
• Gingival recontouring

Contraindications

• Infrabony pockets
• Pocket depth beyond the mucogingival junction (MGJ)
• Narrow zone of keratinized gingiva
• Need for bone access
• Esthetic concerns

Electrosurgical

Periodontal Treatment Plan Goals

Immediate Goals

• Eliminate disease
• Restore oral cavity health state
• Arrest disease progression

Intermediate Goals

• Reconstruct healthy dentition
• Address esthetic requirements
• Endodontic, orthodontic, and periodontal therapy

Long-Term Goals

• Maintain oral health
• Professional supportive therapy

Phases of Periodontal Therapy

Preliminary Phase

Emergency treatment.

Phase I: Nonsurgical Phase

1. Preliminary scaling
2. Scaling and root planing
3. Antimicrobial therapy
4. Diet control
5. Patient motivation
6. Correction of iatrogenic factors
7. Treatment of deep caries
8. Occlusal adjustment
9. Extraction of hopeless teeth

Phase II: Surgical Phase

1. Treatment of pockets greater than 5mm
2. Class II and III furcation involvement
3. Removal of local deposits
4. Distal of last molar treatment
5. Correction