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

Apoptosis

“A pattern of cell death in which cells activate enzymes that degrade the cell's own nuclear DNA and nuclear and cytoplasmic proteins.”

Causes

I. Physiologic (Most Common)

• Programmed destruction of cells during embryogenesis.
• Hormone-dependent involution of tissues in the adult (e.g., endometrium).
• Cell loss in proliferating cell populations, such as epithelial cells in intestinal crypts.
• Death of host cells after serving their useful purpose (e.g., neutrophils in an acute inflammatory response).

II. Pathologic

• DNA damage due to radiation, cytotoxic drugs, and hypoxia.
• Accumulation of misfolded proteins causing endoplasmic reticulum (ER) stress (e.g., degenerative diseases of the CNS).
• Cell death associated with viral infections, such as

Aggressive Periodontitis: Localized vs. Generalized

This section outlines the key similarities and differences between Localized Aggressive Periodontitis (LAP) and Generalized Aggressive Periodontitis (GAP).

Localized Aggressive Periodontitis (LAP)

• Circumpubertal onset.
• Robust serum antibody response to infecting agents.
• Localized first molar/incisor presentation with interproximal attachment loss on at least two permanent teeth, one of which is a first molar.
• Lack of clinical inflammation.
• Presence of deep periodontal pockets.
• Amount of plaque inconsistent with the amount of periodontal destruction.
• Plaque forms a thin biofilm, rarely mineralizing into calculus.
• Distolabial migration and diastema formation.
• Increasing mobility of first molars.
• Sensitivity

Core Branches of Pharmacology

• Pharmacodynamics: The study of biological effects produced by drugs and how those effects are generated.
• Pharmacokinetics: The study of drug movement through the body via ADME (Absorption, Distribution, Metabolism, and Excretion).
• Toxicology: The study of mechanisms and conditions by which chemicals produce harmful effects on living tissues or organisms.
• Specialized Fields: Systems pharmacology, Pharmacogenetics, Clinical pharmacology, and Molecular pharmacology.

Drug Nomenclature and Ideal Characteristics

Drugs are identified by their chemical name, generic name (e.g., paracetamol), and trade name (e.g., Panadol). An ideal drug should possess:

• Effectiveness, Safety, and Selectivity.
• Reversible action and Predictability

UNIT 1: Cell Injury and Adaptations

1. Key Factors That Cause Cell Injury and How Injury Occurs

Causes:

Hypoxia/ischemia (most common): loss of blood supply, anemia, carbon monoxide, respiratory failure.

Physical agents: trauma, extreme heat/cold, radiation, electric shock, pressure changes.

Chemical agents and drugs: alcohol, acetaminophen overdose, carbon tetrachloride, heavy metals, poisons.

Infectious agents: bacteria, viruses, fungi, parasites (direct damage or toxins).

Immunologic reactions: hypersensitivity, autoimmunity.

Genetic derangements: enzyme deficiencies, sickle cell disease.

Nutritional imbalances: deficiency or excess (e.g., obesity, atherosclerosis).

Aging

How injury occurs (common mechanisms):

ATP depletion: the Na+/K+ pump fails, so... Continue reading "Cell Injury, Stress, Nutrition and Infectious Diseases: Key Concepts" »

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

Trichuris trichiura

• Life cycle: Ingest embryonated egg → intestine → adult → eggs in feces → soil → ingestion.
• Infective stage: Embryonated egg.
• Location: Ileocecal and large intestine.
• Vector: None.
• Causes: Dysentery, anemia, and rectal prolapse.
• Identification: Barrel-shaped egg with 2 polar plugs.

Ascaris lumbricoides

• Life cycle: Ingest egg → duodenum → blood → lungs → pharynx → swallowed → duodenum → adult.
• Infective stage: Embryonated egg.
• Location: Duodenum and small intestine; larvae migrate through lungs.
• Vector: None.
• Causes: Pneumonitis, malnutrition, and intestinal blockage.
• Identification: Bumpy/mammillated egg and 3 lips.

Necator americanus

• Life cycle: Egg → J1 → J3 → skin → blood → lungs → pharynx → swallowed

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